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Date: Mon, 21 Feb 2022 10:15:47 +0100
From: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
To: AngeloGioacchino Del Regno
<angelogioacchino.delregno@...labora.com>
Cc: thierry.reding@...il.com, lee.jones@...aro.org,
matthias.bgg@...il.com, linux-pwm@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] pwm: pwm-mtk-disp: Switch to regmap for mmio access
On Mon, Jan 03, 2022 at 04:35:06PM +0100, AngeloGioacchino Del Regno wrote:
> Switch to using the generic regmap API instead of calls to readl/writel
> for MMIO register access, allowing us to reduce code size.
>
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
> ---
> drivers/pwm/pwm-mtk-disp.c | 77 ++++++++++++++++----------------------
> 1 file changed, 32 insertions(+), 45 deletions(-)
>
> diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c
> index c605013e4114..4a6fab144cee 100644
> --- a/drivers/pwm/pwm-mtk-disp.c
> +++ b/drivers/pwm/pwm-mtk-disp.c
> @@ -14,6 +14,7 @@
> #include <linux/of_device.h>
> #include <linux/platform_device.h>
> #include <linux/pwm.h>
> +#include <linux/regmap.h>
> #include <linux/slab.h>
>
> #define DISP_PWM_EN 0x00
> @@ -47,7 +48,7 @@ struct mtk_disp_pwm {
> const struct mtk_pwm_data *data;
> struct clk *clk_main;
> struct clk *clk_mm;
> - void __iomem *base;
> + struct regmap *regmap;
> bool enabled;
> };
>
> @@ -56,22 +57,11 @@ static inline struct mtk_disp_pwm *to_mtk_disp_pwm(struct pwm_chip *chip)
> return container_of(chip, struct mtk_disp_pwm, chip);
> }
>
> -static void mtk_disp_pwm_update_bits(struct mtk_disp_pwm *mdp, u32 offset,
> - u32 mask, u32 data)
> -{
> - void __iomem *address = mdp->base + offset;
> - u32 value;
> -
> - value = readl(address);
> - value &= ~mask;
> - value |= data;
> - writel(value, address);
> -}
> -
> static int mtk_disp_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> const struct pwm_state *state)
> {
> struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
> + const struct mtk_pwm_data *pdata = mdp->data;
> u32 clk_div, period, high_width, value;
> u64 div, rate;
> int err;
> @@ -80,8 +70,7 @@ static int mtk_disp_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> return -EINVAL;
>
> if (!state->enabled) {
> - mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, mdp->data->enable_mask,
> - 0x0);
> + regmap_clear_bits(mdp->regmap, DISP_PWM_EN, pdata->enable_mask);
>
> if (mdp->enabled) {
> clk_disable_unprepare(mdp->clk_mm);
> @@ -138,37 +127,25 @@ static int mtk_disp_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> high_width = mul_u64_u64_div_u64(state->duty_cycle, rate, div);
> value = period | (high_width << PWM_HIGH_WIDTH_SHIFT);
>
> - mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
> - PWM_CLKDIV_MASK,
> - clk_div << PWM_CLKDIV_SHIFT);
> - mtk_disp_pwm_update_bits(mdp, mdp->data->con1,
> - PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK,
> - value);
> + regmap_update_bits(mdp->regmap, pdata->con0, PWM_CLKDIV_MASK,
> + clk_div << PWM_CLKDIV_SHIFT);
> + regmap_update_bits(mdp->regmap, pdata->con1,
> + PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK, value);
>
> if (mdp->data->has_commit) {
> - mtk_disp_pwm_update_bits(mdp, mdp->data->commit,
> - mdp->data->commit_mask,
> - mdp->data->commit_mask);
> - mtk_disp_pwm_update_bits(mdp, mdp->data->commit,
> - mdp->data->commit_mask,
> - 0x0);
> + regmap_set_bits(mdp->regmap, pdata->commit, pdata->commit_mask);
> + regmap_clear_bits(mdp->regmap, pdata->commit, pdata->commit_mask);
> } else {
> /*
> * For MT2701, disable double buffer before writing register
> * and select manual mode and use PWM_PERIOD/PWM_HIGH_WIDTH.
