[PATCH v4 3/6] ARM: at91/gpio: add DT support

[Nicolas Ferre <nicolas.ferre-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org>]

From: Jean-Christophe PLAGNIOL-VILLARD <plagnioj-sclMFOaUSTBWk0Htik3J/w@public.gmane.org>

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj-sclMFOaUSTBWk0Htik3J/w@public.gmane.org>
Signed-off-by: Nicolas Ferre <nicolas.ferre-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org>
Acked-by: Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>
---
v4: - at91_gpio_setup_clk() returns an error code

v3: - Corrections proposed by Russell King:
      - use of clk_prepare()/clk_unprepare()
      - helper function to setup the clock for both DT/non DT init functions

v2: - no BUG_ON() anymore in case of an "interrupts" property missing
      just stop configuring the gpio bank
    - review error path in both of_at91_gpio_init_one() and
      at91_gpio_init_one()
    - use for_each_compatible_node() iterator instead of a homemade loop

---
 .../devicetree/bindings/gpio/gpio_at91.txt         |   20 +++
 arch/arm/boot/dts/at91sam9g20.dtsi                 |   28 ++++
 arch/arm/boot/dts/at91sam9g45.dtsi                 |   45 ++++++
 arch/arm/mach-at91/gpio.c                          |  163 ++++++++++++++++---
 4 files changed, 230 insertions(+), 26 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/gpio/gpio_at91.txt

diff --git a/Documentation/devicetree/bindings/gpio/gpio_at91.txt b/Documentation/devicetree/bindings/gpio/gpio_at91.txt
new file mode 100644
index 0000000..a7bcaec
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio_at91.txt
@@ -0,0 +1,20 @@
+* Atmel GPIO controller (PIO)
+
+Required properties:
+- compatible: "atmel,at91rm9200-gpio"
+- reg: Should contain GPIO controller registers location and length
+- interrupts: Should be the port interrupt shared by all the pins.
+- #gpio-cells: Should be two.  The first cell is the pin number and
+  the second cell is used to specify optional parameters (currently
+  unused).
+- gpio-controller: Marks the device node as a GPIO controller.
+
+Example:
+	pioA: gpio@fffff200 {
+		compatible = "atmel,at91rm9200-gpio";
+		reg = <0xfffff200 0x100>;
+		interrupts = <2 4>;
+		#gpio-cells = <2>;
+		gpio-controller;
+	};
+
diff --git a/arch/arm/boot/dts/at91sam9g20.dtsi b/arch/arm/boot/dts/at91sam9g20.dtsi
index 0782f80..ea942b5 100644
--- a/arch/arm/boot/dts/at91sam9g20.dtsi
+++ b/arch/arm/boot/dts/at91sam9g20.dtsi
@@ -23,6 +23,9 @@
 		serial4 = &usart3;
 		serial5 = &usart4;
 		serial6 = &usart5;
+		gpio0 = &pioA;
+		gpio1 = &pioB;
+		gpio2 = &pioC;
 	};
 	cpus {
 		cpu@0 {
@@ -54,6 +57,31 @@
 				reg = <0xfffff000 0x200>;
 			};
 
+
+			pioA: gpio@fffff400 {
+				compatible = "atmel,at91rm9200-gpio";
+				reg = <0xfffff400 0x100>;
+				interrupts = <2 4>;
+				#gpio-cells = <2>;
+				gpio-controller;
+			};
+
+			pioB: gpio@fffff600 {
+				compatible = "atmel,at91rm9200-gpio";
+				reg = <0xfffff600 0x100>;
+				interrupts = <3 4>;
+				#gpio-cells = <2>;
+				gpio-controller;
+			};
+
+			pioC: gpio@fffff800 {
+				compatible = "atmel,at91rm9200-gpio";
+				reg = <0xfffff800 0x100>;
+				interrupts = <4 4>;
+				#gpio-cells = <2>;
+				gpio-controller;
+			};
+
 			dbgu: serial@fffff200 {
 				compatible = "atmel,at91sam9260-usart";
 				reg = <0xfffff200 0x200>;
diff --git a/arch/arm/boot/dts/at91sam9g45.dtsi b/arch/arm/boot/dts/at91sam9g45.dtsi
index e89b1d7..ebc9617 100644
--- a/arch/arm/boot/dts/at91sam9g45.dtsi
+++ b/arch/arm/boot/dts/at91sam9g45.dtsi
@@ -22,6 +22,11 @@
 		serial2 = &usart1;
 		serial3 = &usart2;
 		serial4 = &usart3;
+		gpio0 = &pioA;
+		gpio1 = &pioB;
+		gpio2 = &pioC;
+		gpio3 = &pioD;
+		gpio4 = &pioE;
 	};
 	cpus {
 		cpu@0 {
@@ -59,6 +64,46 @@
 				interrupts = <21 4>;
 			};
 
