[U-Boot] [PATCH v2 1/2] bcm: Add GPIO driver

Vikram Narayanan
2012-07-11T20:37:26Z

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

Signed-off-by: Vikram Narayanan <vikram186@gmail.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Albert Aribaud <albert.u.boot@aribaud.net>
---
arch/arm/include/asm/arch-bcm2835/gpio.h | 71 ++++++++++++++++++++++++
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio_bcm2835.c | 87 ++++++++++++++++++++++++++++++
3 files changed, 159 insertions(+), 0 deletions(-)
create mode 100644 arch/arm/include/asm/arch-bcm2835/gpio.h
create mode 100644 drivers/gpio/gpio_bcm2835.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..3ab06e0
--- /dev/null
+++ b/arch/arm/include/asm/arch-bcm2835/gpio.h
@@ -0,0 +1,71 @@
+/*
+ * Copyright (C) 2012 Vikram Narayananan
+ * <vikram186@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_NUM_GPIOS 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_MASK(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 fb3b09a..7653e84 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) += gpio_bcm2835.o

COBJS := $(COBJS-y)
SRCS := $(COBJS:.o=.c)
diff --git a/drivers/gpio/gpio_bcm2835.c b/drivers/gpio/gpio_bcm2835.c
new file mode 100644
index 0000000..23cdd90
--- /dev/null
+++ b/drivers/gpio/gpio_bcm2835.c
@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 2012 Vikram Narayananan
+ * <vikram186@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_NUM_GPIOS) ? 0 : 1;
+}
+
+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_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));
+ 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;
+
+ 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)]);
+
+ 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;
+
+ val = readl(&reg->gplev[BCM2835_GPIO_COMMON_BANK(gpio)]);
+
+ return (val >> BCM2835_GPIO_COMMON_MASK(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_MASK(gpio),
+ output_reg[BCM2835_GPIO_COMMON_BANK(gpio)]);
+
+ return 0;
+}
+
--
1.7.4.1