[PATCHv5 0/2] Add support for the OLED in the CFA10036

[PATCHv5 0/2] Add support for the OLED in the CFA10036

[Maxime Ripard]

Hi everyone,

This patchset adds support for the solomon SSD1307 OLED controller present
in the CFA-10036 board.

It first adds the framebuffer driver for this controller, and then the
needed bits to enable it in the cfa10036 dts.

Considering that the driver has been around since almost two months now, and
I have not received any comments on the framebuffer part, I'd very much like it
to be included in 3.7 if possible.

Thanks,
Maxime

Changes from v4:
  * Fix kernel crash when writing more data than the internal buffer space by
    adding boundary check for the fb_write function

Changes from v3:
  * Changed the dt property name to remove the leading oled- and changed the
    reset-gpio property to reset-gpios

Changes from v2:
  * Add the pin name as comment to the pwm4 pinctrl declaration
  * Change slightly the documentation of the dt bindings for the gpios to remove
    the mxs-specific cell.

Changes from v1:
  * Did some factorisation of the ssd1307fb_write* functions.
  * Filled the smem_start field of the fb_fix_screeninfo structure
  * Fixed the broken pwm declaration
  * Change the names of oled-reset-gpios and reset-active-low properties in the
    device tree to oled-reset-gpio and oled-reset-active-low for consistency

Maxime Ripard (2):
  video: Add support for the Solomon SSD1307 OLED Controller
  ARM: dts: mxs: add oled support for the cfa-10036

 .../devicetree/bindings/video/ssd1307fb.txt        |   24 ++
 arch/arm/boot/dts/imx28-cfa10036.dts               |   20 +
 drivers/video/Kconfig                              |   13 +
 drivers/video/Makefile                             |    1 +
 drivers/video/ssd1307fb.c                          |  407 ++++++++++++++++++++
 5 files changed, 465 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/video/ssd1307fb.txt
 create mode 100644 drivers/video/ssd1307fb.c

-- 
1.7.9.5

[PATCH 1/2] video: Add support for the Solomon SSD1307 OLED Controller

[Maxime Ripard]

This patch adds 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.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Brian Lilly <brian@crystalfontz.com>
---
 .../devicetree/bindings/video/ssd1307fb.txt        |   24 ++
 drivers/video/Kconfig                              |   13 +
 drivers/video/Makefile                             |    1 +
 drivers/video/ssd1307fb.c                          |  407 ++++++++++++++++++++
 4 files changed, 445 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/video/ssd1307fb.txt
 create mode 100644 drivers/video/ssd1307fb.c

diff --git a/Documentation/devicetree/bindings/video/ssd1307fb.txt b/Documentation/devicetree/bindings/video/ssd1307fb.txt
new file mode 100644
index 0000000..3d0060c
--- /dev/null
+++ b/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;
+};
diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index 0217f74..2776829 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -2469,4 +2469,17 @@ 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
+	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
diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index ee8dafb..6bbb72c 100644
--- a/drivers/video/Makefile
+++ b/drivers/video/Makefile
@@ -164,6 +164,7 @@ 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
diff --git a/drivers/video/ssd1307fb.c b/drivers/video/ssd1307fb.c
new file mode 100644
index 0000000..49e42ed
--- /dev/null
+++ b/drivers/video/ssd1307fb.c
@@ -0,0 +1,407 @@
+/*
+ * Driver for the Solomon SSD1307 OLED controler
+ *
+ * Copyright 2012 Free Electrons
+ *
+ * Licensed under the GPLv2 or later.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/i2c.h>
+#include <linux/fb.h>
+#include <linux/uaccess.h>
+#include <linux/of_device.h>
+#include <linux/of_gpio.h>
+#include <linux/pwm.h>
+#include <linux/delay.h>
+
+#define SSD1307FB_WIDTH			96
+#define SSD1307FB_HEIGHT		16
+
+#define SSD1307FB_DATA			0x40
+#define SSD1307FB_COMMAND		0x80
+
+#define SSD1307FB_CONTRAST		0x81
+#define SSD1307FB_SEG_REMAP_ON		0xa1
+#define SSD1307FB_DISPLAY_OFF		0xae
+#define SSD1307FB_DISPLAY_ON		0xaf
+#define SSD1307FB_START_PAGE_ADDRESS	0xb0
+
+struct ssd1307fb_par {
+	struct i2c_client *client;
+	struct fb_info *info;
+	struct pwm_device *pwm;
+	u32 pwm_period;
+	int reset;
+};
+
+static struct fb_fix_screeninfo ssd1307fb_fix __devinitdata = {
+	.id		= "Solomon SSD1307",
+	.type		= FB_TYPE_PACKED_PIXELS,
+	.visual		= FB_VISUAL_MONO10,
+	.xpanstep	= 0,
+	.ypanstep	= 0,
+	.ywrapstep	= 0,
+	.line_length	= SSD1307FB_WIDTH / 8,
+	.accel		= FB_ACCEL_NONE,
+};
+
+static struct fb_var_screeninfo ssd1307fb_var __devinitdata = {
+	.xres		= SSD1307FB_WIDTH,
+	.yres		= SSD1307FB_HEIGHT,
+	.xres_virtual	= SSD1307FB_WIDTH,
+	.yres_virtual	= SSD1307FB_HEIGHT,
+	.bits_per_pixel	= 1,
+};
+
+static int ssd1307fb_write_array(struct i2c_client *client, u8 type, u8* cmd, u32 len)
+{
+	u8 *buf;
+	int ret = 0;
+
+	buf = kzalloc(len + 1, GFP_KERNEL);
+	if (!buf) {
+		dev_err(&client->dev, "Couldn't allocate sending buffer.\n");
+		return -ENOMEM;
+	}
+
+	buf[0] = type;
+	memcpy(buf + 1, cmd, len);
+
+	ret = i2c_master_send(client, buf, len + 1);
+	if (ret != len + 1) {
+		dev_err(&client->dev, "Couldn't send I2C command.\n");
+		goto error;
+	}
+
+error:
+	kfree(buf);
+	return ret;
+}
+
+static inline int ssd1307fb_write_cmd_array(struct i2c_client *client, u8* cmd, u32 len)
+{
+	return ssd1307fb_write_array(client, SSD1307FB_COMMAND, cmd, len);
+}
+
+static inline int ssd1307fb_write_cmd(struct i2c_client *client, u8 cmd)
+{
+	return ssd1307fb_write_cmd_array(client, &cmd, 1);
+}
+
+static inline int ssd1307fb_write_data_array(struct i2c_client *client, u8* cmd, u32 len)
+{
+	return ssd1307fb_write_array(client, SSD1307FB_DATA, cmd, len);
+}
+
+static inline int ssd1307fb_write_data(struct i2c_client *client, u8 data)
+{
+	return ssd1307fb_write_data_array(client, &data, 1);
+}
+
+static void ssd1307fb_update_display(struct ssd1307fb_par *par)
+{
+	u8 *vmem = par->info->screen_base;
+	int i, j, k;
+
+	/*
+	 * The screen is divided in pages, each having a height of 8
+	 * pixels, and the width of the screen. When sending a byte of
+	 * data to the controller, it gives the 8 bits for the current
+	 * column. I.e, the first byte are the 8 bits of the first
+	 * column, then the 8 bits for the second column, etc.
+	 *
+	 *
+	 * Representation of the screen, assuming it is 5 bits
+	 * wide. Each letter-number combination is a bit that controls
+	 * one pixel.
+	 *
+	 * A0 A1 A2 A3 A4
+	 * B0 B1 B2 B3 B4
+	 * C0 C1 C2 C3 C4
+	 * D0 D1 D2 D3 D4
+	 * E0 E1 E2 E3 E4
+	 * F0 F1 F2 F3 F4
+	 * G0 G1 G2 G3 G4
+	 * H0 H1 H2 H3 H4
+	 *
+	 * If you want to update this screen, you need to send 5 bytes:
+	 *  (1) A0 B0 C0 D0 E0 F0 G0 H0
+	 *  (2) A1 B1 C1 D1 E1 F1 G1 H1
+	 *  (3) A2 B2 C2 D2 E2 F2 G2 H2
+	 *  (4) A3 B3 C3 D3 E3 F3 G3 H3
+	 *  (5) A4 B4 C4 D4 E4 F4 G4 H4
+	 */
+
+	for (i = 0; i < (SSD1307FB_HEIGHT / 8); i++) {
+		ssd1307fb_write_cmd(par->client, SSD1307FB_START_PAGE_ADDRESS + (i + 1));
+		ssd1307fb_write_cmd(par->client, 0x00);
+		ssd1307fb_write_cmd(par->client, 0x10);
+
+		for (j = 0; j < SSD1307FB_WIDTH; j++) {
+			u8 buf = 0;
+			for (k = 0; k < 8; k++) {
+				u32 page_length = SSD1307FB_WIDTH * i;
+				u32 index = page_length + (SSD1307FB_WIDTH * k + j) / 8;
+				u8 byte = *(vmem + index);
+				u8 bit = byte & (1 << (7 - (j % 8)));
+				bit = bit >> (7 - (j % 8));
+				buf |= bit << k;
+			}
+			ssd1307fb_write_data(par->client, buf);
+		}
+	}
+}
+
+
+static ssize_t ssd1307fb_write(struct fb_info *info, const char __user *buf,
+		size_t count, loff_t *ppos)
+{
+	struct ssd1307fb_par *par = info->par;
+	unsigned long total_size;
+	unsigned long p = *ppos;
+	u8 __iomem *dst;
+	int err = 0;
+
+	total_size = info->screen_size;
+
+	if (total_size = 0)
+		total_size = info->fix.smem_len;
+
+	if (p > total_size)
+		return -EFBIG;
+
+	if (count > total_size) {
+		err = -EFBIG;
+		count = total_size;
+	}
+
+	if (count + p > total_size) {
+		if (!err)
+			err = -ENOSPC;
+
+		count = total_size - p;
+	}
+
+	dst = (void __force *) (info->screen_base + p);
+
+	if (copy_from_user(dst, buf, count))
+		err = -EFAULT;
