Re: [PATCH v5] clk: si570: Add a driver for SI570 oscillators

From: Mike Turquette
Date: Tue Dec 17 2013 - 18:44:46 EST

Quoting Guenter Roeck (2013-12-14 08:33:27)
> On 10/02/2013 04:17 PM, Mike Turquette wrote:
> > Quoting SÃren Brinkmann (2013-10-02 10:20:38)
> >> Hi Mike,
> >>
> >> could you please comment on this/apply it to clk-next?
> >
> > It looks good and is in the queue. Will show up in clk-next in a few
> > days.
> >
> Hi Mike,
>
> trying again ... what happened with this driver ? Any reason for not pushing it after all ?

This got reverted with several other patches right before 3.12 dropped.
Unfortunately clk-next broke linux-next two days before 3.12 came out
and I had to revert to a known good state, excluding this driver.

I've added it back to clk-next now towards 3.13. Sorry for the
inconvenience.

Regards,
Mike

>
> Thanks,
> Guenter
>
> > Thanks,
> > Mike
> >
> >>
> >> Thanks,
> >> SÃren
> >>
> >> On Sat, Sep 21, 2013 at 04:40:39PM -0700, Soren Brinkmann wrote:
> >>> Add a driver for SILabs 570, 571, 598, 599 programmable oscillators.
> >>> The devices generate low-jitter clock signals and are reprogrammable via
> >>> an I2C interface.
> >>>
> >>> Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
> >>> Signed-off-by: Soren Brinkmann <soren.brinkmann@xxxxxxxxxx>
> >>> ---
> >>> v5:
> >>> - fix typo in bindings documentation
> >>> - mention the unit for the 'temperature-stability' property
> >>> - remove calls to clk_unregister() (the device managed code takes care
> >>> of it)
> >>>
> >>> v4:
> >>> - actually check and handle error on clk_set_rate() call
> >>>
> >>> v3:
> >>> - add delay in the path for small frequency changes, which can take up
> >>> to 100us according to the data sheet
> >>> - use real range for usleep_range() argument
> >>> - use dev_err() over dev_warn() in set_rate()
> >>> - add list of applicable devices for 7ppm DT prop
> >>> - remove comments regarding platform data
> >>> - ignore 7ppm DT prop for incompatible devices
> >>> - replace raw numbers with #defines
> >>> - convert DT prop 'temperature-stability' from boolean to u32
> >>> - make 'temperature-stability' DT prop required (actually not fully
> >>> true, for 59x it is ignored and the driver does not require its
> >>> presence)
> >>>
> >>> v2:
> >>> - document clock-output-names in bindings documentation
> >>> - don't use wildcards in compatibility string
> >>> - change Kconfig entry to "... 570 and compatible devices"
> >>> - change some indentation flaws
> >>> - use 10000 as MIN and MAX value in usleep_range
> >>> - fail probe() if 'factory-fout' is not provided in DT
> >>> - default factory fout #defines removed
> >>> - use i2c driver_data instead of OF data
> >>> - remove some related structs and data
> >>> - rename DT property 'initial-fout' => 'clock-frequency' (like si5351
> >>> driver)
> >>> - add some more details regarding the 'factory-fout' DT property
> >>> ---
> >>> .../devicetree/bindings/clock/silabs,si570.txt | 39 ++
> >>> drivers/clk/Kconfig | 10 +
> >>> drivers/clk/Makefile | 1 +
> >>> drivers/clk/clk-si570.c | 531 +++++++++++++++++++++
> >>> 4 files changed, 581 insertions(+)
> >>> create mode 100644 Documentation/devicetree/bindings/clock/silabs,si570.txt
> >>> create mode 100644 drivers/clk/clk-si570.c
> >>>
> >>> diff --git a/Documentation/devicetree/bindings/clock/silabs,si570.txt b/Documentation/devicetree/bindings/clock/silabs,si570.txt
> >>> new file mode 100644
> >>> index 0000000..c09f21e
> >>> --- /dev/null
> >>> +++ b/Documentation/devicetree/bindings/clock/silabs,si570.txt
> >>> @@ -0,0 +1,39 @@
> >>> +Binding for Silicon Labs 570, 571, 598 and 599 programmable
> >>> +I2C clock generators.
