Re: [PATCH 2/3] pwm: Add MediaTek MT2701 display PWM driver support

From: weiqing kong
Date: Wed Jun 08 2016 - 08:06:06 EST

On Wed, 2016-06-08 at 13:22 +0200, Matthias Brugger wrote:
>
> On 08/06/16 09:21, weiqing kong wrote:
> > On Fri, 2016-06-03 at 17:35 +0200, Matthias Brugger wrote:
> >>
> >> On 30/05/16 10:41, Weiqing Kong wrote:
> >>> Use the mtk_pwm_data struction to define different registers
> >>> and add MT2701 specific register operations, such as MT2701
> >>> doesn't have commit register, needs to disable double buffer
> >>> before writing register, and needs to select manual mode
> >>> and use PWM_PERIOD/PWM_HIGH_WIDTH.
> >>>
> >>> Signed-off-by: Weiqing Kong <weiqing.kong@xxxxxxxxxxxx>
> >>> ---
> >>> drivers/pwm/pwm-mtk-disp.c | 89 +++++++++++++++++++++++++++++++++++++---------
> >>> 1 file changed, 72 insertions(+), 17 deletions(-)
> >>>
> >>> diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c
> >>> index 0ad3385..03b9c9e 100644
> >>> --- a/drivers/pwm/pwm-mtk-disp.c
> >>> +++ b/drivers/pwm/pwm-mtk-disp.c
> >>> @@ -18,33 +18,44 @@
> >>> #include <linux/io.h>
> >>> #include <linux/module.h>
> >>> #include <linux/of.h>
> >>> +#include <linux/of_device.h>
> >>> #include <linux/platform_device.h>
> >>> #include <linux/pwm.h>
> >>> #include <linux/slab.h>
> >>>
> >>> #define DISP_PWM_EN 0x00
> >>> -#define PWM_ENABLE_MASK BIT(0)
> >>>
> >>> #define DISP_PWM_COMMIT 0x08
> >>> #define PWM_COMMIT_MASK BIT(0)
> >>>
> >>> -#define DISP_PWM_CON_0 0x10
> >>> #define PWM_CLKDIV_SHIFT 16
> >>> #define PWM_CLKDIV_MAX 0x3ff
> >>> #define PWM_CLKDIV_MASK (PWM_CLKDIV_MAX << PWM_CLKDIV_SHIFT)
> >>>
> >>> -#define DISP_PWM_CON_1 0x14
> >>> #define PWM_PERIOD_BIT_WIDTH 12
> >>> #define PWM_PERIOD_MASK ((1 << PWM_PERIOD_BIT_WIDTH) - 1)
> >>>
> >>> #define PWM_HIGH_WIDTH_SHIFT 16
> >>> #define PWM_HIGH_WIDTH_MASK (0x1fff << PWM_HIGH_WIDTH_SHIFT)
> >>>
> >>> +#define MT2701_PWM_MANUAL_SEL_MASK BIT(1)
> >>> +#define MT2701_PWM_BLS_DEBUG 0xb0
> >>
> >> Do we need to set magic 0x3 in the debug register? If so, this should be
> >> part of mtk_pwm_data, just as con0_sel.
> >
> > Do you mean that add bls_debug into struct mtk_pwm_data,
> > and set 0x3 in mt2701 data, 0x0 in mt8173 data?
> >
>
> Yes.
>
> >>
> >>> +#define MT2701_PWM_BLS_DEBUG_MASK 0x3
> >>> +
> >>> +struct mtk_pwm_data {
> >>> + unsigned int enable_bit;
> >>> + unsigned int con0;
> >>> + unsigned int con0_sel;
> >>> + unsigned int con1;
> >>> + bool have_commit_reg;
> >>> +};
> >>> +
> >>> struct mtk_disp_pwm {
> >>> struct pwm_chip chip;
> >>> struct clk *clk_main;
> >>> struct clk *clk_mm;
> >>> void __iomem *base;
> >>> + const struct mtk_pwm_data *data;
> >>
> >> Couldn't that just be the offset for the commit register and set it to
> >> 0x0 if the commit register is not present. Right now, we suppose the
> >> DISP_PWM_EN is at offset 0x0, so this should not be a problem.
> >>
> >
> > Do you mean that replace have_commit_reg with commit_reg_offset?
> > just like this?
> > bool have_commit_reg;
> > ->
> > unsigned int commit_reg_offset;
> > and set commit_reg_offset 0x0 in mt2701, 0x1 in mt8173?
> >
>
> No, you can set comit_reg_offset to the value of DISP_PWM_COMMIT for
> mt8173 and 0x0 for mt2701. Then you can get rid of DISP_PWM_COMMIT.
>
> Regards,
> Matthias

ok, I got it, thanks.