+			pioA: gpio@fffff200 {
+				compatible = "atmel,at91rm9200-gpio";
+				reg = <0xfffff200 0x100>;
+				interrupts = <2 4>;
+				#gpio-cells = <2>;
+				gpio-controller;
+			};
+
+			pioB: gpio@fffff400 {
+				compatible = "atmel,at91rm9200-gpio";
+				reg = <0xfffff400 0x100>;
+				interrupts = <3 4>;
+				#gpio-cells = <2>;
+				gpio-controller;
+			};
+
+			pioC: gpio@fffff600 {
+				compatible = "atmel,at91rm9200-gpio";
+				reg = <0xfffff600 0x100>;
+				interrupts = <4 4>;
+				#gpio-cells = <2>;
+				gpio-controller;
+			};
+
+			pioD: gpio@fffff800 {
+				compatible = "atmel,at91rm9200-gpio";
+				reg = <0xfffff800 0x100>;
+				interrupts = <5 4>;
+				#gpio-cells = <2>;
+				gpio-controller;
+			};
+
+			pioE: gpio@fffffa00 {
+				compatible = "atmel,at91rm9200-gpio";
+				reg = <0xfffffa00 0x100>;
+				interrupts = <5 4>;
+				#gpio-cells = <2>;
+				gpio-controller;
+			};
+
 			dbgu: serial@ffffee00 {
 				compatible = "atmel,at91sam9260-usart";
 				reg = <0xffffee00 0x200>;
diff --git a/arch/arm/mach-at91/gpio.c b/arch/arm/mach-at91/gpio.c
index 7ffb893..3561912 100644
--- a/arch/arm/mach-at91/gpio.c
+++ b/arch/arm/mach-at91/gpio.c
@@ -21,6 +21,7 @@
 #include <linux/module.h>
 #include <linux/io.h>
 #include <linux/irqdomain.h>
+#include <linux/of_address.h>
 
 #include <mach/hardware.h>
 #include <mach/at91_pio.h>
@@ -303,9 +304,10 @@ void at91_gpio_suspend(void)
 		__raw_writel(backups[i], pio + PIO_IDR);
 		__raw_writel(wakeups[i], pio + PIO_IER);
 
-		if (!wakeups[i])
+		if (!wakeups[i]) {
+			clk_unprepare(gpio_chip[i].clock);
 			clk_disable(gpio_chip[i].clock);
-		else {
+		} else {
 #ifdef CONFIG_PM_DEBUG
 			printk(KERN_DEBUG "GPIO-%c may wake for %08x\n", 'A'+i, wakeups[i]);
 #endif
@@ -320,8 +322,10 @@ void at91_gpio_resume(void)
 	for (i = 0; i < gpio_banks; i++) {
 		void __iomem	*pio = gpio_chip[i].regbase;
 
-		if (!wakeups[i])
-			clk_enable(gpio_chip[i].clock);
+		if (!wakeups[i]) {
+			if (clk_prepare(gpio_chip[i].clock) == 0)
+				clk_enable(gpio_chip[i].clock);
+		}
 
 		__raw_writel(wakeups[i], pio + PIO_IDR);
 		__raw_writel(backups[i], pio + PIO_IER);
@@ -624,40 +628,147 @@ static void at91_gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
 	}
 }
 
