linux-kernel - Re: [PATCH] phy: samsung: Use readl_poll

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Date:   Fri, 3 Jul 2020 18:43:49 +0200
From:   Krzysztof Kozlowski <krzk@...nel.org>
To:     Anand Moon <linux.amoon@...il.com>
Cc:     linux-arm-kernel@...ts.infradead.org,
        linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
        Kishon Vijay Abraham I <kishon@...com>,
        Vinod Koul <vkoul@...nel.org>, Kukjin Kim <kgene@...nel.org>,
        Marek Szyprowski <m.szyprowski@...sung.com>
Subject: Re: [PATCH] phy: samsung: Use readl_poll_timeout function

On Fri, Jul 03, 2020 at 01:20:12PM +0000, Anand Moon wrote:
> User readl_poll_timeout function instead of open
> coded handling in crport_handshake function.
> 
> Signed-off-by: Anand Moon <linux.amoon@...il.com>
> ---
>  drivers/phy/samsung/phy-exynos5-usbdrd.c | 37 +++++++++---------------
>  1 file changed, 13 insertions(+), 24 deletions(-)
> 
> diff --git a/drivers/phy/samsung/phy-exynos5-usbdrd.c b/drivers/phy/samsung/phy-exynos5-usbdrd.c
> index e510732afb8b..83274c5e3820 100644
> --- a/drivers/phy/samsung/phy-exynos5-usbdrd.c
> +++ b/drivers/phy/samsung/phy-exynos5-usbdrd.c
> @@ -16,6 +16,7 @@
>  #include <linux/of.h>
>  #include <linux/of_address.h>
>  #include <linux/of_device.h>
> +#include <linux/iopoll.h>
>  #include <linux/phy/phy.h>
>  #include <linux/platform_device.h>
>  #include <linux/mutex.h>
> @@ -556,40 +557,28 @@ static int exynos5_usbdrd_phy_power_off(struct phy *phy)
>  static int crport_handshake(struct exynos5_usbdrd_phy *phy_drd,
>  			    u32 val, u32 cmd)
>  {
> -	u32 usec = 100;
> +	u32 timeout_us = 1000, sleep_us = 10;
>  	unsigned int result;

You silently (without mentioning in commit msg and explaining why)
changed both the sleep time and total timeout.

Nope, please explain why you chosen such values and change them in
separate patch.

> +	int err;
>  
>  	writel(val | cmd, phy_drd->reg_phy + EXYNOS5_DRD_PHYREG0);
>  
> -	do {
> -		result = readl(phy_drd->reg_phy + EXYNOS5_DRD_PHYREG1);
> -		if (result & PHYREG1_CR_ACK)
> -			break;
> -
> -		udelay(1);
> -	} while (usec-- > 0);
> -
> -	if (!usec) {
> -		dev_err(phy_drd->dev,
> -			"CRPORT handshake timeout1 (0x%08x)\n", val);
> +	err = readl_poll_timeout(phy_drd->reg_phy + EXYNOS5_DRD_PHYREG1,
> +			result,	(result & PHYREG1_CR_ACK), sleep_us, timeout_us);
> +	if (err) {
> +		dev_err(phy_drd->dev, "CRPORT handshake timeout1 (0x%08x)\n", val);
>  		return -ETIME;
>  	}
>  
> -	usec = 100;
> +	timeout_us = 1000;
> +	sleep_us = 10;

The same.

Best regards,
Krzysztof