Re: [PATCH 05/11] drm/bridge: analogix-anx78xx: correct value of TX_P0
From: Brian Masney <hidden>
Date: 2019-09-16 10:36:18
Also in:
dri-devel, linux-arm-msm, linux-devicetree, lkml
On Mon, Sep 16, 2019 at 12:02:09PM +0200, Andrzej Hajda wrote:
On 15.08.2019 02:48, Brian Masney wrote:quoted
When attempting to configure this driver on a Nexus 5 phone (msm8974), setting up the dummy i2c bus for TX_P0 would fail due to an -EBUSY error. The downstream MSM kernel sources [1] shows that the proper value for TX_P0 is 0x78, not 0x70, so correct the value to allow device probing to succeed. [1] https://github.com/AICP/kernel_lge_hammerhead/blob/n7.1/drivers/video/slimport/slimport_tx_reg.h Signed-off-by: Brian Masney <redacted> --- drivers/gpu/drm/bridge/analogix-anx78xx.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/drivers/gpu/drm/bridge/analogix-anx78xx.h b/drivers/gpu/drm/bridge/analogix-anx78xx.h index 25e063bcecbc..bc511fc605c9 100644 --- a/drivers/gpu/drm/bridge/analogix-anx78xx.h +++ b/drivers/gpu/drm/bridge/analogix-anx78xx.h@@ -6,7 +6,7 @@ #ifndef __ANX78xx_H #define __ANX78xx_H -#define TX_P0 0x70 +#define TX_P0 0x78This bothers me little. There are no upstream users, grepping android sources suggests that both values can be used [1][2] (grep for "#define TX_P0"), moreover there is code suggesting both values can be valid [3]. Could you verify datasheet which i2c slave addresses are valid for this chip, if both I guess this patch should be reworked. [1]: https://android.googlesource.com/kernel/msm/+/android-msm-flo-3.4-jb-mr2/drivers/misc/slimport_anx7808/slimport_tx_reg.h [2]: https://github.com/AndroidGX/SimpleGX-MM-6.0_H815_20d/blob/master/drivers/video/slimport/anx7812/slimport7812_tx_reg.h [3]: https://github.com/commaai/android_kernel_leeco_msm8996/blob/master/drivers/video/msm/mdss/dp/slimport_custom_declare.h#L73
This address is 0x78 on my Nexus 5. Given [3] above it looks like we need to support both addresses. What do you think about moving these addresses into device tree? The downstream and upstream kernel sources divide these addresses by two to get the i2c address. Here's the code in upstream: https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/bridge/analogix-anx78xx.c#L1353 https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/bridge/analogix-anx78xx.c#L41 I'm not sure why the actual i2c address isn't used in this code. Brian _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel