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

[weiqing kong <weiqing.kong-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>]

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-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
> > ---
> >   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?

> 
> > +#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?

> >   };
> >
> >   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",
> >


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