> >>> +
> >>> +Reference
> >>> +This binding uses the common clock binding[1]. Details about the devices can be
> >>> +found in the data sheets[2][3].
> >>> +
> >>> +[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
> >>> +[2] Si570/571 Data Sheet
> >>> + http://www.silabs.com/Support%20Documents/TechnicalDocs/si570.pdf
> >>> +[3] Si598/599 Data Sheet
> >>> + http://www.silabs.com/Support%20Documents/TechnicalDocs/si598-99.pdf
> >>> +
> >>> +Required properties:
> >>> + - compatible: Shall be one of "silabs,si570", "silabs,si571",
> >>> + "silabs,si598", "silabs,si599"
> >>> + - reg: I2C device address.
> >>> + - #clock-cells: From common clock bindings: Shall be 0.
> >>> + - factory-fout: Factory set default frequency. This frequency is part specific.
> >>> + The correct frequency for the part used has to be provided in
> >>> + order to generate the correct output frequencies. For more
> >>> + details, please refer to the data sheet.
> >>> + - temperature-stability: Temperature stability of the device in PPM. Should be
> >>> + one of: 7, 20, 50 or 100.
> >>> +
> >>> +Optional properties:
> >>> + - clock-output-names: From common clock bindings. Recommended to be "si570".
> >>> + - clock-frequency: Output frequency to generate. This defines the output
> >>> + frequency set during boot. It can be reprogrammed during
> >>> + runtime through the common clock framework.
> >>> +
> >>> +Example:
> >>> + si570: clock-generator@5d {
> >>> + #clock-cells = <0>;
> >>> + compatible = "silabs,si570";
> >>> + temperature-stability = <50>;
> >>> + reg = <0x5d>;
> >>> + factory-fout = <156250000>;
> >>> + };
> >>> diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
> >>> index 279407a..349b88a 100644
> >>> --- a/drivers/clk/Kconfig
> >>> +++ b/drivers/clk/Kconfig
> >>> @@ -64,6 +64,16 @@ config COMMON_CLK_SI5351
> >>> This driver supports Silicon Labs 5351A/B/C programmable clock
> >>> generators.
> >>>
> >>> +config COMMON_CLK_SI570
> >>> + tristate "Clock driver for SiLabs 570 and compatible devices"
> >>> + depends on I2C
> >>> + depends on OF
> >>> + select REGMAP_I2C
> >>> + help
> >>> + ---help---
> >>> + This driver supports Silicon Labs 570/571/598/599 programmable
> >>> + clock generators.
> >>> +
> >>> config COMMON_CLK_S2MPS11
> >>> tristate "Clock driver for S2MPS11 MFD"
> >>> depends on MFD_SEC_CORE
> >>> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
> >>> index 7b11106..c0e94b3 100644
> >>> --- a/drivers/clk/Makefile
> >>> +++ b/drivers/clk/Makefile
> >>> @@ -40,6 +40,7 @@ obj-$(CONFIG_COMMON_CLK_AXI_CLKGEN) += clk-axi-clkgen.o
> >>> obj-$(CONFIG_COMMON_CLK_WM831X) += clk-wm831x.o
> >>> obj-$(CONFIG_COMMON_CLK_MAX77686) += clk-max77686.o
> >>> obj-$(CONFIG_COMMON_CLK_SI5351) += clk-si5351.o
> >>> +obj-$(CONFIG_COMMON_CLK_SI570) += clk-si570.o
> >>> obj-$(CONFIG_COMMON_CLK_S2MPS11) += clk-s2mps11.o
> >>> obj-$(CONFIG_CLK_TWL6040) += clk-twl6040.o
> >>> obj-$(CONFIG_CLK_PPC_CORENET) += clk-ppc-corenet.o
> >>> diff --git a/drivers/clk/clk-si570.c b/drivers/clk/clk-si570.c
> >>> new file mode 100644
> >>> index 0000000..5d0ac9f
> >>> --- /dev/null
> >>> +++ b/drivers/clk/clk-si570.c
> >>> @@ -0,0 +1,531 @@
> >>> +/*
> >>> + * Driver for Silicon Labs Si570/Si571 Programmable XO/VCXO
> >>> + *
> >>> + * Copyright (C) 2010, 2011 Ericsson AB.
