drivers/video: add support for the Solomon SSD1307 OLED Controller

Add support for the Solomon SSD1307 OLED controller found on the
Crystalfontz CFA10036 board.

This controller can drive a display with a resolution up to 128x39 and can
operate over I2C or SPI.

The current driver has only been tested on the CFA-10036, that is using
this controller over I2C to driver a 96x16 OLED screen.

[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Brian Lilly <brian@crystalfontz.com>
Cc: Greg KH <gregkh@linux-foundation.org>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc: Thomas Petazzoni <thomas@free-electrons.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

Documentation/devicetree/bindings/video/ssd1307fb.txt

@@ -0,0 +1,24 @@
+* Solomon SSD1307 Framebuffer Driver
+
+Required properties:
+  - compatible: Should be "solomon,ssd1307fb-<bus>". The only supported bus for
+    now is i2c.
+  - reg: Should contain address of the controller on the I2C bus. Most likely
+         0x3c or 0x3d
+  - pwm: Should contain the pwm to use according to the OF device tree PWM
+         specification [0]
+  - reset-gpios: Should contain the GPIO used to reset the OLED display
+
+Optional properties:
+  - reset-active-low: Is the reset gpio is active on physical low?
+
+[0]: Documentation/devicetree/bindings/pwm/pwm.txt
+
+Examples:
+ssd1307: oled@3c {
+        compatible = "solomon,ssd1307fb-i2c";
+        reg = <0x3c>;
+        pwms = <&pwm 4 3000>;
+        reset-gpios = <&gpio2 7>;
+        reset-active-low;
+};

drivers/video/Kconfig

@@ -2442,4 +2442,19 @@ config FB_SH_MOBILE_MERAM
 	  Up to 4 memory channels can be configured, allowing 4 RGB or
 	  2 YCbCr framebuffers to be configured.
 
+config FB_SSD1307
+	tristate "Solomon SSD1307 framebuffer support"
+	depends on FB && I2C
+	depends on OF
+	depends on GENERIC_GPIO
+	select FB_SYS_FOPS
+	select FB_SYS_FILLRECT
+	select FB_SYS_COPYAREA
+	select FB_SYS_IMAGEBLIT
+	select FB_DEFERRED_IO
+	select PWM
+	help
+	  This driver implements support for the Solomon SSD1307
+	  OLED controller over I2C.
+
 endmenu

drivers/video/Makefile

@@ -161,6 +161,7 @@ obj-$(CONFIG_FB_BFIN_7393)        += bfin_adv7393fb.o
 obj-$(CONFIG_FB_MX3)		  += mx3fb.o
 obj-$(CONFIG_FB_DA8XX)		  += da8xx-fb.o
 obj-$(CONFIG_FB_MXS)		  += mxsfb.o
+obj-$(CONFIG_FB_SSD1307)	  += ssd1307fb.o
 
 # the test framebuffer is last
 obj-$(CONFIG_FB_VIRTUAL)          += vfb.o