[PATCH v4] GPIO PL061: Adding Clk framework support

[viresh.kumar@st.com (Viresh KUMAR)]

From: Viresh KUMAR <viresh.kumar@st.com>

GPIO Clk is never enabled on Platforms, like: SPEAr, which are based upon clock
framework and use PL061 driver. This patch adds support for Clk enabling and
disabling as and when gpios are requested and freed.

Modifications in V4:
 - Not registering gpio_request and gpio_free if clk is not found.

Modifications in V3:
 - if clk_get returns -ENOENT, then work without clk enable/disable.

Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
---
 drivers/gpio/pl061.c |   49 +++++++++++++++++++++++++++++++++++++++++++------
 1 files changed, 43 insertions(+), 6 deletions(-)

diff --git a/drivers/gpio/pl061.c b/drivers/gpio/pl061.c
index 105701a..b826d2b 100644
--- a/drivers/gpio/pl061.c
+++ b/drivers/gpio/pl061.c
@@ -11,7 +11,10 @@
  *
  * Data sheet: ARM DDI 0190B, September 2000
  */
+
+#include <linux/clk.h>
 #include <linux/spinlock.h>
+#include <linux/err.h>
 #include <linux/errno.h>
 #include <linux/module.h>
 #include <linux/list.h>
@@ -56,8 +59,26 @@ struct pl061_gpio {
 	void __iomem		*base;
 	unsigned		irq_base;
 	struct gpio_chip	gc;
+	struct clk		*clk;
 };
 
+static int pl061_request(struct gpio_chip *gc, unsigned offset)
+{
+	struct pl061_gpio *chip = container_of(gc, struct pl061_gpio, gc);
+
+	if (offset >= gc->ngpio)
+		return -EINVAL;
+
+	return clk_enable(chip->clk);
+}
+
+static void pl061_free(struct gpio_chip *gc, unsigned offset)
+{
+	struct pl061_gpio *chip = container_of(gc, struct pl061_gpio, gc);
+
+	clk_disable(chip->clk);
+}
+
 static int pl061_direction_input(struct gpio_chip *gc, unsigned offset)
 {
 	struct pl061_gpio *chip = container_of(gc, struct pl061_gpio, gc);
@@ -260,9 +281,18 @@ static int __init pl061_probe(struct amba_device *dev, struct amba_id *id)
 		goto release_region;
 	}
 
-	spin_lock_init(&chip->lock);
-	spin_lock_init(&chip->irq_lock);
-	INIT_LIST_HEAD(&chip->list);
+	chip->clk = clk_get(&dev->dev, NULL);
+	if (IS_ERR(chip->clk)) {
+		ret = PTR_ERR(chip->clk);
+		/* clk Not present */
+		if (ret == -ENOENT)
+			chip->clk = NULL;
+		else
+			goto iounmap;
+	} else {
+		chip->gc.request = pl061_request;
+		chip->gc.free = pl061_free;
+	}
 
 	chip->gc.direction_input = pl061_direction_input;
 	chip->gc.direction_output = pl061_direction_output;
@@ -277,9 +307,13 @@ static int __init pl061_probe(struct amba_device *dev, struct amba_id *id)
 
 	chip->irq_base = pdata->irq_base;
 
+	spin_lock_init(&chip->lock);
+	spin_lock_init(&chip->irq_lock);
+	INIT_LIST_HEAD(&chip->list);
+
 	ret = gpiochip_add(&chip->gc);
 	if (ret)
-		goto iounmap;
+		goto free_clk;
 
 	/*
 	 * irq_chip support
@@ -292,7 +326,7 @@ static int __init pl061_probe(struct amba_device *dev, struct amba_id *id)
 	irq = dev->irq[0];
 	if (irq < 0) {
 		ret = -ENODEV;
-		goto iounmap;
+		goto free_clk;
 	}
 	set_irq_chained_handler(irq, pl061_irq_handler);
 	if (!test_and_set_bit(irq, init_irq)) { /* list initialized? */
@@ -300,7 +334,7 @@ static int __init pl061_probe(struct amba_device *dev, struct amba_id *id)
 		if (chip_list == NULL) {
 			clear_bit(irq, init_irq);
 			ret = -ENOMEM;
-			goto iounmap;
+			goto free_clk;
 		}
 		INIT_LIST_HEAD(chip_list);
 		set_irq_data(irq, chip_list);
@@ -323,6 +357,9 @@ static int __init pl061_probe(struct amba_device *dev, struct amba_id *id)
 
 	return 0;
 
+free_clk:
+	if (chip->clk)
+		clk_put(chip->clk);
 iounmap:
 	iounmap(chip->base);
 release_region:
-- 
1.6.0.2