Date:	Sat, 12 Dec 2015 23:55:20 +0100
From:	Robert Jarzmik <robert.jarzmik@...e.fr>
To:	Linus Walleij <linus.walleij@...aro.org>,
	Alexandre Courbot <gnurou@...il.com>
Cc:	linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
	Robert Jarzmik <robert.jarzmik@...e.fr>
Subject: [PATCH v2 1/2] gpio: pxa: change the interrupt management

The interrupt management is changed by this patch to rely on chip data
instead of chained interrupts.

The main goal is to loosen the dependency on the global pxa chip
structure in favor of the passed chip data. The secondary goal is to
better show in /proc/interrupts the difference between interrupts for
gpio0 and gpio1 (directly wired to interrupt controller), and the other
gpios (wired onto a third line in the interrupt controller).

The last advantage of this patch is that the interrupt is actually
requested, so that another driver cannot steal this line, or overwrite
the handler.

Signed-off-by: Robert Jarzmik <robert.jarzmik@...e.fr>
---
Since v1: moved CONFIG_OF for pxa_irq_domain_ops
---
 drivers/gpio/gpio-pxa.c | 171 +++++++++++++++++++++++++++---------------------
 1 file changed, 95 insertions(+), 76 deletions(-)

diff --git a/drivers/gpio/gpio-pxa.c b/drivers/gpio/gpio-pxa.c
index 8558abf98204..c6b572be68c0 100644
--- a/drivers/gpio/gpio-pxa.c
+++ b/drivers/gpio/gpio-pxa.c
@@ -64,11 +64,6 @@
 int pxa_last_gpio;
 static int irq_base;
 
-#ifdef CONFIG_OF
-static struct irq_domain *domain;
-static struct device_node *pxa_gpio_of_node;
-#endif
-
 struct pxa_gpio_bank {
 	void __iomem	*regbase;
 	unsigned long	irq_mask;
@@ -87,6 +82,7 @@ struct pxa_gpio_chip {
 	struct device *dev;
 	struct gpio_chip chip;
 	struct pxa_gpio_bank *banks;
+	struct irq_domain *irqdomain;
 
 	int irq0;
 	int irq1;
@@ -231,14 +227,23 @@ static inline int __gpio_is_occupied(struct pxa_gpio_chip *pchip, unsigned gpio)
 	return ret;
 }
 
-static int pxa_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
+int pxa_irq_to_gpio(int irq)
 {
-	return offset + irq_base;
+	struct pxa_gpio_chip *pchip = pxa_gpio_chip;
+	int irq_gpio0;
+
+	irq_gpio0 = irq_find_mapping(pchip->irqdomain, 0);
+	if (irq_gpio0 > 0)
+		return irq - irq_gpio0;
+
+	return irq_gpio0;
 }
 
-int pxa_irq_to_gpio(int irq)
+static int pxa_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
 {
-	return irq - irq_base;
+	struct pxa_gpio_chip *pchip = chip_to_pxachip(chip);
+
+	return irq_find_mapping(pchip->irqdomain, offset);
 }
 
 static int pxa_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
@@ -314,7 +319,7 @@ static int pxa_gpio_of_xlate(struct gpio_chip *gc,
 #endif
 
 static int pxa_init_gpio_chip(struct pxa_gpio_chip *pchip, int ngpio,
-			      void __iomem *regbase)
+			      struct device_node *np, void __iomem *regbase)
 {
 	int i, gpio, nbanks = DIV_ROUND_UP(ngpio, 32);
 	struct pxa_gpio_bank *bank;
@@ -332,7 +337,7 @@ static int pxa_init_gpio_chip(struct pxa_gpio_chip *pchip, int ngpio,
 	pchip->chip.to_irq = pxa_gpio_to_irq;
 	pchip->chip.ngpio = ngpio;
 #ifdef CONFIG_OF_GPIO
-	pchip->chip.of_node = pxa_gpio_of_node;
+	pchip->chip.of_node = np;
 	pchip->chip.of_xlate = pxa_gpio_of_xlate;
 	pchip->chip.of_gpio_n_cells = 2;
 #endif
@@ -362,8 +367,8 @@ static inline void update_edge_detect(struct pxa_gpio_bank *c)
 
 static int pxa_gpio_irq_type(struct irq_data *d, unsigned int type)
 {
-	struct pxa_gpio_chip *pchip = pxa_gpio_chip;
-	int gpio = pxa_irq_to_gpio(d->irq);
+	struct pxa_gpio_chip *pchip = irq_data_get_irq_chip_data(d);
+	unsigned int gpio = irqd_to_hwirq(d);
 	struct pxa_gpio_bank *c = gpio_to_pxabank(&pchip->chip, gpio);
 	unsigned long gpdr, mask = GPIO_bit(gpio);
 
