pinctrl: intel: Allow requesting pins which are in ACPI mode as GPIOs

Reserved for ACPI actually means that in such case the GPIO hardware will
not update the interrupt status register (GPI_IS) even if the pin is
configured to trigger an interrupt. It will update GPI_GPE_STS instead and
does not trigger an interrupt.

Allow using such pins as GPIOs, only prevent their usage as interrupts.

We also rename function intel_pad_reserved_for_acpi() to be
intel_pad_acpi_mode() which reflects the actual meaning better.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/pinctrl/intel/pinctrl-intel.c b/drivers/pinctrl/intel/pinctrl-intel.c
index 19b73de2f238ab481bc2c385dda78a2f29c8dff3..c4274542a5a02aad4e1dca14e5969cebf744a212 100644 (file)
--- a/drivers/pinctrl/intel/pinctrl-intel.c
+++ b/drivers/pinctrl/intel/pinctrl-intel.c
@@ -160,8 +160,7 @@ static bool intel_pad_owned_by_host(struct intel_pinctrl *pctrl, unsigned pin)
        return !(readl(padown) & PADOWN_MASK(padno));
 }
 
-static bool intel_pad_reserved_for_acpi(struct intel_pinctrl *pctrl,
-                                       unsigned pin)
+static bool intel_pad_acpi_mode(struct intel_pinctrl *pctrl, unsigned pin)
 {
        const struct intel_community *community;
        unsigned padno, gpp, offset;
@@ -217,7 +216,6 @@ static bool intel_pad_locked(struct intel_pinctrl *pctrl, unsigned pin)
 static bool intel_pad_usable(struct intel_pinctrl *pctrl, unsigned pin)
 {
        return intel_pad_owned_by_host(pctrl, pin) &&
-               !intel_pad_reserved_for_acpi(pctrl, pin) &&
                !intel_pad_locked(pctrl, pin);
 }
 
@@ -270,7 +268,7 @@ static void intel_pin_dbg_show(struct pinctrl_dev *pctldev, struct seq_file *s,
        seq_printf(s, "0x%08x 0x%08x", cfg0, cfg1);
 
        locked = intel_pad_locked(pctrl, pin);
-       acpi = intel_pad_reserved_for_acpi(pctrl, pin);
+       acpi = intel_pad_acpi_mode(pctrl, pin);
 
        if (locked || acpi) {
                seq_puts(s, " [");
@@ -737,6 +735,16 @@ static int intel_gpio_irq_type(struct irq_data *d, unsigned type)
        if (!reg)
                return -EINVAL;
 
+       /*
+        * If the pin is in ACPI mode it is still usable as a GPIO but it
+        * cannot be used as IRQ because GPI_IS status bit will not be
+        * updated by the host controller hardware.
+        */
+       if (intel_pad_acpi_mode(pctrl, pin)) {
+               dev_warn(pctrl->dev, "pin %u cannot be used as IRQ\n", pin);
+               return -EPERM;
+       }
+
        spin_lock_irqsave(&pctrl->lock, flags);
 
        value = readl(reg);