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authorHans de Goede <hdegoede@redhat.com>2020-09-03 13:23:37 +0200
committerHans de Goede <hdegoede@redhat.com>2020-09-06 15:53:37 +0200
commitf8bd54d2190469e2244ade66cc1551b2a8f4f138 (patch)
tree9fa0e8d09c7aa99eab32cc02a37a363644c53a24
parent9a6ae5b354ed09f61cfa3acbb19fecd64f46b097 (diff)
drm/i915: panel: Use atomic PWM API for devs with an external PWM controller
Now that the PWM drivers which we use have been converted to the atomic PWM API, we can move the i915 panel code over to using the atomic PWM API. The removes a long standing FIXME and this removes a flicker where the backlight brightness would jump to 100% when i915 loads even if using the fastset path. Note that this commit also simplifies pwm_disable_backlight(), by dropping the intel_panel_actually_set_backlight(..., 0) call. This call sets the PWM to 0% duty-cycle. I believe that this call was only present as a workaround for a bug in the pwm-crc.c driver where it failed to clear the PWM_OUTPUT_ENABLE bit. This is fixed by an earlier patch in this series. After the dropping of this workaround, the usleep call, which seems unnecessary to begin with, has no useful effect anymore, so drop that too. Acked-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200903112337.4113-18-hdegoede@redhat.com
-rw-r--r--drivers/gpu/drm/i915/display/intel_display_types.h3
-rw-r--r--drivers/gpu/drm/i915/display/intel_panel.c70
2 files changed, 33 insertions, 40 deletions
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index 5648ec58a32b..b2d0edacc58c 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -28,6 +28,7 @@
#include <linux/async.h>
#include <linux/i2c.h>
+#include <linux/pwm.h>
#include <linux/sched/clock.h>
#include <drm/drm_atomic.h>
@@ -223,7 +224,7 @@ struct intel_panel {
bool util_pin_active_low; /* bxt+ */
u8 controller; /* bxt+ only */
struct pwm_device *pwm;
- int pwm_period_ns;
+ struct pwm_state pwm_state;
/* DPCD backlight */
u8 pwmgen_bit_count;
diff --git a/drivers/gpu/drm/i915/display/intel_panel.c b/drivers/gpu/drm/i915/display/intel_panel.c
index 1e98d2dab0ed..5a201fe8de11 100644
--- a/drivers/gpu/drm/i915/display/intel_panel.c
+++ b/drivers/gpu/drm/i915/display/intel_panel.c
@@ -592,10 +592,10 @@ static u32 bxt_get_backlight(struct intel_connector *connector)
static u32 pwm_get_backlight(struct intel_connector *connector)
{
struct intel_panel *panel = &connector->panel;
- int duty_ns;
+ struct pwm_state state;
- duty_ns = pwm_get_duty_cycle(panel->backlight.pwm);
- return DIV_ROUND_UP(duty_ns * 100, panel->backlight.pwm_period_ns);
+ pwm_get_state(panel->backlight.pwm, &state);
+ return pwm_get_relative_duty_cycle(&state, 100);
}
static void lpt_set_backlight(const struct drm_connector_state *conn_state, u32 level)
@@ -669,10 +669,9 @@ static void bxt_set_backlight(const struct drm_connector_state *conn_state, u32
static void pwm_set_backlight(const struct drm_connector_state *conn_state, u32 level)
{
struct intel_panel *panel = &to_intel_connector(conn_state->connector)->panel;
- int duty_ns = DIV_ROUND_UP(level * panel->backlight.pwm_period_ns, 100);
- pwm_config(panel->backlight.pwm, duty_ns,
- panel->backlight.pwm_period_ns);
+ pwm_set_relative_duty_cycle(&panel->backlight.pwm_state, level, 100);
+ pwm_apply_state(panel->backlight.pwm, &panel->backlight.pwm_state);
}
static void
@@ -841,10 +840,8 @@ static void pwm_disable_backlight(const struct drm_connector_state *old_conn_sta
