pinctrl: mediatek: emulate GPIO interrupt on both-edges

MTK EINT does not support generating interrupt on both edges.
Emulate this by changing edge polarity while enable irq,
set types and interrupt handling. This follows an example of
drivers/gpio/gpio-mxc.c.

Signed-off-by: Yingjoe Chen <yingjoe.chen@mediatek.com>
Signed-off-by: Chaotian Jing <chaotian.jing@mediatek.com>
Acked-by: Hongzhou Yang <hongzhou.yang@mediatek.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/mediatek/pinctrl-mt8135.c

@@ -325,6 +325,9 @@ static const struct mtk_pinctrl_devdata mt8135_pinctrl_data = {
 		.sens      = 0x140,
 		.sens_set  = 0x180,
 		.sens_clr  = 0x1c0,
+		.soft      = 0x200,
+		.soft_set  = 0x240,
+		.soft_clr  = 0x280,
 		.pol       = 0x300,
 		.pol_set   = 0x340,
 		.pol_clr   = 0x380,

drivers/pinctrl/mediatek/pinctrl-mt8173.c

@@ -405,6 +405,9 @@ static const struct mtk_pinctrl_devdata mt8173_pinctrl_data = {
 		.sens      = 0x140,
 		.sens_set  = 0x180,
 		.sens_clr  = 0x1c0,
+		.soft      = 0x200,
+		.soft_set  = 0x240,
+		.soft_clr  = 0x280,
 		.pol       = 0x300,
 		.pol_set   = 0x340,
 		.pol_clr   = 0x380,

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

@@ -792,6 +792,32 @@ static unsigned int mtk_eint_get_mask(struct mtk_pinctrl *pctl,
 	return !!(readl(reg) & bit);
 }
 
+static int mtk_eint_flip_edge(struct mtk_pinctrl *pctl, int hwirq)
+{
+	int start_level, curr_level;
+	unsigned int reg_offset;
+	const struct mtk_eint_offsets *eint_offsets = &(pctl->devdata->eint_offsets);
+	u32 mask = 1 << (hwirq & 0x1f);
+	u32 port = (hwirq >> 5) & eint_offsets->port_mask;
+	void __iomem *reg = pctl->eint_reg_base + (port << 2);
+	const struct mtk_desc_pin *pin;
+
+	pin = mtk_find_pin_by_eint_num(pctl, hwirq);
+	curr_level = mtk_gpio_get(pctl->chip, pin->pin.number);
+	do {
+		start_level = curr_level;
+		if (start_level)
+			reg_offset = eint_offsets->pol_clr;
+		else
+			reg_offset = eint_offsets->pol_set;
+		writel(mask, reg + reg_offset);
+
+		curr_level = mtk_gpio_get(pctl->chip, pin->pin.number);
+	} while (start_level != curr_level);
+
+	return start_level;
+}
+
 static void mtk_eint_mask(struct irq_data *d)
 {
 	struct mtk_pinctrl *pctl = irq_data_get_irq_chip_data(d);
@@ -814,6 +840,9 @@ static void mtk_eint_unmask(struct irq_data *d)
 			eint_offsets->mask_clr);
 
 	writel(mask, reg);
+
+	if (pctl->eint_dual_edges[d->hwirq])
+		mtk_eint_flip_edge(pctl, d->hwirq);
 }
 
 static int mtk_gpio_set_debounce(struct gpio_chip *chip, unsigned offset,
@@ -893,13 +922,17 @@ static int mtk_eint_set_type(struct irq_data *d,
 	void __iomem *reg;
 
 	if (((type & IRQ_TYPE_EDGE_BOTH) && (type & IRQ_TYPE_LEVEL_MASK)) ||
-		((type & IRQ_TYPE_EDGE_BOTH) == IRQ_TYPE_EDGE_BOTH) ||
 		((type & IRQ_TYPE_LEVEL_MASK) == IRQ_TYPE_LEVEL_MASK)) {
 		dev_err(pctl->dev, "Can't configure IRQ%d (EINT%lu) for type 0x%X\n",
 			d->irq, d->hwirq, type);
 		return -EINVAL;
 	}
 
