| Message ID | 20171212174343.192017-1-briannorris@chromium.org |
|---|---|
| State | New |
| Headers | show |
| Series | pinctrl: rockchip: enable clock when reading pin direction register | expand |
Hi Brian, Am Dienstag, 12. Dezember 2017, 09:43:43 CET schrieb Brian Norris: > We generally leave the GPIO clock disabled, unless an interrupt is > requested or we're accessing IO registers. We forgot to do this for the > ->get_direction() callback, which means we can sometimes [1] get > incorrect results [2] from, e.g., /sys/kernel/debug/gpio. > > Enable the clock, so we get the right results! > > [1] Sometimes, because many systems have 1 or mor interrupt requested on > each GPIO bank, so they always leave their clock on. > > [2] Incorrect, meaning the register returns 0, and so we interpret that > as "input". > > Signed-off-by: Brian Norris <briannorris@chromium.org> thanks for catching this and it looks good to me, so Reviewed-by: Heiko Stuebner <heiko@sntech.de> -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Dec 12, 2017 at 6:43 PM, Brian Norris <briannorris@chromium.org> wrote: > We generally leave the GPIO clock disabled, unless an interrupt is > requested or we're accessing IO registers. We forgot to do this for the > ->get_direction() callback, which means we can sometimes [1] get > incorrect results [2] from, e.g., /sys/kernel/debug/gpio. > > Enable the clock, so we get the right results! > > [1] Sometimes, because many systems have 1 or mor interrupt requested on > each GPIO bank, so they always leave their clock on. > > [2] Incorrect, meaning the register returns 0, and so we interpret that > as "input". > > Signed-off-by: Brian Norris <briannorris@chromium.org> Patch applied with Heiko's review tag. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/pinctrl/pinctrl-rockchip.c b/drivers/pinctrl/pinctrl-rockchip.c index 2ba17548ad5b..073de6a9ed34 100644 --- a/drivers/pinctrl/pinctrl-rockchip.c +++ b/drivers/pinctrl/pinctrl-rockchip.c @@ -2014,8 +2014,16 @@ static int rockchip_gpio_get_direction(struct gpio_chip *chip, unsigned offset) { struct rockchip_pin_bank *bank = gpiochip_get_data(chip); u32 data; + int ret; + ret = clk_enable(bank->clk); + if (ret < 0) { + dev_err(bank->drvdata->dev, + "failed to enable clock for bank %s\n", bank->name); + return ret; + } data = readl_relaxed(bank->reg_base + GPIO_SWPORT_DDR); + clk_disable(bank->clk); return !(data & BIT(offset)); }
We generally leave the GPIO clock disabled, unless an interrupt is requested or we're accessing IO registers. We forgot to do this for the ->get_direction() callback, which means we can sometimes [1] get incorrect results [2] from, e.g., /sys/kernel/debug/gpio. Enable the clock, so we get the right results! [1] Sometimes, because many systems have 1 or mor interrupt requested on each GPIO bank, so they always leave their clock on. [2] Incorrect, meaning the register returns 0, and so we interpret that as "input". Signed-off-by: Brian Norris <briannorris@chromium.org> --- drivers/pinctrl/pinctrl-rockchip.c | 8 ++++++++ 1 file changed, 8 insertions(+)