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Commit b3622a28 authored by Tharun Raj Soma's avatar Tharun Raj Soma Committed by Gerrit - the friendly Code Review server
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drm/msm/dsi-staging: add support to enable backlight through PWM 



This change adds display support for panels which control backlight
through PWM gpio.

Change-Id: Iea06efdaa64b771ae95ccab0882dc6f369094779
Signed-off-by: default avatarTharun Raj Soma <tsoma@codeaurora.org>
parent 1e9dad51

Documentation/devicetree/bindings/drm/msm/mdss-dsi-panel.txt

+2 −9
Original line number Diff line number Diff line
@@ -179,12 +179,7 @@ Optional properties: 
                                          "bl_ctrl_dcs" = Backlight controlled by DCS commands.

                                          "bl_ctrl_external" = Backlight controlled by externally

                                          other: Unknown backlight control. (default)

- qcom,mdss-dsi-bl-pwm-pmi:		Boolean to indicate that PWM control is through second pmic chip.

- qcom,mdss-dsi-bl-pmic-bank-select:	LPG channel for backlight.

					Required if backlight pmic control type is PWM

- qcom,mdss-dsi-bl-pmic-pwm-frequency:	PWM period in microseconds.

					Required if backlight pmic control type is PWM

- qcom,mdss-dsi-pwm-gpio:		PMIC gpio binding to backlight.

- qcom,bl-pmic-pwm-period-usecs:	PWM period in microseconds.

					Required if backlight pmic control type is PWM

- qcom,mdss-dsi-bl-min-level:		Specifies the min backlight level supported by the panel.

					0 = default value.
@@ -671,9 +666,7 @@ Example: 
		qcom,mdss-dsi-pan-enable-dynamic-fps;

		qcom,mdss-dsi-pan-fps-update = "dfps_suspend_resume_mode";

		qcom,dsi-supported-dfps-list = <48 55 60>;

		qcom,mdss-dsi-bl-pmic-bank-select = <0>;

		qcom,mdss-dsi-bl-pmic-pwm-frequency = <0>;

		qcom,mdss-dsi-pwm-gpio = <&pm8941_mpps 5 0>;

		qcom,bl-pmic-pwm-period-usecs = <0>;

		qcom,5v-boost-gpio = <&pm8994_gpios 14 0>;

		qcom,mdss-pan-physical-width-dimension = <60>;

		qcom,mdss-pan-physical-height-dimension = <140>;

drivers/gpu/drm/msm/dsi-staging/dsi_panel.c

+87 −22
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <linux/slab.h>

#include <linux/gpio.h>

#include <linux/of_gpio.h>

#include <linux/pwm.h>

#include <video/mipi_display.h>



#include "dsi_panel.h"
@@ -625,6 +626,57 @@ static int dsi_panel_update_backlight(struct dsi_panel *panel, 
	return rc;

}



static int dsi_panel_update_pwm_backlight(struct dsi_panel *panel,

	u32 bl_lvl)

{

	int rc = 0;

	u32 duty = 0;

	u32 period_ns = 0;

	struct dsi_backlight_config *bl;



	if (!panel) {

		pr_err("Invalid Params\n");

		return -EINVAL;

	}



	bl = &panel->bl_config;

	if (!bl->pwm_bl) {

		pr_err("pwm device not found\n");

		return -EINVAL;

	}



	period_ns = bl->pwm_period_usecs * NSEC_PER_USEC;

	duty = bl_lvl * period_ns;

	duty /= bl->bl_max_level;



	rc = pwm_config(bl->pwm_bl, duty, period_ns);

	if (rc) {

		pr_err("[%s] failed to change pwm config, rc=\n", panel->name,

			rc);

		goto error;

	}



	if (bl_lvl == 0 && bl->pwm_enabled) {

		pwm_disable(bl->pwm_bl);

		bl->pwm_enabled = false;

		return 0;

	}



	if (!bl->pwm_enabled) {

		rc = pwm_enable(bl->pwm_bl);

		if (rc) {

			pr_err("[%s] failed to enable pwm, rc=\n", panel->name,

				rc);

			goto error;

		}



		bl->pwm_enabled = true;

	}



error:

	return rc;

}



int dsi_panel_set_backlight(struct dsi_panel *panel, u32 bl_lvl)

