Re: [PATCH] clk: Add Si5341/Si5340 driver

From: Mike Looijmans
Date: Fri Apr 26 2019 - 03:55:39 EST

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I'll send a v2 with lots of changes someday next week (I hope). Comments
interleaved, if I didn't comment or explicitly say "ok", just assume I agree
and will change it.

On 26-04-19 01:36, Stephen Boyd wrote:
> Quoting Mike Looijmans (2019-04-24 02:00:38)
>> Adds a driver for the Si5341 and Si5340 chips. The driver does not fully
>> support all features of these chips, but allows the chip to be used
>> without any support from the "clockbuilder pro" software.
>>
>> If the chip is preprogrammed, that is, you bought one with some defaults
>> burned in, or you programmed the NVM in some way, the driver will just
>> take over the current settings and only change them on demand. Otherwise
>> the input must a fixed XTAL in its most basic configuration (no
>
> must be
>
>> predividers, no feedback, etc.).
>>
>> The driver supports dynamic changes of multisynth, output dividers and
>> enabling or powering down outputs and multisynths.
>>
>> Signed-off-by: Mike Looijmans <mike.looijmans@xxxxxxxx>
>> ---
>> diff --git a/drivers/clk/clk-si5341.c b/drivers/clk/clk-si5341.c
>> new file mode 100644
>> index 000000000000..0d636658853b
>> --- /dev/null
>> +++ b/drivers/clk/clk-si5341.c
>> @@ -0,0 +1,1452 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Driver for Silicon Labs Si5341/Si5340 Clock generator
>> + * Copyright (C) 2019 Topic Embedded Products
>> + * Author: Mike Looijmans <mike.looijmans@xxxxxxxx>
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/clk-provider.h>
>> +#include <linux/delay.h>
>> +#include <linux/gcd.h>
>> +#include <linux/math64.h>
>> +#include <linux/i2c.h>
>> +#include <linux/module.h>
>> +#include <linux/regmap.h>
>> +#include <linux/slab.h>
>> +
>> +#define SI5341_MAX_NUM_OUTPUTS 10
>> +#define SI5340_MAX_NUM_OUTPUTS 4
>> +
>> +#define SI5341_NUM_SYNTH 5
>> +#define SI5340_NUM_SYNTH 4
>> +
>> +/* Range of the synthesizer fractional divider */
>> +#define SI5341_SYNTH_N_MIN 10
>> +#define SI5341_SYNTH_N_MAX 4095
>> +
>> +/* The chip can get its input clock from 3 input pins or an XTAL */
>> +
>> +/* There is one PLL running at 13500â14256 MHz */
>> +#define SI5341_PLL_VCO_MIN 13500000000ull
>> +#define SI5341_PLL_VCO_MAX 14256000000ull
>> +
>> +/* The 5 frequency synthesizers obtain their input from the PLL */
>> +struct clk_si5341_synth {
>> + struct clk_hw hw;
>> + struct clk_si5341 *data;
>> + u8 index;
>> +};
>> +#define to_clk_si5341_synth(_hw) \
>> + container_of(_hw, struct clk_si5341_synth, hw)
>> +
>> +/* The output stages can be connected to any synth (full mux) */
>> +struct clk_si5341_output {
>> + struct clk_hw hw;
>> + struct clk_si5341 *data;
>> + u8 index;
>> +};
>> +#define to_clk_si5341_output(_hw) \
>> + container_of(_hw, struct clk_si5341_output, hw)
>> +
>> +struct clk_si5341 {
>> + struct clk_hw hw;
>> + struct regmap *regmap;
>> + struct i2c_client *i2c_client;
>> + struct clk_si5341_synth synth[SI5341_NUM_SYNTH];
>> + struct clk_si5341_output clk[SI5341_MAX_NUM_OUTPUTS];
>> + struct clk *pxtal;
>> + const char *pxtal_name;
>> + const u16 *reg_output_offset;
>> + const u16 *reg_rdiv_offset;
>> + u64 freq_vco; /* 13500â14256 MHz */
>> + u8 num_outputs;
>> + u8 num_synth;
>> +};
>> +#define to_clk_si5341(_hw) container_of(_hw, struct clk_si5341, hw)
>> +
>> +struct clk_si5341_output_config {
>> + u8 source_index;
>> + u8 out_format_drv_bits;
>> + u8 out_cm_ampl_bits;
>> + bool synth_master;
>> + bool always_on;
>> + u32 synth_frequency;
>> + u32 clock_frequency;
>> +};
>> +
>> +#define SI5341_PAGE 0x0001
>> +#define SI5341_PN_BASE 0x0002
>> +#define SI5341_DEVICE_REV 0x0005
>> +#define SI5341_STATUS 0x000C
>> +#define SI5341_SOFT_RST 0x001C
>> +
>> +/* Input dividers (48-bit) */
>> +#define SI5341_IN_PDIV(x) (0x0208 + ((x) * 10))
>> +#define SI5341_IN_PSET(x) (0x020E + ((x) * 10))
>> +
>> +/* PLL configuration */
>> +#define SI5341_PLL_M_NUM 0x0235
>> +#define SI5341_PLL_M_DEN 0x023B
>> +
>> +/* Output configuration */
>> +#define SI5341_OUT_CONFIG(output) \
>> + ((output)->data->reg_output_offset[(output)->index])
>> +#define SI5341_OUT_FORMAT(output) (SI5341_OUT_CONFIG(output) + 1)
>> +#define SI5341_OUT_CM(output) (SI5341_OUT_CONFIG(output) + 2)
>> +#define SI5341_OUT_MUX_SEL(output) (SI5341_OUT_CONFIG(output) + 3)
>> +#define SI5341_OUT_R_REG(output) \
>> + ((output)->data->reg_rdiv_offset[(output)->index])
>> +
>> +/* Synthesize N divider */
>> +#define SI5341_SYNTH_N_NUM(x) (0x0302 + ((x) * 11))
>> +#define SI5341_SYNTH_N_DEN(x) (0x0308 + ((x) * 11))
>> +#define SI5341_SYNTH_N_UPD(x) (0x030C + ((x) * 11))
>> +
>> +/* Synthesizer output enable, phase bypass, power mode */
>> +#define SI5341_SYNTH_N_CLK_TO_OUTX_EN 0x0A03
>> +#define SI5341_SYNTH_N_PIBYP 0x0A04
>> +#define SI5341_SYNTH_N_PDNB 0x0A05
>> +#define SI5341_SYNTH_N_CLK_DIS 0x0B4A
>> +
>> +/* SI5341_OUT_CONFIG bits */
>> +#define SI5341_OUT_CFG_PDN BIT(0)
>> +#define SI5341_OUT_CFG_OE BIT(1)
>> +#define SI5341_OUT_CFG_RDIV_FORCE2 BIT(2)
>> +
>> +/* Static configuration (to be moved to firmware) */
>> +struct si5341_reg_default {
>> + u16 address;
>> + u8 value;
>> +};
>> +
>> +/* Output configuration registers 0..9 are not quite logically organized */
>
> SUPER SIGH!!!!!!
>
>> +static const u16 si5341_reg_output_offset[] = {
>> + 0x0108,
>> + 0x010D,
>> + 0x0112,
>> + 0x0117,
>> + 0x011C,
>> + 0x0121,
>> + 0x0126,
>> + 0x012B,
>> + 0x0130,
>> + 0x013A,
>> +};
>> +static const u16 si5340_reg_output_offset[] = {
>> + 0x0112,
>> + 0x0117,
>> + 0x0126,
>> + 0x012B,
>> +};
>> +
>> +/* The location of the R divider registers */
>> +static const u16 si5341_reg_rdiv_offset[] = {
>> + 0x024A,
>> + 0x024D,
>> + 0x0250,
>> + 0x0253,
>> + 0x0256,
>> + 0x0259,
>> + 0x025C,
>> + 0x025F,
>> + 0x0262,
>> + 0x0268,
>> +};
>
> Put a newline here please.

