On Fri, Aug 14, 2015 at 04:50:24PM +0100, Sifan Naeem wrote:
> The requested bit rate can be outside the range supported by the driver.
> The maximum bit rate this driver supports at the moment is 400Khz.
>
> If the requested bit rate is larger than the maximum supported by the
> driver, set the bitrate to the maximum supported before bitrate_khz is
> calculated.
>
> Maximum speed supported by the driver can be increased to 1Mhz by
> adding support for "fast plus mode" in the future.
>
> Fixes: commit 27bce457d588 ("i2c: img-scb: Add Imagination Technologies I2C SCB driver")
> Signed-off-by: Sifan Naeem <sifan.naeem@xxxxxxxxxx>
> Reviewed-by: James Hartley <james.hartley@xxxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-img-scb.c | 14 +++++++++++---
> 1 file changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-img-scb.c b/drivers/i2c/busses/i2c-img-scb.c
> index 6c21a7bd9a66..c16caaccc363 100644
> --- a/drivers/i2c/busses/i2c-img-scb.c
> +++ b/drivers/i2c/busses/i2c-img-scb.c
> @@ -1138,9 +1138,6 @@ static int img_i2c_init(struct img_i2c *i2c)
> /* Fencing enabled by default. */
> i2c->need_wr_rd_fence = true;
>
> - bitrate_khz = i2c->bitrate / 1000;
> - clk_khz = clk_get_rate(i2c->scb_clk) / 1000;
> -
> /* Determine what mode we're in from the bitrate */
> timing = timings[0];
> for (i = 0; i < ARRAY_SIZE(timings); i++) {
> @@ -1149,6 +1146,17 @@ static int img_i2c_init(struct img_i2c *i2c)
> break;
> }
> }
> + if (i2c->bitrate > timings[ARRAY_SIZE(timings) - 1].max_bitrate) {
> + dev_warn(i2c->adap.dev.parent,
> + "requested bitrate (%d) is higher than the max bitrate supported (%d)\n",
Technically both i2c->bitrate and timings[].max_bitrate are unsigned, so
%u would be more correct for both.
Otherwise:
Acked-by: James Hogan <james.hogan@xxxxxxxxxx>
Wolfram: are you happy to fix the %u thing when applying it, or would
you prefer me to submit a fixed patch (Sifan is off for a few weeks I
believe).
(Still need to look at the other changes...)
Cheers
James
> + i2c->bitrate,
> + timings[ARRAY_SIZE(timings) - 1].max_bitrate);
> + timing = timings[ARRAY_SIZE(timings) - 1];
> + i2c->bitrate = timing.max_bitrate;
> + }
> +
> + bitrate_khz = i2c->bitrate / 1000;
> + clk_khz = clk_get_rate(i2c->scb_clk) / 1000;
>
> /* Find the prescale that would give us that inc (approx delay = 0) */
> prescale = SCB_OPT_INC * clk_khz / (256 * 16 * bitrate_khz);
> --
> 1.7.9.5
>
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