| Message ID | 20200708082634.30191-2-digetx@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | Improvements for MAX77620 GPIO driver | expand |
On Wed, Jul 8, 2020 at 11:29 AM Dmitry Osipenko <digetx@gmail.com> wrote: > > I noticed on Nexus 7 that after rebooting from downstream kernel to > upstream, the GPIO interrupt is triggering non-stop despite of interrupts > being disabled for all of GPIOs. This happens because Nexus 7 uses a > soft-reboot, meaning that bootloader should take care of resetting > hardware, but bootloader doesn't do it well. In a result, GPIO interrupt > may be left ON at a boot time. Let's mask all GPIO interrupts at the > driver's probe time in order to resolve the issue. ... > + err = regmap_update_bits(mgpio->rmap, GPIO_REG_ADDR(i), > + MAX77620_CNFG_GPIO_INT_MASK, 0); > + if (err < 0) Does ' < 0' meaningful here? > + dev_err(mgpio->dev, "failed to disable interrupt: %d\n", > + err); One line. ... > + max77620_gpio_initialize(mgpio); I guess we have special callback for that, i.e. https://elixir.bootlin.com/linux/v5.8-rc3/C/ident/init_hw.
On Wed, Jul 8, 2020 at 11:51 AM Andy Shevchenko <andy.shevchenko@gmail.com> wrote: > On Wed, Jul 8, 2020 at 11:29 AM Dmitry Osipenko <digetx@gmail.com> wrote: ... > > + max77620_gpio_initialize(mgpio); > > I guess we have special callback for that, i.e. > https://elixir.bootlin.com/linux/v5.8-rc3/C/ident/init_hw. Sorry, here is correct link https://elixir.bootlin.com/linux/v5.8-rc3/source/include/linux/gpio/driver.h#L212
08.07.2020 11:53, Andy Shevchenko пишет: > On Wed, Jul 8, 2020 at 11:51 AM Andy Shevchenko > <andy.shevchenko@gmail.com> wrote: >> On Wed, Jul 8, 2020 at 11:29 AM Dmitry Osipenko <digetx@gmail.com> wrote: > > ... > >>> + max77620_gpio_initialize(mgpio); >> >> I guess we have special callback for that, i.e. >> https://elixir.bootlin.com/linux/v5.8-rc3/C/ident/init_hw. > > Sorry, here is correct link > > https://elixir.bootlin.com/linux/v5.8-rc3/source/include/linux/gpio/driver.h#L212 > Indeed, I missed the init_hw(), thank you!
08.07.2020 11:51, Andy Shevchenko пишет: > On Wed, Jul 8, 2020 at 11:29 AM Dmitry Osipenko <digetx@gmail.com> wrote: >> >> I noticed on Nexus 7 that after rebooting from downstream kernel to >> upstream, the GPIO interrupt is triggering non-stop despite of interrupts >> being disabled for all of GPIOs. This happens because Nexus 7 uses a >> soft-reboot, meaning that bootloader should take care of resetting >> hardware, but bootloader doesn't do it well. In a result, GPIO interrupt >> may be left ON at a boot time. Let's mask all GPIO interrupts at the >> driver's probe time in order to resolve the issue. > > ... > >> + err = regmap_update_bits(mgpio->rmap, GPIO_REG_ADDR(i), >> + MAX77620_CNFG_GPIO_INT_MASK, 0); >> + if (err < 0) > > Does ' < 0' meaningful here? Not really, although [1] explicitly says that regmap_update_bits() returns either 0 or a negative error code. The positive value will be an unexpected return code here. [1] https://elixir.bootlin.com/linux/v5.8-rc3/source/drivers/base/regmap/regmap.c#L2910 This variant of ' < 0' is consistent with all other similar occurrences in the driver's code, so should be better to keep it as-is, IMO. >> + dev_err(mgpio->dev, "failed to disable interrupt: %d\n", >> + err); > > One line. This will make this line inconsistent with the rest of the driver's code. Secondly, this line won't fit to display using my multi-file view-edit setup. I know that 80 chars isn't warned by checkpatch anymore, but still it's a preferred width for all cases where it doesn't hurt readability, which is the case here, IMO.
diff --git a/drivers/gpio/gpio-max77620.c b/drivers/gpio/gpio-max77620.c index 313bd02dd893..473b4e900bbb 100644 --- a/drivers/gpio/gpio-max77620.c +++ b/drivers/gpio/gpio-max77620.c @@ -260,6 +260,25 @@ static int max77620_gpio_set_config(struct gpio_chip *gc, unsigned int offset, return -ENOTSUPP; } +static void max77620_gpio_initialize(struct max77620_gpio *mgpio) +{ + unsigned int i; + int err; + + /* + * GPIO interrupts may be left ON after bootloader, hence let's + * pre-initialize hardware to the expected state by disabling all + * interrupts. + */ + for (i = 0; i < MAX77620_GPIO_NR; i++) { + err = regmap_update_bits(mgpio->rmap, GPIO_REG_ADDR(i), + MAX77620_CNFG_GPIO_INT_MASK, 0); + if (err < 0) + dev_err(mgpio->dev, "failed to disable interrupt: %d\n", + err); + } +} + static int max77620_gpio_probe(struct platform_device *pdev) { struct max77620_chip *chip = dev_get_drvdata(pdev->dev.parent); @@ -292,6 +311,7 @@ static int max77620_gpio_probe(struct platform_device *pdev) mgpio->gpio_chip.of_node = pdev->dev.parent->of_node; #endif + max77620_gpio_initialize(mgpio); platform_set_drvdata(pdev, mgpio); ret = devm_gpiochip_add_data(&pdev->dev, &mgpio->gpio_chip, mgpio);
I noticed on Nexus 7 that after rebooting from downstream kernel to upstream, the GPIO interrupt is triggering non-stop despite of interrupts being disabled for all of GPIOs. This happens because Nexus 7 uses a soft-reboot, meaning that bootloader should take care of resetting hardware, but bootloader doesn't do it well. In a result, GPIO interrupt may be left ON at a boot time. Let's mask all GPIO interrupts at the driver's probe time in order to resolve the issue. Signed-off-by: Dmitry Osipenko <digetx@gmail.com> --- drivers/gpio/gpio-max77620.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)