video: ssd1307fb: Add support for SSD1306 OLED controller

The Solomon SSD1306 OLED controller is very similar to the SSD1307,
except for the fact that the power is given through an external PWM for
the 1307, and while the 1306 can generate its own power without any PWM.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

Documentation/devicetree/bindings/video/ssd1307fb.txt

@@ -1,13 +1,17 @@
 * Solomon SSD1307 Framebuffer Driver
 
 Required properties:
-  - compatible: Should be "solomon,ssd1307fb-<bus>". The only supported bus for
+  - compatible: Should be "solomon,<chip>fb-<bus>". The only supported bus for
-    now is i2c.
+    now is i2c, and the supported chips are ssd1306 and ssd1307.
   - 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]
+         specification [0]. Only required for the ssd1307.
   - reset-gpios: Should contain the GPIO used to reset the OLED display
+  - solomon,height: Height in pixel of the screen driven by the controller
+  - solomon,width: Width in pixel of the screen driven by the controller
+  - solomon,page-offset: Offset of pages (band of 8 pixels) that the screen is
+    mapped to.
 
 Optional properties:
   - reset-active-low: Is the reset gpio is active on physical low?

drivers/video/ssd1307fb.c

@@ -16,24 +16,39 @@
 #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_CHARGE_PUMP		0x8d
 #define SSD1307FB_SEG_REMAP_ON		0xa1
 #define SSD1307FB_DISPLAY_OFF		0xae
+#define SSD1307FB_SET_MULTIPLEX_RATIO	0xa8
 #define SSD1307FB_DISPLAY_ON		0xaf
 #define SSD1307FB_START_PAGE_ADDRESS	0xb0
+#define SSD1307FB_SET_DISPLAY_OFFSET	0xd3
+#define	SSD1307FB_SET_CLOCK_FREQ	0xd5
+#define	SSD1307FB_SET_PRECHARGE_PERIOD	0xd9
+#define	SSD1307FB_SET_COM_PINS_CONFIG	0xda
+#define	SSD1307FB_SET_VCOMH		0xdb
+
+struct ssd1307fb_par;
+
+struct ssd1307fb_ops {
+	int (*init)(struct ssd1307fb_par *);
+	int (*remove)(struct ssd1307fb_par *);
+};
 
 struct ssd1307fb_par {
 	struct i2c_client *client;
+	u32 height;
 	struct fb_info *info;
+	struct ssd1307fb_ops *ops;
+	u32 page_offset;
 	struct pwm_device *pwm;
 	u32 pwm_period;
 	int reset;
+	u32 width;
 };
 
 static struct fb_fix_screeninfo ssd1307fb_fix = {
@@ -43,15 +58,10 @@ static struct fb_fix_screeninfo ssd1307fb_fix = {
 	.xpanstep	= 0,
 	.ypanstep	= 0,
 	.ywrapstep	= 0,
-	.line_length	= SSD1307FB_WIDTH / 8,
 	.accel		= FB_ACCEL_NONE,
 };
 
 static struct fb_var_screeninfo ssd1307fb_var = {
-	.xres		= SSD1307FB_WIDTH,
-	.yres		= SSD1307FB_HEIGHT,
-	.xres_virtual	= SSD1307FB_WIDTH,
-	.yres_virtual	= SSD1307FB_HEIGHT,
 	.bits_per_pixel	= 1,
 };
 
@@ -134,16 +144,17 @@ static void ssd1307fb_update_display(struct ssd1307fb_par *par)
 	 *  (5) A4 B4 C4 D4 E4 F4 G4 H4
 	 */
 
-	for (i = 0; i < (SSD1307FB_HEIGHT / 8); i++) {
+	for (i = 0; i < (par->height / 8); i++) {
-		ssd1307fb_write_cmd(par->client, SSD1307FB_START_PAGE_ADDRESS + (i + 1));
+		ssd1307fb_write_cmd(par->client,
+				    SSD1307FB_START_PAGE_ADDRESS + i + par->page_offset);
 		ssd1307fb_write_cmd(par->client, 0x00);
 		ssd1307fb_write_cmd(par->client, 0x10);
 