> >>> + * Copyright (C) 2011 Guenter Roeck.
> >>> + * Copyright (C) 2011 - 2013 Xilinx Inc.
> >>> + *
> >>> + * Author: Guenter Roeck <guenter.roeck@xxxxxxxxxxxx>
> >>> + * SÃren Brinkmann <soren.brinkmann@xxxxxxxxxx>
> >>> + *
> >>> + * This program is free software; you can redistribute it and/or modify
> >>> + * it under the terms of the GNU General Public License as published by
> >>> + * the Free Software Foundation; either version 2 of the License, or
> >>> + * (at your option) any later version.
> >>> + *
> >>> + * This program is distributed in the hope that it will be useful,
> >>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> >>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> >>> + * GNU General Public License for more details.
> >>> + */
> >>> +
> >>> +#include <linux/clk-provider.h>
> >>> +#include <linux/delay.h>
> >>> +#include <linux/module.h>
> >>> +#include <linux/i2c.h>
> >>> +#include <linux/regmap.h>
> >>> +#include <linux/slab.h>
> >>> +
> >>> +/* Si570 registers */
> >>> +#define SI570_REG_HS_N1 7
> >>> +#define SI570_REG_N1_RFREQ0 8
> >>> +#define SI570_REG_RFREQ1 9
> >>> +#define SI570_REG_RFREQ2 10
> >>> +#define SI570_REG_RFREQ3 11
> >>> +#define SI570_REG_RFREQ4 12
> >>> +#define SI570_REG_CONTROL 135
> >>> +#define SI570_REG_FREEZE_DCO 137
> >>> +#define SI570_DIV_OFFSET_7PPM 6
> >>> +
> >>> +#define HS_DIV_SHIFT 5
> >>> +#define HS_DIV_MASK 0xe0
> >>> +#define HS_DIV_OFFSET 4
> >>> +#define N1_6_2_MASK 0x1f
> >>> +#define N1_1_0_MASK 0xc0
> >>> +#define RFREQ_37_32_MASK 0x3f
> >>> +
> >>> +#define SI570_MIN_FREQ 10000000L
> >>> +#define SI570_MAX_FREQ 1417500000L
> >>> +#define SI598_MAX_FREQ 525000000L
> >>> +
> >>> +#define FDCO_MIN 4850000000LL
> >>> +#define FDCO_MAX 5670000000LL
> >>> +
> >>> +#define SI570_CNTRL_RECALL (1 << 0)
> >>> +#define SI570_CNTRL_FREEZE_M (1 << 5)
> >>> +#define SI570_CNTRL_NEWFREQ (1 << 6)
> >>> +
> >>> +#define SI570_FREEZE_DCO (1 << 4)
> >>> +
> >>> +/**
> >>> + * struct clk_si570:
> >>> + * @hw: Clock hw struct
> >>> + * @regmap: Device's regmap
> >>> + * @div_offset: Rgister offset for dividers
> >>> + * @max_freq: Maximum frequency for this device
> >>> + * @fxtal: Factory xtal frequency
> >>> + * @n1: Clock divider N1
> >>> + * @hs_div: Clock divider HSDIV
> >>> + * @rfreq: Clock multiplier RFREQ
> >>> + * @frequency: Current output frequency
> >>> + * @i2c_client: I2C client pointer
> >>> + */
> >>> +struct clk_si570 {
> >>> + struct clk_hw hw;
> >>> + struct regmap *regmap;
> >>> + unsigned int div_offset;
> >>> + u64 max_freq;
> >>> + u64 fxtal;
> >>> + unsigned int n1;
> >>> + unsigned int hs_div;
> >>> + u64 rfreq;
> >>> + u64 frequency;
> >>> + struct i2c_client *i2c_client;
> >>> +};
> >>> +#define to_clk_si570(_hw) container_of(_hw, struct clk_si570, hw)
> >>> +
> >>> +enum clk_si570_variant {
> >>> + si57x,
> >>> + si59x
> >>> +};
> >>> +
> >>> +/**
> >>> + * si570_get_divs() - Read clock dividers from HW
> >>> + * @data: Pointer to struct clk_si570
> >>> + * @rfreq: Fractional multiplier (output)
> >>> + * @n1: Divider N1 (output)
> >>> + * @hs_div: Divider HSDIV (output)
> >>> + * Returns 0 on success, negative errno otherwise.
