Commit a2ed00da authored by Maxime Ripard's avatar Maxime Ripard Committed by Tomi Valkeinen
Browse files

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: default avatarMaxime 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarTomi Valkeinen <tomi.valkeinen@ti.com>
parent 8f22e8ea

Documentation/devicetree/bindings/video/ssd1307fb.txt

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+24 −0
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* 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

+15 −0
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@@ -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

+1 −0
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@@ -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

drivers/video/ssd1307fb.c

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/*

 * 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;



	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 __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");

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