+	if ((type & IRQ_TYPE_EDGE_BOTH) == IRQ_TYPE_EDGE_BOTH)
+		pctl->eint_dual_edges[d->hwirq] = 1;
+	else
+		pctl->eint_dual_edges[d->hwirq] = 0;
+
 	if (type & (IRQ_TYPE_LEVEL_LOW | IRQ_TYPE_EDGE_FALLING)) {
 		reg = mtk_eint_get_offset(pctl, d->hwirq,
 			eint_offsets->pol_clr);
@@ -920,6 +953,9 @@ static int mtk_eint_set_type(struct irq_data *d,
 		writel(mask, reg);
 	}
 
+	if (pctl->eint_dual_edges[d->hwirq])
+		mtk_eint_flip_edge(pctl, d->hwirq);
+
 	return 0;
 }
 
@@ -986,6 +1022,8 @@ static void mtk_eint_irq_handler(unsigned irq, struct irq_desc *desc)
 	const struct mtk_eint_offsets *eint_offsets =
 		&pctl->devdata->eint_offsets;
 	void __iomem *reg =  mtk_eint_get_offset(pctl, 0, eint_offsets->stat);
+	int dual_edges, start_level, curr_level;
+	const struct mtk_desc_pin *pin;
 
 	chained_irq_enter(chip, desc);
 	for (eint_num = 0; eint_num < pctl->devdata->ap_num; eint_num += 32) {
@@ -997,8 +1035,31 @@ static void mtk_eint_irq_handler(unsigned irq, struct irq_desc *desc)
 			virq = irq_find_mapping(pctl->domain, index);
 			status &= ~BIT(offset);
 
+			dual_edges = pctl->eint_dual_edges[index];
+			if (dual_edges) {
+				/* Clear soft-irq in case we raised it
+				   last time */
+				writel(BIT(offset), reg - eint_offsets->stat +
+					eint_offsets->soft_clr);
+
+				pin = mtk_find_pin_by_eint_num(pctl, index);
+				start_level = mtk_gpio_get(pctl->chip,
+							   pin->pin.number);
+			}
+
 			generic_handle_irq(virq);
 
+			if (dual_edges) {
+				curr_level = mtk_eint_flip_edge(pctl, index);
+
+				/* If level changed, we might lost one edge
+				   interrupt, raised it through soft-irq */
+				if (start_level != curr_level)
+					writel(BIT(offset), reg -
+						eint_offsets->stat +
+						eint_offsets->soft_set);
+			}
+
 			if (index < pctl->devdata->db_cnt)
 				mtk_eint_debounce_process(pctl , index);
 		}
@@ -1149,11 +1210,18 @@ int mtk_pctrl_init(struct platform_device *pdev,
 		goto chip_error;
 	}
 
+	pctl->eint_dual_edges = devm_kzalloc(&pdev->dev,
+			sizeof(int) * pctl->devdata->ap_num, GFP_KERNEL);
+	if (!pctl->eint_dual_edges) {
+		ret = -ENOMEM;
+		goto chip_error;
+	}
+
 	irq = irq_of_parse_and_map(np, 0);
 	if (!irq) {
 		dev_err(&pdev->dev, "couldn't parse and map irq\n");
 		ret = -EINVAL;
-		goto chip_error;
+		goto free_edges;
 	}
 
 	pctl->domain = irq_domain_add_linear(np,
@@ -1161,7 +1229,7 @@ int mtk_pctrl_init(struct platform_device *pdev,
 	if (!pctl->domain) {
 		dev_err(&pdev->dev, "Couldn't register IRQ domain\n");
 		ret = -ENOMEM;
-		goto chip_error;
+		goto free_edges;
 	}
 
 	mtk_eint_init(pctl);
@@ -1179,6 +1247,8 @@ int mtk_pctrl_init(struct platform_device *pdev,
 	set_irq_flags(irq, IRQF_VALID);
 	return 0;
 
+free_edges:
+	kfree(pctl->eint_dual_edges);
 chip_error:
 	gpiochip_remove(pctl->chip);
 pctrl_error:

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

@@ -131,6 +131,9 @@ struct mtk_eint_offsets {
 	unsigned int  sens;
 	unsigned int  sens_set;
 	unsigned int  sens_clr;
+	unsigned int  soft;
+	unsigned int  soft_set;
+	unsigned int  soft_clr;
 	unsigned int  pol;
 	unsigned int  pol_set;
 	unsigned int  pol_clr;
@@ -217,6 +220,7 @@ struct mtk_pinctrl {
 	const struct mtk_pinctrl_devdata  *devdata;
 	void __iomem		*eint_reg_base;
 	struct irq_domain	*domain;
+	int			*eint_dual_edges;
 };
 
 int mtk_pctrl_init(struct platform_device *pdev,