linux-kernel - [PATCH v2 02/18] drm/panel: lvds: Add support for the power-supply property

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Message-Id: <56a41d54acf87cdb2dc6f7e816f13816a66e2697.1511797218.git-series.maxime.ripard@free-electrons.com>
Date:   Mon, 27 Nov 2017 16:41:26 +0100
From:   Maxime Ripard <maxime.ripard@...e-electrons.com>
To:     Daniel Vetter <daniel.vetter@...el.com>,
        David Airlie <airlied@...ux.ie>, Chen-Yu Tsai <wens@...e.org>,
        Maxime Ripard <maxime.ripard@...e-electrons.com>
Cc:     dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Mark Rutland <mark.rutland@....com>,
        Rob Herring <robh+dt@...nel.org>,
        linux-arm-kernel@...ts.infradead.org, linux-clk@...r.kernel.org,
        plaes@...es.org, icenowy@...c.io,
        Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
        jernej.skrabec@...l.net
Subject: [PATCH v2 02/18] drm/panel: lvds: Add support for the power-supply property

A significant number of panels need to power up a regulator in order to
operate properly. Add support for the power-supply property to enable and
disable such a regulator whenever needed.

Reviewed-by: Chen-Yu Tsai <wens@...e.org>
Signed-off-by: Maxime Ripard <maxime.ripard@...e-electrons.com>
---
 drivers/gpu/drm/panel/panel-lvds.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/drivers/gpu/drm/panel/panel-lvds.c b/drivers/gpu/drm/panel/panel-lvds.c
index e2d57c01200b..57e38a9e7ab4 100644
--- a/drivers/gpu/drm/panel/panel-lvds.c
+++ b/drivers/gpu/drm/panel/panel-lvds.c
@@ -17,6 +17,7 @@
 #include <linux/module.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
 #include <linux/slab.h>
 
 #include <drm/drmP.h>
@@ -39,6 +40,7 @@ struct panel_lvds {
 	bool data_mirror;
 
 	struct backlight_device *backlight;
+	struct regulator *supply;
 
 	struct gpio_desc *enable_gpio;
 	struct gpio_desc *reset_gpio;
@@ -69,6 +71,9 @@ static int panel_lvds_unprepare(struct drm_panel *panel)
 	if (lvds->enable_gpio)
 		gpiod_set_value_cansleep(lvds->enable_gpio, 0);
 
+	if (lvds->supply)
+		regulator_disable(lvds->supply);
+
 	return 0;
 }
 
@@ -76,6 +81,17 @@ static int panel_lvds_prepare(struct drm_panel *panel)
 {
 	struct panel_lvds *lvds = to_panel_lvds(panel);
 
+	if (lvds->supply) {
+		int err;
+
+		err = regulator_enable(lvds->supply);
+		if (err < 0) {
+			dev_err(lvds->dev, "failed to enable supply: %d\n",
+				err);
+			return err;
+		}
+	}
+
 	if (lvds->enable_gpio)
 		gpiod_set_value_cansleep(lvds->enable_gpio, 1);
 
@@ -196,6 +212,13 @@ static int panel_lvds_probe(struct platform_device *pdev)
 	if (ret < 0)
 		return ret;
 
+	lvds->supply = devm_regulator_get_optional(lvds->dev, "power");
+	if (IS_ERR(lvds->supply)) {
+		ret = PTR_ERR(lvds->supply);
+		dev_err(lvds->dev, "failed to request regulator: %d\n", ret);
+		return ret;
+	}
+
 	/* Get GPIOs and backlight controller. */
 	lvds->enable_gpio = devm_gpiod_get_optional(lvds->dev, "enable",
 						     GPIOD_OUT_LOW);
-- 
git-series 0.9.1