+
+	if  (!err)
+		*ppos += count;
+
+	ssd1307fb_update_display(par);
+
+	return (err) ? err : count;
+}
+
+static void ssd1307fb_fillrect(struct fb_info *info, const struct fb_fillrect *rect)
+{
+	struct ssd1307fb_par *par = info->par;
+	sys_fillrect(info, rect);
+	ssd1307fb_update_display(par);
+}
+
+static void ssd1307fb_copyarea(struct fb_info *info, const struct fb_copyarea *area) 
+{
+	struct ssd1307fb_par *par = info->par;
+	sys_copyarea(info, area);
+	ssd1307fb_update_display(par);
+}
+
+static void ssd1307fb_imageblit(struct fb_info *info, const struct fb_image *image) 
+{
+	struct ssd1307fb_par *par = info->par;
+	sys_imageblit(info, image);
+	ssd1307fb_update_display(par);
+}
+
+static struct fb_ops ssd1307fb_ops = {
+	.owner		= THIS_MODULE,
+	.fb_read	= fb_sys_read,
+	.fb_write	= ssd1307fb_write,
+	.fb_fillrect	= ssd1307fb_fillrect,
+	.fb_copyarea	= ssd1307fb_copyarea,
+	.fb_imageblit	= ssd1307fb_imageblit,
+};
+
+static void ssd1307fb_deferred_io(struct fb_info *info,
+				struct list_head *pagelist)
+{
+	ssd1307fb_update_display(info->par);
+}
+
+static struct fb_deferred_io ssd1307fb_defio = {
+	.delay		= HZ,
+	.deferred_io	= ssd1307fb_deferred_io,
+};
+
+static int __devinit ssd1307fb_probe(struct i2c_client *client, const struct i2c_device_id *id)
+{
+	struct fb_info *info;
+	u32 vmem_size = SSD1307FB_WIDTH * SSD1307FB_HEIGHT / 8;
+	struct ssd1307fb_par *par;
+	u8 *vmem;
+	int ret;
+
+	if (!client->dev.of_node) {
+		dev_err(&client->dev, "No device tree data found!\n");
+		return -EINVAL;
+	}
+
+	info = framebuffer_alloc(sizeof(struct ssd1307fb_par), &client->dev);
+	if (!info) {
+		dev_err(&client->dev, "Couldn't allocate framebuffer.\n");
+		return -ENOMEM;
+	}
+
+	vmem = devm_kzalloc(&client->dev, vmem_size, GFP_KERNEL);
+	if (!vmem) {
+		dev_err(&client->dev, "Couldn't allocate graphical memory.\n");
+		ret = -ENOMEM;
+		goto fb_alloc_error;
+	}
+
+	info->fbops = &ssd1307fb_ops;
+	info->fix = ssd1307fb_fix;
+	info->fbdefio = &ssd1307fb_defio;
+
+	info->var = ssd1307fb_var;
+	info->var.red.length = 1;
+	info->var.red.offset = 0;
+	info->var.green.length = 1;
+	info->var.green.offset = 0;
+	info->var.blue.length = 1;
+	info->var.blue.offset = 0;
+
+	info->screen_base = (u8 __force __iomem *)vmem;
+	info->fix.smem_start = (unsigned long)vmem;
+	info->fix.smem_len = vmem_size;
+
+	fb_deferred_io_init(info);
+
+	par = info->par;
+	par->info = info;
+	par->client = client;
+
+	par->reset = of_get_named_gpio(client->dev.of_node,
+					 "reset-gpios", 0);
+	if (gpio_is_valid(par->reset)) {
+		int flags = GPIOF_OUT_INIT_HIGH;
+		if (of_get_property(client->dev.of_node,
+				    "reset-active-low", NULL))
+			flags = GPIOF_OUT_INIT_LOW;
+		ret = devm_gpio_request_one(&client->dev, par->reset,
+					    flags, "oled-reset");
+		if (ret) {
+			dev_err(&client->dev,
+				"failed to request gpio %d: %d\n",
+				par->reset, ret);
+			goto reset_oled_error;
+		}
+	}
+
+	par->pwm = pwm_get(&client->dev, NULL);
+	if (IS_ERR(par->pwm)) {
+		dev_err(&client->dev, "Could not get PWM from device tree!\n");
+		ret = PTR_ERR(par->pwm);
+		goto pwm_error;
+	}
+
+	par->pwm_period = pwm_get_period(par->pwm);
+
+	dev_dbg(&client->dev, "Using PWM%d with a %dns period.\n", par->pwm->pwm, par->pwm_period);
+
+	ret = register_framebuffer(info);
+	if (ret) {
+		dev_err(&client->dev, "Couldn't register the framebuffer\n");
+		goto fbreg_error;
+	}
+
+	i2c_set_clientdata(client, info);
+
+	/* Reset the screen */
+	gpio_set_value(par->reset, 1);
+	udelay(4);
+	gpio_set_value(par->reset, 0);
+	udelay(4);
+
+	/* Enable the PWM */
+	pwm_config(par->pwm, par->pwm_period / 2, par->pwm_period);
+	pwm_enable(par->pwm);
+
+	/* Map column 127 of the OLED to segment 0 */
+	ret = ssd1307fb_write_cmd(client, SSD1307FB_SEG_REMAP_ON);
+	if (ret < 0) {
+		dev_err(&client->dev, "Couldn't remap the screen.\n");
+		goto remap_error;
+	}
+
+	/* Turn on the display */
+	ret = ssd1307fb_write_cmd(client, SSD1307FB_DISPLAY_ON);
+	if (ret < 0) {
+		dev_err(&client->dev, "Couldn't turn the display on.\n");
+		goto remap_error;
+	}
+
+	dev_info(&client->dev, "fb%d: %s framebuffer device registered, using %d bytes of video memory\n", info->node, info->fix.id, vmem_size);
+
+	return 0;
+
+remap_error:
+	unregister_framebuffer(info);
+	pwm_disable(par->pwm);
+fbreg_error:
+	pwm_put(par->pwm);
+pwm_error:
+reset_oled_error:
+	fb_deferred_io_cleanup(info);
+fb_alloc_error:
+	framebuffer_release(info);
+	return ret;
+}
+
+static int __devexit ssd1307fb_remove(struct i2c_client *client)
+{
+	struct fb_info *info = i2c_get_clientdata(client);
+	struct ssd1307fb_par *par = info->par;
+
+	unregister_framebuffer(info);
+	pwm_disable(par->pwm);
+	pwm_put(par->pwm);
+	fb_deferred_io_cleanup(info);
+	framebuffer_release(info);
+
+	return 0;
+}
+
+static const struct i2c_device_id ssd1307fb_i2c_id[] = {
+	{ "ssd1307fb", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ssd1307fb_i2c_id);
+
+static const struct of_device_id ssd1307fb_of_match[] = {
+	{ .compatible = "solomon,ssd1307fb-i2c" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ssd1307fb_of_match);
+
+static struct i2c_driver ssd1307fb_driver = {
+	.probe = ssd1307fb_probe,
+	.remove = __devexit_p(ssd1307fb_remove),
+	.id_table = ssd1307fb_i2c_id,
+	.driver = {
+		.name = "ssd1307fb",
+		.of_match_table = of_match_ptr(ssd1307fb_of_match),
+		.owner = THIS_MODULE,
+	},
+};
+
+module_i2c_driver(ssd1307fb_driver);
+
+MODULE_DESCRIPTION("FB driver for the Solomon SSD1307 OLED controler");
+MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
+MODULE_LICENSE("GPL");
-- 
1.7.9.5

