From bad4c8f1bc25970895aee312c93130cff7cdcf0f Mon Sep 17 00:00:00 2001 From: John Stultz Date: Mon, 16 Jan 2017 16:52:52 -0800 Subject: [PATCH] drm/bridge: adv7511: Re-write the i2c address before EDID probing commit 3587c856675c45809010c2cee5b21096f6e8e938 upstream. I've found that by just turning the chip on and off via the POWER_DOWN register, I end up getting i2c_transfer errors on HiKey. Investigating further, it turns out that some of the register state in hardware is getting lost, as the device registers are reset when the chip is powered down. Thus this patch simply re-writes the i2c address to the ADV7511_REG_EDID_I2C_ADDR register to ensure its properly set before we try to read the EDID data. Cc: David Airlie Cc: Archit Taneja Cc: Wolfram Sang Cc: Lars-Peter Clausen Cc: Laurent Pinchart Cc: dri-devel@lists.freedesktop.org Reviewed-by: Laurent Pinchart Tested-by: Laurent Pinchart Signed-off-by: John Stultz Signed-off-by: Archit Taneja Link: http://patchwork.freedesktop.org/patch/msgid/1484614372-15342-7-git-send-email-john.stultz@linaro.org Signed-off-by: Nhan Nguyen Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c index 352629a9ecc3..a68f94daf9b6 100644 --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c @@ -573,9 +573,17 @@ static int adv7511_get_modes(struct adv7511 *adv7511, unsigned int count; /* Reading the EDID only works if the device is powered */ - if (!adv7511->powered) + if (!adv7511->powered) { + unsigned int edid_i2c_addr = + (adv7511->i2c_main->addr << 1) + 4; + __adv7511_power_on(adv7511); + /* Reset the EDID_I2C_ADDR register as it might be cleared */ + regmap_write(adv7511->regmap, ADV7511_REG_EDID_I2C_ADDR, + edid_i2c_addr); + } + edid = drm_do_get_edid(connector, adv7511_get_edid_block, adv7511); if (!adv7511->powered) -- 2.17.1