drivers/video/ssd1307fb.c - pub/scm/linux/kernel/git/joro/linux - Git at Google

 /*
  * 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 = {
 	.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 = {
 	.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 << (j % 8));
 				bit = bit >> (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;

 	total_size = info->fix.smem_len;

 	if (p > total_size)
 		return -EINVAL;

 	if (count + p > total_size)
 		count = total_size - p;

 	if (!count)
 		return -EINVAL;

 	dst = (void __force *) (info->screen_base + p);

 	if (copy_from_user(dst, buf, count))
 		return -EFAULT;

 	ssd1307fb_update_display(par);

 	*ppos += count;

 	return 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 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 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 = 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");
	/*
	* 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 = {
	.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 = {
	.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 << (j % 8));
	bit = bit >> (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;

	total_size = info->fix.smem_len;

	if (p > total_size)
	return -EINVAL;

	if (count + p > total_size)
	count = total_size - p;

	if (!count)
	return -EINVAL;

	dst = (void __force *) (info->screen_base + p);

	if (copy_from_user(dst, buf, count))
	return -EFAULT;

	ssd1307fb_update_display(par);

	*ppos += count;

	return 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 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 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 = 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");