Re: [PATCH 1/2] video: Add support for the Solomon SSD1307 OLED Controller

[Maxime Ripard]

Hi Florian,


Le 20/09/2012 18:33, Maxime Ripard a écrit :
> This patch adds 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.
> 
> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> Cc: Brian Lilly <brian@crystalfontz.com>

Would you consider merging this patch or review it?
It has been around for quite some time now and has not received any
comments for at least the 2 last versions, so I guess there is not much
left holding it back (unless, of course, if you have some comments to
address), and I really would like to have it in 3.7.

Thanks,

Maxime



-- 
Maxime Ripard, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

Re: [PATCH 1/2] video: Add support for the Solomon SSD1307 OLED Controller

[Maxime Ripard]

Hello Florian,

Le 21/09/2012 16:04, Maxime Ripard a écrit :
> Le 20/09/2012 18:33, Maxime Ripard a écrit :
>> This patch adds 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.
>>
>> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
>> Cc: Brian Lilly <brian@crystalfontz.com>
> 
> Would you consider merging this patch or review it?
> It has been around for quite some time now and has not received any
> comments for at least the 2 last versions, so I guess there is not much
> left holding it back (unless, of course, if you have some comments to
> address), and I really would like to have it in 3.7.

I guess we missed the 3.7 merge here. That's no big deal, but I sent the
patch series on a regular basis, starting 07/17 (sent new versions on
07/31, 08/23, 09/05 and 09/20), addressed all the issues that were
raised, and never got any feedback from you, either positive or
negative. The patches affecting the MX28 device trees have already been
merged by Shawn Guo into its tree, so only the driver and the bindings
remain to be merged. So I'm kind of lost on what should I do here?

Is it because I have an obviously broken driver or you don't have enough
time, or you don't want to merge drivers for such type of low resolution
controllers, or any other reason?

Thanks for your answer,
Maxime


-- 
Maxime Ripard, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

Re: [PATCH 1/2] video: Add support for the Solomon SSD1307 OLED Controller

[Florian Tobias Schandinat]

Hi Maxime,

On 09/25/2012 10:06 AM, Maxime Ripard wrote:
> Hello Florian,
> 
> Le 21/09/2012 16:04, Maxime Ripard a écrit :
>> Le 20/09/2012 18:33, Maxime Ripard a écrit :
>>> This patch adds 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.
>>>
>>> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
>>> Cc: Brian Lilly <brian@crystalfontz.com>
>>
>> Would you consider merging this patch or review it?
>> It has been around for quite some time now and has not received any
>> comments for at least the 2 last versions, so I guess there is not much
>> left holding it back (unless, of course, if you have some comments to
>> address), and I really would like to have it in 3.7.
> 
> I guess we missed the 3.7 merge here. That's no big deal, but I sent the
> patch series on a regular basis, starting 07/17 (sent new versions on
> 07/31, 08/23, 09/05 and 09/20), addressed all the issues that were
> raised, and never got any feedback from you, either positive or
> negative. The patches affecting the MX28 device trees have already been
> merged by Shawn Guo into its tree, so only the driver and the bindings
> remain to be merged. So I'm kind of lost on what should I do here?
> 
> Is it because I have an obviously broken driver or you don't have enough
> time, or you don't want to merge drivers for such type of low resolution
> controllers, or any other reason?

I don't see any reason to not support low resolutions, might be a nice
status monitor for embedded devices.
It's not your fault. It's just that for the past two months writing my
thesis reduced my free time (and hence the time that I could potentially
use for reviewing patches) to approximately zero. While I managed to get
some smaller patches done, there really wasn't any time to process the
3-4 completely new things pending and some scarier patches which touch
the core infrastructure.
I think that it should be better soon, at least my thesis is now done,
but I also have to fix up the rest of my life that was neglected while
writing, including my paid jobs.


