video/atmel_lcdfb: Introduce regulator support

This adds regulator support to enable/disable the LCD voltage, using
'lcd-supply' as regulator name.

Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

Documentation/devicetree/bindings/video/atmel,lcdc.txt

@@ -20,6 +20,9 @@ Required nodes:
 - default-mode: a videomode within the display with timing parameters
 	as specified below.
 
+Optional properties:
+- lcd-supply: Regulator for LCD supply voltage.
+
 Example:
 
 	fb0: fb@0x00500000 {

drivers/video/fbdev/atmel_lcdfb.c

@@ -24,6 +24,7 @@
 #include <linux/of_device.h>
 #include <linux/of_gpio.h>
 #include <video/of_display_timing.h>
+#include <linux/regulator/consumer.h>
 #include <video/videomode.h>
 
 #include <mach/cpu.h>
@@ -60,6 +61,7 @@ struct atmel_lcdfb_info {
 	struct atmel_lcdfb_pdata pdata;
 
 	struct atmel_lcdfb_config *config;
+	struct regulator	*reg_lcd;
 };
 
 struct atmel_lcdfb_power_ctrl_gpio {
@@ -302,10 +304,24 @@ static void init_contrast(struct atmel_lcdfb_info *sinfo)
 
 static inline void atmel_lcdfb_power_control(struct atmel_lcdfb_info *sinfo, int on)
 {
+	int ret;
 	struct atmel_lcdfb_pdata *pdata = &sinfo->pdata;
 
 	if (pdata->atmel_lcdfb_power_control)
 		pdata->atmel_lcdfb_power_control(pdata, on);
+	else if (sinfo->reg_lcd) {
+		if (on) {
+			ret = regulator_enable(sinfo->reg_lcd);
+			if (ret)
+				dev_err(&sinfo->pdev->dev,
+					"lcd regulator enable failed:	%d\n", ret);
+		} else {
+			ret = regulator_disable(sinfo->reg_lcd);
+			if (ret)
+				dev_err(&sinfo->pdev->dev,
+					"lcd regulator disable failed: %d\n", ret);
+		}
+	}
 }
 
 static struct fb_fix_screeninfo atmel_lcdfb_fix __initdata = {
@@ -1193,6 +1209,10 @@ static int __init atmel_lcdfb_probe(struct platform_device *pdev)
 	if (!sinfo->config)
 		goto free_info;
 
+	sinfo->reg_lcd = devm_regulator_get(&pdev->dev, "lcd");
+	if (IS_ERR(sinfo->reg_lcd))
+		sinfo->reg_lcd = NULL;
+
 	info->flags = ATMEL_LCDFB_FBINFO_DEFAULT;
 	info->pseudo_palette = sinfo->pseudo_palette;
 	info->fbops = &atmel_lcdfb_ops;