ok

>
>> +static const u16 si5340_reg_rdiv_offset[] = {
>> + 0x0250,
>> + 0x0253,
>> + 0x025C,
>> + 0x025F,
>> +};
>> +
>> +/*
>> + * Programming sequence from ClockBuilder, settings to initialize the system
>> + * using only the XTAL input, without pre-divider.
>> + * This also contains settings that aren't mentioned anywhere in the datasheet.
>
> That's awful! What a non-surprise!
>
>> + * The "known" settings like synth and output configuration are done later.
>> + */
>> +static const struct si5341_reg_default si5341_reg_defaults[] = {
>> + { 0x0017, 0x3A }, /* INT mask (disable interrupts) */
>> + { 0x0018, 0xFF }, /* INT mask */
>> + { 0x0021, 0x0F }, /* Select XTAL as input */
>> + { 0x0022, 0x00 }, /* Not in datasheet */
>> + { 0x002B, 0x02 }, /* SPI config */
>> + { 0x002C, 0x20 }, /* LOS enable for XTAL */
>> + { 0x002D, 0x00 }, /* LOS timing */
>> + { 0x002E, 0x00 },
>> + { 0x002F, 0x00 },
>> + { 0x0030, 0x00 },
>> + { 0x0031, 0x00 },
>> + { 0x0032, 0x00 },
>> + { 0x0033, 0x00 },
>> + { 0x0034, 0x00 },
>> + { 0x0035, 0x00 },
>> + { 0x0036, 0x00 },
>> + { 0x0037, 0x00 },
>> + { 0x0038, 0x00 }, /* LOS setting (thresholds) */
>> + { 0x0039, 0x00 },
>> + { 0x003A, 0x00 },
>> + { 0x003B, 0x00 },
>> + { 0x003C, 0x00 },
>> + { 0x003D, 0x00 }, /* LOS setting (thresholds) end */
>> + { 0x0041, 0x00 }, /* LOS0_DIV_SEL */
>> + { 0x0042, 0x00 }, /* LOS1_DIV_SEL */
>> + { 0x0043, 0x00 }, /* LOS2_DIV_SEL */
>> + { 0x0044, 0x00 }, /* LOS3_DIV_SEL */
>> + { 0x009E, 0x00 }, /* Not in datasheet */
>> + { 0x0102, 0x01 }, /* Enable outputs */
>> + { 0x013F, 0x00 }, /* Not in datasheet */
>> + { 0x0140, 0x00 }, /* Not in datasheet */
>> + { 0x0141, 0x40 }, /* OUT LOS */
>> + { 0x0202, 0x00 }, /* XAXB_FREQ_OFFSET (=0)*/
>> + { 0x0203, 0x00 },
>> + { 0x0204, 0x00 },
>> + { 0x0205, 0x00 },
>> + { 0x0206, 0x00 }, /* PXAXB (2^x) */
>> + { 0x0208, 0x00 }, /* Px divider setting (usually 0) */
>> + { 0x0209, 0x00 },
>> + { 0x020A, 0x00 },
>> + { 0x020B, 0x00 },
>> + { 0x020C, 0x00 },
>> + { 0x020D, 0x00 },
>> + { 0x020E, 0x00 },
>> + { 0x020F, 0x00 },
>> + { 0x0210, 0x00 },
>> + { 0x0211, 0x00 },
>> + { 0x0212, 0x00 },
>> + { 0x0213, 0x00 },
>> + { 0x0214, 0x00 },
>> + { 0x0215, 0x00 },
>> + { 0x0216, 0x00 },
>> + { 0x0217, 0x00 },
>> + { 0x0218, 0x00 },
>> + { 0x0219, 0x00 },
>> + { 0x021A, 0x00 },
>> + { 0x021B, 0x00 },
>> + { 0x021C, 0x00 },
>> + { 0x021D, 0x00 },
>> + { 0x021E, 0x00 },
>> + { 0x021F, 0x00 },
>> + { 0x0220, 0x00 },
>> + { 0x0221, 0x00 },
>> + { 0x0222, 0x00 },
>> + { 0x0223, 0x00 },
>> + { 0x0224, 0x00 },
>> + { 0x0225, 0x00 },
>> + { 0x0226, 0x00 },
>> + { 0x0227, 0x00 },
>> + { 0x0228, 0x00 },
>> + { 0x0229, 0x00 },
>> + { 0x022A, 0x00 },
>> + { 0x022B, 0x00 },
>> + { 0x022C, 0x00 },
>> + { 0x022D, 0x00 },
>> + { 0x022E, 0x00 },
>> + { 0x022F, 0x00 }, /* Px divider setting (usually 0) end */
>> + { 0x026B, 0x00 }, /* DESIGN_ID (ASCII string) */
>> + { 0x026C, 0x00 },
>> + { 0x026D, 0x00 },
>> + { 0x026E, 0x00 },
>> + { 0x026F, 0x00 },
>> + { 0x0270, 0x00 },
>> + { 0x0271, 0x00 },
>> + { 0x0272, 0x00 }, /* DESIGN_ID (ASCII string) end */
>> + { 0x0339, 0x1F }, /* N_FSTEP_MSK */
>> + { 0x033B, 0x00 }, /* Nx_FSTEPW (Frequency step) */
>> + { 0x033C, 0x00 },
>> + { 0x033D, 0x00 },
>> + { 0x033E, 0x00 },
>> + { 0x033F, 0x00 },
>> + { 0x0340, 0x00 },
>> + { 0x0341, 0x00 },
>> + { 0x0342, 0x00 },
>> + { 0x0343, 0x00 },
>> + { 0x0344, 0x00 },
>> + { 0x0345, 0x00 },
>> + { 0x0346, 0x00 },
>> + { 0x0347, 0x00 },
>> + { 0x0348, 0x00 },
>> + { 0x0349, 0x00 },
>> + { 0x034A, 0x00 },
>> + { 0x034B, 0x00 },
>> + { 0x034C, 0x00 },
>> + { 0x034D, 0x00 },
>> + { 0x034E, 0x00 },
>> + { 0x034F, 0x00 },
>> + { 0x0350, 0x00 },
>> + { 0x0351, 0x00 },
>> + { 0x0352, 0x00 },
>> + { 0x0353, 0x00 },
>> + { 0x0354, 0x00 },
>> + { 0x0355, 0x00 },
>> + { 0x0356, 0x00 },
>> + { 0x0357, 0x00 },
>> + { 0x0358, 0x00 }, /* Nx_FSTEPW (Frequency step) end */
>> + { 0x0359, 0x00 }, /* Nx_DELAY */
>> + { 0x035A, 0x00 },
>> + { 0x035B, 0x00 },
>> + { 0x035C, 0x00 },
>> + { 0x035D, 0x00 },
>> + { 0x035E, 0x00 },
>> + { 0x035F, 0x00 },
>> + { 0x0360, 0x00 },
>> + { 0x0361, 0x00 },
>> + { 0x0362, 0x00 }, /* Nx_DELAY end */
>> + { 0x0802, 0x00 }, /* Not in datasheet */
>> + { 0x0803, 0x00 }, /* Not in datasheet */
>> + { 0x0804, 0x00 }, /* Not in datasheet */
>> + { 0x090E, 0x02 }, /* XAXB_EXTCLK_EN=0 XAXB_PDNB=1 (use XTAL) */
>> + { 0x091C, 0x04 }, /* ZDM_EN=4 (Normal mode) */
>> + { 0x0943, 0x00 }, /* IO_VDD_SEL=0 (0=1v8, use 1=3v3) */
>> + { 0x0949, 0x00 }, /* IN_EN (disable input clocks) */
>> + { 0x094A, 0x00 }, /* INx_TO_PFD_EN (disabled) */
>> + { 0x0A02, 0x00 }, /* Not in datasheet */
>> + { 0x0B44, 0x0F }, /* PDIV_ENB (datasheet does not mention what it is) */
>> +};
>> +
>> +/* Read and interpret a 44-bit followed by a 32-bit value in the regmap */
>> +static int si5341_decode_44_32(struct regmap *regmap, unsigned int reg,
>> + u64 *val1, u32 *val2)
>> +{
>> + int err;
>> + u8 r[10];
>> +
>> + err = regmap_bulk_read(regmap, reg, r, 10);
>> + if (err < 0)
>> + return err;
>> +
>> + *val1 = ((u64)((r[5] & 0x0f) << 8 | r[4]) << 32) |
>> + (u32)(r[3] << 24 | r[2] << 16 | r[1] << 8 | r[0]);
>> + *val2 = r[9] << 24 | r[8] << 16 | r[7] << 8 | r[6];
>
> Is this almost get_unaligned_le64()? Maybe with some masking thrown in
> to ignore bytes at r6 and r7. And then a get_unaligned_le32() after that
> starting at r6.

