drm/i915: Use the CRC gpio for panel enable/disable

The CRC (Crystal Cove) PMIC, controls the panel enable and disable
signals for BYT for dsi panels. This is indicated in the VBT fields. Use
that to initialize and use GPIO based control for these signals.

v2: Use the newer gpiod interface(Alexandre)
v3: Remove the redundant checks and unused code (Ville)
v4: Moved PWM vs SoC backlight #defines to intel_bios.h (Jani)

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>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Tested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Shobhit Kumar <shobhit.kumar@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_bios.h

@@ -778,6 +778,13 @@ int intel_parse_bios(struct drm_device *dev);
 #define MIPI_DSI_UNDEFINED_PANEL_ID	0
 #define MIPI_DSI_GENERIC_PANEL_ID	1
 
+/*
+ * PMIC vs SoC Backlight support specified in pwm_blc
+ * field in mipi_config block below.
+*/
+#define PPS_BLC_PMIC   0
+#define PPS_BLC_SOC    1
+
 struct mipi_config {
 	u16 panel_id;
 

drivers/gpu/drm/i915/intel_dsi.c

@@ -31,6 +31,7 @@
 #include <drm/drm_panel.h>
 #include <drm/drm_mipi_dsi.h>
 #include <linux/slab.h>
+#include <linux/gpio/consumer.h>
 #include "i915_drv.h"
 #include "intel_drv.h"
 #include "intel_dsi.h"
@@ -415,6 +416,12 @@ static void intel_dsi_pre_enable(struct intel_encoder *encoder)
 
 	DRM_DEBUG_KMS("\n");
 
+	/* Panel Enable over CRC PMIC */
+	if (intel_dsi->gpio_panel)
+		gpiod_set_value_cansleep(intel_dsi->gpio_panel, 1);
+
+	msleep(intel_dsi->panel_on_delay);
+
 	/* Disable DPOunit clock gating, can stall pipe
 	 * and we need DPLL REFA always enabled */
 	tmp = I915_READ(DPLL(pipe));
@@ -432,8 +439,6 @@ static void intel_dsi_pre_enable(struct intel_encoder *encoder)
 	/* put device in ready state */
 	intel_dsi_device_ready(encoder);
 
-	msleep(intel_dsi->panel_on_delay);
-
 	drm_panel_prepare(intel_dsi->panel);
 
 	for_each_dsi_port(port, intel_dsi->ports)
@@ -576,6 +581,10 @@ static void intel_dsi_post_disable(struct intel_encoder *encoder)
 
 	msleep(intel_dsi->panel_off_delay);
 	msleep(intel_dsi->panel_pwr_cycle_delay);
+
+	/* Panel Disable over CRC PMIC */
+	if (intel_dsi->gpio_panel)
+		gpiod_set_value_cansleep(intel_dsi->gpio_panel, 0);
 }
 
 static bool intel_dsi_get_hw_state(struct intel_encoder *encoder,
@@ -955,6 +964,11 @@ static void intel_dsi_encoder_destroy(struct drm_encoder *encoder)
 		/* XXX: Logically this call belongs in the panel driver. */
 		drm_panel_remove(intel_dsi->panel);
 	}
+
+	/* dispose of the gpios */
+	if (intel_dsi->gpio_panel)
+		gpiod_put(intel_dsi->gpio_panel);
+
 	intel_encoder_destroy(encoder);
 }
 
@@ -1071,6 +1085,20 @@ void intel_dsi_init(struct drm_device *dev)
 		goto err;
 	}
 
+	/*
+	 * In case of BYT with CRC PMIC, we need to use GPIO for
+	 * Panel control.
+	 */
+	if (dev_priv->vbt.dsi.config->pwm_blc == PPS_BLC_PMIC) {
+		intel_dsi->gpio_panel =
+			gpiod_get(dev->dev, "panel", GPIOD_OUT_HIGH);
+
+		if (IS_ERR(intel_dsi->gpio_panel)) {
+			DRM_ERROR("Failed to own gpio for panel control\n");
+			intel_dsi->gpio_panel = NULL;
+		}
+	}
+
 	intel_encoder->type = INTEL_OUTPUT_DSI;
 	intel_encoder->cloneable = 0;
 	drm_connector_init(dev, connector, &intel_dsi_connector_funcs,

drivers/gpu/drm/i915/intel_dsi.h

@@ -42,6 +42,9 @@ struct intel_dsi {
 	struct drm_panel *panel;
 	struct intel_dsi_host *dsi_hosts[I915_MAX_PORTS];
 
+	/* GPIO Desc for CRC based Panel control */
+	struct gpio_desc *gpio_panel;
+
 	struct intel_connector *attached_connector;
 
 	/* bit mask of ports being driven */