@@ -405,16 +410,13 @@ static int pxa_gpio_irq_type(struct irq_data *d, unsigned int type)
 	return 0;
 }
 
-static void pxa_gpio_demux_handler(struct irq_desc *desc)
+static irqreturn_t pxa_gpio_demux_handler(int in_irq, void *d)
 {
 	int loop, gpio, n, handled = 0;
 	unsigned long gedr;
-	struct irq_chip *chip = irq_desc_get_chip(desc);
-	struct pxa_gpio_chip *pchip = pxa_gpio_chip;
+	struct pxa_gpio_chip *pchip = d;
 	struct pxa_gpio_bank *c;
 
-	chained_irq_enter(chip, desc);
-
 	do {
 		loop = 0;
 		for_each_gpio_bank(gpio, c, pchip) {
@@ -428,15 +430,31 @@ static void pxa_gpio_demux_handler(struct irq_desc *desc)
 				generic_handle_irq(gpio_to_irq(gpio + n));
 			}
 		}
+		handled += loop;
 	} while (loop);
 
-	chained_irq_exit(chip, desc);
+	return handled ? IRQ_HANDLED : IRQ_NONE;
+}
+
+static irqreturn_t pxa_gpio_direct_handler(int in_irq, void *d)
+{
+	struct pxa_gpio_chip *pchip = d;
+
+	if (in_irq == pchip->irq0) {
+		generic_handle_irq(gpio_to_irq(0));
+	} else if (in_irq == pchip->irq1) {
+		generic_handle_irq(gpio_to_irq(1));
+	} else {
+		pr_err("%s() unknown irq %d\n", __func__, in_irq);
+		return IRQ_NONE;
+	}
+	return IRQ_HANDLED;
 }
 
 static void pxa_ack_muxed_gpio(struct irq_data *d)
 {
-	struct pxa_gpio_chip *pchip = pxa_gpio_chip;
-	int gpio = pxa_irq_to_gpio(d->irq);
+	struct pxa_gpio_chip *pchip = irq_data_get_irq_chip_data(d);
+	unsigned int gpio = irqd_to_hwirq(d);
 	void __iomem *base = gpio_bank_base(&pchip->chip, gpio);
 
 	writel_relaxed(GPIO_bit(gpio), base + GEDR_OFFSET);
@@ -444,8 +462,8 @@ static void pxa_ack_muxed_gpio(struct irq_data *d)
 
 static void pxa_mask_muxed_gpio(struct irq_data *d)
 {
-	struct pxa_gpio_chip *pchip = pxa_gpio_chip;
-	int gpio = pxa_irq_to_gpio(d->irq);
+	struct pxa_gpio_chip *pchip = irq_data_get_irq_chip_data(d);
+	unsigned int gpio = irqd_to_hwirq(d);
 	struct pxa_gpio_bank *b = gpio_to_pxabank(&pchip->chip, gpio);
 	void __iomem *base = gpio_bank_base(&pchip->chip, gpio);
 	uint32_t grer, gfer;
@@ -460,8 +478,8 @@ static void pxa_mask_muxed_gpio(struct irq_data *d)
 
 static int pxa_gpio_set_wake(struct irq_data *d, unsigned int on)
 {
-	int gpio = pxa_irq_to_gpio(d->irq);
-	struct pxa_gpio_chip *pchip = pxa_gpio_chip;
+	struct pxa_gpio_chip *pchip = irq_data_get_irq_chip_data(d);
+	unsigned int gpio = irqd_to_hwirq(d);
 
 	if (pchip->set_wake)
 		return pchip->set_wake(gpio, on);
@@ -471,8 +489,8 @@ static int pxa_gpio_set_wake(struct irq_data *d, unsigned int on)
 
 static void pxa_unmask_muxed_gpio(struct irq_data *d)
 {
-	struct pxa_gpio_chip *pchip = pxa_gpio_chip;
-	int gpio = pxa_irq_to_gpio(d->irq);
+	struct pxa_gpio_chip *pchip = irq_data_get_irq_chip_data(d);
+	unsigned int gpio = irqd_to_hwirq(d);
 	struct pxa_gpio_bank *c = gpio_to_pxabank(&pchip->chip, gpio);
 
 	c->irq_mask |= GPIO_bit(gpio);
@@ -513,24 +531,12 @@ static int pxa_gpio_nums(struct platform_device *pdev)
 	return count;
 }
 