I'll look into it, I just hadn't found those.

>> +
>> + return 0;
>> +}
>> +
>> +static int si5341_encode_44_32(struct regmap *regmap, unsigned int reg,
>> + u64 n_num, u32 n_den)
>> +{
>> + u8 r[10];
>> +
>> + /* Shift left as far as possible without overflowing */
>> + while (!(n_num & BIT(43)) && !(n_den & BIT(31))) {
>> + n_num <<= 1;
>> + n_den <<= 1;
>> + }
>> +
>> + /* 44 bits (6 bytes) numerator */
>> + r[0] = n_num & 0xff;
>> + r[1] = (n_num >> 8) & 0xff;
>> + r[2] = (n_num >> 16) & 0xff;
>> + r[3] = (n_num >> 24) & 0xff;
>> + r[4] = (n_num >> 32) & 0xff;
>> + r[5] = (n_num >> 40) & 0x0f;
>> + /* 32 bits denominator */
>> + r[6] = n_den & 0xff;
>> + r[7] = (n_den >> 8) & 0xff;
>> + r[8] = (n_den >> 16) & 0xff;
>> + r[9] = (n_den >> 24) & 0xff;
>
> Maybe some put_unaligned_le64() and put_unaligned_le32()?

same, yes

>> +
>> + /* Program the fraction */
>> + return regmap_bulk_write(regmap, reg, r, sizeof(r));
>> +}
>> +
>> +/* VCO, we assume it runs at a constant frequency */
>> +static unsigned long si5341_clk_recalc_rate(struct clk_hw *hw,
>> + unsigned long parent_rate)
>> +{
>> + struct clk_si5341 *data = to_clk_si5341(hw);
>> + int err;
>> + u64 res;
>> + u64 m_num;
>> + u32 m_den;
>> + unsigned int shift;
>> +
>> + /* Assume that PDIV is not being used, just read the PLL setting */
>> + err = si5341_decode_44_32(data->regmap, SI5341_PLL_M_NUM,
>> + &m_num, &m_den);
>> + if (err < 0)
>> + return 0;
>> +
>> + if (!m_num || !m_den)
>> + return 0;
>> +
>> + /*
>> + * Though m_num is 64-bit, only the upper bits are actually used. While
>> + * calculating m_num and m_den, they are shifted as far as possible to
>> + * the left. To avoid 96-bit division here, we just shift them back so
>> + * we can do with just 64 bits.
>> + */
>> + shift = 0;
>> + res = m_num;
>> + while (res & 0xffff00000000) {
>> + ++shift;
>> + res >>= 1;
>> + }
>> + res *= parent_rate;
>> + do_div(res, (m_den >> shift));
>> +
>> + dev_dbg(&data->i2c_client->dev,
>> + "%s(p=%lu) m=0x%llx/0x%x shift=%u res=%llu\n",
>> + __func__, parent_rate, m_num, m_den, shift, res);
>> +
>> + /* We cannot return the actual frequency in 32 bit, store it locally */
>> + data->freq_vco = res;
>> +
>> + /* Report kHz since the value is out of range */
>> + do_div(res, 1000);
>> +
>> + return (unsigned long)res;
>
> Uh oh. Do you need really high frequencies that don't fit in 32-bits?

The PLL runs at about 14GHz and can be configured with sub-hertz accuracy.

I also thought about subtracting the minimum frequency, since the PLL range is
relatively small, that would also bring things back into the 32 bit range. But
would be hard to understand.

>> +}
>> +
>> +static const struct clk_ops si5341_clk_ops = {
>> + .recalc_rate = si5341_clk_recalc_rate,
>> +};
>> +
>> +/* Synthesizers, there are 5 synthesizers that connect to any of the outputs */
>> +
>> +/* The synthesizer is on if all power and enable bits are set */
>> +static int si5341_synth_clk_is_on(struct clk_hw *hw)
>> +{
>> + struct clk_si5341_synth *synth = to_clk_si5341_synth(hw);
>> + int err;
>> + u32 val;
>> + u8 index = synth->index;
>> +
>> + err = regmap_read(synth->data->regmap,
>> + SI5341_SYNTH_N_CLK_TO_OUTX_EN, &val);
>> + if (err < 0)
>> + return err;
>
> Should return 0 for off I suppose. Our "fail to read on/off" logic isn't
> really there.

ok, I'll return 0 then.

>
>> +
>> + dev_dbg(&synth->data->i2c_client->dev, "%s(%u): %#x\n",
>> + __func__, index, val);
>> +
>> + if (!(val & BIT(index)))
>> + return false;
>> +
>> + err = regmap_read(synth->data->regmap, SI5341_SYNTH_N_PDNB, &val);
>> + if (err < 0)
>> + return err;
>
> Sam comment.
>
>> +
>> + if (!(val & BIT(index)))
>> + return false;
>
> false is not int, but ok.
>
>> +
>> + /* This bit must be 0 for the synthesizer to receive clock input */
>> + err = regmap_read(synth->data->regmap, SI5341_SYNTH_N_CLK_DIS, &val);
>> + if (err < 0)
>> + return err;
>> +
>> + return !(val & BIT(index));
>> +}
>> +
>> +static void si5341_synth_clk_unprepare(struct clk_hw *hw)
>> +{
>> + struct clk_si5341_synth *synth = to_clk_si5341_synth(hw);
>> + u8 index = synth->index;
>> + u8 mask = BIT(index);
>
> I hope that index isn't large causing overflow here.

Index is in range 0..4

>
>> +
>> + dev_dbg(&synth->data->i2c_client->dev, "%s(%u)\n", __func__, index);
>> +
>> + /* Disable output */
>> + regmap_update_bits(synth->data->regmap,
>> + SI5341_SYNTH_N_CLK_TO_OUTX_EN, mask, 0);
>> + /* Power down */
>> + regmap_update_bits(synth->data->regmap,
>> + SI5341_SYNTH_N_PDNB, mask, 0);
>> + /* Disable clock input to synth (set to 1 to disable) */
>> + regmap_update_bits(synth->data->regmap,
>> + SI5341_SYNTH_N_CLK_DIS, mask, mask);
>> +}
>> +
>> +static int si5341_synth_clk_prepare(struct clk_hw *hw)
>> +{
>> + struct clk_si5341_synth *synth = to_clk_si5341_synth(hw);
>> + int err;
>> + u8 index = synth->index;
>> + u8 mask = BIT(index);
>> +
>> + dev_dbg(&synth->data->i2c_client->dev, "%s(%u)\n", __func__, index);
>> +
>> + /* Power up */
>> + err = regmap_update_bits(synth->data->regmap,
>> + SI5341_SYNTH_N_PDNB, mask, mask);
>> + if (err < 0)
>> + return err;
>> +
>> + /* Enable clock input to synth (set bit to 0 to enable) */
>> + err = regmap_update_bits(synth->data->regmap,
>> + SI5341_SYNTH_N_CLK_DIS, mask, 0);
>> + if (err < 0)
>> + return err;
>> +
>> + /* Enable output */
>> + return regmap_update_bits(synth->data->regmap,
>> + SI5341_SYNTH_N_CLK_TO_OUTX_EN, mask, mask);
>> +}
>> +
>> +/* Synth clock frequency: Fvco * n_den / n_den, with Fvco in 13500-14256 MHz */
>> +static unsigned long si5341_synth_clk_recalc_rate(struct clk_hw *hw,
>> + unsigned long parent_rate)
>> +{
>> + struct clk_si5341_synth *synth = to_clk_si5341_synth(hw);
>> + u64 f;
>> + u64 n_num;
>> + u32 n_den;
>> + int err;
>> +
>> + err = si5341_decode_44_32(synth->data->regmap,
>> + SI5341_SYNTH_N_NUM(synth->index), &n_num, &n_den);
>> + if (err < 0)
>> + return err;
>> +
>> + /*
>> + * n_num and n_den are shifted left as much as possible, so to prevent
>> + * overflow in 64-bit math, we shift n_den 4 bits to the right
>> + */
>> + f = synth->data->freq_vco;
>> + f *= (n_den >> 4);
>
> Do we need these parenthesis? Maybe n_den >>= 4 should preceded this
> line.