{

	int rc = 0;
@@ -643,6 +695,9 @@ int dsi_panel_set_backlight(struct dsi_panel *panel, u32 bl_lvl) 
		break;

	case DSI_BACKLIGHT_EXTERNAL:

		break;

	case DSI_BACKLIGHT_PWM:

		rc = dsi_panel_update_pwm_backlight(panel, bl_lvl);

		break;

	default:

		pr_err("Backlight type(%d) not supported\n", bl->type);

		rc = -ENOTSUPP;
@@ -667,6 +722,7 @@ static u32 dsi_panel_get_brightness(struct dsi_backlight_config *bl) 
		break;

	case DSI_BACKLIGHT_DCS:

	case DSI_BACKLIGHT_EXTERNAL:

	case DSI_BACKLIGHT_PWM:

	default:

		/*

		 * Ideally, we should read the backlight level from the
@@ -686,6 +742,22 @@ void dsi_panel_bl_handoff(struct dsi_panel *panel) 
	bl->bl_level = dsi_panel_get_brightness(bl);

}



static int dsi_panel_pwm_register(struct dsi_panel *panel)

{

	int rc = 0;

	struct dsi_backlight_config *bl = &panel->bl_config;



	bl->pwm_bl = devm_of_pwm_get(panel->parent, panel->panel_of_node, NULL);

	if (IS_ERR_OR_NULL(bl->pwm_bl)) {

		rc = PTR_ERR(bl->pwm_bl);

		pr_err("[%s] failed to request pwm, rc=%d\n", panel->name,

			rc);

		return rc;

	}



	return 0;

}



static int dsi_panel_bl_register(struct dsi_panel *panel)

{

	int rc = 0;
@@ -702,6 +774,9 @@ static int dsi_panel_bl_register(struct dsi_panel *panel) 
		break;

	case DSI_BACKLIGHT_EXTERNAL:

		break;

	case DSI_BACKLIGHT_PWM:

		rc = dsi_panel_pwm_register(panel);

		break;

	default:

		pr_err("Backlight type(%d) not supported\n", bl->type);

		rc = -ENOTSUPP;
@@ -712,6 +787,13 @@ static int dsi_panel_bl_register(struct dsi_panel *panel) 
	return rc;

}



static void dsi_panel_pwm_unregister(struct dsi_panel *panel)

{

	struct dsi_backlight_config *bl = &panel->bl_config;



	devm_pwm_put(panel->parent, bl->pwm_bl);

}



static int dsi_panel_bl_unregister(struct dsi_panel *panel)

{

	int rc = 0;
@@ -727,6 +809,9 @@ static int dsi_panel_bl_unregister(struct dsi_panel *panel) 
		break;

	case DSI_BACKLIGHT_EXTERNAL:

		break;

	case DSI_BACKLIGHT_PWM:

		dsi_panel_pwm_unregister(panel);

		break;

	default:

		pr_err("Backlight type(%d) not supported\n", bl->type);

		rc = -ENOTSUPP;
@@ -2042,34 +2127,14 @@ static int dsi_panel_parse_bl_pwm_config(struct dsi_panel *panel) 
	struct dsi_backlight_config *config = &panel->bl_config;

	struct dsi_parser_utils *utils = &panel->utils;



	rc = utils->read_u32(utils->data, "qcom,dsi-bl-pmic-bank-select",

	rc = utils->read_u32(utils->data, "qcom,bl-pmic-pwm-period-usecs",

				  &val);

	if (rc) {

		pr_err("bl-pmic-bank-select is not defined, rc=%d\n", rc);

		goto error;

	}

	config->pwm_pmic_bank = val;



	rc = utils->read_u32(utils->data, "qcom,dsi-bl-pmic-pwm-frequency",

				  &val);

	if (rc) {

		pr_err("bl-pmic-bank-select is not defined, rc=%d\n", rc);

		pr_err("bl-pmic-pwm-period-usecs is not defined, rc=%d\n", rc);

		goto error;

	}

	config->pwm_period_usecs = val;



	config->pwm_pmi_control = utils->read_bool(utils->data,

						"qcom,mdss-dsi-bl-pwm-pmi");



	config->pwm_gpio = utils->get_named_gpio(utils->data,

					     "qcom,mdss-dsi-pwm-gpio",

					     0);

	if (!gpio_is_valid(config->pwm_gpio)) {

		pr_err("pwm gpio is invalid\n");

		rc = -EINVAL;

		goto error;

	}



error:

	return rc;

}

drivers/gpu/drm/msm/dsi-staging/dsi_panel.h

+2 −3
Original line number Diff line number Diff line
@@ -111,10 +111,9 @@ struct dsi_backlight_config { 


	int en_gpio;

	/* PWM params */

	bool pwm_pmi_control;

	u32 pwm_pmic_bank;

	struct pwm_device *pwm_bl;

	bool pwm_enabled;

	u32 pwm_period_usecs;

	int pwm_gpio;



	/* WLED params */

	struct led_trigger *wled;