RE: [v11 2/2] clk: ls1028a: Add clock driver for Display output interface

[Wen He]

> -----Original Message-----
> From: Wen He <wen.he_1@xxxxxxx>
> Sent: 2019年12月5日 15:27
> To: Michael Turquette <mturquette@xxxxxxxxxxxx>; Stephen Boyd
> <sboyd@xxxxxxxxxx>; Rob Herring <robh+dt@xxxxxxxxxx>; Mark Rutland
> <mark.rutland@xxxxxxx>; Michael Walle <michael@xxxxxxxx>; Leo Li
> <leoyang.li@xxxxxxx>; devicetree@xxxxxxxxxxxxxxx; linux-clk@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx
> Cc: Wen He <wen.he_1@xxxxxxx>
> Subject: [v11 2/2] clk: ls1028a: Add clock driver for Display output interface
> 

Hi Maintainer, 

Do you have any comments for this patch?

Best Regards,
Wen

> Add clock driver for QorIQ LS1028A Display output interfaces(LCD, DPHY), as
> implemented in TSMC CLN28HPM PLL, this PLL supports the programmable
> integer division and range of the display output pixel clock's 27-594MHz.
> 
> Signed-off-by: Wen He <wen.he_1@xxxxxxx>
> Signed-off-by: Michael Walle <michael@xxxxxxxx>
> ---
>  drivers/clk/Kconfig      |  10 ++
>  drivers/clk/Makefile     |   1 +
>  drivers/clk/clk-plldig.c | 297
> +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 308 insertions(+)
>  create mode 100644 drivers/clk/clk-plldig.c
> 
> diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig index
> 0530bebfc25a..9f6b0196c604 100644
> --- a/drivers/clk/Kconfig
> +++ b/drivers/clk/Kconfig
> @@ -218,6 +218,16 @@ config CLK_QORIQ
>  	  This adds the clock driver support for Freescale QorIQ platforms
>  	  using common clock framework.
> 
> +config CLK_LS1028A_PLLDIG
> +        tristate "Clock driver for LS1028A Display output"
> +        depends on ARCH_LAYERSCAPE || COMPILE_TEST
> +        default ARCH_LAYERSCAPE
> +        help
> +          This driver support the Display output interfaces(LCD, DPHY) pixel
> clocks
> +          of the QorIQ Layerscape LS1028A, as implemented TSMC
> CLN28HPM PLL. Not all
> +          features of the PLL are currently supported by the driver. By
> default,
> +          configured bypass mode with this PLL.
> +
>  config COMMON_CLK_XGENE
>  	bool "Clock driver for APM XGene SoC"
>  	default ARCH_XGENE
> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile index
> 0138fb14e6f8..97d1e5bc6de5 100644
> --- a/drivers/clk/Makefile
> +++ b/drivers/clk/Makefile
> @@ -43,6 +43,7 @@ obj-$(CONFIG_ARCH_NPCM7XX)	    	+=
> clk-npcm7xx.o
>  obj-$(CONFIG_ARCH_NSPIRE)		+= clk-nspire.o
>  obj-$(CONFIG_COMMON_CLK_OXNAS)		+= clk-oxnas.o
>  obj-$(CONFIG_COMMON_CLK_PALMAS)		+= clk-palmas.o
> +obj-$(CONFIG_CLK_LS1028A_PLLDIG)	+= clk-plldig.o
>  obj-$(CONFIG_COMMON_CLK_PWM)		+= clk-pwm.o
>  obj-$(CONFIG_CLK_QORIQ)			+= clk-qoriq.o
>  obj-$(CONFIG_COMMON_CLK_RK808)		+= clk-rk808.o
> diff --git a/drivers/clk/clk-plldig.c b/drivers/clk/clk-plldig.c new file mode
> 100644 index 000000000000..1942686f0254
> --- /dev/null
> +++ b/drivers/clk/clk-plldig.c
> @@ -0,0 +1,297 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright 2019 NXP
> + *
> + * Clock driver for LS1028A Display output interfaces(LCD, DPHY).
> + */
> +
> +#include <linux/clk-provider.h>
> +#include <linux/device.h>
> +#include <linux/module.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/iopoll.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/bitfield.h>
> +
> +/* PLLDIG register offsets and bit masks */
> +#define PLLDIG_REG_PLLSR            0x24
> +#define PLLDIG_LOCK_MASK            BIT(2)
> +#define PLLDIG_REG_PLLDV            0x28
> +#define PLLDIG_MFD_MASK             GENMASK(7, 0)
> +#define PLLDIG_RFDPHI1_MASK         GENMASK(30, 25)
> +#define PLLDIG_REG_PLLFM            0x2c
> +#define PLLDIG_SSCGBYP_ENABLE       BIT(30)