I'll remove the parenthesis

>
>> +
>> + /* Now we need to to 64-bit division: f/n_num */
>> + /* And compensate for the 4 bits we dropped */
>> + f = div64_u64(f, (n_num >> 4));
>> +
>> + dev_dbg(&synth->data->i2c_client->dev,
>> + "%s(%u) p=%lu n=0x%llx d=0x%x f=%llu\n",
>> + __func__, synth->index, parent_rate, n_num, n_den, f);
>> +
>> + return (unsigned long)f;
>
> Drop useless cast please.
>
>> +}
>> +
>> +static long si5341_synth_clk_round_rate(struct clk_hw *hw, unsigned long rate,
>> + unsigned long *parent_rate)
>> +{
>> + struct clk_si5341_synth *synth = to_clk_si5341_synth(hw);
>> + u64 f;
>> +
>> + dev_dbg(&synth->data->i2c_client->dev, "%s(%u) r=%lu p=%lu\n",
>> + __func__, synth->index, rate, *parent_rate);
>> +
>> + /* The synthesizer accuracy is such that anything in range will work */
>> + f = synth->data->freq_vco;
>> + do_div(f, SI5341_SYNTH_N_MAX);
>> + if (rate < (unsigned long)f)
>
> Why are we casting f to unsigned long?

"f" will be in 32-bit range after the division, so I want to prevent a 64-bit
compare on 32-bit platforms.

>
>> + return (long)f;
>
> Drop cast?

ok

>
>> +
>> + f = synth->data->freq_vco;
>> + do_div(f, SI5341_SYNTH_N_MIN);
>> + if (rate > (unsigned long)f)
>> + return (long)f;
>
> Drop cast? Or make rate = f?
>
>> +
>> + return (long)rate;
>
> Drop cast?
>
>> +}
>> +
>> +static int si5341_synth_program(struct clk_si5341_synth *synth,
>> + u64 n_num, u32 n_den, bool is_integer)
>> +{
>> + int err;
>> + u8 index = synth->index;
>> +
>> + err = si5341_encode_44_32(synth->data->regmap,
>> + SI5341_SYNTH_N_NUM(index), n_num, n_den);
>> +
>> + /* Set the bit that indicates if the fraction is integer */
>
> Useless comment.
>
>> + err = regmap_update_bits(synth->data->regmap,
>> + SI5341_SYNTH_N_PIBYP, BIT(index), is_integer ? BIT(index) : 0);
>> + if (err < 0)
>> + return err;
>> +
>> + /* Write to the update bit to make the change take effect */
>
> Useless comment?
>
>> + return regmap_write(synth->data->regmap,
>> + SI5341_SYNTH_N_UPD(index), 0x01);
>> +}
>> +
>> +
>> +static int si5341_synth_clk_set_rate(struct clk_hw *hw, unsigned long rate,
>> + unsigned long parent_rate)
>> +{
>> + struct clk_si5341_synth *synth = to_clk_si5341_synth(hw);
>> + u64 n_num;
>> + u32 n_den;
>> + u32 r;
>> + u32 g;
>> + bool is_integer;
>> +
>> + dev_dbg(&synth->data->i2c_client->dev, "%s(%u) r=%lu p=%lu\n",
>> + __func__, synth->index, rate, parent_rate);
>> +
>> + /* obvious solution */
>
> What?
>
>> + n_num = synth->data->freq_vco;
>> + n_den = rate;
>> +
>> + /* see if there's an integer solution */
>> + r = do_div(n_num, rate);
>> + is_integer = (r == 0);
>> + if (is_integer) {
>> + /* Integer divider equal to n_num */
>> + n_den = 1;
>> + } else {
>> + /* Calculate a fractional solution */
>> + g = gcd(r, rate);
>> + n_den = rate / g;
>> + n_num *= n_den;
>> + n_num += r / g;
>> + }
>> +
>> + dev_dbg(&synth->data->i2c_client->dev,
>> + "%s(%u): n=0x%llx d=0x%x %s\n", __func__,
>> + synth->index, n_num, n_den,
>> + is_integer ? "int" : "frac");
>> +
>> + return si5341_synth_program(synth, n_num, n_den, is_integer);
>> +}
>> +
>> +static const struct clk_ops si5341_synth_clk_ops = {
>> + .is_prepared = si5341_synth_clk_is_on,
>> + .prepare = si5341_synth_clk_prepare,
>> + .unprepare = si5341_synth_clk_unprepare,
>> + .recalc_rate = si5341_synth_clk_recalc_rate,
>> + .round_rate = si5341_synth_clk_round_rate,
>> + .set_rate = si5341_synth_clk_set_rate,
>> +};
>> +
>> +static int si5341_output_clk_is_on(struct clk_hw *hw)
>> +{
>> + struct clk_si5341_output *output = to_clk_si5341_output(hw);
>> + int err;
>> + u32 val;
>> +
>> + err = regmap_read(output->data->regmap,
>> + SI5341_OUT_CONFIG(output), &val);
>> + if (err < 0)
>> + return err;

I guess that I cannot return errors here

>> +
>> + dev_dbg(&output->data->i2c_client->dev, "%s(%u): %#x\n",
>> + __func__, output->index, val);
>> +
>> + /* Bit 0=PDN, 1=OE so only a value of 0x2 enables the output */
>> + return (val & 0x03) == SI5341_OUT_CFG_OE;
>> +}
>> +
>> +static void si5341_output_clk_unprepare(struct clk_hw *hw)
>> +{
>> + struct clk_si5341_output *output = to_clk_si5341_output(hw);
>> +
>> + dev_dbg(&output->data->i2c_client->dev, "%s(%u)\n",
>> + __func__, output->index);
>> +
>> + /* Disable and then power down the output */
>> + regmap_update_bits(output->data->regmap,
>> + SI5341_OUT_CONFIG(output),
>> + SI5341_OUT_CFG_OE, 0);
>> + regmap_update_bits(output->data->regmap,
>> + SI5341_OUT_CONFIG(output),
>> + SI5341_OUT_CFG_PDN, SI5341_OUT_CFG_PDN);
>> +}
>> +
>> +static int si5341_output_clk_prepare(struct clk_hw *hw)
>> +{
>> + struct clk_si5341_output *output = to_clk_si5341_output(hw);
>> + int err;
>> +
>> + dev_dbg(&output->data->i2c_client->dev, "%s(%u)\n",
>> + __func__, output->index);
>
> Can you just use the tracepoints in clk framework? These prints are
> really cluttering the code up making it hard to see what's going on.

I'd have to figure out about what those are.

I can simply remove them, they were useful during development but probably
outlived their purpose now.

