[PATCH 4/4] video: fbdev: pxafb: Add support for lcd-supply regulator

Daniel Mack
2018-06-24T15:38:17Z

Optionally obtain a lcd-supply regulator during probe and use it in
__pxafb_lcd_power() to switch the power supply of LCD panels.

This helps boards booted from DT to control such voltages without
callbacks.

Signed-off-by: Daniel Mack <daniel@zonque.org>
---
.../bindings/display/marvell,pxa2xx-lcdc.txt | 3 +++
drivers/video/fbdev/pxafb.c | 24 +++++++++++++++++++
drivers/video/fbdev/pxafb.h | 3 +++
3 files changed, 30 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/marvell,pxa2xx-lcdc.txt b/Documentation/devicetree/bindings/display/marvell,pxa2xx-lcdc.txt
index f79641bd5f18..45ffd6c41748 100644
--- a/Documentation/devicetree/bindings/display/marvell,pxa2xx-lcdc.txt
+++ b/Documentation/devicetree/bindings/display/marvell,pxa2xx-lcdc.txt
@@ -10,6 +10,9 @@ Required properties:
- interrupts : framebuffer controller interrupt.
- clocks: phandle to input clocks

+Optional properties:
+ - lcd-supply: A phandle to a power regulator that controls the LCD voltage.
+
Required nodes:
- port: connection to the LCD panel (see video-interfaces.txt)
This node must have its properties bus-width and remote-endpoint set.
diff --git a/drivers/video/fbdev/pxafb.c b/drivers/video/fbdev/pxafb.c
index 68459b07d442..bbed039617a4 100644
--- a/drivers/video/fbdev/pxafb.c
+++ b/drivers/video/fbdev/pxafb.c
@@ -56,6 +56,7 @@
#include <linux/freezer.h>
#include <linux/console.h>
#include <linux/of_graph.h>
+#include <linux/regulator/consumer.h>
#include <video/of_display_timing.h>
#include <video/videomode.h>

@@ -1423,6 +1424,21 @@ static inline void __pxafb_lcd_power(struct pxafb_info *fbi, int on)

if (fbi->lcd_power)
fbi->lcd_power(on, &fbi->fb.var);
+
+ if (fbi->lcd_supply && fbi->lcd_supply_enabled != on) {
+ int ret;
+
+ if (on)
+ ret = regulator_enable(fbi->lcd_supply);
+ else
+ ret = regulator_disable(fbi->lcd_supply);
+
+ if (ret < 0)
+ pr_warn("Unable to %s LCD supply regulator: %d\n",
+ on ? "enable" : "disable", ret);
+ else
+ fbi->lcd_supply_enabled = on;
+ }
}

static void pxafb_enable_controller(struct pxafb_info *fbi)
@@ -2299,6 +2315,14 @@ static int pxafb_probe(struct platform_device *dev)
fbi->backlight_power = inf->pxafb_backlight_power;
fbi->lcd_power = inf->pxafb_lcd_power;

+ fbi->lcd_supply = devm_regulator_get_optional(&dev->dev, "lcd");
+ if (IS_ERR(fbi->lcd_supply)) {
+ if (PTR_ERR(fbi->lcd_supply) = -EPROBE_DEFER)
+ return -EPROBE_DEFER;
+
+ fbi->lcd_supply = NULL;
+ }
+
r = platform_get_resource(dev, IORESOURCE_MEM, 0);
if (r = NULL) {
dev_err(&dev->dev, "no I/O memory resource defined\n");
diff --git a/drivers/video/fbdev/pxafb.h b/drivers/video/fbdev/pxafb.h
index 5dc414e26fc8..b641289c8a99 100644
--- a/drivers/video/fbdev/pxafb.h
+++ b/drivers/video/fbdev/pxafb.h
@@ -165,6 +165,9 @@ struct pxafb_info {
struct notifier_block freq_policy;
#endif

+ struct regulator *lcd_supply;
+ bool lcd_supply_enabled;
+
void (*lcd_power)(int, struct fb_var_screeninfo *);
void (*backlight_power)(int);

--
2.17.1