> >>> + *
> >>> + * Retrieve clock dividers and multipliers from the HW.
> >>> + */
> >>> +static int si570_get_divs(struct clk_si570 *data, u64 *rfreq,
> >>> + unsigned int *n1, unsigned int *hs_div)
> >>> +{
> >>> + int err;
> >>> + u8 reg[6];
> >>> + u64 tmp;
> >>> +
> >>> + err = regmap_bulk_read(data->regmap, SI570_REG_HS_N1 + data->div_offset,
> >>> + reg, ARRAY_SIZE(reg));
> >>> + if (err)
> >>> + return err;
> >>> +
> >>> + *hs_div = ((reg[0] & HS_DIV_MASK) >> HS_DIV_SHIFT) + HS_DIV_OFFSET;
> >>> + *n1 = ((reg[0] & N1_6_2_MASK) << 2) + ((reg[1] & N1_1_0_MASK) >> 6) + 1;
> >>> + /* Handle invalid cases */
> >>> + if (*n1 > 1)
> >>> + *n1 &= ~1;
> >>> +
> >>> + tmp = reg[1] & RFREQ_37_32_MASK;
> >>> + tmp = (tmp << 8) + reg[2];
> >>> + tmp = (tmp << 8) + reg[3];
> >>> + tmp = (tmp << 8) + reg[4];
> >>> + tmp = (tmp << 8) + reg[5];
> >>> + *rfreq = tmp;
> >>> +
> >>> + return 0;
> >>> +}
> >>> +
> >>> +/**
> >>> + * si570_get_defaults() - Get default values
> >>> + * @data: Driver data structure
> >>> + * @fout: Factory frequency output
> >>> + * Returns 0 on success, negative errno otherwise.
> >>> + */
> >>> +static int si570_get_defaults(struct clk_si570 *data, u64 fout)
> >>> +{
> >>> + int err;
> >>> + u64 fdco;
> >>> +
> >>> + regmap_write(data->regmap, SI570_REG_CONTROL, SI570_CNTRL_RECALL);
> >>> +
> >>> + err = si570_get_divs(data, &data->rfreq, &data->n1, &data->hs_div);
> >>> + if (err)
> >>> + return err;
> >>> +
> >>> + /*
> >>> + * Accept optional precision loss to avoid arithmetic overflows.
> >>> + * Acceptable per Silicon Labs Application Note AN334.
> >>> + */
> >>> + fdco = fout * data->n1 * data->hs_div;
> >>> + if (fdco >= (1LL << 36))
> >>> + data->fxtal = div64_u64(fdco << 24, data->rfreq >> 4);
> >>> + else
> >>> + data->fxtal = div64_u64(fdco << 28, data->rfreq);
> >>> +
> >>> + data->frequency = fout;
> >>> +
> >>> + return 0;
> >>> +}
> >>> +
> >>> +/**
> >>> + * si570_update_rfreq() - Update clock multiplier
> >>> + * @data: Driver data structure
> >>> + * Passes on regmap_bulk_write() return value.
