Message ID | 20170806234953.30682-1-christophe.jaillet@wanadoo.fr |
---|---|
State | Changes Requested |
Headers | show |
On Mon, Aug 07, 2017 at 01:49:53AM +0200, Christophe JAILLET wrote: > 'devm_pinctrl_get()' never returns NULL, so this test can be simplified. That's wrong. If CONFIG_PINCTRL is disabled devm_pinctrl_get returns NULL. But I think this shouldn't be considered an error, so your change is right, just the commit log is not. > diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c > index 54a47b40546f..7e84662fe1c0 100644 > --- a/drivers/i2c/busses/i2c-imx.c > +++ b/drivers/i2c/busses/i2c-imx.c > @@ -997,7 +997,7 @@ 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); > } Side note: I'm not sure, this construct is valid. IIRC PTR_ERR should only be called for values x where IS_ERR(x) is true. Here it is at least surprising that an message hints to a problem but the return code is 0. @Julia: I'm sure coccinelle can find more of those?! Best regards Uwe
Le 07/08/2017 à 08:36, Uwe Kleine-König a écrit : > On Mon, Aug 07, 2017 at 01:49:53AM +0200, Christophe JAILLET wrote: >> 'devm_pinctrl_get()' never returns NULL, so this test can be simplified. > That's wrong. If CONFIG_PINCTRL is disabled devm_pinctrl_get returns > NULL. But I think this shouldn't be considered an error, so your change > is right, just the commit log is not. With that said, in fact, I think that the test is correct as is. If CONFIG_PINCTRL is disabled, we will display an info about a missing functionality, but would still continue normally without it (i.e. return PTR_ERR(NULL) = 0 = success), as stated in the comment in front of 'i2c_imx_init_recovery_info': "These alternative pinmux settings can be described in the device tree by a separate pinctrl state "gpio". If this is missing this is not a big problem, the only implication is that we can't do bus recovery." So, I won't propose any v2 patch with an updated commit log. Feel free to update it yourself and apply it if you don't share my analysis above. Sorry for the noise. CJ > >> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c >> index 54a47b40546f..7e84662fe1c0 100644 >> --- a/drivers/i2c/busses/i2c-imx.c >> +++ b/drivers/i2c/busses/i2c-imx.c >> @@ -997,7 +997,7 @@ 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); >> } > Side note: I'm not sure, this construct is valid. IIRC PTR_ERR should > only be called for values x where IS_ERR(x) is true. Here it is at least > surprising that an message hints to a problem but the return code is 0. > > @Julia: I'm sure coccinelle can find more of those?! > > Best regards > Uwe >
On Tue, Aug 08, 2017 at 09:40:59AM +0200, Christophe JAILLET wrote: > Le 07/08/2017 à 08:36, Uwe Kleine-König a écrit : > > On Mon, Aug 07, 2017 at 01:49:53AM +0200, Christophe JAILLET wrote: > > > 'devm_pinctrl_get()' never returns NULL, so this test can be simplified. > > That's wrong. If CONFIG_PINCTRL is disabled devm_pinctrl_get returns > > NULL. But I think this shouldn't be considered an error, so your change > > is right, just the commit log is not. > With that said, in fact, I think that the test is correct as is. > If CONFIG_PINCTRL is disabled, we will display an info about a missing > functionality, but would still continue normally without it (i.e. return > PTR_ERR(NULL) = 0 = success), as stated in the comment in front of > 'i2c_imx_init_recovery_info': > "These alternative pinmux settings can be described in the device tree > by > a separate pinctrl state "gpio". If this is missing this is not a big > problem, the only implication is that we can't do bus recovery." > > So, I won't propose any v2 patch with an updated commit log. > Feel free to update it yourself and apply it if you don't share my analysis > above. Then the only issue (maybe?) is that the driver makes use of PTR_ERR(NULL) == 0 which I'm not sure is explicitly allowed. Best regards Uwe
On Tue, Aug 08, 2017 at 10:15:01AM +0200, Uwe Kleine-König wrote: > On Tue, Aug 08, 2017 at 09:40:59AM +0200, Christophe JAILLET wrote: > > Le 07/08/2017 à 08:36, Uwe Kleine-König a écrit : > > > On Mon, Aug 07, 2017 at 01:49:53AM +0200, Christophe JAILLET wrote: > > > > 'devm_pinctrl_get()' never returns NULL, so this test can be simplified. > > > That's wrong. If CONFIG_PINCTRL is disabled devm_pinctrl_get returns > > > NULL. But I think this shouldn't be considered an error, so your change > > > is right, just the commit log is not. > > With that said, in fact, I think that the test is correct as is. > > If CONFIG_PINCTRL is disabled, we will display an info about a missing > > functionality, but would still continue normally without it (i.e. return > > PTR_ERR(NULL) = 0 = success), as stated in the comment in front of > > 'i2c_imx_init_recovery_info': > > "These alternative pinmux settings can be described in the device tree > > by > > a separate pinctrl state "gpio". If this is missing this is not a big > > problem, the only implication is that we can't do bus recovery." > > > > So, I won't propose any v2 patch with an updated commit log. > > Feel free to update it yourself and apply it if you don't share my analysis > > above. > > Then the only issue (maybe?) is that the driver makes use of > PTR_ERR(NULL) == 0 which I'm not sure is explicitly allowed. I'll drop this patch for now. If somebody wants this applied, please send a V2 with the issues here addressed.
diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c index 54a47b40546f..7e84662fe1c0 100644 --- a/drivers/i2c/busses/i2c-imx.c +++ b/drivers/i2c/busses/i2c-imx.c @@ -997,7 +997,7 @@ 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); }
'devm_pinctrl_get()' never returns NULL, so this test can be simplified. Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> --- drivers/i2c/busses/i2c-imx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)