drivers/video: add support for the Solomon SSD1307 OLED Controller
authorMaxime Ripard <maxime.ripard@free-electrons.com>
Fri, 7 Dec 2012 20:30:38 +0000 (12:30 -0800)
committerTomi Valkeinen <tomi.valkeinen@ti.com>
Mon, 10 Dec 2012 09:33:53 +0000 (11:33 +0200)
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: Maxime 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Documentation/devicetree/bindings/video/ssd1307fb.txt [new file with mode: 0644]
drivers/video/Kconfig
drivers/video/Makefile
drivers/video/ssd1307fb.c [new file with mode: 0644]

diff --git a/Documentation/devicetree/bindings/video/ssd1307fb.txt b/Documentation/devicetree/bindings/video/ssd1307fb.txt
new file mode 100644 (file)
index 0000000..3d0060c
--- /dev/null
@@ -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;
+};
index 9018a90b4588eea1295530424c66ab84fef9cc7a..9c31277b3a811067a1e7985eaa2256e379a149e3 100644 (file)
@@ -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
index 23e948ebfab8931b790617cf9341a081b1f9edae..768a137a1bacd3f8eca7dfde548cce68c41176bb 100644 (file)
@@ -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 (file)
index 0000000..6101f5c
--- /dev/null
@@ -0,0 +1,396 @@
+/*
+ * 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");