Best regards,

Florian Tobias Schandinat

Re: [PATCH 1/2] video: Add support for the Solomon SSD1307 OLED Controller

[Maxime Ripard]

Hi Florian,

Le 11/10/2012 03:06, Florian Tobias Schandinat a écrit :
> Hi Maxime,
> 
> On 09/25/2012 10:06 AM, Maxime Ripard wrote:
>> Hello Florian,
>>
>> Le 21/09/2012 16:04, Maxime Ripard a écrit :
>>> Le 20/09/2012 18:33, Maxime Ripard a écrit :
>>>> This patch adds 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.
>>>>
>>>> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
>>>> Cc: Brian Lilly <brian@crystalfontz.com>
>>>
>>> Would you consider merging this patch or review it?
>>> It has been around for quite some time now and has not received any
>>> comments for at least the 2 last versions, so I guess there is not much
>>> left holding it back (unless, of course, if you have some comments to
>>> address), and I really would like to have it in 3.7.
>>
>> I guess we missed the 3.7 merge here. That's no big deal, but I sent the
>> patch series on a regular basis, starting 07/17 (sent new versions on
>> 07/31, 08/23, 09/05 and 09/20), addressed all the issues that were
>> raised, and never got any feedback from you, either positive or
>> negative. The patches affecting the MX28 device trees have already been
>> merged by Shawn Guo into its tree, so only the driver and the bindings
>> remain to be merged. So I'm kind of lost on what should I do here?
>>
>> Is it because I have an obviously broken driver or you don't have enough
>> time, or you don't want to merge drivers for such type of low resolution
>> controllers, or any other reason?
> 
> I don't see any reason to not support low resolutions, might be a nice
> status monitor for embedded devices.
> It's not your fault. It's just that for the past two months writing my
> thesis reduced my free time (and hence the time that I could potentially
> use for reviewing patches) to approximately zero. While I managed to get
> some smaller patches done, there really wasn't any time to process the
> 3-4 completely new things pending and some scarier patches which touch
> the core infrastructure.
> I think that it should be better soon, at least my thesis is now done,
> but I also have to fix up the rest of my life that was neglected while
> writing, including my paid jobs.

Ok, that's fine :)

How do you want to proceed? To you want me to resend the patchset, or
you will review this one when you will have some time?

Thanks,
Maxime

-- 
Maxime Ripard, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

[PATCH 2/2] ARM: dts: mxs: add oled support for the cfa-10036

[Maxime Ripard]

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Brian Lilly <brian@crystalfontz.com>
---
 arch/arm/boot/dts/imx28-cfa10036.dts |   20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/arch/arm/boot/dts/imx28-cfa10036.dts b/arch/arm/boot/dts/imx28-cfa10036.dts
index c03a577..e5ee46e 100644
--- a/arch/arm/boot/dts/imx28-cfa10036.dts
+++ b/arch/arm/boot/dts/imx28-cfa10036.dts
@@ -33,11 +33,31 @@
 		};
 
 		apbx@80040000 {
+			pwm: pwm@80064000 {
+				pinctrl-names = "default";
+				pinctrl-0 = <&pwm4_pins_a>;
+				status = "okay";
+			};
+
 			duart: serial@80074000 {
 				pinctrl-names = "default";
 				pinctrl-0 = <&duart_pins_b>;
 				status = "okay";
 			};
+
+			i2c0: i2c@80058000 {
+				pinctrl-names = "default";
+				pinctrl-0 = <&i2c0_pins_b>;
+				status = "okay";
+
+				ssd1307: oled@3c {
+					compatible = "solomon,ssd1307fb-i2c";
+					reg = <0x3c>;
+					pwms = <&pwm 4 3000>;
+					reset-gpios = <&gpio2 7 1>;
+					reset-active-low;
+				};
+			};
 		};
 	};
 
-- 
1.7.9.5

[PATCHv6 0/2] Add support for the OLED in the CFA10036

[Maxime Ripard]

Hi everyone,

This patchset adds support for the solomon SSD1307 OLED controller present
in the CFA-10036 board.

It first adds the framebuffer driver for this controller, and then the
needed bits to enable it in the cfa10036 dts.

Considering that the driver has been around since almost three months now, and
I have not received any comments on the framebuffer part, I'd very much like it
to be included in 3.8 if possible.

Thanks,
Maxime

Changes from v5:
  * Fixed bogus reset code

Maxime Ripard (2):
  video: Add support for the Solomon SSD1307 OLED Controller
  ARM: dts: mxs: add oled support for the cfa-10036

 .../devicetree/bindings/video/ssd1307fb.txt        |   24 ++
 arch/arm/boot/dts/imx28-cfa10036.dts               |   19 +
 drivers/video/Kconfig                              |   13 +
 drivers/video/Makefile                             |    1 +
 drivers/video/ssd1307fb.c                          |  407 ++++++++++++++++++++
 5 files changed, 464 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/video/ssd1307fb.txt
 create mode 100644 drivers/video/ssd1307fb.c

-- 
1.7.9.5

[PATCH 1/2] video: Add support for the Solomon SSD1307 OLED Controller

[Maxime Ripard]

This patch adds 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.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Brian Lilly <brian@crystalfontz.com>
---
 .../devicetree/bindings/video/ssd1307fb.txt        |   24 ++
 drivers/video/Kconfig                              |   13 +
 drivers/video/Makefile                             |    1 +
 drivers/video/ssd1307fb.c                          |  407 ++++++++++++++++++++
 4 files changed, 445 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/video/ssd1307fb.txt
 create mode 100644 drivers/video/ssd1307fb.c

