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

From: m18063
Date: Mon Oct 23 2017 - 04:22:41 EST


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);
>
>