>
>> +
>> + /* Power up first, then enable the output */
>
> This comment could come above the function instead of inline.

ok

>
>> + err = regmap_update_bits(output->data->regmap,
>> + SI5341_OUT_CONFIG(output),
>> + SI5341_OUT_CFG_PDN, 0);
>> + if (err < 0)
>> + return err;
>> +
>> + return regmap_update_bits(output->data->regmap,
>> + SI5341_OUT_CONFIG(output),
>> + SI5341_OUT_CFG_OE, SI5341_OUT_CFG_OE);
>> +}
>> +
>> +static unsigned long si5341_output_clk_recalc_rate(struct clk_hw *hw,
>> + unsigned long parent_rate)
>> +{
>> + struct clk_si5341_output *output = to_clk_si5341_output(hw);
>> + int err;
>> + u32 val;
>> + u32 r_divider;
>> + u8 r[3];
>> +
>> + err = regmap_read(output->data->regmap,
>> + SI5341_OUT_CONFIG(output), &val);
>> + if (err < 0)
>> + return err;
>> +
>> + /* If bit(2) is set, the divider is forcibly set to "2" */
>
> That's obvious from the code.
>
>> + if (val & SI5341_OUT_CFG_RDIV_FORCE2) {
>> + r_divider = 2;
>> + } else {
>> + err = regmap_bulk_read(output->data->regmap,
>> + SI5341_OUT_R_REG(output), r, 3);
>> + if (err < 0)
>> + return err;
>> +
>> + /* Calculate value as 24-bit integer, (Rx_REG+1)x2 */
>> + r_divider = ((r[2] << 16 | r[1] << 8 | r[0]) + 1) << 1;
>> + }
>> +
>> + dev_dbg(&output->data->i2c_client->dev,
>> + "%s(%u): p=%lu rd=%u %lu\n",
>> + __func__, output->index, parent_rate,
>> + r_divider, parent_rate / r_divider);
>> +
>> + return parent_rate / r_divider;
>> +}
>> +
>> +static long si5341_output_clk_round_rate(struct clk_hw *hw, unsigned long rate,
>> + unsigned long *parent_rate)
>> +{
>> + struct clk_si5341_output *output = to_clk_si5341_output(hw);
>> + unsigned long r;
>> +
>> + dev_dbg(&output->data->i2c_client->dev, "%s(%u): %lu\n",
>> + __func__, output->index, rate);
>> +
>> + r = *parent_rate >> 1;
>> +
>> + /* If rate is an even divisor, no changes to parent required */
>> + if (r && !(r % rate))
>> + return (long)rate;
>> +
>> + if (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) {
>> + if (rate > 200000000)
>> + /* minimum r-divider is 2 */
>> + r = 2;
>> + else
>> + /* Take a parent frequency near 400 MHz */
>> + r = (400000000u / rate) & ~1;
>
> Style: Please enclose in braces if there's more than one line,
> regardless of comment being one of those lines or not.
>
>> + *parent_rate = r * rate;
>> + } else {
>> + /* We cannot change our parent's rate, report what we can do */
>> + r /= rate;
>> + rate = *parent_rate / (r << 1);
>> + }
>> +
>> + return (long)rate;
>
> Please drop useless cast.
>
>> +}
>> +
>> +static int si5341_output_clk_set_rate(struct clk_hw *hw, unsigned long rate,
>> + unsigned long parent_rate)
>> +{
>> + struct clk_si5341_output *output = to_clk_si5341_output(hw);
>> + /* Frequency divider is (r_div + 1) * 2 */
>> + u32 r_div = (parent_rate / rate) >> 1;
>> + int err;
>> + u8 r[3];
>> +
>> + if (r_div <= 1)
>> + r_div = 0;
>> + else if (r_div >= BIT(24))
>> + r_div = BIT(24) - 1;
>> + else
>> + --r_div;
>> +
>> + /* For a value of "2", we set the "OUT0_RDIV_FORCE2" bit */
>> + err = regmap_update_bits(output->data->regmap,
>> + SI5341_OUT_CONFIG(output),
>> + SI5341_OUT_CFG_RDIV_FORCE2,
>> + (r_div == 0) ? SI5341_OUT_CFG_RDIV_FORCE2 : 0);
>> + if (err < 0)
>> + return err;
>> +
>> + /* Just always write the R_REG */
>> + r[0] = r_div & 0xff;
>> + r[1] = (r_div >> 8) & 0xff;
>> + r[2] = (r_div >> 16) & 0xff;
>> + err = regmap_bulk_write(output->data->regmap,
>> + SI5341_OUT_R_REG(output), r, 3);
>> +
>> + dev_dbg(&output->data->i2c_client->dev, "%s(%u): r=%lu p=%lu rd=%u\n",
>> + __func__, output->index, rate, parent_rate, r_div);
>> +
>> + return 0;
>> +}
>> +
>> +static int si5341_output_reparent(struct clk_si5341_output *output, u8 index)
>> +{
>> + return regmap_update_bits(output->data->regmap,
>> + SI5341_OUT_MUX_SEL(output), 0x07, index);
>> +}
>> +
>> +static int si5341_output_set_parent(struct clk_hw *hw, u8 index)
>> +{
>> + struct clk_si5341_output *output = to_clk_si5341_output(hw);
>> +
>> + dev_dbg(&output->data->i2c_client->dev, "%s(%u): N%u\n",
>> + __func__, output->index, index);
>> +
>> + if (index >= output->data->num_synth)
>> + return -EINVAL;
>> +
>> + return si5341_output_reparent(output, index);
>> +}
>> +
>> +static u8 si5341_output_get_parent(struct clk_hw *hw)
>> +{
>> + struct clk_si5341_output *output = to_clk_si5341_output(hw);
>> + int err;
>> + u32 val;
>> +
>> + err = regmap_read(output->data->regmap,
>> + SI5341_OUT_MUX_SEL(output), &val);
>> +
>> + dev_dbg(&output->data->i2c_client->dev, "%s(%u): N%u\n",
>> + __func__, output->index, val & 0x7);
>> +
>> + return val & 0x7;
>> +}
>> +
>> +static const struct clk_ops si5341_output_clk_ops = {
>> + .is_prepared = si5341_output_clk_is_on,
>> + .prepare = si5341_output_clk_prepare,
>> + .unprepare = si5341_output_clk_unprepare,
>> + .recalc_rate = si5341_output_clk_recalc_rate,
>> + .round_rate = si5341_output_clk_round_rate,
>> + .set_rate = si5341_output_clk_set_rate,
>> + .set_parent = si5341_output_set_parent,
>> + .get_parent = si5341_output_get_parent,
>> +};
>> +
>> +/* Called by probe, before output is actually registered */
>> +static int si5341_output_set_parent_and_freq(
>> + struct clk_si5341_output *output, u8 index, u32 parent_rate)
>> +{
>> + int err;
>> +
>> + if (index < output->data->num_synth) {
>> + err = si5341_output_reparent(output, index);
>
> Maybe this can be done via assigned-clock-parents?

Maybe, I'd have to expose the "synth" clocks to the devicetree for that.
That'll be an improvement anyway.

See also my comments in the devicetree patch mail.

>
>> + if (err < 0)
>> + return err;
>> + }
>> +
>> + if (parent_rate) {
>> + index = si5341_output_get_parent(&output->hw);
>> + err = clk_set_rate(output->data->synth[index].hw.clk,
>
> And assigned-clock-rates.
>
>> + parent_rate);
>> + }
>> +
>> + return err;
>> +}
>> +
>> +/*
>> + * The chip can be bought in a pre-programmed version, or one can program the
>> + * NVM in the chip to boot up in a preset mode. This routine tries to determine
>> + * if that's the case, or if we need to reset and program everything from
>> + * scratch. Returns negative error, or true/false.
>> + */
>> +static int si5341_is_programmed_already(struct clk_si5341 *data)
>> +{
>> + int err;
>> + u32 v;
>> + u8 r[4];
>> + u8 i;
>> +
>> + err = regmap_read(data->regmap, 0x00E2, &v);
>> + if (err < 0)
>> + return err;
>> +
>> + /* Read the PLL divider value, it must have a non-zero value */
>> + err = regmap_bulk_read(data->regmap, SI5341_PLL_M_DEN, r, 4);
>> + if (err < 0)
>> + return err;
>> +
>> + dev_dbg(&data->i2c_client->dev, "%s: %#x md=%#x\n",
>> + __func__, v,
>> + r[3] << 24 | r[2] << 16 | r[1] << 8 | r[0]);
>
> There isn't a macro for this byte to word? get_unaligned_le32()?