>
> >>> };
> >>>
> >>> static inline struct mtk_disp_pwm *to_mtk_disp_pwm(struct pwm_chip *chip)
> >>> @@ -106,12 +117,18 @@ static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
> >>> return err;
> >>> }
> >>>
> >>> - mtk_disp_pwm_update_bits(mdp, DISP_PWM_CON_0, PWM_CLKDIV_MASK,
> >>> + mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
> >>> + PWM_CLKDIV_MASK,
> >>> clk_div << PWM_CLKDIV_SHIFT);
> >>> - mtk_disp_pwm_update_bits(mdp, DISP_PWM_CON_1,
> >>> - PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK, value);
> >>> - mtk_disp_pwm_update_bits(mdp, DISP_PWM_COMMIT, PWM_COMMIT_MASK, 1);
> >>> - mtk_disp_pwm_update_bits(mdp, DISP_PWM_COMMIT, PWM_COMMIT_MASK, 0);
> >>> + mtk_disp_pwm_update_bits(mdp, mdp->data->con1,
> >>> + PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK,
> >>> + value);
> >>> + if (mdp->data->have_commit_reg) {
> >>> + mtk_disp_pwm_update_bits(mdp, DISP_PWM_COMMIT,
> >>> + PWM_COMMIT_MASK, 0x1);
> >>> + mtk_disp_pwm_update_bits(mdp, DISP_PWM_COMMIT,
> >>> + PWM_COMMIT_MASK, 0x0);
> >>
> >> should be renamed to MT8173_PWM_COMMIT_MASK, although I'm not really a
> >> friend of mixing up SoC specific defines with a Soc specific
> >> mtk_disp_pwm structure.
> >>
> >> Regards,
> >> Matthias
> >
> > ok, I will modify it as you said. thanks for you suggestion.
> >
> >>
> >>> + }
> >>>
> >>> clk_disable(mdp->clk_mm);
> >>> clk_disable(mdp->clk_main);
> >>> @@ -134,7 +151,9 @@ static int mtk_disp_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
> >>> return err;
> >>> }
> >>>
> >>> - mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, PWM_ENABLE_MASK, 1);
> >>> + mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN,
> >>> + mdp->data->enable_bit,
> >>> + mdp->data->enable_bit);
> >>>
> >>> return 0;
> >>> }
> >>> @@ -143,7 +162,8 @@ static void mtk_disp_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
> >>> {
> >>> struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
> >>>
> >>> - mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, PWM_ENABLE_MASK, 0);
> >>> + mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN,
> >>> + mdp->data->enable_bit, 0x0);
> >>>
> >>> clk_disable(mdp->clk_mm);
> >>> clk_disable(mdp->clk_main);
> >>> @@ -156,12 +176,41 @@ static const struct pwm_ops mtk_disp_pwm_ops = {
> >>> .owner = THIS_MODULE,
> >>> };
> >>>
> >>> +static const struct mtk_pwm_data mt8173_pwm_data = {
> >>> + .enable_bit = BIT(0),
> >>> + .con0 = 0x10,
> >>> + .con0_sel = 0x0,
> >>> + .con1 = 0x14,
> >>> + .have_commit_reg = true,
> >>> +};
> >>> +
> >>> +static const struct mtk_pwm_data mt2701_pwm_data = {
> >>> + .enable_bit = BIT(16),
> >>> + .con0 = 0xa8,
> >>> + .con0_sel = 0x2,
> >>> + .con1 = 0xac,
> >>> + .have_commit_reg = false,
> >>> +};
> >>> +
> >>> +static const struct of_device_id mtk_disp_pwm_of_match[] = {
> >>> + { .compatible = "mediatek,mt2701-disp-bls", .data = &mt2701_pwm_data},
> >>> + { .compatible = "mediatek,mt6595-disp-pwm", .data = &mt8173_pwm_data},
> >>> + { .compatible = "mediatek,mt8173-disp-pwm", .data = &mt8173_pwm_data},
> >>> + { }
> >>> +};
> >>> +MODULE_DEVICE_TABLE(of, mtk_disp_pwm_of_match);
> >>> +
> >>> static int mtk_disp_pwm_probe(struct platform_device *pdev)
> >>> {
> >>> + const struct of_device_id *id;
> >>> struct mtk_disp_pwm *mdp;
> >>> struct resource *r;
> >>> int ret;
> >>>
> >>> + id = of_match_device(mtk_disp_pwm_of_match, &pdev->dev);
> >>> + if (!id)
> >>> + return -EINVAL;
> >>> +
> >>> mdp = devm_kzalloc(&pdev->dev, sizeof(*mdp), GFP_KERNEL);
> >>> if (!mdp)
> >>> return -ENOMEM;
> >>> @@ -191,6 +240,7 @@ static int mtk_disp_pwm_probe(struct platform_device *pdev)
> >>> mdp->chip.ops = &mtk_disp_pwm_ops;
> >>> mdp->chip.base = -1;
> >>> mdp->chip.npwm = 1;
> >>> + mdp->data = id->data;
> >>>
> >>> ret = pwmchip_add(&mdp->chip);
> >>> if (ret < 0) {
> >>> @@ -200,6 +250,18 @@ static int mtk_disp_pwm_probe(struct platform_device *pdev)
> >>>
> >>> platform_set_drvdata(pdev, mdp);
> >>>
> >>> + /*
> >>> + * For MT2701, disable double buffer before writing register
> >>> + * and select manual mode and use PWM_PERIOD/PWM_HIGH_WIDTH.
> >>> + */
> >>> + if (!mdp->data->have_commit_reg) {
> >>> + mtk_disp_pwm_update_bits(mdp, MT2701_PWM_BLS_DEBUG,
> >>> + MT2701_PWM_BLS_DEBUG_MASK, 0x3);
> >>> + mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
> >>> + MT2701_PWM_MANUAL_SEL_MASK,
> >>> + mdp->data->con0_sel);
> >>> + }
> >>> +
> >>> return 0;
> >>>
> >>> disable_clk_mm:
> >>> @@ -221,13 +283,6 @@ static int mtk_disp_pwm_remove(struct platform_device *pdev)
> >>> return ret;
> >>> }
> >>>
> >>> -static const struct of_device_id mtk_disp_pwm_of_match[] = {
> >>> - { .compatible = "mediatek,mt8173-disp-pwm" },
> >>> - { .compatible = "mediatek,mt6595-disp-pwm" },
> >>> - { }
> >>> -};
> >>> -MODULE_DEVICE_TABLE(of, mtk_disp_pwm_of_match);
> >>> -
> >>> static struct platform_driver mtk_disp_pwm_driver = {
> >>> .driver = {
> >>> .name = "mediatek-disp-pwm",
> >>>
> >
> >