From 793b5726f7e998c7cec93ea5ee7910dd6ddb1e5e Mon Sep 17 00:00:00 2001 From: Mike Frysinger Date: Wed, 21 Jul 2010 13:38:02 -0400 Subject: [PATCH] i2c: soft_i2c: add simple GPIO implementation Since the vast majority of GPIO I2C implementations behave the same way, support the common GPIO framework with default settings. This adds two new defines CONFIG_SOFT_I2C_GPIO_{SCL,SDA} so that boards which want GPIO I2C support need only define these. Signed-off-by: Mike Frysinger Tested-by: Thomas Chou --- README | 10 ++++++++ drivers/i2c/soft_i2c.c | 52 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 62 insertions(+) diff --git a/README b/README index a9c98f218e..c9fb284378 100644 --- a/README +++ b/README @@ -1495,6 +1495,16 @@ The following options need to be configured: #define I2C_DELAY udelay(2) + CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA + + If your arch supports the generic GPIO framework (asm/gpio.h), + then you may alternatively define the two GPIOs that are to be + used as SCL / SDA. Any of the previous I2C_xxx macros will + have GPIO-based defaults assigned to them as appropriate. + + You should define these to the GPIO value as given directly to + the generic GPIO functions. + CONFIG_SYS_I2C_INIT_BOARD When a board is reset during an i2c bus transfer diff --git a/drivers/i2c/soft_i2c.c b/drivers/i2c/soft_i2c.c index e0cf1e10db..1a1809ac16 100644 --- a/drivers/i2c/soft_i2c.c +++ b/drivers/i2c/soft_i2c.c @@ -51,6 +51,58 @@ #endif #include +#if defined(CONFIG_SOFT_I2C_GPIO_SCL) +# include + +# ifndef I2C_GPIO_SYNC +# define I2C_GPIO_SYNC +# endif + +# ifndef I2C_INIT +# define I2C_INIT \ + do { \ + gpio_request(CONFIG_SOFT_I2C_GPIO_SCL, "soft_i2c"); \ + gpio_request(CONFIG_SOFT_I2C_GPIO_SDA, "soft_i2c"); \ + } while (0) +# endif + +# ifndef I2C_ACTIVE +# define I2C_ACTIVE do { } while (0) +# endif + +# ifndef I2C_TRISTATE +# define I2C_TRISTATE do { } while (0) +# endif + +# ifndef I2C_READ +# define I2C_READ gpio_get_value(CONFIG_SOFT_I2C_GPIO_SDA) +# endif + +# ifndef I2C_SDA +# define I2C_SDA(bit) \ + do { \ + if (bit) \ + gpio_direction_input(CONFIG_SOFT_I2C_GPIO_SDA); \ + else \ + gpio_direction_output(CONFIG_SOFT_I2C_GPIO_SDA, 0); \ + I2C_GPIO_SYNC; \ + } while (0) +# endif + +# ifndef I2C_SCL +# define I2C_SCL(bit) \ + do { \ + gpio_direction_output(CONFIG_SOFT_I2C_GPIO_SCL, bit); \ + I2C_GPIO_SYNC; \ + } while (0) +# endif + +# ifndef I2C_DELAY +# define I2C_DELAY udelay(5) /* 1/4 I2C clock duration */ +# endif + +#endif + /* #define DEBUG_I2C */ #ifdef DEBUG_I2C -- 2.25.1