-#ifdef CONFIG_OF
-static const struct of_device_id pxa_gpio_dt_ids[] = {
-	{ .compatible = "intel,pxa25x-gpio",	.data = &pxa25x_id, },
-	{ .compatible = "intel,pxa26x-gpio",	.data = &pxa26x_id, },
-	{ .compatible = "intel,pxa27x-gpio",	.data = &pxa27x_id, },
-	{ .compatible = "intel,pxa3xx-gpio",	.data = &pxa3xx_id, },
-	{ .compatible = "marvell,pxa93x-gpio",	.data = &pxa93x_id, },
-	{ .compatible = "marvell,mmp-gpio",	.data = &mmp_id, },
-	{ .compatible = "marvell,mmp2-gpio",	.data = &mmp2_id, },
-	{ .compatible = "marvell,pxa1928-gpio",	.data = &pxa1928_id, },
-	{}
-};
-
 static int pxa_irq_domain_map(struct irq_domain *d, unsigned int irq,
 			      irq_hw_number_t hw)
 {
 	irq_set_chip_and_handler(irq, &pxa_muxed_gpio_chip,
 				 handle_edge_irq);
+	irq_set_chip_data(irq, d->host_data);
 	irq_set_noprobe(irq);
 	return 0;
 }
@@ -540,11 +546,23 @@ const struct irq_domain_ops pxa_irq_domain_ops = {
 	.xlate	= irq_domain_xlate_twocell,
 };
 
+#ifdef CONFIG_OF
+static const struct of_device_id pxa_gpio_dt_ids[] = {
+	{ .compatible = "intel,pxa25x-gpio",	.data = &pxa25x_id, },
+	{ .compatible = "intel,pxa26x-gpio",	.data = &pxa26x_id, },
+	{ .compatible = "intel,pxa27x-gpio",	.data = &pxa27x_id, },
+	{ .compatible = "intel,pxa3xx-gpio",	.data = &pxa3xx_id, },
+	{ .compatible = "marvell,pxa93x-gpio",	.data = &pxa93x_id, },
+	{ .compatible = "marvell,mmp-gpio",	.data = &mmp_id, },
+	{ .compatible = "marvell,mmp2-gpio",	.data = &mmp2_id, },
+	{ .compatible = "marvell,pxa1928-gpio",	.data = &pxa1928_id, },
+	{}
+};
+
 static int pxa_gpio_probe_dt(struct platform_device *pdev,
 			     struct pxa_gpio_chip *pchip)
 {
 	int nr_gpios;
-	struct device_node *np = pdev->dev.of_node;
 	const struct of_device_id *of_id =
 				of_match_device(pxa_gpio_dt_ids, &pdev->dev);
 	const struct pxa_gpio_id *gpio_id;
@@ -564,10 +582,7 @@ static int pxa_gpio_probe_dt(struct platform_device *pdev,
 		dev_err(&pdev->dev, "Failed to allocate IRQ numbers\n");
 		return irq_base;
 	}
-	domain = irq_domain_add_legacy(np, nr_gpios, irq_base, 0,
-				       &pxa_irq_domain_ops, pchip);
-	pxa_gpio_of_node = np;
-	return 0;
+	return irq_base;
 }
 #else
 #define pxa_gpio_probe_dt(pdev, pchip)		(-1)
@@ -581,7 +596,7 @@ static int pxa_gpio_probe(struct platform_device *pdev)
 	struct clk *clk;
 	struct pxa_gpio_platform_data *info;
 	void __iomem *gpio_reg_base;
-	int gpio, irq, ret, use_of = 0;
+	int gpio, ret;
 	int irq0 = 0, irq1 = 0, irq_mux, gpio_offset = 0;
 
 	pchip = devm_kzalloc(&pdev->dev, sizeof(*pchip), GFP_KERNEL);
@@ -597,22 +612,29 @@ static int pxa_gpio_probe(struct platform_device *pdev)
 		pxa_last_gpio = pxa_gpio_nums(pdev);
 		pchip->set_wake = info->gpio_set_wake;
 	} else {
-		irq_base = 0;
-		use_of = 1;
-		ret = pxa_gpio_probe_dt(pdev, pchip);
-		if (ret < 0)
+		irq_base = pxa_gpio_probe_dt(pdev, pchip);
+		if (irq_base < 0)
 			return -EINVAL;
 	}
 
 	if (!pxa_last_gpio)
 		return -EINVAL;
 
