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authorStephen Warren <swarren@wwwdotorg.org>2012-08-05 16:07:21 +0000
committerAlbert ARIBAUD <albert.u.boot@aribaud.net>2012-09-01 14:58:21 +0200
commitefad6cf8818620b0d85405df2b810760b62acbb8 (patch)
tree45fa8ee97e49c985752e31cc7dfe84db4f6cf18d /drivers
parent86c632651d317fbb9de92489b7a5febece3c4436 (diff)
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ARM: add basic support for the Broadcom BCM2835 SoC
This SoC is used in the Raspberry Pi, for example. For more details, see: http://www.broadcom.com/products/BCM2835 http://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf. Initial support is enough to boot to a serial console, execute a minimal set of U-Boot commands, download data over a serial port, and boot a Linux kernel. No storage or network drivers are implemented. GPIO driver originally by Vikram Narayanan <vikram186@gmail.com> with many fixes from myself. Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/gpio/Makefile1
-rw-r--r--drivers/gpio/bcm2835_gpio.c89
2 files changed, 90 insertions, 0 deletions
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 3c67599..17f4b73 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -43,6 +43,7 @@ COBJS-$(CONFIG_MPC83XX_GPIO) += mpc83xx_gpio.o
COBJS-$(CONFIG_SH_GPIO_PFC) += sh_pfc.o
COBJS-$(CONFIG_OMAP_GPIO) += omap_gpio.o
COBJS-$(CONFIG_DB8500_GPIO) += db8500_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..1d50dbd
--- /dev/null
+++ b/drivers/gpio/bcm2835_gpio.c
@@ -0,0 +1,89 @@
+/*
+ * 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.
+ */
+
+#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 bcm2835_gpio_regs *reg =
+ (struct bcm2835_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)]);
+
+ return 0;
+}
+
+int gpio_direction_output(unsigned gpio, int value)
+{
+ struct bcm2835_gpio_regs *reg =
+ (struct bcm2835_gpio_regs *)BCM2835_GPIO_BASE;
+ unsigned val;
+
+ 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)]);
+
+ return 0;
+}
+
+int gpio_get_value(unsigned gpio)
+{
+ struct bcm2835_gpio_regs *reg =
+ (struct bcm2835_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 bcm2835_gpio_regs *reg =
+ (struct bcm2835_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;
+}