> >>> + */
> >>> +static int si570_update_rfreq(struct clk_si570 *data)
> >>> +{
> >>> + u8 reg[5];
> >>> +
> >>> + reg[0] = ((data->n1 - 1) << 6) |
> >>> + ((data->rfreq >> 32) & RFREQ_37_32_MASK);
> >>> + reg[1] = (data->rfreq >> 24) & 0xff;
> >>> + reg[2] = (data->rfreq >> 16) & 0xff;
> >>> + reg[3] = (data->rfreq >> 8) & 0xff;
> >>> + reg[4] = data->rfreq & 0xff;
> >>> +
> >>> + return regmap_bulk_write(data->regmap, SI570_REG_N1_RFREQ0 +
> >>> + data->div_offset, reg, ARRAY_SIZE(reg));
> >>> +}
> >>> +
> >>> +/**
> >>> + * si570_calc_divs() - Caluclate clock dividers
> >>> + * @frequency: Target frequency
> >>> + * @data: Driver data structure
> >>> + * @out_rfreq: RFREG fractional multiplier (output)
> >>> + * @out_n1: Clock divider N1 (output)
> >>> + * @out_hs_div: Clock divider HSDIV (output)
> >>> + * Returns 0 on success, negative errno otherwise.
> >>> + *
> >>> + * Calculate the clock dividers (@out_hs_div, @out_n1) and clock multiplier
> >>> + * (@out_rfreq) for a given target @frequency.
> >>> + */
> >>> +static int si570_calc_divs(unsigned long frequency, struct clk_si570 *data,
> >>> + u64 *out_rfreq, unsigned int *out_n1, unsigned int *out_hs_div)
> >>> +{
> >>> + int i;
> >>> + unsigned int n1, hs_div;
> >>> + u64 fdco, best_fdco = ULLONG_MAX;
> >>> + static const uint8_t si570_hs_div_values[] = { 11, 9, 7, 6, 5, 4 };
> >>> +
> >>> + for (i = 0; i < ARRAY_SIZE(si570_hs_div_values); i++) {
> >>> + hs_div = si570_hs_div_values[i];
> >>> + /* Calculate lowest possible value for n1 */
> >>> + n1 = div_u64(div_u64(FDCO_MIN, hs_div), frequency);
> >>> + if (!n1 || (n1 & 1))
> >>> + n1++;
> >>> + while (n1 <= 128) {
> >>> + fdco = (u64)frequency * (u64)hs_div * (u64)n1;
> >>> + if (fdco > FDCO_MAX)
> >>> + break;
> >>> + if (fdco >= FDCO_MIN && fdco < best_fdco) {
> >>> + *out_n1 = n1;
> >>> + *out_hs_div = hs_div;
> >>> + *out_rfreq = div64_u64(fdco << 28, data->fxtal);
> >>> + best_fdco = fdco;
> >>> + }
> >>> + n1 += (n1 == 1 ? 1 : 2);
> >>> + }
> >>> + }
> >>> +
> >>> + if (best_fdco == ULLONG_MAX)
> >>> + return -EINVAL;
> >>> +
> >>> + return 0;
> >>> +}
> >>> +
> >>> +static unsigned long si570_recalc_rate(struct clk_hw *hw,
> >>> + unsigned long parent_rate)
> >>> +{
> >>> + int err;
> >>> + u64 rfreq, rate;
> >>> + unsigned int n1, hs_div;
> >>> + struct clk_si570 *data = to_clk_si570(hw);
> >>> +
> >>> + err = si570_get_divs(data, &rfreq, &n1, &hs_div);
> >>> + if (err) {
> >>> + dev_err(&data->i2c_client->dev, "unable to recalc rate\n");
