[PATCHv14][ 1/4] video: imxfb: Introduce regulator support.

[Denis Carikli <denis@eukrea.com>]

This commit is based on the following commit by Fabio Estevam:
  4344429 video: mxsfb: Introduce regulator support

Cc: Eric Bénard <eric@eukrea.com>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-fbdev@vger.kernel.org
Signed-off-by: Denis Carikli <denis@eukrea.com>
---
ChangeLog v13->v14:
- Remove people not concerned by this patch from the Cc list.
- Simplified the regulator handling: The regulator-core now supplies
  a dummy regulator if one hasn't been hooked up explicitely.
  So we don't need to handle that case in the driver.
  The code has been updated to do that, and the error messages
  were updated accordingly.

ChangeLog v9->v10:
- Added a return 0; at the end of imxfb_disable_controller.

ChangeLog v8->v9:
- return an error if regulator_{enable,disable} fails in
  imxfb_{enable,disable}_controller, and use it.
---
 drivers/video/imxfb.c |   38 +++++++++++++++++++++++++-------------
 1 file changed, 25 insertions(+), 13 deletions(-)

diff --git a/drivers/video/imxfb.c b/drivers/video/imxfb.c
index 44ee678..dd8a35d 100644
--- a/drivers/video/imxfb.c
+++ b/drivers/video/imxfb.c
@@ -28,6 +28,7 @@
 #include <linux/cpufreq.h>
 #include <linux/clk.h>
 #include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
 #include <linux/dma-mapping.h>
 #include <linux/io.h>
 #include <linux/math64.h>
@@ -145,6 +146,7 @@ struct imxfb_info {
 	struct clk		*clk_ipg;
 	struct clk		*clk_ahb;
 	struct clk		*clk_per;
+	struct regulator	*reg_lcd;
 	enum imxfb_type		devtype;
 	bool			enabled;
 
@@ -561,14 +563,16 @@ static void imxfb_exit_backlight(struct imxfb_info *fbi)
 }
 #endif
 
-static void imxfb_enable_controller(struct imxfb_info *fbi)
+static int imxfb_enable_controller(struct imxfb_info *fbi)
 {
-
 	if (fbi->enabled)
-		return;
+		return 0;
 
 	pr_debug("Enabling LCD controller\n");
 
+	if (regulator_enable(fbi->reg_lcd))
+		dev_err(&fbi->pdev->dev, "Failed to enable regulator.\n");
+
 	writel(fbi->screen_dma, fbi->regs + LCDC_SSA);
 
 	/* panning offset 0 (0 pixel offset)        */
@@ -593,12 +597,14 @@ static void imxfb_enable_controller(struct imxfb_info *fbi)
 		fbi->backlight_power(1);
 	if (fbi->lcd_power)
 		fbi->lcd_power(1);
+
+	return 0;
 }
 
-static void imxfb_disable_controller(struct imxfb_info *fbi)
+static int imxfb_disable_controller(struct imxfb_info *fbi)
 {
 	if (!fbi->enabled)
-		return;
+		return 0;
 
 	pr_debug("Disabling LCD controller\n");
 
@@ -613,6 +619,11 @@ static void imxfb_disable_controller(struct imxfb_info *fbi)
 	fbi->enabled = false;
 
 	writel(0, fbi->regs + LCDC_RMCR);
+
+	if(regulator_disable(fbi->reg_lcd))
+		dev_err(&fbi->pdev->dev, "Failed to disable regulator.\n");
+
+	return 0;
 }
 
 static int imxfb_blank(int blank, struct fb_info *info)
@@ -626,13 +637,12 @@ static int imxfb_blank(int blank, struct fb_info *info)
 	case FB_BLANK_VSYNC_SUSPEND:
 	case FB_BLANK_HSYNC_SUSPEND:
 	case FB_BLANK_NORMAL:
-		imxfb_disable_controller(fbi);
-		break;
+		return imxfb_disable_controller(fbi);
 
 	case FB_BLANK_UNBLANK:
-		imxfb_enable_controller(fbi);
-		break;
+		return imxfb_enable_controller(fbi);
 	}
+
 	return 0;
 }
 
@@ -734,8 +744,7 @@ static int imxfb_suspend(struct platform_device *dev, pm_message_t state)
 
 	pr_debug("%s\n", __func__);
 
-	imxfb_disable_controller(fbi);
-	return 0;
+	return imxfb_disable_controller(fbi);
 }
 
 static int imxfb_resume(struct platform_device *dev)
@@ -745,8 +754,7 @@ static int imxfb_resume(struct platform_device *dev)
 
 	pr_debug("%s\n", __func__);
 
-	imxfb_enable_controller(fbi);
-	return 0;
+	return imxfb_enable_controller(fbi);
 }
 #else
 #define imxfb_suspend	NULL
@@ -1020,6 +1028,10 @@ static int imxfb_probe(struct platform_device *pdev)
 		goto failed_register;
 	}
 
+	fbi->reg_lcd = devm_regulator_get(&pdev->dev, "lcd");
+	if (IS_ERR(fbi->reg_lcd))
+		return PTR_ERR(fbi->reg_lcd);
+
 	imxfb_enable_controller(fbi);
 	fbi->pdev = pdev;
 #ifdef PWMR_BACKLIGHT_AVAILABLE
-- 
1.7.9.5