Re: [PATCH 4/9] pinctrl: samsung: Use generic of_device_get_match_data helper

Krzysztof Kozlowski
2016-12-26T09:41:42Z

On Mon, Dec 26, 2016 at 02:44:26PM +0900, Tomasz Figa wrote:
> 2016-12-25 21:56 GMT+09:00 Krzysztof Kozlowski <krzk@kernel.org>:
> > On Fri, Dec 23, 2016 at 01:24:44PM +0100, Marek Szyprowski wrote:
> >> Replace custom code with generic helper.
> >>
> >> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> >> ---
> >> drivers/pinctrl/samsung/pinctrl-samsung.c | 9 ++++-----
> >> 1 file changed, 4 insertions(+), 5 deletions(-)
> >>
> >> diff --git a/drivers/pinctrl/samsung/pinctrl-samsung.c b/drivers/pinctrl/samsung/pinctrl-samsung.c
> >> index 4d9262051ff1..a6c2ea74e0f3 100644
> >> --- a/drivers/pinctrl/samsung/pinctrl-samsung.c
> >> +++ b/drivers/pinctrl/samsung/pinctrl-samsung.c
> >> @@ -27,6 +27,7 @@
> >> #include <linux/err.h>
> >> #include <linux/gpio.h>
> >> #include <linux/irqdomain.h>
> >> +#include <linux/of_device.h>
> >> #include <linux/spinlock.h>
> >> #include <linux/syscore_ops.h>
> >>
> >> @@ -967,15 +968,13 @@ static int samsung_gpiolib_unregister(struct platform_device *pdev,
> >> return 0;
> >> }
> >>
> >> -static const struct of_device_id samsung_pinctrl_dt_match[];
> >> -
> >> /* retrieve the soc specific data */
> >> static const struct samsung_pin_ctrl *
> >> samsung_pinctrl_get_soc_data(struct samsung_pinctrl_drv_data *d,
> >> struct platform_device *pdev)
> >> {
> >> int id;
> >> - const struct of_device_id *match;
> >> + const struct samsung_pin_ctrl *match_data;
> >> struct device_node *node = pdev->dev.of_node;
> >> struct device_node *np;
> >> const struct samsung_pin_bank_data *bdata;
> >> @@ -990,8 +989,8 @@ static int samsung_gpiolib_unregister(struct platform_device *pdev,
> >> dev_err(&pdev->dev, "failed to get alias id\n");
> >> return ERR_PTR(-ENOENT);
> >> }
> >> - match = of_match_node(samsung_pinctrl_dt_match, node);
> >> - ctrl = (struct samsung_pin_ctrl *)match->data + id;
> >> + match_data = of_device_get_match_data(&pdev->dev);
> >> + ctrl = match_data + id;
> >
> > Either you need a check for match_data != NULL or just remove match_data
> > and:
> > ctrl = of_device_get_match_data();
> > ctrl += id;
> >
> > Actually match_data can be removed even with the check for non-NULL...
>
> I don't think this function can ever return NULL if the match array
> contains a non-NULL value for each compatible string and the driver
> can be probed only by DT.

Practically it cannot (or it should not) but defensive coding is a good
practice...

> But you still need to cast the match data pointer to the correct type
> and using a variable for it IMHO makes the code cleaner.

What do you mean by casting through variable? match_data and ctrl are
the same type so there is no change by intermediate variable. It just
obfuscates the code.

BR,
Krzysztof