Re: [PATCH v3 04/11] pwm: imx: Rewrite imx_pwm_*_v1 code to facilitate switch to atomic pwm operation

Stefan Agner
2016-11-22T21:37:54Z

On 2016-11-01 00:10, Lukasz Majewski wrote:
> The code has been rewritten to remove "generic" calls to
> imx_pwm_{enable|disable|config}.
>
> Such approach would facilitate switch to atomic PWM (a.k.a ->apply())
> implementation.
>
> Suggested-by: Stefan Agner <stefan@agner.ch>
> Suggested-by: Boris Brezillon <boris.brezillon@free-electrons.com>
> Signed-off-by: Lukasz Majewski <l.majewski@majess.pl>
> ---
> Changes for v3:
> - Remove ipg clock
>
> Changes for v2:
> - Add missing clock unprepare for clk_ipg
> - Enable peripheral PWM clock (clk_per)
> ---
> drivers/pwm/pwm-imx.c | 36 ++++++++++++++++++++++++------------
> 1 file changed, 24 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/pwm/pwm-imx.c b/drivers/pwm/pwm-imx.c
> index d594501..8497902 100644
> --- a/drivers/pwm/pwm-imx.c
> +++ b/drivers/pwm/pwm-imx.c
> @@ -64,8 +64,6 @@ struct imx_chip {
> static int imx_pwm_config_v1(struct pwm_chip *chip,
> struct pwm_device *pwm, int duty_ns, int period_ns)
> {
> - struct imx_chip *imx = to_imx_chip(chip);
> -
> /*
> * The PWM subsystem allows for exact frequencies. However,
> * I cannot connect a scope on my device to the PWM line and
> @@ -83,6 +81,7 @@ static int imx_pwm_config_v1(struct pwm_chip *chip,
> * both the prescaler (/1 .. /128) and then by CLKSEL
> * (/2 .. /16).
> */
> + struct imx_chip *imx = to_imx_chip(chip);

This change is unnecessary.

It is also common to have declarations at the beginning of the function
and separated with a newline from code.

But otherwise looks good to me:

Reviewed-by: Stefan Agner <stefan@agner.ch>

--
Stefan

> u32 max = readl(imx->mmio_base + MX1_PWMP);
> u32 p = max * duty_ns / period_ns;
> writel(max - p, imx->mmio_base + MX1_PWMS);
> @@ -90,19 +89,34 @@ static int imx_pwm_config_v1(struct pwm_chip *chip,
> return 0;
> }
>
> -static void imx_pwm_set_enable_v1(struct pwm_chip *chip, bool enable)
> +static int imx_pwm_enable_v1(struct pwm_chip *chip, struct pwm_device *pwm)
> {
> struct imx_chip *imx = to_imx_chip(chip);
> + int ret;
> u32 val;
>
> + ret = clk_prepare_enable(imx->clk_per);
> + if (ret)
> + return ret;
> +
> val = readl(imx->mmio_base + MX1_PWMC);
> + val |= MX1_PWMC_EN;
> + writel(val, imx->mmio_base + MX1_PWMC);
>
> - if (enable)
> - val |= MX1_PWMC_EN;
> - else
> - val &= ~MX1_PWMC_EN;
> + return 0;
> +}
> +
> +static void imx_pwm_disable_v1(struct pwm_chip *chip, struct pwm_device *pwm)
> +{
> + struct imx_chip *imx = to_imx_chip(chip);
> + u32 val;
> +
> + val = readl(imx->mmio_base + MX1_PWMC);
> + val &= ~MX1_PWMC_EN;
>
> writel(val, imx->mmio_base + MX1_PWMC);
> +
> + clk_disable_unprepare(imx->clk_per);
> }
>
> static int imx_pwm_config_v2(struct pwm_chip *chip,
> @@ -231,9 +245,9 @@ static void imx_pwm_disable(struct pwm_chip *chip,
> struct pwm_device *pwm)
> }
>
> static struct pwm_ops imx_pwm_ops_v1 = {
> - .enable = imx_pwm_enable,
> - .disable = imx_pwm_disable,
> - .config = imx_pwm_config,
> + .enable = imx_pwm_enable_v1,
> + .disable = imx_pwm_disable_v1,
> + .config = imx_pwm_config_v1,
> .owner = THIS_MODULE,
> };
>
> @@ -252,8 +266,6 @@ struct imx_pwm_data {
> };
>
> static struct imx_pwm_data imx_pwm_data_v1 = {
> - .config = imx_pwm_config_v1,
> - .set_enable = imx_pwm_set_enable_v1,
> .pwm_ops = &imx_pwm_ops_v1,
> };