> +#define PLLDIG_REG_PLLFD            0x30
> +#define PLLDIG_FDEN                 BIT(30)
> +#define PLLDIG_FRAC_MASK            GENMASK(15, 0)
> +#define PLLDIG_REG_PLLCAL1          0x38
> +#define PLLDIG_REG_PLLCAL2          0x3c
> +
> +/* Range of the VCO frequencies, in Hz */
> +#define PLLDIG_MIN_VCO_FREQ         650000000
> +#define PLLDIG_MAX_VCO_FREQ         1300000000
> +
> +/* Range of the output frequencies, in Hz */
> +#define PHI1_MIN_FREQ               27000000
> +#define PHI1_MAX_FREQ               600000000
> +
> +/* Maximum value of the reduced frequency divider */
> +#define MAX_RFDPHI1          63UL
> +
> +/* Best value of multiplication factor divider */
> +#define PLLDIG_DEFAULT_MFD   44
> +
> +/*
> + * Denominator part of the fractional part of the
> + * loop multiplication factor.
> + */
> +#define MFDEN          20480
> +
> +static const struct clk_parent_data parent_data[] = {
> +	{.index = 0},
> +};
> +
> +struct clk_plldig {
> +	struct clk_hw hw;
> +	void __iomem *regs;
> +	unsigned int vco_freq;
> +};
> +
> +#define to_clk_plldig(_hw)	container_of(_hw, struct clk_plldig, hw)
> +
> +static int plldig_enable(struct clk_hw *hw) {
> +	struct clk_plldig *data = to_clk_plldig(hw);
> +	u32 val;
> +
> +	val = readl(data->regs + PLLDIG_REG_PLLFM);
> +	/*
> +	 * Use Bypass mode with PLL off by default, the frequency overshoot
> +	 * detector output was disable. SSCG Bypass mode should be enable.
> +	 */
> +	val |= PLLDIG_SSCGBYP_ENABLE;
> +	writel(val, data->regs + PLLDIG_REG_PLLFM);
> +
> +	return 0;
> +}
> +
> +static void plldig_disable(struct clk_hw *hw) {
> +	struct clk_plldig *data = to_clk_plldig(hw);
> +	u32 val;
> +
> +	val = readl(data->regs + PLLDIG_REG_PLLFM);
> +
> +	val &= ~PLLDIG_SSCGBYP_ENABLE;
> +	val |= FIELD_PREP(PLLDIG_SSCGBYP_ENABLE, 0x0);
> +
> +	writel(val, data->regs + PLLDIG_REG_PLLFM); }
> +
> +static int plldig_is_enabled(struct clk_hw *hw) {
> +	struct clk_plldig *data = to_clk_plldig(hw);
> +
> +	return (readl(data->regs + PLLDIG_REG_PLLFM) &
> +			      PLLDIG_SSCGBYP_ENABLE);
> +}
> +
> +static unsigned long plldig_recalc_rate(struct clk_hw *hw,
> +					unsigned long parent_rate)
> +{
> +	struct clk_plldig *data = to_clk_plldig(hw);
> +	u32 val, rfdphi1;
> +
> +	val = readl(data->regs + PLLDIG_REG_PLLDV);
> +
> +	/* Check if PLL is bypassed */
> +	if (val & PLLDIG_SSCGBYP_ENABLE)
> +		return parent_rate;
> +
> +	rfdphi1 = FIELD_GET(PLLDIG_RFDPHI1_MASK, val);
> +
> +	/*
> +	 * If RFDPHI1 has a value of 1 the VCO frequency is also divided by
> +	 * one.
> +	 */
> +	if (!rfdphi1)
> +		rfdphi1 = 1;
> +
> +	return DIV_ROUND_UP(data->vco_freq, rfdphi1); }
> +
> +static unsigned long plldig_calc_target_div(unsigned long vco_freq,
> +					    unsigned long target_rate)
> +{
> +	unsigned long div;
> +
> +	div = DIV_ROUND_CLOSEST(vco_freq, target_rate);
> +	div = max(1UL, div);
> +	div = min(div, MAX_RFDPHI1);
> +
> +	return div;
> +}
> +
> +static int plldig_determine_rate(struct clk_hw *hw,
> +				 struct clk_rate_request *req)
> +{
> +	struct clk_plldig *data = to_clk_plldig(hw);
> +	unsigned int div;
> +
> +	if (req->rate < PHI1_MIN_FREQ)
> +		req->rate = PHI1_MIN_FREQ;
> +	if (req->rate > PHI1_MAX_FREQ)
> +		req->rate = PHI1_MAX_FREQ;
> +
> +	div = plldig_calc_target_div(data->vco_freq, req->rate);
> +	req->rate = DIV_ROUND_UP(data->vco_freq, div);
> +
> +	return 0;
> +}
> +
> +static int plldig_set_rate(struct clk_hw *hw, unsigned long rate,
> +		unsigned long parent_rate)
> +{
> +	struct clk_plldig *data = to_clk_plldig(hw);
> +	unsigned int val, cond;
> +	unsigned int rfdphi1;
> +
> +	if (rate < PHI1_MIN_FREQ)
> +		rate = PHI1_MIN_FREQ;
> +	if (rate > PHI1_MAX_FREQ)
