pinctrl: mediatek: avoid virtual gpio trying to set reg

for virtual gpios, they should not do reg setting and
should behave as expected for eint function.

Signed-off-by: Mars Cheng <mars.cheng@mediatek.com>
Signed-off-by: Hanks Chen <hanks.chen@mediatek.com>
Acked-by: Sean Wang <sean.wang@kernel.org>
Link: https://lore.kernel.org/r/1595503197-15246-4-git-send-email-hanks.chen@mediatek.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Author: Hanks-Chen

drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c

@@ -243,6 +243,28 @@ static int mtk_xt_find_eint_num(struct mtk_pinctrl *hw, unsigned long eint_n)
 	return EINT_NA;
 }
 
+/*
+ * Virtual GPIO only used inside SOC and not being exported to outside SOC.
+ * Some modules use virtual GPIO as eint (e.g. pmif or usb).
+ * In MTK platform, external interrupt (EINT) and GPIO is 1-1 mapping
+ * and we can set GPIO as eint.
+ * But some modules use specific eint which doesn't have real GPIO pin.
+ * So we use virtual GPIO to map it.
+ */
+
+bool mtk_is_virt_gpio(struct mtk_pinctrl *hw, unsigned int gpio_n)
+{
+	const struct mtk_pin_desc *desc;
+	bool virt_gpio = false;
+
+	desc = (const struct mtk_pin_desc *)&hw->soc->pins[gpio_n];
+
+	if (desc->funcs && !desc->funcs[desc->eint.eint_m].name)
+		virt_gpio = true;
+
+	return virt_gpio;
+}
+
 static int mtk_xt_get_gpio_n(void *data, unsigned long eint_n,
 			     unsigned int *gpio_n,
 			     struct gpio_chip **gpio_chip)
@@ -295,6 +317,9 @@ static int mtk_xt_set_gpio_as_eint(void *data, unsigned long eint_n)
 	if (err)
 		return err;
 
+	if (mtk_is_virt_gpio(hw, gpio_n))
+		return 0;
+
 	desc = (const struct mtk_pin_desc *)&hw->soc->pins[gpio_n];
 
 	err = mtk_hw_set_value(hw, desc, PINCTRL_PIN_REG_MODE,

drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.h

@@ -315,4 +315,5 @@ int mtk_pinconf_adv_drive_set(struct mtk_pinctrl *hw,
 int mtk_pinconf_adv_drive_get(struct mtk_pinctrl *hw,
 			      const struct mtk_pin_desc *desc, u32 *val);
 
+bool mtk_is_virt_gpio(struct mtk_pinctrl *hw, unsigned int gpio_n);
 #endif /* __PINCTRL_MTK_COMMON_V2_H */

drivers/pinctrl/mediatek/pinctrl-paris.c

@@ -769,6 +769,13 @@ static int mtk_gpio_get_direction(struct gpio_chip *chip, unsigned int gpio)
 	if (gpio >= hw->soc->npins)
 		return -EINVAL;
 
+	/*
+	 * "Virtual" GPIOs are always and only used for interrupts
+	 * Since they are only used for interrupts, they are always inputs
+	 */
+	if (mtk_is_virt_gpio(hw, gpio))
+		return 1;
+
 	desc = (const struct mtk_pin_desc *)&hw->soc->pins[gpio];
 
 	err = mtk_hw_get_value(hw, desc, PINCTRL_PIN_REG_DIR, &value);