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SubjectRe: [PATCH v4 1/1] pwm: mediatek: add MT2712/MT7622 support
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Hi Claudiu,

Thanks for your comments.
I updated this file, according to your suggestions.
Please have a review.

Regards
Zhi

On Tue, 2017-10-24 at 16:25 +0300, m18063 wrote:
> Hi Zhi,
>
> Please see my answer below.
>
> On 23.10.2017 14:13, Zhi Mao wrote:
> > Hi Claudiu
> >
> > please check the comments as below.
> >
> > Regards
> > Zhi
> >
> > On Mon, 2017-10-23 at 11:22 +0300, m18063 wrote:
> >> 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@mediatek.com>
> >>> ---
> >>> 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);
> > Here, the member of "mtk_pwm_platform_data" is an extension interface of
> > pwm information for MTK SOC chips. At present, we use it to initialize
> > npwms,
>
> and maybe we will have more informations to use, in later.
>
> The use of *maybe* in here suggest me that this will not necessary happen.
> Actually, what I wanted to emphasize is that, for the moment, you are keeping
> same information in both driver private data structure and PWM framework data
> structure. So, even if in future you will add more members to this data structure,
> you will have the number of PWMs stored in both, your driver data structure
> (via "struct mtk_pwm_platform_data *data" member) and PWM framework
> (via "struct pwm_chip chip" member of struct mtk_pwm_chip).
>
> For instance, if you will add more info to this data structure you could do it this way:
>
> struct mtk_pwm_platform_data_other {
> typex memberx;
> typey membery;
> // ...
> };
>
> struct mtk_pwm_platform_data {
> unsigned int num_pwms;
> struct mtk_pwm_platform_data_other other_data;
> };
>
> And have struct mtk_pwm_chip as follows:
> struct mtk_pwm_chip {
> struct pwm_chip chip;
> void __iomem *regs;
> struct clk *clks[MTK_CLK_MAX];
> struct mtk_pwm_platform_data_other *other_data;
> }
>
> and in probe:
>
> static int mtk_pwm_probe(struct platform_device *pdev)
> {
> struct mtk_pwm_platform_data *data;
> // ...
> data = of_device_get_match_data(&pdev->dev);
> if (data == NULL)
> return -EINVAL;
> pc->other_data = data->other_data;
> // ...
> pc->chip.dev = &pdev->dev;
> pc->chip.ops = &mtk_pwm_ops;
> pc->chip.base = -1;
> pc->chip.npwm = data->num_pwms; /* Here you store the num_pwms in PWM framework
> * data structure and you could use it from here. */
>
> // ...
> }
>
> At this moment I think there is no need for "const struct mtk_pwm_platform_data" member
> to be part of struct mtk_pwm_chip.
>
> Thanks,
> Claudiu
>
> > so, we want to keep it and make the interface more flexible.
> >
> >>> +};
> >>> +
> >>> +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).
> >>
> > Here, I will add the NULL pointer checking for "pc->data", and it will
> > be released, soon.
> >
> >>> +
> >>> 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);
> >>>
> >>>
> >
> >


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