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From a6dcfa6147cf37b207ea8b1185637eafffcd836f Mon Sep 17 00:00:00 2001
From: Anthony Koo <Anthony.Koo@amd.com>
Date: Thu, 28 Mar 2019 12:39:48 -0400
Subject: [PATCH 1769/2940] drm/amd/display: Add switch for Fractional PWM on
or off
[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>
---
drivers/gpu/drm/amd/display/dc/dc.h | 1 +
drivers/gpu/drm/amd/display/dc/dce/dce_abm.c | 18 ++++++++++++++++++
2 files changed, 19 insertions(+)
diff --git a/drivers/gpu/drm/amd/display/dc/dc.h b/drivers/gpu/drm/amd/display/dc/dc.h
index facc830fa428..8a645ec8e293 100644
--- a/drivers/gpu/drm/amd/display/dc/dc.h
+++ b/drivers/gpu/drm/amd/display/dc/dc.h
@@ -186,6 +186,7 @@ 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;
};
diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c b/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c
index da96229db53a..855360b1414f 100644
--- a/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c
+++ b/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c
@@ -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;
}
--
2.17.1
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