linux-kernel - Re: [PATCH v2 2/3] pwm: imx27: Add 32k clock for pwm in i.MX8QXP MIPI subsystem

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Message-ID: <4cdcfde7-1b79-411d-9a1b-131105b113ab@wanadoo.fr>
Date: Tue, 16 Jul 2024 20:49:04 +0200
From: Christophe JAILLET <christophe.jaillet@...adoo.fr>
To: Frank Li <Frank.Li@....com>
Cc: conor+dt@...nel.org, devicetree@...r.kernel.org, festevam@...il.com,
 francesco@...cini.it, imx@...ts.linux.dev, kernel@...gutronix.de,
 krzk+dt@...nel.org, linux-arm-kernel@...ts.infradead.org,
 linux-kernel@...r.kernel.org, linux-pwm@...r.kernel.org,
 p.zabel@...gutronix.de, pratikmanvar09@...il.com, robh@...nel.org,
 s.hauer@...gutronix.de, shawnguo@...nel.org, ukleinek@...nel.org,
 victor.liu@....com
Subject: Re: [PATCH v2 2/3] pwm: imx27: Add 32k clock for pwm in i.MX8QXP MIPI
 subsystem

Le 15/07/2024 à 22:29, Frank Li a écrit :
> From: Liu Ying <victor.liu-3arQi8VN3Tc@...lic.gmane.org>
> 
> PWM in i.MX8QXP MIPI subsystem needs the clock '32k'. Use it if the DTS
> provides that.
> 
> Signed-off-by: Liu Ying <victor.liu-3arQi8VN3Tc@...lic.gmane.org>
> Signed-off-by: Frank Li <Frank.Li-3arQi8VN3Tc@...lic.gmane.org>
> ---
> Change from v1 to v2
> - remove if check for clk
> - use dev_err_probe
> - remove int val

Hi,

maybe, switching to clk_bulk_get_all() and the clk_bulk API would 
simplify the code?

See [1] for a similar discussion related to devicetrees and binding if 
such a change is done.
I'm not familiar with it, so I just point it out.

Just my 2c.

CJ

[1]: 
https://lore.kernel.org/all/65b422fe-ecc1-4f57-bb72-f2fef3a5af28@collabora.com/

> ---
>   drivers/pwm/pwm-imx27.c | 26 +++++++++++++++++++++-----
>   1 file changed, 21 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/pwm/pwm-imx27.c b/drivers/pwm/pwm-imx27.c
> index 9e2bbf5b4a8ce..253afe94c4776 100644
> --- a/drivers/pwm/pwm-imx27.c
> +++ b/drivers/pwm/pwm-imx27.c
> @@ -15,6 +15,7 @@
>   #include <linux/delay.h>
>   #include <linux/err.h>
>   #include <linux/io.h>
> +#include <linux/iopoll.h>
>   #include <linux/kernel.h>
>   #include <linux/module.h>
>   #include <linux/of.h>
> @@ -82,6 +83,7 @@
>   struct pwm_imx27_chip {
>   	struct clk	*clk_ipg;
>   	struct clk	*clk_per;
> +	struct clk	*clk_32k;
>   	void __iomem	*mmio_base;
>   
>   	/*
> @@ -101,23 +103,32 @@ static int pwm_imx27_clk_prepare_enable(struct pwm_imx27_chip *imx)
>   {
>   	int ret;
>   
> +	ret = clk_prepare_enable(imx->clk_32k);
> +	if (ret)
> +		goto err1;
> +
>   	ret = clk_prepare_enable(imx->clk_ipg);
>   	if (ret)
> -		return ret;
> +		goto err2;
>   
>   	ret = clk_prepare_enable(imx->clk_per);
> -	if (ret) {
> -		clk_disable_unprepare(imx->clk_ipg);
> -		return ret;
> -	}
> +	if (ret)
> +		goto err3;
>   
>   	return 0;
> +err3:
> +	clk_disable_unprepare(imx->clk_ipg);
> +err2:
> +	clk_disable_unprepare(imx->clk_32k);
> +err1:
> +	return ret;
>   }
>   
>   static void pwm_imx27_clk_disable_unprepare(struct pwm_imx27_chip *imx)
>   {
>   	clk_disable_unprepare(imx->clk_per);
>   	clk_disable_unprepare(imx->clk_ipg);
> +	clk_disable_unprepare(imx->clk_32k);
>   }
>   
>   static int pwm_imx27_get_state(struct pwm_chip *chip,
> @@ -325,6 +336,11 @@ static int pwm_imx27_probe(struct platform_device *pdev)
>   		return dev_err_probe(&pdev->dev, PTR_ERR(imx->clk_per),
>   				     "failed to get peripheral clock\n");
>   
> +	imx->clk_32k = devm_clk_get_optional(&pdev->dev, "32k");
> +	if (IS_ERR(imx->clk_32k))
> +		return dev_err_probe(&pdev->dev, PTR_ERR(imx->clk_32k),
> +				     "failed to get 32k clock\n");
> +
>   	chip->ops = &pwm_imx27_ops;
>   
>   	imx->mmio_base = devm_platform_ioremap_resource(pdev, 0);
>