I'm just getting old :) I've been typing this for years now...

>
>> +
>> + for (i = 0; i < 4; ++i)
>> + if (r[i])
>> + return true;
>
> This for loop could just be 'convert r into u32; print it; test it for 0'.
>
>> +
>> + return false;
>> +}
>> +
>> +static struct clk_hw *of_clk_si5341_get(
>> + struct of_phandle_args *clkspec, void *_data)
>
> Please fix this style:
>
> static struct clk_hw *
> of_clk_si5341_get(struct of_phandle_args *clkspec, void *_data)

ok

>
>> +{
>> + struct clk_si5341 *data = _data;
>> + unsigned int idx = clkspec->args[0];
>> +
>> + if (idx >= data->num_outputs) {
>> + dev_err(&data->i2c_client->dev, "invalid index %u\n", idx);
>> + return ERR_PTR(-EINVAL);
>> + }
>> +
>> + return &data->clk[idx].hw;
>> +}
>> +
>> +static int si5341_probe_chip_id(struct clk_si5341 *data)
>> +{
>> + int err;
>> + u8 reg[4];
>> +
>> + err = regmap_bulk_read(data->regmap, SI5341_PN_BASE, reg, 4);
>
> ARRAY_SIZE(reg) instead of 4?

ok

>
>> + if (err < 0) {
>> + dev_err(&data->i2c_client->dev, "Failed to read chip ID\n");
>> + return err;
>> + }
>> +
>> + dev_info(&data->i2c_client->dev, "Chip: %x Grade: %u Rev: %u\n",
>> + (reg[1] << 8) | reg[0], reg[2], reg[3]);
>> +
>> + /* The 5341 has 10 outputs, the 5340 has only 4 */
>
> Alright! Thanks for the info!
>
>> + switch (reg[0]) {
>> + case 0x40:
>> + data->num_outputs = SI5340_MAX_NUM_OUTPUTS;
>> + data->num_synth = SI5340_NUM_SYNTH;
>> + data->reg_output_offset = si5340_reg_output_offset;
>> + data->reg_rdiv_offset = si5340_reg_rdiv_offset;
>> + break;
>> + case 0x41:
>> + data->num_outputs = SI5341_MAX_NUM_OUTPUTS;
>> + data->num_synth = SI5341_NUM_SYNTH;
>> + data->reg_output_offset = si5341_reg_output_offset;
>> + data->reg_rdiv_offset = si5341_reg_rdiv_offset;
>> + break;
>> + default:
>> + dev_err(&data->i2c_client->dev, "Model '%x' not supported\n",
>> + (reg[1] << 8) | reg[0]);
>> + return -EINVAL;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +/* Read active settings into the regmap cache for later reference */
>> +static int si5341_read_settings(struct clk_si5341 *data)
>> +{
>> + int err;
>> + u8 i;
>> + u8 r[10];
>> +
>> + err = regmap_bulk_read(data->regmap, SI5341_PLL_M_NUM, r, 10);
>> + if (err < 0)
>> + return err;
>> +
>> + err = regmap_bulk_read(data->regmap,
>> + SI5341_SYNTH_N_CLK_TO_OUTX_EN, r, 3);
>> + if (err < 0)
>> + return err;
>> +
>> + err = regmap_bulk_read(data->regmap,
>> + SI5341_SYNTH_N_CLK_DIS, r, 1);
>> + if (err < 0)
>> + return err;
>> +
>> + for (i = 0; i < data->num_synth; ++i) {
>> + err = regmap_bulk_read(data->regmap,
>> + SI5341_SYNTH_N_NUM(i), r, 10);
>> + if (err < 0)
>> + return err;
>> + }
>> +
>> + for (i = 0; i < data->num_outputs; ++i) {
>> + err = regmap_bulk_read(data->regmap,
>> + data->reg_output_offset[i], r, 4);
>> + if (err < 0)
>> + return err;
>> +
>> + err = regmap_bulk_read(data->regmap,
>> + data->reg_rdiv_offset[i], r, 3);
>> + if (err < 0)
>> + return err;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int si5341_write_multiple(struct clk_si5341 *data,
>> + const struct si5341_reg_default *values, unsigned int num_values)
>> +{
>> + unsigned int i;
>> + int res;
>> +
>> + for (i = 0; i < num_values; ++i) {
>> + res = regmap_write(data->regmap,
>> + values[i].address, values[i].value);
>> + if (res < 0) {
>> + dev_err(&data->i2c_client->dev,
>> + "Failed to write %#x:%#x\n",
>> + values[i].address, values[i].value);
>> + return res;
>> + }
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +const struct si5341_reg_default si5341_preamble[] = {
>> + {0x0B25, 0x00},
>
> Please put space around { and }
>
> { 0x0b25, 0x00 },
>
>> + {0x0502, 0x01},
>> + {0x0505, 0x03},
>> + {0x0957, 0x1F},
>> + {0x0B4E, 0x1A},
>> +};
>> +
>> +static int si5341_send_preamble(struct clk_si5341 *data)
>> +{
>> + int res;
>> + u32 revision;
>> +
>> + /* For revision 2 and up, the values are slightly different */
>> + res = regmap_read(data->regmap, SI5341_DEVICE_REV, &revision);
>> + if (res < 0)
>> + return res;
>> +
>> + /* Write "preamble" as specified by datasheet */
>> + res = regmap_write(data->regmap, 0xB24, revision < 2 ? 0xD8 : 0xC0);
>> + if (res < 0)
>> + return res;
>> + res = si5341_write_multiple(data,
>> + si5341_preamble, ARRAY_SIZE(si5341_preamble));
>> + if (res < 0)
>> + return res;
>> +
>> + /* Wait for 300 ms */
>
> Yeah that's obvious. Does the datasheet say to do that? That would be
> more useful to indicate here instead of repeating what the code does.

ok

>
>> + msleep(300);
>> +
>> + return 0;
>> +}
>> +
>> +/* Perform a soft reset and write post-amble */
>> +static int si5341_finalize_defaults(struct clk_si5341 *data)
>> +{
>> + int res;
>> + u32 revision;
>> +
>> + res = regmap_read(data->regmap, SI5341_DEVICE_REV, &revision);
>> + if (res < 0)
>> + return res;
>> +
>> + dev_dbg(&data->i2c_client->dev, "%s rev=%u\n", __func__, revision);
>> +
>> + /* Perform a soft reset */
>
> Obvious.
>
>> + res = regmap_write(data->regmap, SI5341_SOFT_RST, 0x01);
>> + if (res < 0)
>> + return res;
>> +
>> + /* Write post-amble */
>> + res = regmap_write(data->regmap, 0xB24, revision < 2 ? 0xDB : 0xC3);
>
> Why no define for SI5341_POST_AMBLE?
>
>> + if (res < 0)
>> + return res;
>> + res = regmap_write(data->regmap, 0x0B25, 0x02);
>
> And what register is this?

It's the "post_amble" I guess... The datasheet doesn't mention it, other than
"thou shallt write this".

