Please ignore this series. Sorry for the inconvenience.
Will send a new patch series after it has been reviewed internally.
Sifan
> -----Original Message-----
> From: Sifan Naeem
> Sent: 10 July 2015 16:12
> To: James Hogan; IMG - IMGWorks Software Upstream Review
> Cc: Sifan Naeem; stable@xxxxxxxxxxxxxxx
> Subject: [PATCH 3/8] i2c: img-scb: fix LOW and HIGH period values for the SCL
> clock
>
> After determining the minimum value for the High period (TCKH) the
> remainder of the internal clock pulses is set as the Low period (TCKL).
> This causes the i2c clock duty cycle to be much less than 50%.
>
> The fix suggested here, start with TCKH and TCKL at 50% of the internal clock
> pulses and adjusts the TCKH and TCKL values from there if the minimum
> value for TCKL is not met. This will make sure the i2c clock duty cycle is at 50%
> or close 50% whenever possible.
>
> Fixes: 27bce457d588 (i2c: img-scb: Add Imagination Technologies I2C SCB
> driver)
> Signed-off-by: Sifan Naeem <sifan.naeem@xxxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-img-scb.c | 37 +++++++++++++++++++++-------------
> ---
> 1 file changed, 21 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-img-scb.c b/drivers/i2c/busses/i2c-img-
> scb.c
> index 42114a8..fa643d7 100644
> --- a/drivers/i2c/busses/i2c-img-scb.c
> +++ b/drivers/i2c/busses/i2c-img-scb.c
> @@ -1182,27 +1182,32 @@ static int img_i2c_init(struct img_i2c *i2c)
> ((bitrate_khz * clk_period) / 2))
> int_bitrate++;
>
> - /* Setup TCKH value */
> - tckh = timing.tckh / clk_period;
> - if (timing.tckh % clk_period)
> - tckh++;
> + /*
> + * Setup clock duty cycle, start with 50% and adjust TCKH and TCKL
> + * values from there if they don't meet minimum timing
> requirements
> + */
> + tckh = tckl = int_bitrate / 2;
> + if (int_bitrate % 2)
> + tckl++;
> +
> + /* Adjust TCKH and TCKL values */
> + data = timing.tckl / clk_period;
> + if (timing.tckl % clk_period)
> + data++;
> +
> + if (tckl < data) {
> + tckl = data;
> + tckh = int_bitrate - tckl;
> + }
>
> if (tckh > 0)
> - data = tckh - 1;
> - else
> - data = 0;
> -
> - img_i2c_writel(i2c, SCB_TIME_TCKH_REG, data);
> -
> - /* Setup TCKL value */
> - tckl = int_bitrate - tckh;
> + tckh -= 1;
>
> if (tckl > 0)
> - data = tckl - 1;
> - else
> - data = 0;
> + tckl -= 1;
>
> - img_i2c_writel(i2c, SCB_TIME_TCKL_REG, data);
> + img_i2c_writel(i2c, SCB_TIME_TCKH_REG, tckh);
> + img_i2c_writel(i2c, SCB_TIME_TCKL_REG, tckl);
>
> /* Setup TSDH value */
> tsdh = timing.tsdh / clk_period;
> --
> 1.7.9.5
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