Re: [PATCH v7 08/15] gpiolib: regmap: add write_data_after_dir quirk
From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Date: 2026-09-15 15:08:11
Also in:
linux-clk, linux-devicetree, linux-gpio, linux-serial, lkml
On Tue, Sep 15, 2026 at 07:15:38PM +0800, Long Zhao via B4 Relay wrote:
Some controllers ignore data-register writes while a line is still an input. Optionally write the output value again after switching the direction, matching the existing PL061 behaviour.
...
- gpio_regmap_set(chip, offset, value); + ret = gpio_regmap_set(chip, offset, value); + if (ret) + return ret;
I think that this might lead to regressions when the end driver just leaves the output in the previous state in case of errors. In any case, even if this is a correct update, it needs to be done separately with the justification that shows that all current users won't have regressions or the regression is actually a fix of the behaviour.
+ ret = gpio_regmap_set_direction(chip, offset, true); + if (ret) + return ret; - return gpio_regmap_set_direction(chip, offset, true); + /* + * gpio value is set again, because pl061 doesn't allow to set value of + * a gpio pin before configuring it in OUT mode. + */ + if (gpio->write_data_after_dir) + return gpio_regmap_set(chip, offset, value);
Taking the above into account I'm not sure if we want the inconsistency with the above. Perhaps also ignore the returned value for now?
+ return 0;
-- With Best Regards, Andy Shevchenko