-		for (j = 0; j < SSD1307FB_WIDTH; j++) {
+		for (j = 0; j < par->width; j++) {
 			u8 buf = 0;
 			for (k = 0; k < 8; k++) {
-				u32 page_length = SSD1307FB_WIDTH * i;
+				u32 page_length = par->width * i;
-				u32 index = page_length + (SSD1307FB_WIDTH * k + j) / 8;
+				u32 index = page_length + (par->width * k + j) / 8;
 				u8 byte = *(vmem + index);
 				u8 bit = byte & (1 << (j % 8));
 				bit = bit >> (j % 8);
@@ -227,16 +238,147 @@ static struct fb_deferred_io ssd1307fb_defio = {
 	.deferred_io	= ssd1307fb_deferred_io,
 };
 
+static int ssd1307fb_ssd1307_init(struct ssd1307fb_par *par)
+{
+	int ret;
+
+	par->pwm = pwm_get(&par->client->dev, NULL);
+	if (IS_ERR(par->pwm)) {
+		dev_err(&par->client->dev, "Could not get PWM from device tree!\n");
+		return PTR_ERR(par->pwm);
+	}
+
+	par->pwm_period = pwm_get_period(par->pwm);
+	/* Enable the PWM */
+	pwm_config(par->pwm, par->pwm_period / 2, par->pwm_period);
+	pwm_enable(par->pwm);
+
+	dev_dbg(&par->client->dev, "Using PWM%d with a %dns period.\n",
+		par->pwm->pwm, par->pwm_period);
+
+	/* Map column 127 of the OLED to segment 0 */
+	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SEG_REMAP_ON);
+	if (ret < 0)
+		return ret;
+
+	/* Turn on the display */
+	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_ON);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int ssd1307fb_ssd1307_remove(struct ssd1307fb_par *par)
+{
+	pwm_disable(par->pwm);
+	pwm_put(par->pwm);
+	return 0;
+}
+
+static struct ssd1307fb_ops ssd1307fb_ssd1307_ops = {
+	.init	= ssd1307fb_ssd1307_init,
+	.remove	= ssd1307fb_ssd1307_remove,
+};
+
+static int ssd1307fb_ssd1306_init(struct ssd1307fb_par *par)
+{
+	int ret;
+
+	/* Set initial contrast */
+	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CONTRAST);
+	ret = ret & ssd1307fb_write_cmd(par->client, 0x7f);
+	if (ret < 0)
+		return ret;
+
+	/* Set COM direction */
+	ret = ssd1307fb_write_cmd(par->client, 0xc8);
+	if (ret < 0)
+		return ret;
+
+	/* Set segment re-map */
+	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SEG_REMAP_ON);
+	if (ret < 0)
+		return ret;
+
+	/* Set multiplex ratio value */
+	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_MULTIPLEX_RATIO);
+	ret = ret & ssd1307fb_write_cmd(par->client, par->height - 1);
+	if (ret < 0)
+		return ret;
+
+	/* set display offset value */
+	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_DISPLAY_OFFSET);
+	ret = ssd1307fb_write_cmd(par->client, 0x20);
+	if (ret < 0)
+		return ret;
+
+	/* Set clock frequency */
+	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_CLOCK_FREQ);
+	ret = ret & ssd1307fb_write_cmd(par->client, 0xf0);
+	if (ret < 0)
+		return ret;
+
+	/* Set precharge period in number of ticks from the internal clock */
+	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PRECHARGE_PERIOD);
+	ret = ret & ssd1307fb_write_cmd(par->client, 0x22);
+	if (ret < 0)
+		return ret;
+
+	/* Set COM pins configuration */
+	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COM_PINS_CONFIG);
+	ret = ret & ssd1307fb_write_cmd(par->client, 0x22);
+	if (ret < 0)
+		return ret;
+
+	/* Set VCOMH */
+	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_VCOMH);
+	ret = ret & ssd1307fb_write_cmd(par->client, 0x49);
+	if (ret < 0)
+		return ret;
+
+	/* Turn on the DC-DC Charge Pump */
+	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CHARGE_PUMP);
+	ret = ret & ssd1307fb_write_cmd(par->client, 0x14);
+	if (ret < 0)
+		return ret;
+
+	/* Turn on the display */
+	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_ON);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static struct ssd1307fb_ops ssd1307fb_ssd1306_ops = {
+	.init	= ssd1307fb_ssd1306_init,
+};
+
+static const struct of_device_id ssd1307fb_of_match[] = {
+	{
+		.compatible = "solomon,ssd1306fb-i2c",
+		.data = (void *)&ssd1307fb_ssd1306_ops,
+	},
+	{
+		.compatible = "solomon,ssd1307fb-i2c",
+		.data = (void *)&ssd1307fb_ssd1307_ops,
+	},
+	{},
+};
+MODULE_DEVICE_TABLE(of, ssd1307fb_of_match);
+
 static int 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 device_node *node = client->dev.of_node;
+	u32 vmem_size;
 	struct ssd1307fb_par *par;
 	u8 *vmem;
 	int ret;
 