diff --git a/Documentation/devicetree/bindings/video/ssd1307fb.txt b/Documentation/devicetree/bindings/video/ssd1307fb.txt
new file mode 100644
index 0000000..3d0060c
--- /dev/null
+++ b/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;
+};
diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index d08d799..294de9c 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -2442,4 +2442,17 @@ 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
+	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
diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index 23e948e..768a137 100644
--- a/drivers/video/Makefile
+++ b/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
diff --git a/drivers/video/ssd1307fb.c b/drivers/video/ssd1307fb.c
new file mode 100644
index 0000000..ed18f19
--- /dev/null
+++ b/drivers/video/ssd1307fb.c
@@ -0,0 +1,407 @@
+/*
+ * Driver for the Solomon SSD1307 OLED controler
+ *
+ * Copyright 2012 Free Electrons
+ *
+ * Licensed under the GPLv2 or later.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/i2c.h>
+#include <linux/fb.h>
+#include <linux/uaccess.h>
+#include <linux/of_device.h>
+#include <linux/of_gpio.h>
+#include <linux/pwm.h>
+#include <linux/delay.h>
+
+#define SSD1307FB_WIDTH			96
+#define SSD1307FB_HEIGHT		16
+
+#define SSD1307FB_DATA			0x40
+#define SSD1307FB_COMMAND		0x80
+
+#define SSD1307FB_CONTRAST		0x81
+#define SSD1307FB_SEG_REMAP_ON		0xa1
+#define SSD1307FB_DISPLAY_OFF		0xae
+#define SSD1307FB_DISPLAY_ON		0xaf
+#define SSD1307FB_START_PAGE_ADDRESS	0xb0
+
+struct ssd1307fb_par {
+	struct i2c_client *client;
+	struct fb_info *info;
+	struct pwm_device *pwm;
+	u32 pwm_period;
+	int reset;
+};
+
+static struct fb_fix_screeninfo ssd1307fb_fix __devinitdata = {
+	.id		= "Solomon SSD1307",
+	.type		= FB_TYPE_PACKED_PIXELS,
+	.visual		= FB_VISUAL_MONO10,
+	.xpanstep	= 0,
+	.ypanstep	= 0,
+	.ywrapstep	= 0,
+	.line_length	= SSD1307FB_WIDTH / 8,
+	.accel		= FB_ACCEL_NONE,
+};
+
+static struct fb_var_screeninfo ssd1307fb_var __devinitdata = {
+	.xres		= SSD1307FB_WIDTH,
+	.yres		= SSD1307FB_HEIGHT,
+	.xres_virtual	= SSD1307FB_WIDTH,
+	.yres_virtual	= SSD1307FB_HEIGHT,
+	.bits_per_pixel	= 1,
+};
+
+static int ssd1307fb_write_array(struct i2c_client *client, u8 type, u8* cmd, u32 len)
+{
+	u8 *buf;
+	int ret = 0;
+
+	buf = kzalloc(len + 1, GFP_KERNEL);
+	if (!buf) {
+		dev_err(&client->dev, "Couldn't allocate sending buffer.\n");
+		return -ENOMEM;
+	}
+
+	buf[0] = type;
+	memcpy(buf + 1, cmd, len);
+
+	ret = i2c_master_send(client, buf, len + 1);
+	if (ret != len + 1) {
+		dev_err(&client->dev, "Couldn't send I2C command.\n");
+		goto error;
+	}
+
+error:
+	kfree(buf);
+	return ret;
+}
+
+static inline int ssd1307fb_write_cmd_array(struct i2c_client *client, u8* cmd, u32 len)
+{
+	return ssd1307fb_write_array(client, SSD1307FB_COMMAND, cmd, len);
+}
+
+static inline int ssd1307fb_write_cmd(struct i2c_client *client, u8 cmd)
+{
+	return ssd1307fb_write_cmd_array(client, &cmd, 1);
+}
+
+static inline int ssd1307fb_write_data_array(struct i2c_client *client, u8* cmd, u32 len)
+{
+	return ssd1307fb_write_array(client, SSD1307FB_DATA, cmd, len);
+}
+
+static inline int ssd1307fb_write_data(struct i2c_client *client, u8 data)
+{
+	return ssd1307fb_write_data_array(client, &data, 1);
+}
+
+static void ssd1307fb_update_display(struct ssd1307fb_par *par)
+{
+	u8 *vmem = par->info->screen_base;
+	int i, j, k;
+
+	/*
+	 * The screen is divided in pages, each having a height of 8
+	 * pixels, and the width of the screen. When sending a byte of
+	 * data to the controller, it gives the 8 bits for the current
+	 * column. I.e, the first byte are the 8 bits of the first
+	 * column, then the 8 bits for the second column, etc.
+	 *
+	 *
+	 * Representation of the screen, assuming it is 5 bits
+	 * wide. Each letter-number combination is a bit that controls
+	 * one pixel.
+	 *
+	 * A0 A1 A2 A3 A4
+	 * B0 B1 B2 B3 B4
+	 * C0 C1 C2 C3 C4
+	 * D0 D1 D2 D3 D4
+	 * E0 E1 E2 E3 E4
+	 * F0 F1 F2 F3 F4
+	 * G0 G1 G2 G3 G4
+	 * H0 H1 H2 H3 H4
+	 *
+	 * If you want to update this screen, you need to send 5 bytes:
+	 *  (1) A0 B0 C0 D0 E0 F0 G0 H0
+	 *  (2) A1 B1 C1 D1 E1 F1 G1 H1
+	 *  (3) A2 B2 C2 D2 E2 F2 G2 H2
+	 *  (4) A3 B3 C3 D3 E3 F3 G3 H3
+	 *  (5) A4 B4 C4 D4 E4 F4 G4 H4
+	 */
+
+	for (i = 0; i < (SSD1307FB_HEIGHT / 8); i++) {
+		ssd1307fb_write_cmd(par->client, SSD1307FB_START_PAGE_ADDRESS + (i + 1));
+		ssd1307fb_write_cmd(par->client, 0x00);
+		ssd1307fb_write_cmd(par->client, 0x10);
+
+		for (j = 0; j < SSD1307FB_WIDTH; j++) {
+			u8 buf = 0;
+			for (k = 0; k < 8; k++) {
+				u32 page_length = SSD1307FB_WIDTH * i;
+				u32 index = page_length + (SSD1307FB_WIDTH * k + j) / 8;
+				u8 byte = *(vmem + index);
+				u8 bit = byte & (1 << (7 - (j % 8)));
+				bit = bit >> (7 - (j % 8));
+				buf |= bit << k;
+			}
+			ssd1307fb_write_data(par->client, buf);
+		}
+	}
+}
+
+
+static ssize_t ssd1307fb_write(struct fb_info *info, const char __user *buf,
+		size_t count, loff_t *ppos)
+{
+	struct ssd1307fb_par *par = info->par;
+	unsigned long total_size;
+	unsigned long p = *ppos;
+	u8 __iomem *dst;
+	int err = 0;
+
+	total_size = info->screen_size;
+
+	if (total_size = 0)
+		total_size = info->fix.smem_len;
+
+	if (p > total_size)
+		return -EFBIG;
+
+	if (count > total_size) {
+		err = -EFBIG;
+		count = total_size;
+	}
+
+	if (count + p > total_size) {
+		if (!err)
+			err = -ENOSPC;
+
+		count = total_size - p;
+	}
+
+	dst = (void __force *) (info->screen_base + p);
+
+	if (copy_from_user(dst, buf, count))
+		err = -EFAULT;
+
+	if  (!err)
+		*ppos += count;
+
+	ssd1307fb_update_display(par);
+
+	return (err) ? err : count;
+}
+
+static void ssd1307fb_fillrect(struct fb_info *info, const struct fb_fillrect *rect)
+{
+	struct ssd1307fb_par *par = info->par;
+	sys_fillrect(info, rect);
+	ssd1307fb_update_display(par);
+}
+
+static void ssd1307fb_copyarea(struct fb_info *info, const struct fb_copyarea *area) 
+{
+	struct ssd1307fb_par *par = info->par;
+	sys_copyarea(info, area);
+	ssd1307fb_update_display(par);
+}
+
+static void ssd1307fb_imageblit(struct fb_info *info, const struct fb_image *image) 
+{
+	struct ssd1307fb_par *par = info->par;
+	sys_imageblit(info, image);
+	ssd1307fb_update_display(par);
+}
+
+static struct fb_ops ssd1307fb_ops = {
+	.owner		= THIS_MODULE,
+	.fb_read	= fb_sys_read,
+	.fb_write	= ssd1307fb_write,
+	.fb_fillrect	= ssd1307fb_fillrect,
+	.fb_copyarea	= ssd1307fb_copyarea,
+	.fb_imageblit	= ssd1307fb_imageblit,
+};
+
+static void ssd1307fb_deferred_io(struct fb_info *info,
+				struct list_head *pagelist)
+{
+	ssd1307fb_update_display(info->par);
+}
+
+static struct fb_deferred_io ssd1307fb_defio = {
+	.delay		= HZ,
+	.deferred_io	= ssd1307fb_deferred_io,
+};
+
+static int __devinit ssd1307fb_probe(struct i2c_client *client, const struct i2c_device_id *id)
+{
+	struct fb_info *info;
+	u32 vmem_size = SSD1307FB_WIDTH * SSD1307FB_HEIGHT / 8;
+	struct ssd1307fb_par *par;
+	u8 *vmem;
+	int ret;
+
+	if (!client->dev.of_node) {
+		dev_err(&client->dev, "No device tree data found!\n");
+		return -EINVAL;
+	}
+
+	info = framebuffer_alloc(sizeof(struct ssd1307fb_par), &client->dev);
+	if (!info) {
+		dev_err(&client->dev, "Couldn't allocate framebuffer.\n");
+		return -ENOMEM;
+	}
+
+	vmem = devm_kzalloc(&client->dev, vmem_size, GFP_KERNEL);
+	if (!vmem) {
+		dev_err(&client->dev, "Couldn't allocate graphical memory.\n");
+		ret = -ENOMEM;
+		goto fb_alloc_error;
+	}
+
+	info->fbops = &ssd1307fb_ops;
+	info->fix = ssd1307fb_fix;
+	info->fbdefio = &ssd1307fb_defio;
+
+	info->var = ssd1307fb_var;
+	info->var.red.length = 1;
+	info->var.red.offset = 0;
+	info->var.green.length = 1;
+	info->var.green.offset = 0;
+	info->var.blue.length = 1;
+	info->var.blue.offset = 0;
+
+	info->screen_base = (u8 __force __iomem *)vmem;
+	info->fix.smem_start = (unsigned long)vmem;
+	info->fix.smem_len = vmem_size;
+
+	fb_deferred_io_init(info);
+
+	par = info->par;
+	par->info = info;
+	par->client = client;
+
+	par->reset = of_get_named_gpio(client->dev.of_node,
+					 "reset-gpios", 0);
+	if (!gpio_is_valid(par->reset)) {
+		ret = -EINVAL;
+		goto reset_oled_error;
+	}
+
+	ret = devm_gpio_request_one(&client->dev, par->reset,
+				    GPIOF_OUT_INIT_HIGH,
+				    "oled-reset");
+	if (ret) {
+		dev_err(&client->dev,
+			"failed to request gpio %d: %d\n",
+			par->reset, ret);
+		goto reset_oled_error;
+	}
+
+	par->pwm = pwm_get(&client->dev, NULL);
+	if (IS_ERR(par->pwm)) {
+		dev_err(&client->dev, "Could not get PWM from device tree!\n");
+		ret = PTR_ERR(par->pwm);
+		goto pwm_error;
+	}
+
+	par->pwm_period = pwm_get_period(par->pwm);
+
+	dev_dbg(&client->dev, "Using PWM%d with a %dns period.\n", par->pwm->pwm, par->pwm_period);
+
+	ret = register_framebuffer(info);
+	if (ret) {
+		dev_err(&client->dev, "Couldn't register the framebuffer\n");
+		goto fbreg_error;
+	}
+
+	i2c_set_clientdata(client, info);
+
+	/* Reset the screen */
+	gpio_set_value(par->reset, 0);
+	udelay(4);
+	gpio_set_value(par->reset, 1);
+	udelay(4);
+
+	/* Enable the PWM */
+	pwm_config(par->pwm, par->pwm_period / 2, par->pwm_period);
+	pwm_enable(par->pwm);
+
+	/* Map column 127 of the OLED to segment 0 */
+	ret = ssd1307fb_write_cmd(client, SSD1307FB_SEG_REMAP_ON);
+	if (ret < 0) {
+		dev_err(&client->dev, "Couldn't remap the screen.\n");
+		goto remap_error;
+	}
+
+	/* Turn on the display */
+	ret = ssd1307fb_write_cmd(client, SSD1307FB_DISPLAY_ON);
+	if (ret < 0) {
+		dev_err(&client->dev, "Couldn't turn the display on.\n");
+		goto remap_error;
+	}
+
+	dev_info(&client->dev, "fb%d: %s framebuffer device registered, using %d bytes of video memory\n", info->node, info->fix.id, vmem_size);
+
+	return 0;
+
+remap_error:
+	unregister_framebuffer(info);
+	pwm_disable(par->pwm);
+fbreg_error:
+	pwm_put(par->pwm);
+pwm_error:
+reset_oled_error:
+	fb_deferred_io_cleanup(info);
+fb_alloc_error:
+	framebuffer_release(info);
+	return ret;
+}
+
+static int __devexit ssd1307fb_remove(struct i2c_client *client)
+{
+	struct fb_info *info = i2c_get_clientdata(client);
+	struct ssd1307fb_par *par = info->par;
+
+	unregister_framebuffer(info);
+	pwm_disable(par->pwm);
+	pwm_put(par->pwm);
+	fb_deferred_io_cleanup(info);
+	framebuffer_release(info);
+
+	return 0;
+}
+
+static const struct i2c_device_id ssd1307fb_i2c_id[] = {
+	{ "ssd1307fb", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ssd1307fb_i2c_id);
+
+static const struct of_device_id ssd1307fb_of_match[] = {
+	{ .compatible = "solomon,ssd1307fb-i2c" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ssd1307fb_of_match);
+
+static struct i2c_driver ssd1307fb_driver = {
+	.probe = ssd1307fb_probe,
+	.remove = __devexit_p(ssd1307fb_remove),
+	.id_table = ssd1307fb_i2c_id,
+	.driver = {
+		.name = "ssd1307fb",
+		.of_match_table = of_match_ptr(ssd1307fb_of_match),
+		.owner = THIS_MODULE,
+	},
+};
+
+module_i2c_driver(ssd1307fb_driver);
+
+MODULE_DESCRIPTION("FB driver for the Solomon SSD1307 OLED controler");
+MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
+MODULE_LICENSE("GPL");
-- 
1.7.9.5