> >>> + return data->frequency;
> >>> + }
> >>> +
> >>> + rfreq = div_u64(rfreq, hs_div * n1);
> >>> + rate = (data->fxtal * rfreq) >> 28;
> >>> +
> >>> + return rate;
> >>> +}
> >>> +
> >>> +static long si570_round_rate(struct clk_hw *hw, unsigned long rate,
> >>> + unsigned long *parent_rate)
> >>> +{
> >>> + int err;
> >>> + u64 rfreq;
> >>> + unsigned int n1, hs_div;
> >>> + struct clk_si570 *data = to_clk_si570(hw);
> >>> +
> >>> + if (!rate)
> >>> + return 0;
> >>> +
> >>> + if (div64_u64(abs(rate - data->frequency) * 10000LL,
> >>> + data->frequency) < 35) {
> >>> + rfreq = div64_u64((data->rfreq * rate) +
> >>> + div64_u64(data->frequency, 2), data->frequency);
> >>> + n1 = data->n1;
> >>> + hs_div = data->hs_div;
> >>> +
> >>> + } else {
> >>> + err = si570_calc_divs(rate, data, &rfreq, &n1, &hs_div);
> >>> + if (err) {
> >>> + dev_err(&data->i2c_client->dev,
> >>> + "unable to round rate\n");
> >>> + return 0;
> >>> + }
> >>> + }
> >>> +
> >>> + return rate;
> >>> +}
> >>> +
> >>> +/**
> >>> + * si570_set_frequency() - Adjust output frequency
> >>> + * @data: Driver data structure
> >>> + * @frequency: Target frequency
> >>> + * Returns 0 on success.
> >>> + *
> >>> + * Update output frequency for big frequency changes (> 3,500 ppm).
> >>> + */
> >>> +static int si570_set_frequency(struct clk_si570 *data, unsigned long frequency)
> >>> +{
> >>> + int err;
> >>> +
> >>> + err = si570_calc_divs(frequency, data, &data->rfreq, &data->n1,
> >>> + &data->hs_div);
> >>> + if (err)
> >>> + return err;
> >>> +
> >>> + /*
> >>> + * The DCO reg should be accessed with a read-modify-write operation
> >>> + * per AN334
> >>> + */
> >>> + regmap_write(data->regmap, SI570_REG_FREEZE_DCO, SI570_FREEZE_DCO);
> >>> + regmap_write(data->regmap, SI570_REG_HS_N1 + data->div_offset,
> >>> + ((data->hs_div - HS_DIV_OFFSET) << HS_DIV_SHIFT) |
> >>> + (((data->n1 - 1) >> 2) & N1_6_2_MASK));
> >>> + si570_update_rfreq(data);
> >>> + regmap_write(data->regmap, SI570_REG_FREEZE_DCO, 0);
> >>> + regmap_write(data->regmap, SI570_REG_CONTROL, SI570_CNTRL_NEWFREQ);
> >>> +
> >>> + /* Applying a new frequency can take up to 10ms */
> >>> + usleep_range(10000, 12000);
> >>> +
> >>> + return 0;
> >>> +}
> >>> +
> >>> +/**
> >>> + * si570_set_frequency_small() - Adjust output frequency
> >>> + * @data: Driver data structure
> >>> + * @frequency: Target frequency
> >>> + * Returns 0 on success.
> >>> + *
> >>> + * Update output frequency for small frequency changes (< 3,500 ppm).
