[PATCH 1/4] video: Add support for the Solomon SSD1307 OLED Controller

Maxime Ripard
2012-07-17T15:59:44Z

This patches adds support for the Solomon SSD1307 OLED
controller found on the Crystalfontz CFA10036 board.

It is a monochrome 128x39 display, that can operate over
I2C or SPI.

The current driver as only be 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 | 14 +
drivers/video/Makefile | 1 +
drivers/video/ssd1307fb.c | 414 ++++++++++++++++++++
4 files changed, 453 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..73ba41c
--- /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]
+ - oled-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 at 3c {
+ compatible = "solomon,ssd1307fb-i2c";
+ reg = <0x3c>;
+ pwms = <&pwm 4 3000>;
+ oled-reset-gpios = <&gpio2 7 1>;
+ reset-active-low;
+};
diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index 0217f74..21ae6dd 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -2469,4 +2469,18 @@ 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..5d24360
--- /dev/null
+++ b/drivers/video/ssd1307fb.c
@@ -0,0 +1,414 @@
+/*
+ * 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_cmd_array(struct i2c_client *client, u8* cmd, u32 len)
+{
+ u8 *buf;
+ int ret;
+
+ buf = kzalloc(len + 1, GFP_KERNEL);
+ if (!buf) {
+ dev_err(&client->dev, "Couldn't allocate sending buffer.\n");
+ ret = -ENOMEM;
+ goto error;
+ }
+
+ buf[0] = SSD1307FB_COMMAND;
+ 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;
+ }
+
+ kfree(buf);
+ return 0;
+
+error:
+ kfree(buf);
+ return ret;
+}
+
+static inline int ssd1307fb_write_cmd(struct i2c_client *client, u8 cmd)
+{
+ return ssd1307fb_write_cmd_array(client, &cmd, 1);
+}
+
+static int ssd1307fb_write_data_array(struct i2c_client *client, u8* cmd, u32 len)
+{
+ u8 *buf;
+ int ret;
+
+ buf = kzalloc(len + 1, GFP_KERNEL);
+ if (!buf) {
+ dev_err(&client->dev, "Couldn't allocate sending buffer.\n");
+ ret = -ENOMEM;
+ goto error;
+ }
+
+ buf[0] = SSD1307FB_DATA;
+ 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 data.\n");
+ goto error;
+ }
+
+ kfree(buf);
+ return 0;
+
+error:
+ kfree(buf);
+ return ret;
+}
+
+static inline int ssd1307fb_write_data(struct i2c_client *client, u8 data)
+{
+ return ssd1307fb_write_data_array(client, &data, 1);
+}
+
+static int ssd1307fb_set(struct i2c_client *client, u8 value)
+{
+ int i, j, ret;
+
+ for (i = 1; i <= (SSD1307FB_HEIGHT / 8); i++) {
+ ret = ssd1307fb_write_cmd(client, SSD1307FB_START_PAGE_ADDRESS + i);
+ if (ret)
+ goto i2c_error;
+
+ ret = ssd1307fb_write_cmd(client, 0x00);
+ if (ret)
+ goto i2c_error;
+
+ ret = ssd1307fb_write_cmd(client, 0x10);
+ if (ret)
+ goto i2c_error;
+
+ for (j = 0; j < SSD1307FB_WIDTH; j++)
+ ssd1307fb_write_data(client, value);
+ }
+
+ return 0;
+
+i2c_error:
+ dev_err(&client->dev, "Couldn't send i2c command: %d\n", ret);
+ return ret;
+}
+
+static void ssd1307fb_update_display(struct ssd1307fb_par *par)
+{
+ u8 *vmem = par->info->screen_base;
+ int i, j, k;
+
+ /*
+ * A page is 8 bit large and covers all the line. In order to
+ * update the screen, you have to send a byte, each byte
+ * containing a bit per pixel to set, on the same column. That
+ * way, by sending a byte, you will only portion of the screen
+ * that has a height of 8 bit and a width of 1, the right-most
+ * bit being on the top of this frame. So we have to do a bit
+ * of magic here...
+ */
+
+ 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);
+ }
+ }
+
+ return;
+}
+
+
+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");
+ ret = -EINVAL;
+ goto generic_error;
+ }
+
+ info = framebuffer_alloc(sizeof(struct ssd1307fb_par), &client->dev);
+ if (!info) {
+ ret = -ENOMEM;
+ goto generic_error;
+ }
+
+ vmem = devm_kzalloc(&client->dev, vmem_size, GFP_KERNEL);
+
+ 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_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,
+ "oled-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) {
+ 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) {
+ 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);
+ framebuffer_release(info);
+generic_error:
+ 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