3.16.83-rc1 review patch. If anyone has any objections, please let me know.
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From: Mika Westerberg mika.westerberg@linux.intel.com
commit f8323b6bb2cc7d26941d4838dd4375952980a88a upstream.
Zotac ZBOX PI320, a Baytrail based mini-PC, has power button connected to a GPIO pin and it is exposed to the operating system as Windows 8 button array. This is implemented in Linux as a driver using gpio_keys.
However, BIOS on this particula machine forgot to mux the pin to be a GPIO instead of native function, which results following message to be seen on the console:
byt_gpio INT33FC:02: pin 16 cannot be used as GPIO.
This causes power button to not work as the driver was not able to request the GPIO it needs.
So instead of completely preventing this we allow turning the pin as GPIO but issue warning that something might be wrong.
Reported-by: Benjamin Adler benadler@gmx.net Signed-off-by: Mika Westerberg mika.westerberg@linux.intel.com Signed-off-by: Linus Walleij linus.walleij@linaro.org [bwh: Backported to 3.16: adjust filename] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- drivers/pinctrl/pinctrl-baytrail.c | 35 +++++++++++++++--------- 1 file changed, 22 insertions(+), 13 deletions(-)
--- a/drivers/pinctrl/pinctrl-baytrail.c +++ b/drivers/pinctrl/pinctrl-baytrail.c @@ -160,40 +160,49 @@ static void __iomem *byt_gpio_reg(struct return vg->reg_base + reg_offset + reg; }
-static bool is_special_pin(struct byt_gpio *vg, unsigned offset) +static u32 byt_get_gpio_mux(struct byt_gpio *vg, unsigned offset) { /* SCORE pin 92-93 */ if (!strcmp(vg->range->name, BYT_SCORE_ACPI_UID) && offset >= 92 && offset <= 93) - return true; + return 1;
/* SUS pin 11-21 */ if (!strcmp(vg->range->name, BYT_SUS_ACPI_UID) && offset >= 11 && offset <= 21) - return true; + return 1;
- return false; + return 0; }
static int byt_gpio_request(struct gpio_chip *chip, unsigned offset) { struct byt_gpio *vg = to_byt_gpio(chip); void __iomem *reg = byt_gpio_reg(chip, offset, BYT_CONF0_REG); - u32 value; - bool special; + u32 value, gpio_mux;
/* * In most cases, func pin mux 000 means GPIO function. * But, some pins may have func pin mux 001 represents - * GPIO function. Only allow user to export pin with - * func pin mux preset as GPIO function by BIOS/FW. + * GPIO function. + * + * Because there are devices out there where some pins were not + * configured correctly we allow changing the mux value from + * request (but print out warning about that). */ value = readl(reg) & BYT_PIN_MUX; - special = is_special_pin(vg, offset); - if ((special && value != 1) || (!special && value)) { - dev_err(&vg->pdev->dev, - "pin %u cannot be used as GPIO.\n", offset); - return -EINVAL; + gpio_mux = byt_get_gpio_mux(vg, offset); + if (WARN_ON(gpio_mux != value)) { + unsigned long flags; + + spin_lock_irqsave(&vg->lock, flags); + value = readl(reg) & ~BYT_PIN_MUX; + value |= gpio_mux; + writel(value, reg); + spin_unlock_irqrestore(&vg->lock, flags); + + dev_warn(&vg->pdev->dev, + "pin %u forcibly re-configured as GPIO\n", offset); }
pm_runtime_get(&vg->pdev->dev);