Re: [PATCH -next v2] I2C: Fix return value check for devm_pinctrl_get()

[Ruan Jinjie <ruanjinjie@huawei.com>]

On 2023/8/18 1:30, Leo Li wrote:
> 
> 
>> -----Original Message-----
>> From: Ruan Jinjie <ruanjinjie@huawei.com>
>> Sent: Wednesday, August 16, 2023 9:20 PM
>> To: linux-i2c@vger.kernel.org; linux-arm-kernel@lists.infradead.org; Codrin
>> Ciubotariu <codrin.ciubotariu@microchip.com>; Andi Shyti
>> <andi.shyti@kernel.org>; Nicolas Ferre <nicolas.ferre@microchip.com>;
>> Alexandre Belloni <alexandre.belloni@bootlin.com>; Claudiu Beznea
>> <claudiu.beznea@tuxon.dev>; Oleksij Rempel <linux@rempel-privat.de>;
>> Pengutronix Kernel Team <kernel@pengutronix.de>; Shawn Guo
>> <shawnguo@kernel.org>; Sascha Hauer <s.hauer@pengutronix.de>; Fabio
>> Estevam <festevam@gmail.com>; dl-linux-imx <linux-imx@nxp.com>;
>> Wolfram Sang <wsa@kernel.org>; Linus Walleij <linus.walleij@linaro.org>;
>> Uwe Kleine-König <u.kleine-koenig@pengutronix.de>; Leo Li
>> <leoyang.li@nxp.com>
>> Cc: ruanjinjie@huawei.com
>> Subject: [PATCH -next v2] I2C: Fix return value check for devm_pinctrl_get()
>>
>> The devm_pinctrl_get() function returns error pointers and never returns
>> NULL. Update the checks accordingly.
> 
> Not exactly.  It can return NULL when CONFIG_PINCTRL is not defined.  We probably should fix that API too.
> 
> include/linux/pinctrl/consumer.h:
> static inline struct pinctrl * __must_check devm_pinctrl_get(struct device *dev)
> {
>         return NULL;
> }

As ARCH_AT91 select PINCTRL and I2C_AT91 depends on ARCH_AT91, it can
not be NULL except for I2C_AT91  is selected by COMPILE_TEST.

And ARCH_MXC select PINCTRL and I2C_IMX depends on ARCH_MXC it can not
be NULL except for I2C_IMX is selected by ARCH_LAYERSCAPE or COLDFIRE or
COMPILE_TEST.

In general, it is possible to be null.

> 
> Regards,
> Leo
>>
>> Fixes: 543aa2c4da8b ("i2c: at91: Move to generic GPIO bus recovery")
>> Fixes: fd8961c5ba9e ("i2c: imx: make bus recovery through pinctrl optional")
>> Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com>
>> ---
>> v2:
>> - Remove NULL check instead of using IS_ERR_OR_NULL() to avoid leaving
>> them behind.
>> - Update the commit title and message.
>> ---
>>  drivers/i2c/busses/i2c-at91-master.c | 2 +-
>>  drivers/i2c/busses/i2c-imx.c         | 2 +-
>>  2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/i2c/busses/i2c-at91-master.c b/drivers/i2c/busses/i2c-
>> at91-master.c
>> index 94cff1cd527e..2bf1df5ef473 100644
>> --- a/drivers/i2c/busses/i2c-at91-master.c
>> +++ b/drivers/i2c/busses/i2c-at91-master.c
>> @@ -831,7 +831,7 @@ static int at91_init_twi_recovery_gpio(struct
>> platform_device *pdev,
>>  	struct i2c_bus_recovery_info *rinfo = &dev->rinfo;
>>
>>  	rinfo->pinctrl = devm_pinctrl_get(&pdev->dev);
>> -	if (!rinfo->pinctrl || IS_ERR(rinfo->pinctrl)) {
>> +	if (IS_ERR(rinfo->pinctrl)) {
>>  		dev_info(dev->dev, "can't get pinctrl, bus recovery not
>> supported\n");
>>  		return PTR_ERR(rinfo->pinctrl);
>>  	}
>> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c index
>> 10e89586ca72..05d55893f04e 100644
>> --- a/drivers/i2c/busses/i2c-imx.c
>> +++ b/drivers/i2c/busses/i2c-imx.c
>> @@ -1388,7 +1388,7 @@ static int i2c_imx_init_recovery_info(struct
>> imx_i2c_struct *i2c_imx,
>>  	struct i2c_bus_recovery_info *rinfo = &i2c_imx->rinfo;
>>
>>  	i2c_imx->pinctrl = devm_pinctrl_get(&pdev->dev);
>> -	if (!i2c_imx->pinctrl || IS_ERR(i2c_imx->pinctrl)) {
>> +	if (IS_ERR(i2c_imx->pinctrl)) {
>>  		dev_info(&pdev->dev, "can't get pinctrl, bus recovery not
>> supported\n");
>>  		return PTR_ERR(i2c_imx->pinctrl);
>>  	}
>> --
>> 2.34.1
>