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drm/amd/display: Add switch for Fractional PWM on or off

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[Why]
Some LED Driver might not like Fractional PWM especially at extreme
ranges near 0% or 100%.
For example, backlight flashing could be observed.
We want a way to switch fractional PWM on/off either for debug, or
possibly production.

[How]
Add DC code that can send new FW command to enable/disable
fractional PWM.

Signed-off-by: Anthony Koo <Anthony.Koo@amd.com>
Reviewed-by: Aric Cyr <Aric.Cyr@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Anthony Koo 2019-03-28 12:39:48 -04:00 committed by Alex Deucher
parent 93abb05fd5
commit 3be0a0b850
2 changed files with 19 additions and 0 deletions
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1
drivers/gpu/drm/amd/display/dc/dc.h
View File

@ -183,6 +183,7 @@ struct dc_config {
bool disable_disp_pll_sharing;
bool fbc_support;
bool optimize_edp_link_rate;
bool disable_fractional_pwm;
bool allow_seamless_boot_optimization;
};

18
drivers/gpu/drm/amd/display/dc/dce/dce_abm.c
View File

@ -50,6 +50,7 @@
#define MCP_ABM_LEVEL_SET 0x65
#define MCP_ABM_PIPE_SET 0x66
#define MCP_BL_SET 0x67
#define MCP_BL_SET_PWM_FRAC 0x6A /* Enable or disable Fractional PWM */
#define MCP_DISABLE_ABM_IMMEDIATELY 255
@ -390,6 +391,23 @@ static bool dce_abm_init_backlight(struct abm *abm)
REG_UPDATE(BL_PWM_GRP1_REG_LOCK,
BL_PWM_GRP1_REG_LOCK, 0);
/* Wait until microcontroller is ready to process interrupt */
REG_WAIT(MASTER_COMM_CNTL_REG, MASTER_COMM_INTERRUPT, 0, 100, 800);
/* Set PWM fractional enable/disable */
value = (abm->ctx->dc->config.disable_fractional_pwm == false) ? 1 : 0;
REG_WRITE(MASTER_COMM_DATA_REG1, value);
/* Set command to enable or disable fractional PWM microcontroller */
REG_UPDATE(MASTER_COMM_CMD_REG, MASTER_COMM_CMD_REG_BYTE0,
MCP_BL_SET_PWM_FRAC);
/* Notify microcontroller of new command */
REG_UPDATE(MASTER_COMM_CNTL_REG, MASTER_COMM_INTERRUPT, 1);
/* Ensure command has been executed before continuing */
REG_WAIT(MASTER_COMM_CNTL_REG, MASTER_COMM_INTERRUPT, 0, 100, 800);
return true;
}