>
>> + if (res < 0)
>> + return res;
>> +
>> + return 0;
>> +}
>> +
>> +
>> +static const struct regmap_range si5341_regmap_volatile_range[] = {
>> + regmap_reg_range(0x000C, 0x0012), /* Status */
>> + regmap_reg_range(0x001C, 0x001E), /* reset, finc/fdec */
>> + regmap_reg_range(0x00E2, 0x00FE), /* NVM, interrupts, device ready */
>> + /* Update bits for synth config */
>> + regmap_reg_range(SI5341_SYNTH_N_UPD(0), SI5341_SYNTH_N_UPD(0)),
>> + regmap_reg_range(SI5341_SYNTH_N_UPD(1), SI5341_SYNTH_N_UPD(1)),
>> + regmap_reg_range(SI5341_SYNTH_N_UPD(2), SI5341_SYNTH_N_UPD(2)),
>> + regmap_reg_range(SI5341_SYNTH_N_UPD(3), SI5341_SYNTH_N_UPD(3)),
>> + regmap_reg_range(SI5341_SYNTH_N_UPD(4), SI5341_SYNTH_N_UPD(4)),
>> +};
>> +
>> +const struct regmap_access_table si5341_regmap_volatile = {
>> + .yes_ranges = si5341_regmap_volatile_range,
>> + .n_yes_ranges = ARRAY_SIZE(si5341_regmap_volatile_range),
>> +};
>> +
>> +/* Pages 0, 1, 2, 3, 9, A, B are valid, so there are 12 pages */
>> +static const struct regmap_range_cfg si5341_regmap_ranges[] = {
>> + {
>> + .range_min = 0,
>> + .range_max = 12 * 256,
>> + .selector_reg = SI5341_PAGE,
>> + .selector_mask = 0xff,
>> + .selector_shift = 0,
>> + .window_start = 0,
>> + .window_len = 256,
>> + },
>> +};
>> +
>> +static const struct regmap_config si5341_regmap_config = {
>> + .reg_bits = 8,
>> + .val_bits = 8,
>> + .cache_type = REGCACHE_RBTREE,
>> + .max_register = 0,
>> + .ranges = si5341_regmap_ranges,
>> + .num_ranges = ARRAY_SIZE(si5341_regmap_ranges),
>> + .max_register = 12 * 256,
>
> Maybe 12 * 256 should be a define.

ok

>
>> + .volatile_table = &si5341_regmap_volatile,
>> +};
>> +
>> +static int si5341_dt_parse_dt(struct i2c_client *client,
>> + struct clk_si5341_output_config *config)
>> +{
>> + struct device_node *child;
>> + struct device_node *np = client->dev.of_node;
>> + u32 num;
>> + u32 val;
>> +
>> + memset(config, 0, sizeof(struct clk_si5341_output_config) *
>> + SI5341_MAX_NUM_OUTPUTS);
>> + /* Set defaults to no forced source, not a master */
>> + for (num = 0; num < SI5341_MAX_NUM_OUTPUTS; ++num)
>> + config[num].source_index = 0xff;
>> +
>> + for_each_child_of_node(np, child) {
>> + if (of_property_read_u32(child, "reg", &num)) {
>> + dev_err(&client->dev, "missing reg property of %s\n",
>> + child->name);
>> + goto put_child;
>> + }
>> +
>> + if (num >= SI5341_MAX_NUM_OUTPUTS) {
>> + dev_err(&client->dev, "invalid clkout %d\n", num);
>> + goto put_child;
>> + }
>> +
>> + if (!of_property_read_u32(child, "silabs,format", &val)) {
>> + /* Set cm and ampl conservatively to 3v3 settings */
>> + switch (val) {
>> + case 1: /* normal differential */
>> + config[num].out_cm_ampl_bits = 0x33;
>> + break;
>> + case 2: /* low-power differential */
>> + config[num].out_cm_ampl_bits = 0x13;
>> + break;
>> + case 4: /* LVCMOS */
>> + config[num].out_cm_ampl_bits = 0x33;
>> + /* Set SI recommended impedance for LVCMOS */
>> + config[num].out_format_drv_bits |= 0xc0;
>> + break;
>> + default:
>> + dev_err(&client->dev,
>> + "invalid silabs,format %u for %u\n",
>> + val, num);
>> + goto put_child;
>> + }
>> + config[num].out_format_drv_bits &= ~0x07;
>> + config[num].out_format_drv_bits |= val & 0x07;
>> + /* Always enable the SYNC feature */
>> + config[num].out_format_drv_bits |= 0x08;
>> + }
>> +
>> + if (!of_property_read_u32(child, "silabs,common-mode", &val)) {
>> + if (val > 0xf) {
>> + dev_err(&client->dev,
>> + "invalid silabs,common-mode %u\n",
>> + val);
>> + goto put_child;
>> + }
>> + config[num].out_cm_ampl_bits &= 0xf0;
>> + config[num].out_cm_ampl_bits |= val & 0x0f;
>> + }
>> +
>> + if (!of_property_read_u32(child, "silabs,amplitude", &val)) {
>> + if (val > 0xf) {
>> + dev_err(&client->dev,
>> + "invalid silabs,amplitude %u\n",
>> + val);
>> + goto put_child;
>> + }
>> + config[num].out_cm_ampl_bits &= 0x0f;
>> + config[num].out_cm_ampl_bits |= (val << 4) & 0xf0;
>> + }
>> +
>> + if (!of_property_read_u32(child, "silabs,synth-source",
>> + &val)) {
>> + /* Chip type not known at this point, assume largest */
>> + if (val >= SI5341_NUM_SYNTH) {
>> + dev_err(&client->dev,
>> + "invalid synth-source %u for %u\n",
>> + val, num);
>> + goto put_child;
>> + }
>> +
>> + config[num].source_index = val;
>> + }
>> +
>> + if (!of_property_read_u32(child, "silabs,synth-frequency",
>> + &val)) {
>> + if (config[num].source_index >= SI5341_NUM_SYNTH) {
>> + dev_err(&client->dev,
>> + "synth-frequency requires synth-source "
>> + "for %u\n", num);
>> + goto put_child;
>> + }
>> +
>> + config[num].synth_frequency = val;
>> + }
>> +
>> + if (!of_property_read_u32(child, "clock-frequency", &val))
>> + config[num].clock_frequency = val;
>> +
>> + if (of_property_read_bool(child, "silabs,disable-high"))
>> + config[num].out_format_drv_bits |= 0x10;
>> +
>> + config[num].synth_master =
>> + of_property_read_bool(child, "silabs,synth-master");
>> +
>> + config[num].always_on =
>> + of_property_read_bool(child, "always-on");
>> + }
>> +
>> + return 0;
>> +
>> +put_child:
>> + of_node_put(child);
>> + return -EINVAL;
>> +}
>> +
>> +/*
>> + * If not pre-configured, calculate and set the PLL configuration manually.
>> + * For low-jitter performance, the PLL should be set such that the synthesizers
>> + * only need integer division.
>> + * Without any user guidance, we'll set the PLL to 14GHz, which still allows
>> + * the chip to generate any frequency on its outputs, but jitter performance
>> + * may be sub-optimal.
>> + */
>> +static int si5341_initialize_pll(struct clk_si5341 *data)
>> +{
>> + struct device_node *np = data->i2c_client->dev.of_node;
>> + u32 m_num = 0;
>> + u32 m_den = 0;
>> +
>> + if (of_property_read_u32(np, "silabs,pll-m-num", &m_num)) {
>> + dev_err(&data->i2c_client->dev,
>> + "PLL configuration requires silabs,pll-m-num\n");
>> + }
>> + if (of_property_read_u32(np, "silabs,pll-m-den", &m_den)) {
>> + dev_err(&data->i2c_client->dev,
>> + "PLL configuration requires silabs,pll-m-den\n");
>> + }
>> +
>> + if (!m_num || !m_den) {
>> + dev_err(&data->i2c_client->dev,
>> + "PLL configuration invalid, assume 14GHz\n");
>> + m_den = clk_get_rate(data->pxtal) / 10;
>> + m_num = 1400000000;
>> + }
>> +
>> + return si5341_encode_44_32(data->regmap,
>> + SI5341_PLL_M_NUM, m_num, m_den);
>> +}
>> +
>> +static int si5341_probe(struct i2c_client *client,
>> + const struct i2c_device_id *id)
>> +{
>> + struct clk_si5341 *data;
>> + struct clk_init_data init;
>> + const char *root_clock_name;
>> + const char *synth_clock_names[SI5341_NUM_SYNTH];
>> + int err;
>> + struct clk_si5341_output_config config[SI5341_MAX_NUM_OUTPUTS];
>> + u8 i;
>
> Why not just an int or unsigned int? Why a u8?

