[PATCH v2 2/6] GPIO: xilinx: Add support for dual channel

[Michal Simek]

Supporting the second channel in the driver.
Offset is 0x8 and both channnels share the same
IRQ.

Signed-off-by: Michal Simek <michal.simek@xxxxxxxxxx>

---
Changes in v2:
- Use kernel doc format - suggested by Linus Walleij
- Do not use __raw_readl/__raw_writel IO in this patch
- Use of_property_read_u32 helper function
- Use BIT()
- Change patch subject

 drivers/gpio/gpio-xilinx.c | 103 +++++++++++++++++++++++++++++++++++++++------
 1 file changed, 91 insertions(+), 12 deletions(-)

diff --git a/drivers/gpio/gpio-xilinx.c b/drivers/gpio/gpio-xilinx.c
index 2aad534..626eaa8 100644
--- a/drivers/gpio/gpio-xilinx.c
+++ b/drivers/gpio/gpio-xilinx.c
@@ -1,7 +1,7 @@
 /*
- * Xilinx gpio driver
+ * Xilinx gpio driver for xps/axi_gpio IP.
  *
- * Copyright 2008 Xilinx, Inc.
+ * Copyright 2008 - 2013 Xilinx, Inc.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2
@@ -12,6 +12,7 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */

+#include <linux/bitops.h>
 #include <linux/init.h>
 #include <linux/errno.h>
 #include <linux/module.h>
@@ -26,11 +27,26 @@
 #define XGPIO_DATA_OFFSET   (0x0)	/* Data register  */
 #define XGPIO_TRI_OFFSET    (0x4)	/* I/O direction register  */

+#define XGPIO_CHANNEL_OFFSET	0x8
+
+/* Read/Write access to the GPIO registers */
+#define xgpio_readreg(offset)		in_be32(offset)
+#define xgpio_writereg(offset, val)	out_be32(offset, val)
+
+/**
+ * struct xgpio_instance - Stores information about GPIO device
+ * struct of_mm_gpio_chip mmchip: OF GPIO chip for memory mapped banks
+ * gpio_state: GPIO state shadow register
+ * gpio_dir: GPIO direction shadow register
+ * offset: GPIO channel offset
+ * gpio_lock: Lock used for synchronization
+ */
 struct xgpio_instance {
 	struct of_mm_gpio_chip mmchip;
-	u32 gpio_state;		/* GPIO state shadow register */
-	u32 gpio_dir;		/* GPIO direction shadow register */
-	spinlock_t gpio_lock;	/* Lock used for synchronization */
+	u32 gpio_state;
+	u32 gpio_dir;
+	u32 offset;
+	spinlock_t gpio_lock;
 };

 /**
@@ -44,8 +60,12 @@ struct xgpio_instance {
 static int xgpio_get(struct gpio_chip *gc, unsigned int gpio)
 {
 	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
+	struct xgpio_instance *chip =
+	    container_of(mm_gc, struct xgpio_instance, mmchip);

-	return (in_be32(mm_gc->regs + XGPIO_DATA_OFFSET) >> gpio) & 1;
+	void __iomem *regs = mm_gc->regs + chip->offset;
+
+	return !!(xgpio_readreg(regs + XGPIO_DATA_OFFSET) & BIT(gpio));
 }

 /**
@@ -63,6 +83,7 @@ static void xgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
 	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
 	struct xgpio_instance *chip =
 	    container_of(mm_gc, struct xgpio_instance, mmchip);
+	void __iomem *regs = mm_gc->regs;

 	spin_lock_irqsave(&chip->gpio_lock, flags);

@@ -71,7 +92,9 @@ static void xgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
 		chip->gpio_state |= 1 << gpio;
 	else
 		chip->gpio_state &= ~(1 << gpio);
-	out_be32(mm_gc->regs + XGPIO_DATA_OFFSET, chip->gpio_state);
+
+	xgpio_writereg(regs + chip->offset + XGPIO_DATA_OFFSET,
+							 chip->gpio_state);

 	spin_unlock_irqrestore(&chip->gpio_lock, flags);
 }
@@ -91,12 +114,13 @@ static int xgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
 	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
 	struct xgpio_instance *chip =
 	    container_of(mm_gc, struct xgpio_instance, mmchip);
+	void __iomem *regs = mm_gc->regs;

 	spin_lock_irqsave(&chip->gpio_lock, flags);