+static int __init at91_gpio_setup_clk(int i)
+{
+	struct at91_gpio_chip *at91_gpio = &gpio_chip[i];
+
+	/* retreive PIO controller's clock */
+	at91_gpio->clock = clk_get_sys(NULL, at91_gpio->chip.label);
+	if (IS_ERR(at91_gpio->clock)) {
+		pr_err("at91_gpio.%d, failed to get clock, ignoring.\n", i);
+		goto err;
+	}
+
+	if (clk_prepare(at91_gpio->clock))
+		goto clk_prep_err;
+
+	/* enable PIO controller's clock */
+	if(clk_enable(at91_gpio->clock)) {
+		pr_err("at91_gpio.%d, failed to enable clock, ignoring.\n", i);
+		goto clk_err;
+	}
+
+	return 0;
+
+clk_err:
+	clk_unprepare(at91_gpio->clock);
+clk_prep_err:
+	clk_put(at91_gpio->clock);
+err:
+	return -EINVAL;
+}
+
+#ifdef CONFIG_OF_GPIO
+static void __init of_at91_gpio_init_one(struct device_node *np)
+{
+	int alias_id;
+	struct at91_gpio_chip *at91_gpio;
+
+	if (!np)
+		return;
+
+	alias_id = of_alias_get_id(np, "gpio");
+	if (alias_id >= MAX_GPIO_BANKS) {
+		pr_err("at91_gpio, failed alias id(%d) > MAX_GPIO_BANKS(%d), ignoring.\n",
+						alias_id, MAX_GPIO_BANKS);
+		return;
+	}
+
+	at91_gpio = &gpio_chip[alias_id];
+	at91_gpio->chip.base = alias_id * at91_gpio->chip.ngpio;
+
+	at91_gpio->regbase = of_iomap(np, 0);
+	if (!at91_gpio->regbase) {
+		pr_err("at91_gpio.%d, failed to map registers, ignoring.\n",
+								alias_id);
+		return;
+	}
+
+	/* Get the interrupts property */
+	if (of_property_read_u32(np, "interrupts", &at91_gpio->id)) {
+		pr_err("at91_gpio.%d, failed to get interrupts property, ignoring.\n",
+								alias_id);
+		goto ioremap_err;
+	}
+
+	/* Setup clock */
+	if (at91_gpio_setup_clk(alias_id))
+		goto ioremap_err;
+
+	at91_gpio->chip.of_node = np;
+	gpio_banks = max(gpio_banks, alias_id + 1);
+	return;
+
+ioremap_err:
+	iounmap(at91_gpio->regbase);
+}
+
+static int __init of_at91_gpio_init(void)
+{
+	struct device_node *np = NULL;
+
+	/*
+	 * This isn't ideal, but it gets things hooked up until this
+	 * driver is converted into a platform_device
+	 */
+	for_each_compatible_node(np, NULL, "atmel,at91rm9200-gpio")
+		of_at91_gpio_init_one(np);
+
+	return gpio_banks > 0 ? 0 : -EINVAL;
+}
+#else
+static int __init of_at91_gpio_init(void)
+{
+	return -EINVAL;
+}
+#endif
+
+static void __init at91_gpio_init_one(int i, u32 regbase, int id)
+{
+	struct at91_gpio_chip *at91_gpio = &gpio_chip[i];
+
+	at91_gpio->chip.base = i * at91_gpio->chip.ngpio;
+	at91_gpio->id = id;
+
+	at91_gpio->regbase = ioremap(regbase, 512);
+	if (!at91_gpio->regbase) {
+		pr_err("at91_gpio.%d, failed to map registers, ignoring.\n", i);
+		return;
+	}
+
+	if (at91_gpio_setup_clk(i))
+		goto ioremap_err;
+
+	gpio_banks = max(gpio_banks, i + 1);
+	return;
+
+ioremap_err:
+	iounmap(at91_gpio->regbase);
+}
+
 /*
  * Called from the processor-specific init to enable GPIO pin support.
  */
 void __init at91_gpio_init(struct at91_gpio_bank *data, int nr_banks)
 {
-	unsigned		i;
+	unsigned i;
 	struct at91_gpio_chip *at91_gpio, *last = NULL;
 
 	BUG_ON(nr_banks > MAX_GPIO_BANKS);
 
-	gpio_banks = nr_banks;
+	if (of_at91_gpio_init() < 0) {
+		/* No GPIO controller found in device tree */
+		for (i = 0; i < nr_banks; i++)
+			at91_gpio_init_one(i, data[i].regbase, data[i].id);
+	}
 
-	for (i = 0; i < nr_banks; i++) {
+	for (i = 0; i < gpio_banks; i++) {
 		at91_gpio = &gpio_chip[i];
 
-		at91_gpio->id = data[i].id;
-		at91_gpio->chip.base = i * 32;
-
-		at91_gpio->regbase = ioremap(data[i].regbase, 512);
-		if (!at91_gpio->regbase) {
-			pr_err("at91_gpio.%d, failed to map registers, ignoring.\n", i);
-			continue;
-		}
-
-		at91_gpio->clock = clk_get_sys(NULL, at91_gpio->chip.label);
-		if (!at91_gpio->clock) {
-			pr_err("at91_gpio.%d, failed to get clock, ignoring.\n", i);
-			continue;
-		}
-
-		/* enable PIO controller's clock */
-		clk_enable(at91_gpio->clock);
-
-		/* AT91SAM9263_ID_PIOCDE groups PIOC, PIOD, PIOE */
+		/*
+		 * GPIO controller are grouped on some SoC:
+		 * PIOC, PIOD and PIOE can share the same IRQ line
+		 */
 		if (last && last->id == at91_gpio->id)
 			last->next = at91_gpio;
 		last = at91_gpio;
-- 
1.7.5.4