Hi Andrey,
Thank you for the patch.
On Tue, Feb 26, 2019 at 11:36:05AM -0800, Andrey Smirnov wrote:
> Replace explicit polling in tc_link_training() with equivalent call to
> regmap_read_poll_timeout() for simplicity. No functional change
> intended (not including slightly altered debug output).
>
> Signed-off-by: Andrey Smirnov <andrew.smir...@gmail.com>
> Cc: Archit Taneja <arch...@codeaurora.org>
> Cc: Andrzej Hajda <a.ha...@samsung.com>
> Cc: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
> Cc: Chris Healy <cphe...@gmail.com>
> Cc: Lucas Stach <l.st...@pengutronix.de>
> Cc: dri-devel@lists.freedesktop.org
> Cc: linux-ker...@vger.kernel.org
> ---
> drivers/gpu/drm/bridge/tc358767.c | 14 +++++---------
> 1 file changed, 5 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/tc358767.c
> b/drivers/gpu/drm/bridge/tc358767.c
> index 6455e6484722..ea30cec4a0c3 100644
> --- a/drivers/gpu/drm/bridge/tc358767.c
> +++ b/drivers/gpu/drm/bridge/tc358767.c
> @@ -735,7 +735,6 @@ static int tc_link_training(struct tc_data *tc, int
> pattern)
> const char * const *errors;
> u32 srcctrl = tc_srcctrl(tc) | DP0_SRCCTRL_SCRMBLDIS |
> DP0_SRCCTRL_AUTOCORRECT;
> - int timeout;
> int retry;
> u32 value;
> int ret;
> @@ -765,20 +764,17 @@ static int tc_link_training(struct tc_data *tc, int
> pattern)
> tc_write(DP0CTL, DP_EN);
>
> /* wait */
> - timeout = 1000;
> - do {
> - tc_read(DP0_LTSTAT, &value);
> - udelay(1);
> - } while ((!(value & LT_LOOPDONE)) && (--timeout));
> - if (timeout == 0) {
> + ret = regmap_read_poll_timeout(tc->regmap, DP0_LTSTAT, value,
> + value & LT_LOOPDONE, 1, 1000);
> + if (ret) {
> dev_err(tc->dev, "Link training timeout!\n");
> } else {
> int pattern = (value >> 11) & 0x3;
> int error = (value >> 8) & 0x7;
>
> dev_dbg(tc->dev,
> - "Link training phase %d done after %d uS: %s\n",
> - pattern, 1000 - timeout, errors[error]);
> + "Link training phase %d done: %s\n",
> + pattern, errors[error]);
It's probably not a big deal in this specific case, but in general it
can be useful to know how long the poll took. Any hope to enhance
regmap_read_poll_timeout() to return either the elapsed time or the
remaining timeout instead of 0 on success ?
> if (pattern == DP_TRAINING_PATTERN_1 && error == 0)
> break;
> if (pattern == DP_TRAINING_PATTERN_2) {
--
Regards,
Laurent Pinchart
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