From 66bb0a7c612e0cd82ffda8c4fe42f2f404132000 Mon Sep 17 00:00:00 2001 From: Paul Cercueil Date: Wed, 14 Dec 2022 13:58:16 +0100 Subject: [PATCH] drm: bridge: it66121: Fix wait for DDC ready The function it66121_wait_ddc_ready() would previously read the status register until "true", which means it never actually polled anything and would just read the register once. Now, it will properly wait until the DDC hardware is ready or until it reported an error. The 'busy' variable was also renamed to 'error' since these bits are set on error and not when the DDC hardware is busy. Since the DDC ready function is now working properly, the msleep(20) can be removed. Signed-off-by: Paul Cercueil Reviewed-by: Robert Foss Link: https://patchwork.freedesktop.org/patch/msgid/20221214125821.12489-6-paul@crapouillou.net --- drivers/gpu/drm/bridge/ite-it66121.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/bridge/ite-it66121.c b/drivers/gpu/drm/bridge/ite-it66121.c index 0a4fdfd..bfb9c87 100644 --- a/drivers/gpu/drm/bridge/ite-it66121.c +++ b/drivers/gpu/drm/bridge/ite-it66121.c @@ -440,15 +440,17 @@ static int it66121_configure_afe(struct it66121_ctx *ctx, static inline int it66121_wait_ddc_ready(struct it66121_ctx *ctx) { int ret, val; - u32 busy = IT66121_DDC_STATUS_NOACK | IT66121_DDC_STATUS_WAIT_BUS | - IT66121_DDC_STATUS_ARBI_LOSE; + u32 error = IT66121_DDC_STATUS_NOACK | IT66121_DDC_STATUS_WAIT_BUS | + IT66121_DDC_STATUS_ARBI_LOSE; + u32 done = IT66121_DDC_STATUS_TX_DONE; - ret = regmap_read_poll_timeout(ctx->regmap, IT66121_DDC_STATUS_REG, val, true, - IT66121_EDID_SLEEP_US, IT66121_EDID_TIMEOUT_US); + ret = regmap_read_poll_timeout(ctx->regmap, IT66121_DDC_STATUS_REG, val, + val & (error | done), IT66121_EDID_SLEEP_US, + IT66121_EDID_TIMEOUT_US); if (ret) return ret; - if (val & busy) + if (val & error) return -EAGAIN; return 0; @@ -582,9 +584,6 @@ static int it66121_get_edid_block(void *context, u8 *buf, offset += cnt; remain -= cnt; - /* Per programming manual, sleep here before emptying the FIFO */ - msleep(20); - ret = it66121_wait_ddc_ready(ctx); if (ret) return ret; -- 2.7.4