fbdev/ssd1307fb: add support to enable VBAT

SSD1306 needs VBAT when it is wired in charge pump configuration. This
patch adds support to the driver to enable VBAT regulator at init time.

Cc: Rob Herring <robh+dt@kernel.org>
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Benoît Cousson <bcousson@baylibre.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Jyri Sarha <jsarha@ti.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

2 files changed, 20 insertions, 1 deletions

diff --git a/Documentation/devicetree/bindings/display/ssd1307fb.txt b/Documentation/devicetree/bindings/display/ssd1307fb.txt
index 6617df68d8b8..209d931ef16c 100644
--- a/Documentation/devicetree/bindings/display/ssd1307fb.txt
+++ b/Documentation/devicetree/bindings/display/ssd1307fb.txt
@@ -16,6 +16,7 @@ Required properties:
 Optional properties:
   - reset-gpios: The GPIO used to reset the OLED display, if available. See
                  Documentation/devicetree/bindings/gpio/gpio.txt for details.
+  - vbat-supply: The supply for VBAT
   - solomon,segment-no-remap: Display needs normal (non-inverted) data column
                               to segment mapping
   - solomon,com-seq: Display uses sequential COM pin configuration
diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c
index 89372af7bc5b..616a6a3fabf9 100644
--- a/drivers/video/fbdev/ssd1307fb.c
+++ b/drivers/video/fbdev/ssd1307fb.c
@@ -16,6 +16,7 @@
 #include <linux/of_gpio.h>
 #include <linux/pwm.h>
 #include <linux/uaccess.h>
+#include <linux/regulator/consumer.h>
 
 #define SSD1307FB_DATA                  0x40
 #define SSD1307FB_COMMAND               0x80
@@ -74,6 +75,7 @@ struct ssd1307fb_par {
         struct pwm_device *pwm;
         u32 pwm_period;
         struct gpio_desc *reset;
+        struct regulator *vbat_reg;
         u32 seg_remap;
         u32 vcomh;
         u32 width;
@@ -574,6 +576,14 @@ static int ssd1307fb_probe(struct i2c_client *client,
                 goto fb_alloc_error;
         }
 
+        par->vbat_reg = devm_regulator_get_optional(&client->dev, "vbat");
+        if (IS_ERR(par->vbat_reg)) {
+                dev_err(&client->dev, "failed to get VBAT regulator: %ld\n",
+                        PTR_ERR(par->vbat_reg));
+                ret = PTR_ERR(par->vbat_reg);
+                goto fb_alloc_error;
+        }
+
         if (of_property_read_u32(node, "solomon,width", &par->width))
                 par->width = 96;
 
@@ -658,9 +668,15 @@ static int ssd1307fb_probe(struct i2c_client *client,
                 udelay(4);
         }
 
+        ret = regulator_enable(par->vbat_reg);
+        if (ret) {
+                dev_err(&client->dev, "failed to enable VBAT: %d\n", ret);
+                goto reset_oled_error;
+        }
+
         ret = ssd1307fb_init(par);
         if (ret)
-                goto reset_oled_error;
+                goto regulator_enable_error;
 
         ret = register_framebuffer(info);
         if (ret) {
@@ -693,6 +709,8 @@ panel_init_error:
                 pwm_disable(par->pwm);
                 pwm_put(par->pwm);
         };
+regulator_enable_error:
+        regulator_disable(par->vbat_reg);
 reset_oled_error:
         fb_deferred_io_cleanup(info);
 fb_alloc_error: