[PATCH 8/8] drm/i915: Backlight control using CRC PMIC based PWM driver

Shobhit Kumar
2015-04-29T14:00:05Z

Use the CRC PWM device in intel_panel.c and add new MIPI backlight
specififc callbacks

v2: Modify to use pwm_config callback

CC: Samuel Ortiz <sameo@linux.intel.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Shobhit Kumar <shobhit.kumar@intel.com>
---
drivers/gpu/drm/i915/intel_drv.h | 5 +++
drivers/gpu/drm/i915/intel_dsi.c | 6 +++
drivers/gpu/drm/i915/intel_panel.c | 92 +++++++++++++++++++++++++++++++++++---
3 files changed, 98 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 897f17d..b4ebe3b 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -182,7 +182,12 @@ struct intel_panel {
bool enabled;
bool combination_mode; /* gen 2/4 only */
bool active_low_pwm;
+
+ /* PWM chip */
+ struct pwm_device *pwm;
+
struct backlight_device *device;
+
} backlight;

void (*backlight_power)(struct intel_connector *, bool enable);
diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
index be55ffa..83c4540 100644
--- a/drivers/gpu/drm/i915/intel_dsi.c
+++ b/drivers/gpu/drm/i915/intel_dsi.c
@@ -402,6 +402,8 @@ static void intel_dsi_enable(struct intel_encoder *encoder)

intel_dsi_port_enable(encoder);
}
+
+ intel_panel_enable_backlight(intel_dsi->attached_connector);
}

static void intel_dsi_pre_enable(struct intel_encoder *encoder)
@@ -466,6 +468,8 @@ static void intel_dsi_pre_disable(struct intel_encoder *encoder)

DRM_DEBUG_KMS("\n");

+ intel_panel_disable_backlight(intel_dsi->attached_connector);
+
if (is_vid_mode(intel_dsi)) {
/* Send Shutdown command to the panel in LP mode */
for_each_dsi_port(port, intel_dsi->ports)
@@ -1132,6 +1136,8 @@ void intel_dsi_init(struct drm_device *dev)
}

intel_panel_init(&intel_connector->panel, fixed_mode, NULL);
+ intel_panel_setup_backlight(connector,
+ (intel_encoder->crtc_mask = (1 << PIPE_A)) ? PIPE_A: PIPE_B);

return;

diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index 08532d4..5700f6f 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -32,8 +32,12 @@

#include <linux/kernel.h>
#include <linux/moduleparam.h>
+#include <linux/pwm.h>
#include "intel_drv.h"

+#define CRC_PMIC_PWM_PERIOD_NS 21333
+#define CRC_PMIC_PWM_STEPS 255
+
void
intel_fixed_panel_mode(const struct drm_display_mode *fixed_mode,
struct drm_display_mode *adjusted_mode)
@@ -536,6 +540,15 @@ static u32 vlv_get_backlight(struct intel_connector *connector)
return _vlv_get_backlight(dev, pipe);
}

+static u32 vlv_get_mipi_backlight(struct intel_connector *connector)
+{
+ struct intel_panel *panel = &connector->panel;
+ int duty_ns;
+
+ duty_ns = pwm_get_duty_cycle(panel->backlight.pwm);
+ return DIV_ROUND_UP(duty_ns * 100, CRC_PMIC_PWM_PERIOD_NS);
+}
+
static u32 intel_panel_get_backlight(struct intel_connector *connector)
{
struct drm_device *dev = connector->base.dev;
@@ -616,6 +629,14 @@ static void vlv_set_backlight(struct intel_connector *connector, u32 level)
I915_WRITE(VLV_BLC_PWM_CTL(pipe), tmp | level);
}

+static void vlv_set_mipi_backlight(struct intel_connector *connector, u32 level)
+{
+ struct intel_panel *panel = &connector->panel;
+ int duty_ns = DIV_ROUND_UP(level * CRC_PMIC_PWM_PERIOD_NS, 100);
+
+ pwm_config(panel->backlight.pwm, duty_ns, CRC_PMIC_PWM_PERIOD_NS);
+}
+
static void
intel_panel_actually_set_backlight(struct intel_connector *connector, u32 level)
{
@@ -741,6 +762,16 @@ static void vlv_disable_backlight(struct intel_connector *connector)
I915_WRITE(VLV_BLC_PWM_CTL2(pipe), tmp & ~BLM_PWM_ENABLE);
}

