diff options
| author | Andrew Victor <andrew@sanpeople.com> | 2007-11-19 15:47:20 +0300 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2007-11-26 22:40:47 +0300 |
| commit | f230d3f53d72d05bcb5666ab7e2eccd49c8b3a15 (patch) | |
| tree | 0d06454868ca879f06a268de71beb0b1ba6a08d7 /arch/arm/mach-at91/at91rm9200_devices.c | |
| parent | a95c729b7484d2bbb9ab6beef4865641e73deb99 (diff) | |
| download | linux-f230d3f53d72d05bcb5666ab7e2eccd49c8b3a15.tar.xz | |
[ARM] 4650/1: AT91: New-style init of I2C, support for i2c-gpio
The AT91 I2C driver is currently marked as "broken" due to hardware
issues. This patch enables AT91-based platforms to also use the
bitbanged GPIO for I2C.
This updates platform setup logic (setting up an i2c-gpio device
using the same pins as the i2c-at91 device, unless only the BROKEN
driver is enabled).
Also make use of the new-style initialization of I2C devices using
i2c_register_board_info().
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/mach-at91/at91rm9200_devices.c')
| -rw-r--r-- | arch/arm/mach-at91/at91rm9200_devices.c | 41 |
1 files changed, 38 insertions, 3 deletions
diff --git a/arch/arm/mach-at91/at91rm9200_devices.c b/arch/arm/mach-at91/at91rm9200_devices.c index 0417c165d50d..9296833f91cc 100644 --- a/arch/arm/mach-at91/at91rm9200_devices.c +++ b/arch/arm/mach-at91/at91rm9200_devices.c @@ -14,6 +14,7 @@ #include <asm/mach/map.h> #include <linux/platform_device.h> +#include <linux/i2c-gpio.h> #include <asm/arch/board.h> #include <asm/arch/gpio.h> @@ -435,7 +436,40 @@ void __init at91_add_device_nand(struct at91_nand_data *data) {} * TWI (i2c) * -------------------------------------------------------------------- */ -#if defined(CONFIG_I2C_AT91) || defined(CONFIG_I2C_AT91_MODULE) +/* + * Prefer the GPIO code since the TWI controller isn't robust + * (gets overruns and underruns under load) and can only issue + * repeated STARTs in one scenario (the driver doesn't yet handle them). + */ +#if defined(CONFIG_I2C_GPIO) || defined(CONFIG_I2C_GPIO_MODULE) + +static struct i2c_gpio_platform_data pdata = { + .sda_pin = AT91_PIN_PA25, + .sda_is_open_drain = 1, + .scl_pin = AT91_PIN_PA26, + .scl_is_open_drain = 1, + .udelay = 2, /* ~100 kHz */ +}; + +static struct platform_device at91rm9200_twi_device = { + .name = "i2c-gpio", + .id = -1, + .dev.platform_data = &pdata, +}; + +void __init at91_add_device_i2c(struct i2c_board_info *devices, int nr_devices) +{ + at91_set_GPIO_periph(AT91_PIN_PA25, 1); /* TWD (SDA) */ + at91_set_multi_drive(AT91_PIN_PA25, 1); + + at91_set_GPIO_periph(AT91_PIN_PA26, 1); /* TWCK (SCL) */ + at91_set_multi_drive(AT91_PIN_PA26, 1); + + i2c_register_board_info(0, devices, nr_devices); + platform_device_register(&at91rm9200_twi_device); +} + +#elif defined(CONFIG_I2C_AT91) || defined(CONFIG_I2C_AT91_MODULE) static struct resource twi_resources[] = { [0] = { @@ -457,7 +491,7 @@ static struct platform_device at91rm9200_twi_device = { .num_resources = ARRAY_SIZE(twi_resources), }; -void __init at91_add_device_i2c(void) +void __init at91_add_device_i2c(struct i2c_board_info *devices, int nr_devices) { /* pins used for TWI interface */ at91_set_A_periph(AT91_PIN_PA25, 0); /* TWD */ @@ -466,10 +500,11 @@ void __init at91_add_device_i2c(void) at91_set_A_periph(AT91_PIN_PA26, 0); /* TWCK */ at91_set_multi_drive(AT91_PIN_PA26, 1); + i2c_register_board_info(0, devices, nr_devices); platform_device_register(&at91rm9200_twi_device); } #else -void __init at91_add_device_i2c(void) {} +void __init at91_add_device_i2c(struct i2c_board_info *devices, int nr_devices) {} #endif |