[RFC 3/8] gpio: add driver for Canon DIGIC

[Antony Pavlov]

Signed-off-by: Antony Pavlov <antonynpavlov at gmail.com>
---
 drivers/gpio/Kconfig      |   4 ++
 drivers/gpio/Makefile     |   1 +
 drivers/gpio/gpio-digic.c | 176 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 181 insertions(+)
 create mode 100644 drivers/gpio/gpio-digic.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index d5ac532..f112db8 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -9,6 +9,10 @@ menu "GPIO"
 config GPIO_GENERIC
 	bool
 
+config GPIO_DIGIC
+	bool "GPIO support for Canon DIGIC"
+	depends on ARCH_DIGIC
+
 config GPIO_BCM2835
 	bool "GPIO support for BCM2835"
 	depends on ARCH_BCM2835
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index adb668f..c5cf58a 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -2,6 +2,7 @@ obj-$(CONFIG_GPIOLIB)		+= gpiolib.o
 
 obj-$(CONFIG_GPIO_BCM2835)	+= gpio-bcm2835.o
 obj-$(CONFIG_GPIO_CLPS711X)	+= gpio-clps711x.o
+obj-$(CONFIG_GPIO_DIGIC)	+= gpio-digic.o
 obj-$(CONFIG_GPIO_GENERIC)	+= gpio-generic.o
 obj-$(CONFIG_GPIO_IMX)		+= gpio-imx.o
 obj-$(CONFIG_GPIO_ORION)	+= gpio-orion.o
diff --git a/drivers/gpio/gpio-digic.c b/drivers/gpio/gpio-digic.c
new file mode 100644
index 0000000..82eef12
--- /dev/null
+++ b/drivers/gpio/gpio-digic.c
@@ -0,0 +1,176 @@
+/*
+ * Copyright (C) 2013 Antony Pavlov <antonynpavlov at gmail.com>
+ *
+ * This file is part of barebox.
+ * See file CREDITS for list of people who contributed to this project.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <common.h>
+#include <malloc.h>
+#include <errno.h>
+#include <io.h>
+#include <gpio.h>
+#include <init.h>
+
+/*
+ * See http://magiclantern.wikia.com/wiki/Register_Map#GPIO_Ports
+ */
+
+#define DIGIC_GPIO_IN_LVL	1
+#define DIGIC_GPIO_OUT_LVL	2
+#define DIGIC_GPIO_DIR	4
+#define DIGIC_GPIO_TRISTATE	8
+
+struct digic_gpio_chip {
+	void __iomem		*base;
+	struct gpio_chip	gc;
+};
+
+static inline uint32_t digic_gpio_readl(struct digic_gpio_chip *chip, uint32_t offset)
+{
+	return readl(chip->base + 4 * offset);
+}
+
+static inline void digic_gpio_writel(struct digic_gpio_chip *chip, uint32_t val,
+			  uint32_t offset)
+{
+	writel(val, chip->base + 4 * offset);
+}
+
+static int digic_gpio_get_value(struct gpio_chip *gc, unsigned offset)
+{
+	struct digic_gpio_chip *chip = container_of(gc, struct digic_gpio_chip, gc);
+
+	if (offset >= gc->ngpio)
+		return -EINVAL;
+
+	return digic_gpio_readl(chip, offset) & DIGIC_GPIO_IN_LVL;
+}
+
+static void digic_gpio_set_value(struct gpio_chip *gc, unsigned offset, int value)
+{
+	struct digic_gpio_chip *chip = container_of(gc, struct digic_gpio_chip, gc);
+	uint32_t t;
+
+	if (offset >= gc->ngpio)
+		return;
+
+	t = digic_gpio_readl(chip, offset);
+	/* Port direction (1 = OUT, 0 = IN) */
+	if (value) {
+		t |= DIGIC_GPIO_OUT_LVL;
+	} else {
+		t &= ~(DIGIC_GPIO_OUT_LVL);
+	}
+	digic_gpio_writel(chip, t, offset);
+}
+
+static int digic_gpio_direction_input(struct gpio_chip *gc, unsigned offset)
+{
+	struct digic_gpio_chip *chip = container_of(gc, struct digic_gpio_chip, gc);
+	uint32_t t;
+
+	if (offset >= gc->ngpio)
+		return -EINVAL;
+
+	t = digic_gpio_readl(chip, offset);
+	/* Port direction (1 = OUT, 0 = IN) */
+	t &= ~(DIGIC_GPIO_DIR);
+	digic_gpio_writel(chip, t, offset);
+
+	return 0;
+}
+
+static int digic_gpio_direction_output(struct gpio_chip *gc, unsigned offset,
+		int value)
+{
+	struct digic_gpio_chip *chip = container_of(gc, struct digic_gpio_chip, gc);
+	uint32_t t;
+
+	if (offset >= gc->ngpio)
+		return -EINVAL;
+
+	t = digic_gpio_readl(chip, offset);
+	/* Port direction (1 = OUT, 0 = IN) */
+	t |= DIGIC_GPIO_DIR;
+	digic_gpio_writel(chip, t, offset);
+
+	digic_gpio_set_value(gc, offset, value);
+
+	return 0;
+}
+
+static struct gpio_ops digic_gpio_ops = {
+	.direction_input = digic_gpio_direction_input,
+	.direction_output = digic_gpio_direction_output,
+	.get = digic_gpio_get_value,
+	.set = digic_gpio_set_value,
+};
+
+static int digic_gpio_probe(struct device_d *dev)
+{
+	struct digic_gpio_chip *chip;
+	struct resource *res;
+	resource_size_t rsize;
+	int ret = -EINVAL;
+
+	chip = xzalloc(sizeof(*chip));
+
+	res = dev_get_resource(dev, 0);
+	if (!res)
+		goto err;
+
+	rsize = resource_size(res);
+	chip->gc.ngpio = rsize / sizeof(int32_t);
+
+	chip->base = dev_request_mem_region(dev, 0);
+	chip->gc.ops = &digic_gpio_ops;
+	chip->gc.base = 0;
+
+	chip->gc.dev = dev;
+
+	ret = gpiochip_add(&chip->gc);
+	if (ret) {
+		dev_err(dev, "couldn't add gpiochip, ret = %d\n", ret);
+		goto err;
+	}
+
+	dev_info(dev, "probed gpiochip%d with base %d\n", dev->id, chip->gc.base);
+
+	return 0;
+
+err:
+	kfree(chip);
+
+	return ret;
+}
+
+static __maybe_unused struct of_device_id digic_gpio_dt_ids[] = {
+	{
+		.compatible = "canon,digic-gpio",
+	}, {
+		/* sentinel */
+	}
+};
+
+static struct driver_d digic_gpio_driver = {
+	.name = "digic-gpio",
+	.probe = digic_gpio_probe,
+	.of_compatible = DRV_OF_COMPAT(digic_gpio_dt_ids),
+};
+
+static int __init digic_gpio_init(void)
+{
+	return platform_driver_register(&digic_gpio_driver);
+}
+coredevice_initcall(digic_gpio_init);
-- 
1.8.4.rc3