[PATCHv4] Add support for the OLED in the CFA10036

[Maxime Ripard]

Hi everyone,

This patchset adds support for the solomon SSD1307 OLED controller present
in the CFA-10036 board.

It first adds the framebuffer driver for this controller, and then the
needed bits to enable it in the cfa10036 dts.

Considering that the driver has been around since almost two months now, and
I have not received any comments on the framebuffer part, I'd very much like it
to be included in 3.7 if possible.

Thanks,
Maxime

Changes from v3:
  * Changed the dt property name to remove the leading oled- and changed the
    reset-gpio property to reset-gpios

Changes from v2:
  * Add the pin name as comment to the pwm4 pinctrl declaration
  * Change slightly the documentation of the dt bindings for the gpios to remove
    the mxs-specific cell.

Changes from v1:
  * Did some factorisation of the ssd1307fb_write* functions.
  * Filled the smem_start field of the fb_fix_screeninfo structure
  * Fixed the broken pwm declaration
  * Change the names of oled-reset-gpios and reset-active-low properties in the
    device tree to oled-reset-gpio and oled-reset-active-low for consistency

[PATCH 1/2] video: Add support for the Solomon SSD1307 OLED Controller

[Maxime Ripard]

This patch adds 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.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Brian Lilly <brian@crystalfontz.com>
---
 .../devicetree/bindings/video/ssd1307fb.txt        |   24 ++
 drivers/video/Kconfig                              |   13 +
 drivers/video/Makefile                             |    1 +
 drivers/video/ssd1307fb.c                          |  386 ++++++++++++++++++++
 4 files changed, 424 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/video/ssd1307fb.txt
 create mode 100644 drivers/video/ssd1307fb.c

