[U-Boot] [PATCH 1/2] bcm: Add GPIO driver for BCM2835 SoC

[Vikram Narayanan]

Signed-off-by: Vikram Narayanan <vikram186 at gmail.com>
Cc: Stephen Warren <swarren at wwwdotorg.org>
Cc: Albert Aribaud <albert.u.boot at aribaud.net>
---
 arch/arm/include/asm/arch-bcm2835/gpio.h |   49 +++++++++++
 drivers/gpio/Makefile                    |    1 +
 drivers/gpio/rpi_gpio.c                  |  128 ++++++++++++++++++++++++++++++
 3 files changed, 178 insertions(+), 0 deletions(-)
 create mode 100644 arch/arm/include/asm/arch-bcm2835/gpio.h
 create mode 100644 drivers/gpio/rpi_gpio.c

diff --git a/arch/arm/include/asm/arch-bcm2835/gpio.h b/arch/arm/include/asm/arch-bcm2835/gpio.h
new file mode 100644
index 0000000..3cba0fb
--- /dev/null
+++ b/arch/arm/include/asm/arch-bcm2835/gpio.h
@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2012 Vikram Narayananan
+ * <vikram186 at gmail.com>
+ *
+ * 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 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
+ */
+
+#ifndef _BCM2835_GPIO_H_
+#define _BCM2835_GPIO_H_
+
+#define BCM2835_GPIO_BASE	(0x7E200000)
+#define BCM2835_MAX_GPIOS	53
+
+#define BCM2835_GPIO_FSEL_CLR_MASK	(0x7)
+#define BCM2835_GPIO_OUTPUT			(0x1)
+
+#define GPIO_TO_BANK(n)	(n / 10)
+#define GPIO_TO_PIN(n)	(n % 10)
+
+struct bcm_gpio_regs {
+	u32 gpfsel[6];
+	u32 reserved1;
+	u32 gpset0;
+	u32 gpset1;
+	u32 reserved2;
+	u32 gpclr0;
+	u32 gpclr1;
+	u32 reserved3;
+	u32 gplev0;
+	u32 gplev1;
+};
+
+#endif /* _BCM2835_GPIO_H_ */
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index fb3b09a..b042c46 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -39,6 +39,7 @@ COBJS-$(CONFIG_TEGRA2_GPIO)	+= tegra2_gpio.o
 COBJS-$(CONFIG_DA8XX_GPIO)	+= da8xx_gpio.o
 COBJS-$(CONFIG_ALTERA_PIO)	+= altera_pio.o
 COBJS-$(CONFIG_MPC83XX_GPIO)	+= mpc83xx_gpio.o
+COBJS-$(CONFIG_BCM2835_GPIO)	+= rpi_gpio.o
 
 COBJS	:= $(COBJS-y)
 SRCS 	:= $(COBJS:.o=.c)
diff --git a/drivers/gpio/rpi_gpio.c b/drivers/gpio/rpi_gpio.c
new file mode 100644
index 0000000..c2b547f
--- /dev/null
+++ b/drivers/gpio/rpi_gpio.c
@@ -0,0 +1,128 @@
+/*
+ * Copyright (C) 2012 Vikram Narayananan
+ * <vikram186 at gmail.com>
+ *
+ * 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 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 <asm/gpio.h>
+#include <asm/io.h>
+
+struct bcm_gpio {
+	u32 bank;
+	u32 pin;
+};
+
+inline int gpio_is_valid(unsigned gpio)
+{
+	return (gpio > BCM2835_MAX_GPIOS) ? 0 : 1;
+}
+
+static int get_bank_pin(unsigned gpio, struct bcm_gpio *pio)
+{
+	int bank = GPIO_TO_BANK(gpio);
+	int pin = GPIO_TO_PIN(gpio);
+
+	if (!gpio_is_valid(gpio))
+		return -1;
+
+	pin &= 0x09;
+	pio->pin = pin;
+	pio->bank = bank;
+	return 0;
+}
+
+int gpio_request(unsigned gpio, const char *label)
+{
+	return (gpio_is_valid(gpio)) ? 1 : 0;
+}
+
+int gpio_free(unsigned gpio)
+{
+	return 0;
+}
+
+int gpio_direction_input(unsigned gpio)
+{
+	struct bcm_gpio pio;
+	struct bcm_gpio_regs *reg = (struct bcm_gpio_regs *)BCM2835_GPIO_BASE;
+	unsigned val = 0;
+
+	if (get_bank_pin(gpio, &pio))
+		return -1;
+
+	val = readl(&reg->gpfsel[pio.bank]);
+	val &= ~(BCM2835_GPIO_FSEL_CLR_MASK << (pio.pin * 3));
+	writel(val, reg->gpfsel[pio.bank]);
+}
+
+int gpio_direction_output(unsigned gpio, int value)
+{
+	struct bcm_gpio pio;
+	struct bcm_gpio_regs *reg = (struct bcm_gpio_regs *)BCM2835_GPIO_BASE;
+	unsigned val = 0;
+
+	if (get_bank_pin(gpio, &pio))
+		return -1;
+
+	val = readl(&reg->gpfsel[pio.bank]);
+	val &= ~(BCM2835_GPIO_FSEL_CLR_MASK << (pio.pin * 3));
+	val |= (BCM2835_GPIO_OUTPUT << (pio.pin * 3));
+	writel(val, reg->gpfsel[pio.bank]);
+
+	if (value)
+		gpio_set_value(gpio, value);
+}
+
+int gpio_get_value(unsigned gpio)
+{
+	struct bcm_gpio_regs *reg = (struct bcm_gpio_regs *)BCM2835_GPIO_BASE;
+	unsigned val = 0;
+
+	if (!gpio_is_valid(gpio))
+		return -1;
+
+	val = (gpio < 32) ? readl(&reg->gplev0) : readl(&reg->gplev1);
+	gpio &= 0x1f;
+
+	return (val & (1 << gpio)) >> gpio;
+}
+
+int gpio_set_value(unsigned gpio, int value)
+{
+	struct bcm_gpio_regs *reg = (struct bcm_gpio_regs *)BCM2835_GPIO_BASE;
+
+	if (!gpio_is_valid(gpio))
+		return -1;
+
+	if (gpio < 32) {
+		if (value)
+			writel((1 << gpio), reg->gpset0);
+		else
+			writel((1 << gpio), reg->gpclr0);
+	} else {
+		gpio &= 0x1f;
+		if (value)
+			writel((1 << pin), reg->gpset1);
+		else
+			writel((1 << pin), reg->gpclr1);
+	}
+	return 0;
+}
-- 
1.7.4.1