-	if (!client->dev.of_node) {
+	if (!node) {
 		dev_err(&client->dev, "No device tree data found!\n");
 		return -EINVAL;
 	}
@@ -247,6 +389,31 @@ static int ssd1307fb_probe(struct i2c_client *client,
 		return -ENOMEM;
 	}
 
+	par = info->par;
+	par->info = info;
+	par->client = client;
+
+	par->ops = (struct ssd1307fb_ops *)of_match_device(ssd1307fb_of_match,
+							   &client->dev)->data;
+
+	par->reset = of_get_named_gpio(client->dev.of_node,
+					 "reset-gpios", 0);
+	if (!gpio_is_valid(par->reset)) {
+		ret = -EINVAL;
+		goto fb_alloc_error;
+	}
+
+	if (of_property_read_u32(node, "solomon,width", &par->width))
+		par->width = 96;
+
+	if (of_property_read_u32(node, "solomon,height", &par->height))
+		par->width = 16;
+
+	if (of_property_read_u32(node, "solomon,page-offset", &par->page_offset))
+		par->page_offset = 1;
+
+	vmem_size = par->width * par->height / 8;
+
 	vmem = devm_kzalloc(&client->dev, vmem_size, GFP_KERNEL);
 	if (!vmem) {
 		dev_err(&client->dev, "Couldn't allocate graphical memory.\n");
@@ -256,9 +423,15 @@ static int ssd1307fb_probe(struct i2c_client *client,
 
 	info->fbops = &ssd1307fb_ops;
 	info->fix = ssd1307fb_fix;
+	info->fix.line_length = par->width / 8;
 	info->fbdefio = &ssd1307fb_defio;
 
 	info->var = ssd1307fb_var;
+	info->var.xres = par->width;
+	info->var.xres_virtual = par->width;
+	info->var.yres = par->height;
+	info->var.yres_virtual = par->height;
+
 	info->var.red.length = 1;
 	info->var.red.offset = 0;
 	info->var.green.length = 1;
@@ -272,17 +445,6 @@ static int ssd1307fb_probe(struct i2c_client *client,
 
 	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");
@@ -293,23 +455,6 @@ static int ssd1307fb_probe(struct i2c_client *client,
 		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 */
@@ -318,34 +463,25 @@ static int ssd1307fb_probe(struct i2c_client *client,
 	gpio_set_value(par->reset, 1);
 	udelay(4);
 
-	/* Enable the PWM */
+	if (par->ops->init) {
-	pwm_config(par->pwm, par->pwm_period / 2, par->pwm_period);
+		ret = par->ops->init(par);
-	pwm_enable(par->pwm);
+		if (ret)
-
+			goto reset_oled_error;
-	/* 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 = register_framebuffer(info);
-	ret = ssd1307fb_write_cmd(client, SSD1307FB_DISPLAY_ON);
+	if (ret) {
-	if (ret < 0) {
+		dev_err(&client->dev, "Couldn't register the framebuffer\n");
-		dev_err(&client->dev, "Couldn't turn the display on.\n");
+		goto panel_init_error;
-		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:
+panel_init_error:
-	unregister_framebuffer(info);
+	if (par->ops->remove)
-	pwm_disable(par->pwm);
+		par->ops->remove(par);
-fbreg_error:
-	pwm_put(par->pwm);
-pwm_error:
 reset_oled_error:
 	fb_deferred_io_cleanup(info);
 fb_alloc_error:
@@ -359,8 +495,8 @@ static int ssd1307fb_remove(struct i2c_client *client)
 	struct ssd1307fb_par *par = info->par;
 
 	unregister_framebuffer(info);
-	pwm_disable(par->pwm);
+	if (par->ops->remove)
-	pwm_put(par->pwm);
+		par->ops->remove(par);
 	fb_deferred_io_cleanup(info);
 	framebuffer_release(info);
 
@@ -368,17 +504,12 @@ static int ssd1307fb_remove(struct i2c_client *client)
 }
 
 static const struct i2c_device_id ssd1307fb_i2c_id[] = {
+	{ "ssd1306fb", 0 },
 	{ "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 = ssd1307fb_remove,