[U-Boot] [PATCH v3 1/2] gpio: bcm2835: Add GPIO driver

[Vikram Narayanan]

Driver for BCM2835 SoC. This gives the basic functionality of
setting/clearing the output.

Signed-off-by: Vikram Narayanan <vikram186 at gmail.com>
---
 arch/arm/include/asm/arch-bcm2835/gpio.h |   71 ++++++++++++++++++++++++
 drivers/gpio/Makefile                    |    1 +
 drivers/gpio/bcm2835_gpio.c              |   88 ++++++++++++++++++++++++++++++
 3 files changed, 160 insertions(+), 0 deletions(-)
 create mode 100644 arch/arm/include/asm/arch-bcm2835/gpio.h
 create mode 100644 drivers/gpio/bcm2835_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..515456a
--- /dev/null
+++ b/arch/arm/include/asm/arch-bcm2835/gpio.h
@@ -0,0 +1,71 @@
+/*
+ * 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_GPIO_COUNT	53
+
+#define BCM2835_GPIO_FSEL_MASK	0x7
+#define BCM2835_GPIO_INPUT		0x0
+#define BCM2835_GPIO_OUTPUT		0x1
+#define BCM2835_GPIO_ALT0		0x2
+#define BCM2835_GPIO_ALT1		0x3
+#define BCM2835_GPIO_ALT2		0x4
+#define BCM2835_GPIO_ALT3		0x5
+#define BCM2835_GPIO_ALT4		0x6
+#define BCM2835_GPIO_ALT5		0x7
+
+#define BCM2835_GPIO_COMMON_BANK(gpio)			((gpio < 32) ? 0 : 1)
+#define BCM2835_GPIO_COMMON_SHIFT(gpio)		(gpio & 0x1f)
+
+#define BCM2835_GPIO_FSEL_BANK(gpio)	(gpio / 10)
+#define BCM2835_GPIO_FSEL_SHIFT(gpio)	((gpio % 10) * 3)
+
+struct bcm_gpio_regs {
+	u32 gpfsel[6];
+	u32 reserved1;
+	u32 gpset[2];
+	u32 reserved2;
+	u32 gpclr[2];
+	u32 reserved3;
+	u32 gplev[2];
+	u32 reserved4;
+	u32 gpeds[2];
+	u32 reserved5;
+	u32 gpren[2];
+	u32 reserved6;
+	u32 gpfen[2];
+	u32 reserved7;
+	u32 gphen[2];
+	u32 reserved8;
+	u32 gplen[2];
+	u32 reserved9;
+	u32 gparen[2];
+	u32 reserved10;
+	u32 gppud;
+	u32 gppudclk[2];
+};
+
+#endif /* _BCM2835_GPIO_H_ */
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 32a2474..8d2f2b2 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -40,6 +40,7 @@ COBJS-$(CONFIG_TEGRA_GPIO)	+= tegra_gpio.o
 COBJS-$(CONFIG_DA8XX_GPIO)	+= da8xx_gpio.o
 COBJS-$(CONFIG_ALTERA_PIO)	+= altera_pio.o
 COBJS-$(CONFIG_MPC83XX_GPIO)	+= mpc83xx_gpio.o
+COBJS-$(CONFIG_BCM2835_GPIO)	+= bcm2835_gpio.o
 
 COBJS	:= $(COBJS-y)
 SRCS 	:= $(COBJS:.o=.c)
diff --git a/drivers/gpio/bcm2835_gpio.c b/drivers/gpio/bcm2835_gpio.c
new file mode 100644
index 0000000..eb02efa
--- /dev/null
+++ b/drivers/gpio/bcm2835_gpio.c
@@ -0,0 +1,88 @@
+/*
+ * 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>
+
+inline int gpio_is_valid(unsigned gpio)
+{
+	return (gpio < BCM2835_GPIO_COUNT);
+}
+
+int gpio_request(unsigned gpio, const char *label)
+{
+	return gpio_is_valid(gpio);
+}
+
+int gpio_free(unsigned gpio)
+{
+	return 0;
+}
+
+int gpio_direction_input(unsigned gpio)
+{
+	struct bcm_gpio_regs *reg = (struct bcm_gpio_regs *)BCM2835_GPIO_BASE;
+	unsigned val;
+
+	val = readl(&reg->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]);
+	val &= ~(BCM2835_GPIO_FSEL_MASK << BCM2835_GPIO_FSEL_SHIFT(gpio));
+	val |= (BCM2835_GPIO_INPUT << BCM2835_GPIO_FSEL_SHIFT(gpio));
+	writel(val, reg->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]);
+	}
+
+int gpio_direction_output(unsigned gpio, int value)
+{
+	struct bcm_gpio_regs *reg = (struct bcm_gpio_regs *)BCM2835_GPIO_BASE;
+	unsigned val;
+
+	if (value)
+		gpio_set_value(gpio, value);
+
+	val = readl(&reg->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]);
+	val &= ~(BCM2835_GPIO_FSEL_MASK << BCM2835_GPIO_FSEL_SHIFT(gpio));
+	val |= (BCM2835_GPIO_OUTPUT << BCM2835_GPIO_FSEL_SHIFT(gpio));
+	writel(val, reg->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]);
+}
+
+int gpio_get_value(unsigned gpio)
+{
+	struct bcm_gpio_regs *reg = (struct bcm_gpio_regs *)BCM2835_GPIO_BASE;
+	unsigned val;
+
+	val = readl(&reg->gplev[BCM2835_GPIO_COMMON_BANK(gpio)]);
+
+	return (val >> BCM2835_GPIO_COMMON_SHIFT(gpio)) & 0x1;
+}
+
+int gpio_set_value(unsigned gpio, int value)
+{
+	struct bcm_gpio_regs *reg = (struct bcm_gpio_regs *)BCM2835_GPIO_BASE;
+	u32 *output_reg = value ? reg->gpset : reg->gpclr;
+
+	writel(1 << BCM2835_GPIO_COMMON_SHIFT(gpio),
+				output_reg[BCM2835_GPIO_COMMON_BANK(gpio)]);
+
+	return 0;
+}
+
-- 
1.7.4.1