diff --git a/Documentation/devicetree/bindings/video/ssd1307fb.txt b/Documentation/devicetree/bindings/video/ssd1307fb.txt
new file mode 100644
index 0000000..3d0060c
--- /dev/null
+++ b/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;
+};
diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index 0217f74..2776829 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -2469,4 +2469,17 @@ 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
+	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
diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index ee8dafb..6bbb72c 100644
--- a/drivers/video/Makefile
+++ b/drivers/video/Makefile
@@ -164,6 +164,7 @@ 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
diff --git a/drivers/video/ssd1307fb.c b/drivers/video/ssd1307fb.c
new file mode 100644
index 0000000..fc77a8f
--- /dev/null
+++ b/drivers/video/ssd1307fb.c
@@ -0,0 +1,386 @@
+/*
+ * Driver for the Solomon SSD1307 OLED controler
+ *
+ * Copyright 2012 Free Electrons
+ *
+ * Licensed under the GPLv2 or later.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/i2c.h>
+#include <linux/fb.h>
+#include <linux/uaccess.h>
+#include <linux/of_device.h>
+#include <linux/of_gpio.h>
+#include <linux/pwm.h>
+#include <linux/delay.h>
+
+#define SSD1307FB_WIDTH			96
+#define SSD1307FB_HEIGHT		16
+
+#define SSD1307FB_DATA			0x40
+#define SSD1307FB_COMMAND		0x80
+
+#define SSD1307FB_CONTRAST		0x81
+#define SSD1307FB_SEG_REMAP_ON		0xa1
+#define SSD1307FB_DISPLAY_OFF		0xae
+#define SSD1307FB_DISPLAY_ON		0xaf
+#define SSD1307FB_START_PAGE_ADDRESS	0xb0
+
+struct ssd1307fb_par {
+	struct i2c_client *client;
+	struct fb_info *info;
+	struct pwm_device *pwm;
+	u32 pwm_period;
+	int reset;
+};
+
+static struct fb_fix_screeninfo ssd1307fb_fix __devinitdata = {
+	.id		= "Solomon SSD1307",
+	.type		= FB_TYPE_PACKED_PIXELS,
+	.visual		= FB_VISUAL_MONO10,
+	.xpanstep	= 0,
+	.ypanstep	= 0,
+	.ywrapstep	= 0,
+	.line_length	= SSD1307FB_WIDTH / 8,
+	.accel		= FB_ACCEL_NONE,
+};
+
+static struct fb_var_screeninfo ssd1307fb_var __devinitdata = {
+	.xres		= SSD1307FB_WIDTH,
+	.yres		= SSD1307FB_HEIGHT,
+	.xres_virtual	= SSD1307FB_WIDTH,
+	.yres_virtual	= SSD1307FB_HEIGHT,
+	.bits_per_pixel	= 1,
+};
+
+static int ssd1307fb_write_array(struct i2c_client *client, u8 type, u8* cmd, u32 len)
+{
+	u8 *buf;
+	int ret = 0;
+
+	buf = kzalloc(len + 1, GFP_KERNEL);
+	if (!buf) {
+		dev_err(&client->dev, "Couldn't allocate sending buffer.\n");
+		return -ENOMEM;
+	}
+
+	buf[0] = type;
+	memcpy(buf + 1, cmd, len);
+
+	ret = i2c_master_send(client, buf, len + 1);
+	if (ret != len + 1) {
+		dev_err(&client->dev, "Couldn't send I2C command.\n");
+		goto error;
+	}
+
+error:
+	kfree(buf);
+	return ret;
+}
+
+static inline int ssd1307fb_write_cmd_array(struct i2c_client *client, u8* cmd, u32 len)
+{
+	return ssd1307fb_write_array(client, SSD1307FB_COMMAND, cmd, len);
+}
+
+static inline int ssd1307fb_write_cmd(struct i2c_client *client, u8 cmd)
+{
+	return ssd1307fb_write_cmd_array(client, &cmd, 1);
+}
+
+static inline int ssd1307fb_write_data_array(struct i2c_client *client, u8* cmd, u32 len)
+{
+	return ssd1307fb_write_array(client, SSD1307FB_DATA, cmd, len);
+}
+
+static inline int ssd1307fb_write_data(struct i2c_client *client, u8 data)
+{
+	return ssd1307fb_write_data_array(client, &data, 1);
+}
+
+static void ssd1307fb_update_display(struct ssd1307fb_par *par)
+{
+	u8 *vmem = par->info->screen_base;
+	int i, j, k;
+
+	/*
+	 * The screen is divided in pages, each having a height of 8
+	 * pixels, and the width of the screen. When sending a byte of
+	 * data to the controller, it gives the 8 bits for the current
+	 * column. I.e, the first byte are the 8 bits of the first
+	 * column, then the 8 bits for the second column, etc.
+	 *
+	 *
+	 * Representation of the screen, assuming it is 5 bits
+	 * wide. Each letter-number combination is a bit that controls
+	 * one pixel.
+	 *
+	 * A0 A1 A2 A3 A4
+	 * B0 B1 B2 B3 B4
+	 * C0 C1 C2 C3 C4
+	 * D0 D1 D2 D3 D4
+	 * E0 E1 E2 E3 E4
+	 * F0 F1 F2 F3 F4
+	 * G0 G1 G2 G3 G4
+	 * H0 H1 H2 H3 H4
+	 *
+	 * If you want to update this screen, you need to send 5 bytes:
+	 *  (1) A0 B0 C0 D0 E0 F0 G0 H0
+	 *  (2) A1 B1 C1 D1 E1 F1 G1 H1
+	 *  (3) A2 B2 C2 D2 E2 F2 G2 H2
+	 *  (4) A3 B3 C3 D3 E3 F3 G3 H3
+	 *  (5) A4 B4 C4 D4 E4 F4 G4 H4
+	 */
+
+	for (i = 0; i < (SSD1307FB_HEIGHT / 8); i++) {
+		ssd1307fb_write_cmd(par->client, SSD1307FB_START_PAGE_ADDRESS + (i + 1));
+		ssd1307fb_write_cmd(par->client, 0x00);
+		ssd1307fb_write_cmd(par->client, 0x10);
+
+		for (j = 0; j < SSD1307FB_WIDTH; j++) {
+			u8 buf = 0;
+			for (k = 0; k < 8; k++) {
+				u32 page_length = SSD1307FB_WIDTH * i;
+				u32 index = page_length + (SSD1307FB_WIDTH * k + j) / 8;
+				u8 byte = *(vmem + index);
+				u8 bit = byte & (1 << (7 - (j % 8)));
+				bit = bit >> (7 - (j % 8));
+				buf |= bit << k;
+			}
+			ssd1307fb_write_data(par->client, buf);
+		}
+	}
+}
+
+
+static ssize_t ssd1307fb_write(struct fb_info *info, const char __user *buf,
+		size_t count, loff_t *ppos)
+{
+	struct ssd1307fb_par *par = info->par;
+	unsigned long p = *ppos;
+	void *dst;
+	int err = 0;
+
+	dst = (void __force *) (info->screen_base + p);
+
+	if (copy_from_user(dst, buf, count))
+		err = -EFAULT;
+
+	if  (!err)
+		*ppos += count;
+
+	ssd1307fb_update_display(par);
+
+	return (err) ? err : count;
+}
+
+static void ssd1307fb_fillrect(struct fb_info *info, const struct fb_fillrect *rect)
+{
+	struct ssd1307fb_par *par = info->par;
+	sys_fillrect(info, rect);
+	ssd1307fb_update_display(par);
+}
+
+static void ssd1307fb_copyarea(struct fb_info *info, const struct fb_copyarea *area) 
+{
+	struct ssd1307fb_par *par = info->par;
+	sys_copyarea(info, area);
+	ssd1307fb_update_display(par);
+}
+
+static void ssd1307fb_imageblit(struct fb_info *info, const struct fb_image *image) 
+{
+	struct ssd1307fb_par *par = info->par;
+	sys_imageblit(info, image);
+	ssd1307fb_update_display(par);
+}
+
+static struct fb_ops ssd1307fb_ops = {
+	.owner		= THIS_MODULE,
+	.fb_read	= fb_sys_read,
+	.fb_write	= ssd1307fb_write,
+	.fb_fillrect	= ssd1307fb_fillrect,
+	.fb_copyarea	= ssd1307fb_copyarea,
+	.fb_imageblit	= ssd1307fb_imageblit,
+};
+
+static void ssd1307fb_deferred_io(struct fb_info *info,
+				struct list_head *pagelist)
+{
+	ssd1307fb_update_display(info->par);
+}
+
+static struct fb_deferred_io ssd1307fb_defio = {
+	.delay		= HZ,
+	.deferred_io	= ssd1307fb_deferred_io,
+};
+
+static int __devinit ssd1307fb_probe(struct i2c_client *client, const struct i2c_device_id *id)
+{
+	struct fb_info *info;
+	u32 vmem_size = SSD1307FB_WIDTH * SSD1307FB_HEIGHT / 8;
+	struct ssd1307fb_par *par;
+	u8 *vmem;
+	int ret;
+
+	if (!client->dev.of_node) {
+		dev_err(&client->dev, "No device tree data found!\n");
+		return -EINVAL;
+	}
+
+	info = framebuffer_alloc(sizeof(struct ssd1307fb_par), &client->dev);
+	if (!info) {
+		dev_err(&client->dev, "Couldn't allocate framebuffer.\n");
+		return -ENOMEM;
+	}
+
+	vmem = devm_kzalloc(&client->dev, vmem_size, GFP_KERNEL);
+	if (!vmem) {
+		dev_err(&client->dev, "Couldn't allocate graphical memory.\n");
+		ret = -ENOMEM;
+		goto fb_alloc_error;
+	}
+
+	info->fbops = &ssd1307fb_ops;
+	info->fix = ssd1307fb_fix;
+	info->fbdefio = &ssd1307fb_defio;
+
+	info->var = ssd1307fb_var;
+	info->var.red.length = 1;
+	info->var.red.offset = 0;
+	info->var.green.length = 1;
+	info->var.green.offset = 0;
+	info->var.blue.length = 1;
+	info->var.blue.offset = 0;
+
+	info->screen_base = (u8 __force __iomem *)vmem;
+	info->fix.smem_start = (unsigned long)vmem;
+	info->fix.smem_len = vmem_size;
+
+	fb_deferred_io_init(info);
+
+	par = info->par;
+	par->info = info;
+	par->client = client;
+
+	par->reset = of_get_named_gpio(client->dev.of_node,
+					 "reset-gpios", 0);
+	if (gpio_is_valid(par->reset)) {
+		int flags = GPIOF_OUT_INIT_HIGH;
+		if (of_get_property(client->dev.of_node,
+				    "reset-active-low", NULL))
+			flags = GPIOF_OUT_INIT_LOW;
+		ret = devm_gpio_request_one(&client->dev, par->reset,
+					    flags, "oled-reset");
+		if (ret) {
+			dev_err(&client->dev,
+				"failed to request gpio %d: %d\n",
+				par->reset, ret);
+			goto reset_oled_error;
+		}
+	}
+
+	par->pwm = pwm_get(&client->dev, NULL);
+	if (IS_ERR(par->pwm)) {
+		dev_err(&client->dev, "Could not get PWM from device tree!\n");
+		ret = PTR_ERR(par->pwm);
+		goto pwm_error;
+	}
+
+	par->pwm_period = pwm_get_period(par->pwm);
+
+	dev_dbg(&client->dev, "Using PWM%d with a %dns period.\n", par->pwm->pwm, par->pwm_period);
+
+	ret = register_framebuffer(info);
+	if (ret) {
+		dev_err(&client->dev, "Couldn't register the framebuffer\n");
+		goto fbreg_error;
+	}
+
+	i2c_set_clientdata(client, info);
+
+	/* Reset the screen */
+	gpio_set_value(par->reset, 1);
+	udelay(4);
+	gpio_set_value(par->reset, 0);
+	udelay(4);
+
+	/* Enable the PWM */
+	pwm_config(par->pwm, par->pwm_period / 2, par->pwm_period);
+	pwm_enable(par->pwm);
+
+	/* Map column 127 of the OLED to segment 0 */
+	ret = ssd1307fb_write_cmd(client, SSD1307FB_SEG_REMAP_ON);
+	if (ret < 0) {
+		dev_err(&client->dev, "Couldn't remap the screen.\n");
+		goto remap_error;
+	}
+
+	/* Turn on the display */
+	ret = ssd1307fb_write_cmd(client, SSD1307FB_DISPLAY_ON);
+	if (ret < 0) {
+		dev_err(&client->dev, "Couldn't turn the display on.\n");
+		goto remap_error;
+	}
+
+	dev_info(&client->dev, "fb%d: %s framebuffer device registered, using %d bytes of video memory\n", info->node, info->fix.id, vmem_size);
+
+	return 0;
+
+remap_error:
+	unregister_framebuffer(info);
+	pwm_disable(par->pwm);
+fbreg_error:
+	pwm_put(par->pwm);
+pwm_error:
+reset_oled_error:
+	fb_deferred_io_cleanup(info);
+fb_alloc_error:
+	framebuffer_release(info);
+	return ret;
+}
+
+static int __devexit ssd1307fb_remove(struct i2c_client *client)
+{
+	struct fb_info *info = i2c_get_clientdata(client);
+	struct ssd1307fb_par *par = info->par;
+
+	unregister_framebuffer(info);
+	pwm_disable(par->pwm);
+	pwm_put(par->pwm);
+	fb_deferred_io_cleanup(info);
+	framebuffer_release(info);
+
+	return 0;
+}
+
+static const struct i2c_device_id ssd1307fb_i2c_id[] = {
+	{ "ssd1307fb", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ssd1307fb_i2c_id);
+
+static const struct of_device_id ssd1307fb_of_match[] = {
+	{ .compatible = "solomon,ssd1307fb-i2c" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ssd1307fb_of_match);
+
+static struct i2c_driver ssd1307fb_driver = {
+	.probe = ssd1307fb_probe,
+	.remove = __devexit_p(ssd1307fb_remove),
+	.id_table = ssd1307fb_i2c_id,
+	.driver = {
+		.name = "ssd1307fb",
+		.of_match_table = of_match_ptr(ssd1307fb_of_match),
+		.owner = THIS_MODULE,
+	},
+};
+
+module_i2c_driver(ssd1307fb_driver);
+
+MODULE_DESCRIPTION("FB driver for the Solomon SSD1307 OLED controler");
+MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
+MODULE_LICENSE("GPL");
-- 
1.7.9.5