[U-Boot] [PATCH 4/5] i2c: omap24xx: Fix high speed trimming calculation

[Heiko Schocher]

Hello Christophe,

Am 17.01.2016 um 12:09 schrieb Christophe Ricard:
> Work based on i2c-omap.c from linux kernel.
>
> fsscll/fssclh and hsscll/hssclh was always negative in high speed.
>
> i2c high speed frequency start after 400Khz.
>
> Signed-off-by: Christophe Ricard <christophe-h.ricard at st.com>
> ---
>
>   drivers/i2c/omap24xx_i2c.c | 17 +++++++++--------
>   1 file changed, 9 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/i2c/omap24xx_i2c.c b/drivers/i2c/omap24xx_i2c.c
> index 48ca446..774edaf 100644
> --- a/drivers/i2c/omap24xx_i2c.c
> +++ b/drivers/i2c/omap24xx_i2c.c
> @@ -129,7 +129,9 @@ static int omap24_i2c_setspeed(struct udevice *adap, unsigned int speed)
>   	i2c_base = i2c_bus->i2c_base;
>   #endif
>
> -	if (speed >= OMAP_I2C_HIGH_SPEED) {
> +	if (speed > 400000) {

Why you remove the define?

> +		unsigned long scl;
> +
>   		/* High speed */
>   		psc = I2C_IP_CLK / I2C_INTERNAL_SAMPLING_CLK;
>   		psc -= 1;
> @@ -139,12 +141,11 @@ static int omap24_i2c_setspeed(struct udevice *adap, unsigned int speed)
>   		}
>
>   		/* For first phase of HS mode */
> -		fsscll = I2C_INTERNAL_SAMPLING_CLK / (2 * speed);
> +		scl = I2C_INTERNAL_SAMPLING_CLK / 400000;
>
> -		fssclh = fsscll;
> +		fsscll = scl - (scl / 3) - 7;
> +		fssclh = (scl / 3)  - 5;
>
> -		fsscll -= I2C_HIGHSPEED_PHASE_ONE_SCLL_TRIM;
> -		fssclh -= I2C_HIGHSPEED_PHASE_ONE_SCLH_TRIM;
>   		if (((fsscll < 0) || (fssclh < 0)) ||
>   		    ((fsscll > 255) || (fssclh > 255))) {
>   			puts("Error : I2C initializing first phase clock\n");
> @@ -152,10 +153,10 @@ static int omap24_i2c_setspeed(struct udevice *adap, unsigned int speed)
>   		}
>
>   		/* For second phase of HS mode */
> -		hsscll = hssclh = I2C_INTERNAL_SAMPLING_CLK / (2 * speed);
> +		scl = I2C_IP_CLK / speed;
> +		hsscll = scl - (scl / 3) - 7;
> +		hssclh = (scl / 3) - 5;
>
> -		hsscll -= I2C_HIGHSPEED_PHASE_TWO_SCLL_TRIM;
> -		hssclh -= I2C_HIGHSPEED_PHASE_TWO_SCLH_TRIM;
>   		if (((fsscll < 0) || (fssclh < 0)) ||
>   		    ((fsscll > 255) || (fssclh > 255))) {
>   			puts("Error : I2C initializing second phase clock\n");
>

Reviewed-by: Heiko Schocher <hs at denx.de>

bye,
Heiko
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