> >>> + */
> >>> +static int si570_set_frequency_small(struct clk_si570 *data,
> >>> + unsigned long frequency)
> >>> +{
> >>> + /*
> >>> + * This is a re-implementation of DIV_ROUND_CLOSEST
> >>> + * using the div64_u64 function lieu of letting the compiler
> >>> + * insert EABI calls
> >>> + */
> >>> + data->rfreq = div64_u64((data->rfreq * frequency) +
> >>> + div_u64(data->frequency, 2), data->frequency);
> >>> + regmap_write(data->regmap, SI570_REG_CONTROL, SI570_CNTRL_FREEZE_M);
> >>> + si570_update_rfreq(data);
> >>> + regmap_write(data->regmap, SI570_REG_CONTROL, 0);
> >>> +
> >>> + /* Applying a new frequency (small change) can take up to 100us */
> >>> + usleep_range(100, 200);
> >>> +
> >>> + return 0;
> >>> +}
> >>> +
> >>> +static int si570_set_rate(struct clk_hw *hw, unsigned long rate,
> >>> + unsigned long parent_rate)
> >>> +{
> >>> + struct clk_si570 *data = to_clk_si570(hw);
> >>> + struct i2c_client *client = data->i2c_client;
> >>> + int err;
> >>> +
> >>> + if (rate < SI570_MIN_FREQ || rate > data->max_freq) {
> >>> + dev_err(&client->dev,
> >>> + "requested frequency %lu Hz is out of range\n", rate);
> >>> + return -EINVAL;
> >>> + }
> >>> +
> >>> + if (div64_u64(abs(rate - data->frequency) * 10000LL,
> >>> + data->frequency) < 35)
> >>> + err = si570_set_frequency_small(data, rate);
> >>> + else
> >>> + err = si570_set_frequency(data, rate);
> >>> +
> >>> + if (err)
> >>> + return err;
> >>> +
> >>> + data->frequency = rate;
> >>> +
> >>> + return 0;
> >>> +}
> >>> +
> >>> +static const struct clk_ops si570_clk_ops = {
> >>> + .recalc_rate = si570_recalc_rate,
> >>> + .round_rate = si570_round_rate,
> >>> + .set_rate = si570_set_rate,
> >>> +};
> >>> +
> >>> +static bool si570_regmap_is_volatile(struct device *dev, unsigned int reg)
> >>> +{
> >>> + switch (reg) {
> >>> + case SI570_REG_CONTROL:
> >>> + return true;
> >>> + default:
> >>> + return false;
> >>> + }
> >>> +}
> >>> +
> >>> +static bool si570_regmap_is_writeable(struct device *dev, unsigned int reg)
> >>> +{
> >>> + switch (reg) {
> >>> + case SI570_REG_HS_N1 ... (SI570_REG_RFREQ4 + SI570_DIV_OFFSET_7PPM):
> >>> + case SI570_REG_CONTROL:
> >>> + case SI570_REG_FREEZE_DCO:
> >>> + return true;
> >>> + default:
> >>> + return false;
> >>> + }
> >>> +}
> >>> +
> >>> +static struct regmap_config si570_regmap_config = {
> >>> + .reg_bits = 8,
> >>> + .val_bits = 8,
> >>> + .cache_type = REGCACHE_RBTREE,
> >>> + .max_register = 137,
> >>> + .writeable_reg = si570_regmap_is_writeable,
> >>> + .volatile_reg = si570_regmap_is_volatile,
> >>> +};
> >>> +
> >>> +static int si570_probe(struct i2c_client *client,
> >>> + const struct i2c_device_id *id)
> >>> +{
> >>> + struct clk_si570 *data;
> >>> + struct clk_init_data init;
> >>> + struct clk *clk;
> >>> + u32 initial_fout, factory_fout, stability;
> >>> + int err;
> >>> + enum clk_si570_variant variant = id->driver_data;
> >>> +
> >>> + data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
> >>> + if (!data)
> >>> + return -ENOMEM;
> >>> +
> >>> + init.ops = &si570_clk_ops;
> >>> + init.flags = CLK_IS_ROOT;
> >>> + init.num_parents = 0;
> >>> + data->hw.init = &init;
> >>> + data->i2c_client = client;
> >>> +
> >>> + if (variant == si57x) {
> >>> + err = of_property_read_u32(client->dev.of_node,
> >>> + "temperature-stability", &stability);
> >>> + if (err) {
> >>> + dev_err(&client->dev,
> >>> + "'temperature-stability' property missing\n");