 	/* Set the GPIO bit in shadow register and set direction as input */
 	chip->gpio_dir |= (1 << gpio);
-	out_be32(mm_gc->regs + XGPIO_TRI_OFFSET, chip->gpio_dir);
+	xgpio_writereg(regs + chip->offset + XGPIO_TRI_OFFSET, chip->gpio_dir);

 	spin_unlock_irqrestore(&chip->gpio_lock, flags);

@@ -119,6 +143,7 @@ static int xgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
 	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
 	struct xgpio_instance *chip =
 	    container_of(mm_gc, struct xgpio_instance, mmchip);
+	void __iomem *regs = mm_gc->regs;

 	spin_lock_irqsave(&chip->gpio_lock, flags);

@@ -127,11 +152,12 @@ static int xgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
 		chip->gpio_state |= 1 << gpio;
 	else
 		chip->gpio_state &= ~(1 << gpio);
-	out_be32(mm_gc->regs + XGPIO_DATA_OFFSET, chip->gpio_state);
+	xgpio_writereg(regs + chip->offset + XGPIO_DATA_OFFSET,
+		       chip->gpio_state);

 	/* Clear the GPIO bit in shadow register and set direction as output */
 	chip->gpio_dir &= (~(1 << gpio));
-	out_be32(mm_gc->regs + XGPIO_TRI_OFFSET, chip->gpio_dir);
+	xgpio_writereg(regs + chip->offset + XGPIO_TRI_OFFSET, chip->gpio_dir);

 	spin_unlock_irqrestore(&chip->gpio_lock, flags);

@@ -147,8 +173,10 @@ static void xgpio_save_regs(struct of_mm_gpio_chip *mm_gc)
 	struct xgpio_instance *chip =
 	    container_of(mm_gc, struct xgpio_instance, mmchip);

-	out_be32(mm_gc->regs + XGPIO_DATA_OFFSET, chip->gpio_state);
-	out_be32(mm_gc->regs + XGPIO_TRI_OFFSET, chip->gpio_dir);
+	xgpio_writereg(mm_gc->regs + chip->offset + XGPIO_DATA_OFFSET,
+							chip->gpio_state);
+	xgpio_writereg(mm_gc->regs + chip->offset + XGPIO_TRI_OFFSET,
+							 chip->gpio_dir);
 }

 /**
@@ -202,6 +230,57 @@ static int xgpio_of_probe(struct device_node *np)
 		       np->full_name, status);
 		return status;
 	}
+
+	pr_info("XGpio: %s: registered, base is %d\n", np->full_name,
+							chip->mmchip.gc.base);
+
+	tree_info = of_get_property(np, "xlnx,is-dual", NULL);
+	if (tree_info && be32_to_cpup(tree_info)) {
+		chip = kzalloc(sizeof(*chip), GFP_KERNEL);
+		if (!chip)
+			return -ENOMEM;
+
+		/* Add dual channel offset */
+		chip->offset = XGPIO_CHANNEL_OFFSET;
+
+		/* Update GPIO state shadow register with default value */
+		of_property_read_u32(np, "xlnx,dout-default-2",
+				     &chip->gpio_state);
+
+		/* By default, all pins are inputs */
+		chip->gpio_dir = 0xFFFFFFFF;
+
+		/* Update GPIO direction shadow register with default value */
+		of_property_read_u32(np, "xlnx,tri-default-2", &chip->gpio_dir);
+
+		/* By default assume full GPIO controller */
+		chip->mmchip.gc.ngpio = 32;
+
+		/* Check device node and parent device node for device width */
+		of_property_read_u32(np, "xlnx,gpio2-width",
+				     (u32 *)&chip->mmchip.gc.ngpio);
+
+		spin_lock_init(&chip->gpio_lock);
+
+		chip->mmchip.gc.direction_input = xgpio_dir_in;
+		chip->mmchip.gc.direction_output = xgpio_dir_out;
+		chip->mmchip.gc.get = xgpio_get;
+		chip->mmchip.gc.set = xgpio_set;
+
+		chip->mmchip.save_regs = xgpio_save_regs;
+
+		/* Call the OF gpio helper to setup and register the GPIO dev */
+		status = of_mm_gpiochip_add(np, &chip->mmchip);
+		if (status) {
+			kfree(chip);
+			pr_err("%s: error in probe function with status %d\n",
+			np->full_name, status);
+			return status;
+		}
+		pr_info("XGpio: %s: dual channel registered, base is %d\n",
+					np->full_name, chip->mmchip.gc.base);
+	}
+
 	return 0;
 }

--
1.8.2.3

Attachment: pgp00000.pgp
Description: PGP signature