[U-Boot] [PATCH v3 3/9] kmp204x: I2C deblocking support

[York Sun]

On 01/31/2014 04:46 AM, Valentin Longchamp wrote:
> From: Rainer Boschung <rainer.boschung at keymile.com>
> 
> This patch adds support for using some GPIOs that are connected to the
> I2C bus to force the bus lines state and perform some bus deblocking
> sequences.
> 
> The KM common deblocking algorithm from board/keymile/common/common.c is
> used. The GPIO lines used for deblocking the I2C bus are some external
> GPIOs provided by the QRIO CPLD:
>   - SCL = GPIOA_20
>   - SDA = GPIOA_21
> 
> The QRIO GPIOs act in an open-drain-like manner, for 0 the line is
> driven low and for 1 the GPIO is set as input and the line gets
> pulled-up.
> 
> Signed-off-by: Rainer Boschung <rainer.boschung at keymile.com>
> Signed-off-by: Valentin Longchamp <valentin.longchamp at keymile.com>
> 
> ---
> 
> Changes in v3:
> - rewrite the commit message and and the comments for more clarity
> - fix the GPIO numbers that where not correct
> 
> Changes in v2: None
> 
>  board/keymile/kmp204x/kmp204x.c     | 53 ++++++++++++++++++++++++++++++++++---
>  include/configs/km/kmp204x-common.h | 10 +++++++
>  2 files changed, 60 insertions(+), 3 deletions(-)
> 
> diff --git a/board/keymile/kmp204x/kmp204x.c b/board/keymile/kmp204x/kmp204x.c
> index bbb2453..726d26e 100644
> --- a/board/keymile/kmp204x/kmp204x.c
> +++ b/board/keymile/kmp204x/kmp204x.c
> @@ -33,12 +33,51 @@ int checkboard(void)
>  	return 0;
>  }
>  
> -/* TODO: implement the I2C deblocking function */
> -int i2c_make_abort(void)
> +/* I2C deblocking uses the algorithm defined in board/keymile/common/common.c
> + * 2 dedicated QRIO GPIOs externally pull the SCL and SDA lines
> + * For I2C only the low state is activly driven and high state is pulled-up
> + * by a resistor. Therefore the deblock GPIOs are used
> + *  -> as an active output to drive a low state
> + *  -> as an open-drain input to have a pulled-up high state
> + */
> +
> +/* QRIO GPIOs used for deblocking */
> +#define DEBLOCK_PORT1	GPIO_A
> +#define DEBLOCK_SCL1	20
> +#define DEBLOCK_SDA1	21

You changed these macros but didn't change those below. This causes compiling
errors. Please fix it and compile before sending v4.

> +
> +/* By default deblock GPIOs are floating */
> +static void i2c_deblock_gpio_cfg(void)
> +{
> +	/* set I2C bus 1 deblocking GPIOs input, but 0 value for open drain */
> +	qrio_gpio_direction_input(DBLK_PORT1, DBLK_SCL1);
> +	qrio_gpio_direction_input(DBLK_PORT1, DBLK_SDA1);
> +
> +	qrio_set_gpio(DBLK_PORT1, DBLK_SCL1, 0);
> +	qrio_set_gpio(DBLK_PORT1, DBLK_SDA1, 0);
> +}


York