> +		rate = PHI1_MAX_FREQ;
> +
> +	rfdphi1 = plldig_calc_target_div(data->vco_freq, rate);
> +
> +	/* update the divider value */
> +	val = readl(data->regs + PLLDIG_REG_PLLDV);
> +	val &= ~PLLDIG_RFDPHI1_MASK;
> +	val |= FIELD_PREP(PLLDIG_RFDPHI1_MASK, rfdphi1);
> +	writel(val, data->regs + PLLDIG_REG_PLLDV);
> +
> +	/* delay 200us make sure that old lock state is cleared */
> +	udelay(200);
> +
> +	/* Wait until PLL is locked or timeout (maximum 1000 usecs) */
> +	return readl_poll_timeout_atomic(data->regs + PLLDIG_REG_PLLSR, cond,
> +					 cond & PLLDIG_LOCK_MASK, 0,
> +					 USEC_PER_MSEC);
> +}
> +
> +static const struct clk_ops plldig_clk_ops = {
> +	.enable = plldig_enable,
> +	.disable = plldig_disable,
> +	.is_enabled = plldig_is_enabled,
> +	.recalc_rate = plldig_recalc_rate,
> +	.determine_rate = plldig_determine_rate,
> +	.set_rate = plldig_set_rate,
> +};
> +
> +static int plldig_init(struct clk_hw *hw) {
> +	struct clk_plldig *data = to_clk_plldig(hw);
> +	struct clk_hw *parent = clk_hw_get_parent(hw);
> +	unsigned long parent_rate = clk_hw_get_rate(parent);
> +	unsigned long val;
> +	unsigned long long lltmp;
> +	unsigned int mfd, fracdiv = 0;
> +
> +	if (!parent)
> +		return -EINVAL;
> +
> +	if (data->vco_freq) {
> +		mfd = data->vco_freq / parent_rate;
> +		lltmp = data->vco_freq % parent_rate;
> +		lltmp *= MFDEN;
> +		do_div(lltmp, parent_rate);
> +		fracdiv = lltmp;
> +	} else {
> +		mfd = PLLDIG_DEFAULT_MFD;
> +		data->vco_freq = parent_rate * mfd;
> +	}
> +
> +	val = FIELD_PREP(PLLDIG_MFD_MASK, mfd);
> +	writel(val, data->regs + PLLDIG_REG_PLLDV);
> +
> +	if (fracdiv) {
> +		val = FIELD_PREP(PLLDIG_FRAC_MASK, fracdiv);
> +		/* Enable fractional divider */
> +		val |= PLLDIG_FDEN;
> +		writel(val, data->regs + PLLDIG_REG_PLLFD);
> +	}
> +
> +	return 0;
> +}
> +
> +static int plldig_clk_probe(struct platform_device *pdev) {
> +	struct clk_plldig *data;
> +	struct resource *mem;
> +	struct device *dev = &pdev->dev;
> +	int ret;
> +
> +	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;
> +
> +	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	data->regs = devm_ioremap_resource(dev, mem);
> +	if (IS_ERR(data->regs))
> +		return PTR_ERR(data->regs);
> +
> +	data->hw.init = CLK_HW_INIT_PARENTS_DATA("dpclk",
> +						 parent_data,
> +						 &plldig_clk_ops,
> +						 0);
> +
> +	ret = devm_clk_hw_register(dev, &data->hw);
> +	if (ret) {
> +		dev_err(dev, "failed to register %s clock\n",
> +						dev->of_node->name);
> +		return ret;
> +	}
> +
> +	ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get,
> +					  &data->hw);
> +	if (ret) {
> +		dev_err(dev, "unable to add clk provider\n");
> +		return ret;
> +	}
> +
> +	/*
> +	 * The frequency of the VCO cannot be changed during runtime.
> +	 * Therefore, let the user specify a desired frequency.
> +	 */
> +	if (!of_property_read_u32(dev->of_node, "fsl,vco-hz",
> +				  &data->vco_freq)) {
> +		if (data->vco_freq < PLLDIG_MIN_VCO_FREQ ||
> +		    data->vco_freq > PLLDIG_MAX_VCO_FREQ)
> +			return -EINVAL;
> +	}
> +
> +	return plldig_init(&data->hw);
> +}
> +
> +static const struct of_device_id plldig_clk_id[] = {
> +	{ .compatible = "fsl,ls1028a-plldig"},
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, plldig_clk_id);
> +
> +static struct platform_driver plldig_clk_driver = {
> +	.driver = {
> +		.name = "plldig-clock",
> +		.of_match_table = plldig_clk_id,
> +	},
> +	.probe = plldig_clk_probe,
> +};
> +module_platform_driver(plldig_clk_driver);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_AUTHOR("Wen He <wen.he_1@xxxxxxx>");
> MODULE_DESCRIPTION("LS1028A
> +Display output interface pixel clock driver");
> --
> 2.17.1