+static void vlv_disable_mipi_backlight(struct intel_connector *connector)
+{
+ struct intel_panel *panel = &connector->panel;
+
+ /* Disable the backlight */
+ pwm_config(panel->backlight.pwm, 0, CRC_PMIC_PWM_PERIOD_NS);
+ usleep_range(2000, 3000);
+ pwm_disable(panel->backlight.pwm);
+}
+
void intel_panel_disable_backlight(struct intel_connector *connector)
{
struct drm_device *dev = connector->base.dev;
@@ -947,6 +978,16 @@ static void vlv_enable_backlight(struct intel_connector *connector)
I915_WRITE(VLV_BLC_PWM_CTL2(pipe), ctl2 | BLM_PWM_ENABLE);
}

+static void vlv_enable_mipi_backlight(struct intel_connector *connector)
+{
+ struct intel_panel *panel = &connector->panel;
+ int duty_ns = DIV_ROUND_UP(
+ panel->backlight.level * CRC_PMIC_PWM_PERIOD_NS, 100);
+
+ pwm_enable(panel->backlight.pwm);
+ pwm_config(panel->backlight.pwm, duty_ns, CRC_PMIC_PWM_PERIOD_NS);
+}
+
void intel_panel_enable_backlight(struct intel_connector *connector)
{
struct drm_device *dev = connector->base.dev;
@@ -1299,6 +1340,34 @@ static int vlv_setup_backlight(struct intel_connector *connector, enum pipe pipe
return 0;
}

+static int vlv_setup_mipi_backlight(struct intel_connector *connector, enum pipe pipe)
+{
+ struct drm_device *dev = connector->base.dev;
+ struct intel_panel *panel = &connector->panel;
+
+ /* Get the PWM chip for backlight control */
+ panel->backlight.pwm = pwm_get(dev->dev, "pwm_backlight");
+ if (IS_ERR(panel->backlight.pwm)) {
+ DRM_ERROR("Faild to own the pwm chip\n");
+ panel->backlight.pwm = NULL;
+ } else if (pwm_config(panel->backlight.pwm, CRC_PMIC_PWM_PERIOD_NS,
+ CRC_PMIC_PWM_PERIOD_NS) < 0) {
+ DRM_ERROR("Failed to configure the pwm chip\n");
+ pwm_put(panel->backlight.pwm);
+ panel->backlight.pwm = NULL;
+ return -1;
+ }
+
+ panel->backlight.min = 0; /* 0% */
+ panel->backlight.max = 100; /* 100% */
+ panel->backlight.level = DIV_ROUND_UP(
+ pwm_get_duty_cycle(panel->backlight.pwm) * 100,
+ CRC_PMIC_PWM_PERIOD_NS);
+ panel->backlight.enabled = panel->backlight.level ? true : false;
+
+ return 0;
+}
+
int intel_panel_setup_backlight(struct drm_connector *connector, enum pipe pipe)
{
struct drm_device *dev = connector->dev;
@@ -1363,11 +1432,19 @@ void intel_panel_init_backlight_funcs(struct drm_device *dev)
dev_priv->display.set_backlight = pch_set_backlight;
dev_priv->display.get_backlight = pch_get_backlight;
} else if (IS_VALLEYVIEW(dev)) {
- dev_priv->display.setup_backlight = vlv_setup_backlight;
- dev_priv->display.enable_backlight = vlv_enable_backlight;
- dev_priv->display.disable_backlight = vlv_disable_backlight;
- dev_priv->display.set_backlight = vlv_set_backlight;
- dev_priv->display.get_backlight = vlv_get_backlight;
+ if (dev_priv->vbt.has_mipi) {
+ dev_priv->display.setup_backlight = vlv_setup_mipi_backlight;
+ dev_priv->display.enable_backlight = vlv_enable_mipi_backlight;
+ dev_priv->display.disable_backlight = vlv_disable_mipi_backlight;
+ dev_priv->display.set_backlight = vlv_set_mipi_backlight;
+ dev_priv->display.get_backlight = vlv_get_mipi_backlight;
+ } else {
+ dev_priv->display.setup_backlight = vlv_setup_backlight;
+ dev_priv->display.enable_backlight = vlv_enable_backlight;
+ dev_priv->display.disable_backlight = vlv_disable_backlight;
+ dev_priv->display.set_backlight = vlv_set_backlight;
+ dev_priv->display.get_backlight = vlv_get_backlight;
+ }
} else if (IS_GEN4(dev)) {
dev_priv->display.setup_backlight = i965_setup_backlight;
dev_priv->display.enable_backlight = i965_enable_backlight;
@@ -1404,6 +1481,11 @@ void intel_panel_fini(struct intel_panel *panel)
if (panel->downclock_mode)
drm_mode_destroy(intel_connector->base.dev,
panel->downclock_mode);
+
+ /* dispose of the pwm */
+ if (panel->backlight.pwm)
+ pwm_put(panel->backlight.pwm);
+
}

void intel_backlight_register(struct drm_device *dev)
--
2.1.0

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