> */
> - mtk_disp_pwm_update_bits(mdp, mdp->data->bls_debug,
> - mdp->data->bls_debug_mask,
> - mdp->data->bls_debug_mask);
> - mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
> - mdp->data->con0_sel,
> - mdp->data->con0_sel);
> + regmap_set_bits(mdp->regmap, pdata->bls_debug, pdata->bls_debug_mask);
> + regmap_set_bits(mdp->regmap, pdata->con0, pdata->con0_sel);
> }
>
> - mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, mdp->data->enable_mask,
> - mdp->data->enable_mask);
> + regmap_set_bits(mdp->regmap, DISP_PWM_EN, pdata->enable_mask);
> mdp->enabled = true;
> -
Was the empty line here removed on purpose? I would have kept it.
> return 0;
> }
>
> @@ -195,8 +172,8 @@ static void mtk_disp_pwm_get_state(struct pwm_chip *chip,
> }
>
> rate = clk_get_rate(mdp->clk_main);
> - con0 = readl(mdp->base + mdp->data->con0);
> - con1 = readl(mdp->base + mdp->data->con1);
> + regmap_read(mdp->regmap, mdp->data->con0, &con0);
> + regmap_read(mdp->regmap, mdp->data->con1, &con1);
> state->enabled = !!(con0 & BIT(0));
> clk_div = FIELD_GET(PWM_CLKDIV_MASK, con0);
> period = FIELD_GET(PWM_PERIOD_MASK, con1);
> @@ -219,9 +196,17 @@ static const struct pwm_ops mtk_disp_pwm_ops = {
> .owner = THIS_MODULE,
> };
>
> +static const struct regmap_config mtk_disp_pwm_regmap_config = {
> + .reg_bits = 32,
> + .reg_stride = 4,
> + .val_bits = 32,
> + .disable_locking = true,
> +};
> +
> static int mtk_disp_pwm_probe(struct platform_device *pdev)
> {
> struct mtk_disp_pwm *mdp;
> + void __iomem *base;
> int ret;
>
> mdp = devm_kzalloc(&pdev->dev, sizeof(*mdp), GFP_KERNEL);
> @@ -230,9 +215,13 @@ static int mtk_disp_pwm_probe(struct platform_device *pdev)
>
> mdp->data = of_device_get_match_data(&pdev->dev);
>
> - mdp->base = devm_platform_ioremap_resource(pdev, 0);
> - if (IS_ERR(mdp->base))
> - return PTR_ERR(mdp->base);
> + base = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(base))
> + return PTR_ERR(base);
> +
> + mdp->regmap = devm_regmap_init_mmio(&pdev->dev, base, &mtk_disp_pwm_regmap_config);
> + if (IS_ERR(mdp->regmap))
> + return PTR_ERR(mdp->regmap);
>
> mdp->clk_main = devm_clk_get(&pdev->dev, "main");
> if (IS_ERR(mdp->clk_main))
> @@ -247,10 +236,8 @@ static int mtk_disp_pwm_probe(struct platform_device *pdev)
> mdp->chip.npwm = 1;
>
> ret = pwmchip_add(&mdp->chip);
> - if (ret < 0) {
> - dev_err(&pdev->dev, "pwmchip_add() failed: %pe\n", ERR_PTR(ret));
> - return ret;
> - }
> + if (ret < 0)
> + return dev_err_probe(&pdev->dev, ret, "pwmchip_add() failed\n");
I wonder that you convert this to dev_err_probe, but don't use it in the
hunk above. If I'm not mistaken devm_regmap_init_mmio doesn't emit an
error message, so an error message would be appropriate there.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
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