linux-kernel - Re: [PATCH RESEND v9 3/8] drm: atmel_hlcdc: replace regmap_read with regmap_read_poll

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Message-ID: <287606ef-ef90-456f-9190-bb1168b266f2@microchip.com>
Date: Thu, 25 Apr 2024 04:41:12 +0000
From: <Dharma.B@...rochip.com>
To: <Manikandan.M@...rochip.com>, <sam@...nborg.org>, <bbrezillon@...nel.org>,
	<maarten.lankhorst@...ux.intel.com>, <mripard@...nel.org>,
	<tzimmermann@...e.de>, <airlied@...il.com>, <daniel@...ll.ch>,
	<Nicolas.Ferre@...rochip.com>, <alexandre.belloni@...tlin.com>,
	<claudiu.beznea@...on.dev>, <lee@...nel.org>,
	<dri-devel@...ts.freedesktop.org>, <linux-arm-kernel@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>
CC: <Hari.PrasathGE@...rochip.com>, <Balamanikandan.Gunasundar@...rochip.com>,
	<Durai.ManickamKR@...rochip.com>, <Nayabbasha.Sayed@...rochip.com>,
	<Varshini.Rajendran@...rochip.com>, <Balakrishnan.S@...rochip.com>,
	<Charan.Pedumuru@...rochip.com>
Subject: Re: [PATCH RESEND v9 3/8] drm: atmel_hlcdc: replace regmap_read with
 regmap_read_poll_timeout

On 24/04/24 11:03 am, Manikandan Muralidharan wrote:
> Replace regmap_read with regmap_read_poll_timeout to neatly handle
> retries
> 
> Signed-off-by: Manikandan Muralidharan <manikandan.m@...rochip.com>

Acked-by: Dharma Balasubiramani <dharma.b@...rochip.com>

> ---
>   .../gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c    | 44 +++++++++++--------
>   1 file changed, 25 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
> index cc5cf4c2faf7..b229692a27ca 100644
> --- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
> +++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
> @@ -203,19 +203,22 @@ static void atmel_hlcdc_crtc_atomic_disable(struct drm_crtc *c,
>   	pm_runtime_get_sync(dev->dev);
>   
>   	regmap_write(regmap, ATMEL_HLCDC_DIS, ATMEL_HLCDC_DISP);
> -	while (!regmap_read(regmap, ATMEL_HLCDC_SR, &status) &&
> -	       (status & ATMEL_HLCDC_DISP))
> -		cpu_relax();
> +	if (regmap_read_poll_timeout(regmap, ATMEL_HLCDC_SR, status,
> +				     !(status & ATMEL_HLCDC_DISP),
> +				    10, 1000))
> +		dev_warn(dev->dev, "Atmel LCDC status register DISPSTS timeout\n");
>   
>   	regmap_write(regmap, ATMEL_HLCDC_DIS, ATMEL_HLCDC_SYNC);
> -	while (!regmap_read(regmap, ATMEL_HLCDC_SR, &status) &&
> -	       (status & ATMEL_HLCDC_SYNC))
> -		cpu_relax();
> +	if (regmap_read_poll_timeout(regmap, ATMEL_HLCDC_SR, status,
> +				     !(status & ATMEL_HLCDC_SYNC),
> +				    10, 1000))
> +		dev_warn(dev->dev, "Atmel LCDC status register LCDSTS timeout\n");
>   
>   	regmap_write(regmap, ATMEL_HLCDC_DIS, ATMEL_HLCDC_PIXEL_CLK);
> -	while (!regmap_read(regmap, ATMEL_HLCDC_SR, &status) &&
> -	       (status & ATMEL_HLCDC_PIXEL_CLK))
> -		cpu_relax();
> +	if (regmap_read_poll_timeout(regmap, ATMEL_HLCDC_SR, status,
> +				     !(status & ATMEL_HLCDC_PIXEL_CLK),
> +				    10, 1000))
> +		dev_warn(dev->dev, "Atmel LCDC status register CLKSTS timeout\n");
>   
>   	clk_disable_unprepare(crtc->dc->hlcdc->sys_clk);
>   	pinctrl_pm_select_sleep_state(dev->dev);
> @@ -241,20 +244,23 @@ static void atmel_hlcdc_crtc_atomic_enable(struct drm_crtc *c,
>   	clk_prepare_enable(crtc->dc->hlcdc->sys_clk);
>   
>   	regmap_write(regmap, ATMEL_HLCDC_EN, ATMEL_HLCDC_PIXEL_CLK);
> -	while (!regmap_read(regmap, ATMEL_HLCDC_SR, &status) &&
> -	       !(status & ATMEL_HLCDC_PIXEL_CLK))
> -		cpu_relax();
> -
> +	if (regmap_read_poll_timeout(regmap, ATMEL_HLCDC_SR, status,
> +				     status & ATMEL_HLCDC_PIXEL_CLK,
> +				     10, 1000))
> +		dev_warn(dev->dev, "Atmel LCDC status register CLKSTS timeout\n");
>   
>   	regmap_write(regmap, ATMEL_HLCDC_EN, ATMEL_HLCDC_SYNC);
> -	while (!regmap_read(regmap, ATMEL_HLCDC_SR, &status) &&
> -	       !(status & ATMEL_HLCDC_SYNC))
> -		cpu_relax();
> +	if (regmap_read_poll_timeout(regmap, ATMEL_HLCDC_SR, status,
> +				     status & ATMEL_HLCDC_SYNC,
> +				     10, 1000))
> +		dev_warn(dev->dev, "Atmel LCDC status register LCDSTS timeout\n");
>   
>   	regmap_write(regmap, ATMEL_HLCDC_EN, ATMEL_HLCDC_DISP);
> -	while (!regmap_read(regmap, ATMEL_HLCDC_SR, &status) &&
> -	       !(status & ATMEL_HLCDC_DISP))
> -		cpu_relax();
> +	if (regmap_read_poll_timeout(regmap, ATMEL_HLCDC_SR, status,
> +				     status & ATMEL_HLCDC_DISP,
> +				     10, 1000))
> +		dev_warn(dev->dev, "Atmel LCDC status register DISPSTS timeout\n");
> +
>   
>   	pm_runtime_put_sync(dev->dev);
>   

-- 
With Best Regards,
Dharma B.