It's getting compared to a u8 (num_synth and num_output are also u8, so I
figured "i" should be the same type.

>
>> + bool initialization_required;
>> +
>> + data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
>> + if (!data)
>> + return -ENOMEM;
>> +
>> + data->i2c_client = client;
>> +
>> + data->pxtal = devm_clk_get(&client->dev, "xtal");
>> + if (IS_ERR(data->pxtal)) {
>> + if (PTR_ERR(data->pxtal) == -EPROBE_DEFER)
>> + return -EPROBE_DEFER;
>> +
>> + dev_err(&client->dev, "Missing xtal clock input\n");
>> + }
>> +
>> + err = si5341_dt_parse_dt(client, config);
>> + if (err)
>> + return err;
>> +
>> + if (of_property_read_string(client->dev.of_node, "clock-output-names",
>> + &init.name))
>> + init.name = client->dev.of_node->name;
>> + root_clock_name = init.name;
>> +
>> + data->regmap = devm_regmap_init_i2c(client, &si5341_regmap_config);
>> + if (IS_ERR(data->regmap))
>> + return PTR_ERR(data->regmap);
>> +
>> + i2c_set_clientdata(client, data);
>> +
>> + err = si5341_probe_chip_id(data);
>> + if (err < 0)
>> + return err;
>> +
>> + /* "Activate" the xtal (usually a fixed clock) */
>> + clk_prepare_enable(data->pxtal);
>> +
>> + if (of_property_read_bool(client->dev.of_node, "silabs,reprogram")) {
>> + initialization_required = true;
>> + } else {
>> + err = si5341_is_programmed_already(data);
>> + if (err < 0)
>> + return err;
>> +
>> + initialization_required = !err;
>> + }
>> +
>> + if (initialization_required) {
>> + /* Populate the regmap cache in preparation for "cache only" */
>> + err = si5341_read_settings(data);
>> + if (err < 0)
>> + return err;
>> +
>> + err = si5341_send_preamble(data);
>> + if (err < 0)
>> + return err;
>> +
>> + /*
>> + * We intend to send all 'final' register values in a single
>> + * transaction. So cache all register writes until we're done
>> + * configuring.
>> + */
>> + regcache_cache_only(data->regmap, true);
>> +
>> + /* Write the configuration pairs from the firmware blob */
>> + err = si5341_write_multiple(data, si5341_reg_defaults,
>> + ARRAY_SIZE(si5341_reg_defaults));
>> + if (err < 0)
>> + return err;
>> +
>> + /* PLL configuration is required */
>> + err = si5341_initialize_pll(data);
>> + if (err < 0)
>> + return err;
>> + }
>> +
>> + /* Register the PLL */
>> + data->pxtal_name = __clk_get_name(data->pxtal);
>> + init.parent_names = &data->pxtal_name;
>> + init.num_parents = 1; /* For now, only XTAL input supported */
>> + init.ops = &si5341_clk_ops;
>> + init.flags = 0;
>> + data->hw.init = &init;
>> +
>> + err = devm_clk_hw_register(&client->dev, &data->hw);
>> + if (err) {
>> + dev_err(&client->dev, "clock registration failed\n");
>> + return err;
>> + }
>> +
>> + init.num_parents = 1;
>> + init.parent_names = &root_clock_name;
>> + init.ops = &si5341_synth_clk_ops;
>> + for (i = 0; i < data->num_synth; ++i) {
>> + synth_clock_names[i] = kasprintf(GFP_KERNEL, "%s.N%u",
>
> Use devm_kasprintf() and let error paths cleanup?

Definitely better than copying code from my previous drivers :)

>
>> + client->dev.of_node->name, i);
>> + init.name = synth_clock_names[i];
>> + data->synth[i].index = i;
>> + data->synth[i].data = data;
>> + data->synth[i].hw.init = &init;
>> + dev_dbg(&client->dev, "Register %s\n", init.name);
>
> Is this necessary? Maybe we should add a pr_debug() deep in
> clk_register() if you really want to know. I don't think I'd be too
> opposed to that.

It's no longer useful, I'll remove most dev_dbg.

>> + err = devm_clk_hw_register(&client->dev, &data->synth[i].hw);
>> + if (err) {
>> + dev_err(&client->dev,
>> + "synth N%u registration failed\n", i);
>> + }
>> + }
>> +
>> + init.num_parents = data->num_synth;
>> + init.parent_names = synth_clock_names;
>> + init.ops = &si5341_output_clk_ops;
>> + init.flags = 0;
>> + for (i = 0; i < data->num_outputs; ++i) {
>> + init.name = kasprintf(GFP_KERNEL, "%s.%d",
>> + client->dev.of_node->name, i);
>> + init.flags = config[i].synth_master ? CLK_SET_RATE_PARENT : 0;
>
> Ok, so synth_master means that it can change the rate of the parent?

Yep, I borrowed that idea from the si5351 driver.

>
>> + data->clk[i].index = i;
>> + data->clk[i].data = data;
>> + data->clk[i].hw.init = &init;
>> + if (config[i].out_format_drv_bits & 0x07) {
>
> What is magic 0x07? Please make a define for it.

will do.

>
>> + dev_dbg(&client->dev,
>> + "out %u: fmt=%#x cm=%#x\n", i,
>> + config[i].out_format_drv_bits,
>> + config[i].out_cm_ampl_bits);
>
> Can't we get this with regmap tracepoints?

yes, but just removing it is just as well (simply reading regmap registers
from debugfs will also provide this information)

>
>> + regmap_write(data->regmap,
>> + SI5341_OUT_FORMAT(&data->clk[i]),
>> + config[i].out_format_drv_bits);
>> + regmap_write(data->regmap,
>> + SI5341_OUT_CM(&data->clk[i]),
>> + config[i].out_cm_ampl_bits);
>> + }
>> + si5341_output_set_parent_and_freq(&data->clk[i],
>> + config[i].source_index,
>> + config[i].synth_frequency);
>> + dev_dbg(&client->dev, "Register %s\n", init.name);
>
> Ah this again!
>
>> + err = devm_clk_hw_register(&client->dev, &data->clk[i].hw);
>> + kfree(init.name); /* clock framework made a copy of the name */
>> + if (err) {
>> + dev_err(&client->dev,
>> + "output %u registration failed\n", i);
>> + goto error;
>> + }
>> + if (config[i].clock_frequency)
>> + clk_set_rate(data->clk[i].hw.clk,
>> + config[i].clock_frequency);
>> + if (config[i].always_on)
>> + clk_prepare(data->clk[i].hw.clk);
>> + }
>> +
>> + err = of_clk_add_hw_provider(client->dev.of_node, of_clk_si5341_get,
>
> Can you use devm_of_clk_add_hw_provider()?

Yes, devm rulez!

>
>> + data);
>> + if (err) {
>> + dev_err(&client->dev, "unable to add clk provider\n");
>> + goto error;
>> + }
>> +
>> + if (initialization_required) {
>> + /* Synchronize */
>
> Useless comment. Please remove.
>
>> + regcache_cache_only(data->regmap, false);
>> + err = regcache_sync(data->regmap);
>> + if (err < 0)
>> + goto error;
>> +
>> + err = si5341_finalize_defaults(data);
>> + if (err < 0)
>> + goto error;
>> + }
>> +
>> +error:
>> + /* Free the names, clk framework makes copies */
>> + for (i = 0; i < data->num_synth; ++i)
>> + kfree(synth_clock_names[i]);
>> +
>> + return err;
>> +}
>> +

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