Re: [PATCH v4 1/1] pwm: mediatek: add MT2712/MT7622 support

[m18063]

Hi Zhi,

I have few comments regarding your patch. Please see them below.

Thanks,
Claudiu

On 22.08.2017 05:09, Zhi Mao wrote:
> Add support to MT2712 and MT7622.
> Due to register offset address of pwm7 for MT2712 is not fixed 0x40,
> add mtk_pwm_reg_offset array for pwm register offset.
> 
> Signed-off-by: Zhi Mao <zhi.mao@xxxxxxxxxxxx>
> ---
>  drivers/pwm/pwm-mediatek.c |   51 ++++++++++++++++++++++++++++++++++++--------
>  1 file changed, 42 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/pwm/pwm-mediatek.c b/drivers/pwm/pwm-mediatek.c
> index 1d78ab1..ccd86e7 100644
> --- a/drivers/pwm/pwm-mediatek.c
> +++ b/drivers/pwm/pwm-mediatek.c
> @@ -16,6 +16,7 @@
>  #include <linux/module.h>
>  #include <linux/clk.h>
>  #include <linux/of.h>
> +#include <linux/of_device.h>
>  #include <linux/platform_device.h>
>  #include <linux/pwm.h>
>  #include <linux/slab.h>
> @@ -40,11 +41,19 @@ enum {
>  	MTK_CLK_PWM3,
>  	MTK_CLK_PWM4,
>  	MTK_CLK_PWM5,
> +	MTK_CLK_PWM6,
> +	MTK_CLK_PWM7,
> +	MTK_CLK_PWM8,
>  	MTK_CLK_MAX,
>  };
>  
> -static const char * const mtk_pwm_clk_name[] = {
> -	"main", "top", "pwm1", "pwm2", "pwm3", "pwm4", "pwm5"
> +static const char * const mtk_pwm_clk_name[MTK_CLK_MAX] = {
> +	"main", "top", "pwm1", "pwm2", "pwm3", "pwm4", "pwm5", "pwm6", "pwm7",
> +	"pwm8"
> +};
> +
> +struct mtk_pwm_platform_data {
> +	unsigned int num_pwms;
>  };
>  
>  /**
> @@ -57,6 +66,11 @@ struct mtk_pwm_chip {
>  	struct pwm_chip chip;
>  	void __iomem *regs;
>  	struct clk *clks[MTK_CLK_MAX];
> +	const struct mtk_pwm_platform_data *data;
I think you can remove this member since you only use it to initialize chip.npwm,
in probe function, just before platform_set_drvdata().

	pc->chip.npwm = pc->data->pwm_nums;

	platform_set_drvdata(pdev, pc);
> +};
> +
> +static const unsigned int mtk_pwm_reg_offset[] = {
> +	0x0010, 0x0050, 0x0090, 0x00d0, 0x0110, 0x0150, 0x0190, 0x0220
>  };
>  
>  static inline struct mtk_pwm_chip *to_mtk_pwm_chip(struct pwm_chip *chip)
> @@ -103,14 +117,14 @@ static void mtk_pwm_clk_disable(struct pwm_chip *chip, struct pwm_device *pwm)
>  static inline u32 mtk_pwm_readl(struct mtk_pwm_chip *chip, unsigned int num,
>  				unsigned int offset)
>  {
> -	return readl(chip->regs + 0x10 + (num * 0x40) + offset);
> +	return readl(chip->regs + mtk_pwm_reg_offset[num] + offset);
>  }
>  
>  static inline void mtk_pwm_writel(struct mtk_pwm_chip *chip,
>  				  unsigned int num, unsigned int offset,
>  				  u32 value)
>  {
> -	writel(value, chip->regs + 0x10 + (num * 0x40) + offset);
> +	writel(value, chip->regs + mtk_pwm_reg_offset[num] + offset);
>  }
>  
>  static int mtk_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
> @@ -194,15 +208,20 @@ static int mtk_pwm_probe(struct platform_device *pdev)
>  	if (!pc)
>  		return -ENOMEM;
>  
> +	pc->data = of_device_get_match_data(&pdev->dev);
You forgot to check pc->data == NULL (in case device tree inputs are not provided)
and you may use here a stack allocated variable to store the number of PWMs returned
by of_device_get_match_data(). This is used only for pc->chip.npwm, and anyway, if
any, you could get that information from chip.npwm.
You could also check here the number of PWMs returned via of_device_get_match_data()
to avoid waiting for pwmchip_add() to fail (e.g. if number of PWMs is zero, the
pwmchip_add() will fail).

> +
>  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  	pc->regs = devm_ioremap_resource(&pdev->dev, res);
>  	if (IS_ERR(pc->regs))
>  		return PTR_ERR(pc->regs);
>  
> -	for (i = 0; i < MTK_CLK_MAX; i++) {
> +	for (i = 0; i < pc->data->num_pwms + 2; i++) {
>  		pc->clks[i] = devm_clk_get(&pdev->dev, mtk_pwm_clk_name[i]);
> -		if (IS_ERR(pc->clks[i]))
> +		if (IS_ERR(pc->clks[i])) {
> +			dev_err(&pdev->dev, "clock: %s fail: %ld\n",
> +				mtk_pwm_clk_name[i], PTR_ERR(pc->clks[i]));
>  			return PTR_ERR(pc->clks[i]);
> +		}
>  	}
>  
>  	platform_set_drvdata(pdev, pc);
> @@ -210,7 +229,7 @@ static int mtk_pwm_probe(struct platform_device *pdev)
>  	pc->chip.dev = &pdev->dev;
>  	pc->chip.ops = &mtk_pwm_ops;
>  	pc->chip.base = -1;
> -	pc->chip.npwm = 5;
> +	pc->chip.npwm = pc->data->num_pwms;
>  
>  	ret = pwmchip_add(&pc->chip);
>  	if (ret < 0) {
> @@ -228,9 +247,23 @@ static int mtk_pwm_remove(struct platform_device *pdev)
>  	return pwmchip_remove(&pc->chip);
>  }
>  
> +static const struct mtk_pwm_platform_data mt2712_pwm_data = {
> +	.num_pwms = 8,
> +};
> +
> +static const struct mtk_pwm_platform_data mt7622_pwm_data = {
> +	.num_pwms = 6,
> +};
> +
> +static const struct mtk_pwm_platform_data mt7623_pwm_data = {
> +	.num_pwms = 5,
> +};
> +
>  static const struct of_device_id mtk_pwm_of_match[] = {
> -	{ .compatible = "mediatek,mt7623-pwm" },
> -	{ }
> +	{ .compatible = "mediatek,mt2712-pwm", .data = &mt2712_pwm_data },
> +	{ .compatible = "mediatek,mt7622-pwm", .data = &mt7622_pwm_data },
> +	{ .compatible = "mediatek,mt7623-pwm", .data = &mt7623_pwm_data },
> +	{ },
>  };
>  MODULE_DEVICE_TABLE(of, mtk_pwm_of_match);
>  
>