struct intel_connector *connector = to_intel_connector(old_conn_state->connector);
struct intel_panel *panel = &connector->panel;
- /* Disable the backlight */
- intel_panel_actually_set_backlight(old_conn_state, 0);
- usleep_range(2000, 3000);
- pwm_disable(panel->backlight.pwm);
+ panel->backlight.pwm_state.enabled = false;
+ pwm_apply_state(panel->backlight.pwm, &panel->backlight.pwm_state);
}
void intel_panel_disable_backlight(const struct drm_connector_state *old_conn_state)
@@ -1176,9 +1173,12 @@ static void pwm_enable_backlight(const struct intel_crtc_state *crtc_state,
{
struct intel_connector *connector = to_intel_connector(conn_state->connector);
struct intel_panel *panel = &connector->panel;
+ int level = panel->backlight.level;
- pwm_enable(panel->backlight.pwm);
- intel_panel_actually_set_backlight(conn_state, panel->backlight.level);
+ level = intel_panel_compute_brightness(connector, level);
+ pwm_set_relative_duty_cycle(&panel->backlight.pwm_state, level, 100);
+ panel->backlight.pwm_state.enabled = true;
+ pwm_apply_state(panel->backlight.pwm, &panel->backlight.pwm_state);
}
static void __intel_panel_enable_backlight(const struct intel_crtc_state *crtc_state,
@@ -1897,8 +1897,7 @@ static int pwm_setup_backlight(struct intel_connector *connector,
struct drm_i915_private *dev_priv = to_i915(dev);
struct intel_panel *panel = &connector->panel;
const char *desc;
- u32 level, ns;
- int retval;
+ u32 level;
/* Get the right PWM chip for DSI backlight according to VBT */
if (dev_priv->vbt.dsi.config->pwm_blc == PPS_BLC_PMIC) {
@@ -1916,35 +1915,28 @@ static int pwm_setup_backlight(struct intel_connector *connector,
return -ENODEV;
}
- panel->backlight.pwm_period_ns = NSEC_PER_SEC /
- get_vbt_pwm_freq(dev_priv);
-
- /*
- * FIXME: pwm_apply_args() should be removed when switching to
- * the atomic PWM API.
- */
- pwm_apply_args(panel->backlight.pwm);
-
panel->backlight.max = 100; /* 100% */
panel->backlight.min = get_backlight_min_vbt(connector);
- level = intel_panel_compute_brightness(connector, 100);
- ns = DIV_ROUND_UP(level * panel->backlight.pwm_period_ns, 100);
- retval = pwm_config(panel->backlight.pwm, ns,
- panel->backlight.pwm_period_ns);
- if (retval < 0) {
- drm_err(&dev_priv->drm, "Failed to configure the pwm chip\n");
- pwm_put(panel->backlight.pwm);
- panel->backlight.pwm = NULL;
- return retval;
- }
+ if (pwm_is_enabled(panel->backlight.pwm)) {
+ /* PWM is already enabled, use existing settings */
+ pwm_get_state(panel->backlight.pwm, &panel->backlight.pwm_state);
- level = DIV_ROUND_UP(pwm_get_duty_cycle(panel->backlight.pwm) * 100,
- panel->backlight.pwm_period_ns);
- level = intel_panel_compute_brightness(connector, level);
- panel->backlight.level = clamp(level, panel->backlight.min,
- panel->backlight.max);
- panel->backlight.enabled = panel->backlight.level != 0;
+ level = pwm_get_relative_duty_cycle(&panel->backlight.pwm_state,
+ 100);
+ level = intel_panel_compute_brightness(connector, level);
+ panel->backlight.level = clamp(level, panel->backlight.min,
+ panel->backlight.max);
+ panel->backlight.enabled = true;
+
+ drm_dbg_kms(&dev_priv->drm, "PWM already enabled at freq %ld, VBT freq %d, level %d\n",
+ NSEC_PER_SEC / (unsigned long)panel->backlight.pwm_state.period,
+ get_vbt_pwm_freq(dev_priv), level);
+ } else {
+ /* Set period from VBT frequency, leave other settings at 0. */
+ panel->backlight.pwm_state.period =
+ NSEC_PER_SEC / get_vbt_pwm_freq(dev_priv);
+ }
drm_info(&dev_priv->drm, "Using %s PWM for LCD backlight control\n",
desc);