[PATCH 2/5] BCM2835: add gpio driver
Carlo Caione
carlo.caione at gmail.com
Sat Oct 13 10:00:13 EDT 2012
Signed-off-by: Carlo Caione <carlo.caione at gmail.com>
---
drivers/gpio/Kconfig | 4 ++
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-bcm2835.c | 165 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 170 insertions(+)
create mode 100644 drivers/gpio/gpio-bcm2835.c
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index a0e9b58..e8eeb6d 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -6,6 +6,10 @@ if GPIOLIB
menu "GPIO "
+config GPIO_BCM2835
+ bool "GPIO support for BCM2835"
+ depends on ARCH_BCM2835
+
config GPIO_PL061
bool "PrimeCell PL061 GPIO support"
depends on ARM_AMBA
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index e2e97d3..aecdf24 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -1,4 +1,5 @@
obj-$(CONFIG_GPIOLIB) += gpio.o
+obj-$(CONFIG_GPIO_BCM2835) += gpio-bcm2835.o
obj-$(CONFIG_GPIO_PL061) += gpio-pl061.o
obj-$(CONFIG_GPIO_STMPE) += gpio-stmpe.o
diff --git a/drivers/gpio/gpio-bcm2835.c b/drivers/gpio/gpio-bcm2835.c
new file mode 100644
index 0000000..2a9bc59
--- /dev/null
+++ b/drivers/gpio/gpio-bcm2835.c
@@ -0,0 +1,165 @@
+/*
+ * Author: Carlo Caione <carlo at carlocaione.org>
+ *
+ * Based on linux/arch/arm/mach-bcm2708/bcm2708_gpio.c
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ *
+ */
+
+#include <common.h>
+#include <errno.h>
+#include <malloc.h>
+#include <io.h>
+#include <gpio.h>
+#include <init.h>
+#include <mach/platform.h>
+
+#define GPIOFSEL(x) (0x00+(x)*4)
+#define GPIOSET(x) (0x1c+(x)*4)
+#define GPIOCLR(x) (0x28+(x)*4)
+#define GPIOLEV(x) (0x34+(x)*4)
+#define GPIOEDS(x) (0x40+(x)*4)
+#define GPIOREN(x) (0x4c+(x)*4)
+#define GPIOFEN(x) (0x58+(x)*4)
+#define GPIOHEN(x) (0x64+(x)*4)
+#define GPIOLEN(x) (0x70+(x)*4)
+#define GPIOAREN(x) (0x7c+(x)*4)
+#define GPIOAFEN(x) (0x88+(x)*4)
+#define GPIOUD(x) (0x94+(x)*4)
+#define GPIOUDCLK(x) (0x98+(x)*4)
+
+enum {
+ GPIO_FSEL_INPUT, GPIO_FSEL_OUTPUT,
+ GPIO_FSEL_ALT5, GPIO_FSEL_ALT_4,
+ GPIO_FSEL_ALT0, GPIO_FSEL_ALT1,
+ GPIO_FSEL_ALT2, GPIO_FSEL_ALT3,
+};
+
+struct bcm2835_gpio_chip {
+ void __iomem *base;
+ struct gpio_chip chip;
+};
+
+static int bcm2835_set_function(struct gpio_chip *chip, unsigned gpio, int function)
+{
+ struct bcm2835_gpio_chip *bcmgpio = container_of(chip, struct bcm2835_gpio_chip, chip);
+ void __iomem *base = bcmgpio->base;
+ unsigned gpiodir;
+ unsigned gpio_bank = gpio / 10;
+ unsigned gpio_field_offset = (gpio - 10 * gpio_bank) * 3;
+
+ gpiodir = readl(base + GPIOFSEL(gpio_bank));
+ gpiodir &= ~(7 << gpio_field_offset);
+ gpiodir |= function << gpio_field_offset;
+ writel(gpiodir, base + GPIOFSEL(gpio_bank));
+ gpiodir = readl(base + GPIOFSEL(gpio_bank));
+
+ return 0;
+}
+
+static void bcm2835_gpio_set_value(struct gpio_chip *chip, unsigned gpio, int value)
+{
+ struct bcm2835_gpio_chip *bcmgpio = container_of(chip, struct bcm2835_gpio_chip, chip);
+ void __iomem *base = bcmgpio->base;
+ unsigned gpio_bank = gpio / 32;
+ unsigned gpio_field_offset = gpio % 32;
+
+ if (value)
+ writel(1 << gpio_field_offset, base + GPIOSET(gpio_bank));
+ else
+ writel(1 << gpio_field_offset, base + GPIOCLR(gpio_bank));
+}
+
+static int bcm2835_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
+{
+ struct bcm2835_gpio_chip *bcmgpio = container_of(chip, struct bcm2835_gpio_chip, chip);
+ void __iomem *base = bcmgpio->base;
+ unsigned gpio_bank = gpio / 32;
+ unsigned gpio_field_offset = gpio % 32;
+ unsigned lev;
+
+ lev = readl(base + GPIOLEV(gpio_bank));
+ return 0x1 & (lev >> gpio_field_offset);
+}
+
+static int bcm2835_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
+{
+ return bcm2835_set_function(chip, gpio, GPIO_FSEL_INPUT);
+}
+
+static int bcm2835_gpio_direction_output(struct gpio_chip *chip, unsigned gpio, int value)
+{
+ bcm2835_set_function(chip, gpio, GPIO_FSEL_OUTPUT);
+ bcm2835_gpio_set_value(chip, gpio, value);
+
+ return 0;
+}
+
+static struct gpio_ops bcm2835_gpio_ops = {
+ .direction_input = bcm2835_gpio_direction_input,
+ .direction_output = bcm2835_gpio_direction_output,
+ .get = bcm2835_gpio_get_value,
+ .set = bcm2835_gpio_set_value,
+};
+
+static int bcm2835_gpio_probe(struct device_d *dev)
+{
+ struct bcm2835_gpio_chip *bcmgpio;
+ int ret;
+
+ bcmgpio = xzalloc(sizeof(*bcmgpio));
+ bcmgpio->base = dev_request_mem_region(dev, 0);
+ bcmgpio->chip.ops = &bcm2835_gpio_ops;
+ bcmgpio->chip.base = -1;
+ bcmgpio->chip.ngpio = 54;
+ bcmgpio->chip.dev = dev;
+
+ ret = gpiochip_add(&bcmgpio->chip);
+ 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, bcmgpio->chip.base);
+
+ return 0;
+
+err:
+ kfree(bcmgpio);
+
+ return ret;
+}
+
+static __maybe_unused struct of_device_id bcm2835_gpio_dt_ids[] = {
+ {
+ .compatible = "bcm,bcm2835-gpio",
+ }, {
+ /* sentinel */
+ }
+};
+
+static struct driver_d bcm2835_gpio_driver = {
+ .name = "bcm2835-gpio",
+ .probe = bcm2835_gpio_probe,
+ .of_compatible = DRV_OF_COMPAT(bcm2835_gpio_dt_ids),
+};
+
+static int bcm2835_gpio_add(void)
+{
+ platform_driver_register(&bcm2835_gpio_driver);
+ return 0;
+}
+coredevice_initcall(bcm2835_gpio_add);
--
1.7.12.3
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