> >>> + return err;
> >>> + }
> >>> + /* adjust register offsets for 7ppm devices */
> >>> + if (stability == 7)
> >>> + data->div_offset = SI570_DIV_OFFSET_7PPM;
> >>> +
> >>> + data->max_freq = SI570_MAX_FREQ;
> >>> + } else {
> >>> + data->max_freq = SI598_MAX_FREQ;
> >>> + }
> >>> +
> >>> + if (of_property_read_string(client->dev.of_node, "clock-output-names",
> >>> + &init.name))
> >>> + init.name = client->dev.of_node->name;
> >>> +
> >>> + err = of_property_read_u32(client->dev.of_node, "factory-fout",
> >>> + &factory_fout);
> >>> + if (err) {
> >>> + dev_err(&client->dev, "'factory-fout' property missing\n");
> >>> + return err;
> >>> + }
> >>> +
> >>> + data->regmap = devm_regmap_init_i2c(client, &si570_regmap_config);
> >>> + if (IS_ERR(data->regmap)) {
> >>> + dev_err(&client->dev, "failed to allocate register map\n");
> >>> + return PTR_ERR(data->regmap);
> >>> + }
> >>> +
> >>> + i2c_set_clientdata(client, data);
> >>> + err = si570_get_defaults(data, factory_fout);
> >>> + if (err)
> >>> + return err;
> >>> +
> >>> + clk = devm_clk_register(&client->dev, &data->hw);
> >>> + if (IS_ERR(clk)) {
> >>> + dev_err(&client->dev, "clock registration failed\n");
> >>> + return PTR_ERR(clk);
> >>> + }
> >>> + err = of_clk_add_provider(client->dev.of_node, of_clk_src_simple_get,
> >>> + clk);
> >>> + if (err) {
> >>> + dev_err(&client->dev, "unable to add clk provider\n");
> >>> + return err;
> >>> + }
> >>> +
> >>> + /* Read the requested initial output frequency from device tree */
> >>> + if (!of_property_read_u32(client->dev.of_node, "clock-frequency",
> >>> + &initial_fout)) {
> >>> + err = clk_set_rate(clk, initial_fout);
> >>> + if (err) {
> >>> + of_clk_del_provider(client->dev.of_node);
> >>> + return err;
> >>> + }
> >>> + }
> >>> +
> >>> + /* Display a message indicating that we've successfully registered */
> >>> + dev_info(&client->dev, "registered, current frequency %llu Hz\n",
> >>> + data->frequency);
> >>> +
> >>> + return 0;
> >>> +}
> >>> +
> >>> +static int si570_remove(struct i2c_client *client)
> >>> +{
> >>> + of_clk_del_provider(client->dev.of_node);
> >>> + return 0;
> >>> +}
> >>> +
> >>> +static const struct i2c_device_id si570_id[] = {
> >>> + { "si570", si57x },
> >>> + { "si571", si57x },
> >>> + { "si598", si59x },
> >>> + { "si599", si59x },
> >>> + { }
> >>> +};
> >>> +MODULE_DEVICE_TABLE(i2c, si570_id);
> >>> +
> >>> +static const struct of_device_id clk_si570_of_match[] = {
> >>> + { .compatible = "silabs,si570" },
> >>> + { .compatible = "silabs,si571" },
> >>> + { .compatible = "silabs,si598" },
> >>> + { .compatible = "silabs,si599" },
> >>> + { },
> >>> +};
> >>> +MODULE_DEVICE_TABLE(of, clk_si570_of_match);
> >>> +
> >>> +static struct i2c_driver si570_driver = {
> >>> + .driver = {
> >>> + .name = "si570",
> >>> + .of_match_table = of_match_ptr(clk_si570_of_match),
> >>> + },
> >>> + .probe = si570_probe,
> >>> + .remove = si570_remove,
> >>> + .id_table = si570_id,
> >>> +};
> >>> +module_i2c_driver(si570_driver);
> >>> +
> >>> +MODULE_AUTHOR("Guenter Roeck <guenter.roeck@xxxxxxxxxxxx>");
> >>> +MODULE_AUTHOR("Soeren Brinkmann <soren.brinkmann@xxxxxxxxxx");
> >>> +MODULE_DESCRIPTION("Si570 driver");
> >>> +MODULE_LICENSE("GPL");
> >>> --
> >>> 1.8.4
> >>>
> >>>
> > --
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> >
> >
> >
> >
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