+	pchip->irqdomain = irq_domain_add_legacy(pdev->dev.of_node,
+						 pxa_last_gpio + 1, irq_base,
+						 0, &pxa_irq_domain_ops, pchip);
+	if (IS_ERR(pchip->irqdomain))
+		return PTR_ERR(pchip->irqdomain);
+
 	irq0 = platform_get_irq_byname(pdev, "gpio0");
 	irq1 = platform_get_irq_byname(pdev, "gpio1");
 	irq_mux = platform_get_irq_byname(pdev, "gpio_mux");
 	if ((irq0 > 0 && irq1 <= 0) || (irq0 <= 0 && irq1 > 0)
 		|| (irq_mux <= 0))
 		return -EINVAL;
+
+	pchip->irq0 = irq0;
+	pchip->irq1 = irq1;
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	gpio_reg_base = devm_ioremap(&pdev->dev, res->start,
 				     resource_size(res));
@@ -635,7 +657,8 @@ static int pxa_gpio_probe(struct platform_device *pdev)
 	}
 
 	/* Initialize GPIO chips */
-	ret = pxa_init_gpio_chip(pchip, pxa_last_gpio + 1, gpio_reg_base);
+	ret = pxa_init_gpio_chip(pchip, pxa_last_gpio + 1, pdev->dev.of_node,
+				 gpio_reg_base);
 	if (ret) {
 		clk_put(clk);
 		return ret;
@@ -651,35 +674,31 @@ static int pxa_gpio_probe(struct platform_device *pdev)
 			writel_relaxed(~0, c->regbase + ED_MASK_OFFSET);
 	}
 
-	if (!use_of) {
-		if (irq0 > 0) {
-			irq = gpio_to_irq(0);
-			irq_set_chip_and_handler(irq, &pxa_muxed_gpio_chip,
-						 handle_edge_irq);
-			irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE);
-		}
-		if (irq1 > 0) {
-			irq = gpio_to_irq(1);
-			irq_set_chip_and_handler(irq, &pxa_muxed_gpio_chip,
-						 handle_edge_irq);
-			irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE);
-		}
-
-		for (irq  = gpio_to_irq(gpio_offset);
-			irq <= gpio_to_irq(pxa_last_gpio); irq++) {
-			irq_set_chip_and_handler(irq, &pxa_muxed_gpio_chip,
-						 handle_edge_irq);
-			irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE);
-		}
+	if (irq0 > 0) {
+		ret = devm_request_irq(&pdev->dev,
+				       irq0, pxa_gpio_direct_handler, 0,
+				       "gpio-0", pchip);
+		if (ret)
+			dev_err(&pdev->dev, "request of gpio0 irq failed: %d\n",
+				ret);
+	}
+	if (irq1 > 0) {
+		ret = devm_request_irq(&pdev->dev,
+				       irq1, pxa_gpio_direct_handler, 0,
+				       "gpio-1", pchip);
+		if (ret)
+			dev_err(&pdev->dev, "request of gpio1 irq failed: %d\n",
+				ret);
 	}
+	ret = devm_request_irq(&pdev->dev,
+			       irq_mux, pxa_gpio_demux_handler, 0,
+				       "gpio-mux", pchip);
+	if (ret)
+		dev_err(&pdev->dev, "request of gpio-mux irq failed: %d\n",
+				ret);
 
-	if (irq0 > 0)
-		irq_set_chained_handler(irq0, pxa_gpio_demux_handler);
-	if (irq1 > 0)
-		irq_set_chained_handler(irq1, pxa_gpio_demux_handler);
 	pxa_gpio_chip = pchip;
 
-	irq_set_chained_handler(irq_mux, pxa_gpio_demux_handler);
 	return 0;
 }
 
-- 
2.1.4

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