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[ARM] 4650/1: AT91: New-style init of I2C, support for i2c-gpio

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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>
This commit is contained in:
Andrew Victor
2007-11-19 13:47:20 +01:00
committed by Russell King
parent a95c729b74
commit f230d3f53d
19 changed files with 233 additions and 36 deletions
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42
arch/arm/mach-at91/at91sam9260_devices.c
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@@ -13,6 +13,7 @@
#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>
@@ -352,7 +353,41 @@ 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_PA23,
.sda_is_open_drain = 1,
.scl_pin = AT91_PIN_PA24,
.scl_is_open_drain = 1,
.udelay = 2, /* ~100 kHz */
};
static struct platform_device at91sam9260_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_PA23, 1); /* TWD (SDA) */
at91_set_multi_drive(AT91_PIN_PA23, 1);
at91_set_GPIO_periph(AT91_PIN_PA24, 1); /* TWCK (SCL) */
at91_set_multi_drive(AT91_PIN_PA24, 1);
i2c_register_board_info(0, devices, nr_devices);
platform_device_register(&at91sam9260_twi_device);
}
#elif defined(CONFIG_I2C_AT91) || defined(CONFIG_I2C_AT91_MODULE)
static struct resource twi_resources[] = {
[0] = {
@@ -374,7 +409,7 @@ static struct platform_device at91sam9260_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_PA23, 0); /* TWD */
@@ -383,10 +418,11 @@ void __init at91_add_device_i2c(void)
at91_set_A_periph(AT91_PIN_PA24, 0); /* TWCK */
at91_set_multi_drive(AT91_PIN_PA24, 1);
i2c_register_board_info(0, devices, nr_devices);
platform_device_register(&at91sam9260_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