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Message-ID: <5758000F.7050503@gmail.com>
Date: Wed, 8 Jun 2016 13:22:55 +0200
From: Matthias Brugger <matthias.bgg@...il.com>
To: weiqing kong <weiqing.kong@...iatek.com>
Cc: Thierry Reding <thierry.reding@...il.com>,
Mark Rutland <mark.rutland@....com>,
Rob Herring <robh+dt@...nel.org>,
Pawel Moll <pawel.moll@....com>,
Ian Campbell <ijc+devicetree@...lion.org.uk>,
Kumar Gala <galak@...eaurora.org>,
Russell King <linux@....linux.org.uk>,
linux-pwm@...r.kernel.org, devicetree@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org,
srv_heupstream@...iatek.com, Sascha Hauer <kernel@...gutronix.de>,
erin.lo@...iatek.com, yingjoe.chen@...iatek.com,
eddie.huang@...iatek.com, yh.huang@...iatek.com,
yt.shen@...iatek.com
Subject: Re: [PATCH 2/3] pwm: Add MediaTek MT2701 display PWM driver support
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@...iatek.com>
>>> ---
>>> 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
>>> };
>>>
>>> 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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