drivers/video/ssd1307fb.c

   1 /*
   2  * Driver for the Solomon SSD1307 OLED controller
   3  *
   4  * Copyright 2012 Free Electrons
   5  *
   6  * Licensed under the GPLv2 or later.
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/kernel.h>
  11 #include <linux/i2c.h>
  12 #include <linux/fb.h>
  13 #include <linux/uaccess.h>
  14 #include <linux/of_device.h>
  15 #include <linux/of_gpio.h>
  16 #include <linux/pwm.h>
  17 #include <linux/delay.h>
  18
  19 #define SSD1307FB_WIDTH                 96
  20 #define SSD1307FB_HEIGHT                16
  21
  22 #define SSD1307FB_DATA                  0x40
  23 #define SSD1307FB_COMMAND               0x80
  24
  25 #define SSD1307FB_CONTRAST              0x81
  26 #define SSD1307FB_SEG_REMAP_ON          0xa1
  27 #define SSD1307FB_DISPLAY_OFF           0xae
  28 #define SSD1307FB_DISPLAY_ON            0xaf
  29 #define SSD1307FB_START_PAGE_ADDRESS    0xb0
  30
  31 struct ssd1307fb_par {
  32         struct i2c_client *client;
  33         struct fb_info *info;
  34         struct pwm_device *pwm;
  35         u32 pwm_period;
  36         int reset;
  37 };
  38
  39 static struct fb_fix_screeninfo ssd1307fb_fix = {
  40         .id             = "Solomon SSD1307",
  41         .type           = FB_TYPE_PACKED_PIXELS,
  42         .visual         = FB_VISUAL_MONO10,
  43         .xpanstep       = 0,
  44         .ypanstep       = 0,
  45         .ywrapstep      = 0,
  46         .line_length    = SSD1307FB_WIDTH / 8,
  47         .accel          = FB_ACCEL_NONE,
  48 };
  49
  50 static struct fb_var_screeninfo ssd1307fb_var = {
  51         .xres           = SSD1307FB_WIDTH,
  52         .yres           = SSD1307FB_HEIGHT,
  53         .xres_virtual   = SSD1307FB_WIDTH,
  54         .yres_virtual   = SSD1307FB_HEIGHT,
  55         .bits_per_pixel = 1,
  56 };
  57
  58 static int ssd1307fb_write_array(struct i2c_client *client, u8 type, u8 *cmd, u32 len)
  59 {
  60         u8 *buf;
  61         int ret = 0;
  62
  63         buf = kzalloc(len + 1, GFP_KERNEL);
  64         if (!buf) {
  65                 dev_err(&client->dev, "Couldn't allocate sending buffer.\n");
  66                 return -ENOMEM;
  67         }
  68
  69         buf[0] = type;
  70         memcpy(buf + 1, cmd, len);
  71
  72         ret = i2c_master_send(client, buf, len + 1);
  73         if (ret != len + 1) {
  74                 dev_err(&client->dev, "Couldn't send I2C command.\n");
  75                 goto error;
  76         }
  77
  78 error:
  79         kfree(buf);
  80         return ret;
  81 }
  82
  83 static inline int ssd1307fb_write_cmd_array(struct i2c_client *client, u8 *cmd, u32 len)
  84 {
  85         return ssd1307fb_write_array(client, SSD1307FB_COMMAND, cmd, len);
  86 }
  87
  88 static inline int ssd1307fb_write_cmd(struct i2c_client *client, u8 cmd)
  89 {
  90         return ssd1307fb_write_cmd_array(client, &cmd, 1);
  91 }
  92
  93 static inline int ssd1307fb_write_data_array(struct i2c_client *client, u8 *cmd, u32 len)
  94 {
  95         return ssd1307fb_write_array(client, SSD1307FB_DATA, cmd, len);
  96 }
  97
  98 static inline int ssd1307fb_write_data(struct i2c_client *client, u8 data)
  99 {
 100         return ssd1307fb_write_data_array(client, &data, 1);
 101 }
 102
 103 static void ssd1307fb_update_display(struct ssd1307fb_par *par)
 104 {
 105         u8 *vmem = par->info->screen_base;
 106         int i, j, k;
 107
 108         /*
 109          * The screen is divided in pages, each having a height of 8
 110          * pixels, and the width of the screen. When sending a byte of
 111          * data to the controller, it gives the 8 bits for the current
 112          * column. I.e, the first byte are the 8 bits of the first
 113          * column, then the 8 bits for the second column, etc.
 114          *
 115          *
 116          * Representation of the screen, assuming it is 5 bits
 117          * wide. Each letter-number combination is a bit that controls
 118          * one pixel.
 119          *
 120          * A0 A1 A2 A3 A4
 121          * B0 B1 B2 B3 B4
 122          * C0 C1 C2 C3 C4
 123          * D0 D1 D2 D3 D4
 124          * E0 E1 E2 E3 E4
 125          * F0 F1 F2 F3 F4
 126          * G0 G1 G2 G3 G4
 127          * H0 H1 H2 H3 H4
 128          *
 129          * If you want to update this screen, you need to send 5 bytes:
 130          *  (1) A0 B0 C0 D0 E0 F0 G0 H0
 131          *  (2) A1 B1 C1 D1 E1 F1 G1 H1
 132          *  (3) A2 B2 C2 D2 E2 F2 G2 H2
 133          *  (4) A3 B3 C3 D3 E3 F3 G3 H3
 134          *  (5) A4 B4 C4 D4 E4 F4 G4 H4
 135          */
 136
 137         for (i = 0; i < (SSD1307FB_HEIGHT / 8); i++) {
 138                 ssd1307fb_write_cmd(par->client, SSD1307FB_START_PAGE_ADDRESS + (i + 1));
 139                 ssd1307fb_write_cmd(par->client, 0x00);
 140                 ssd1307fb_write_cmd(par->client, 0x10);
 141
 142                 for (j = 0; j < SSD1307FB_WIDTH; j++) {
 143                         u8 buf = 0;
 144                         for (k = 0; k < 8; k++) {
 145                                 u32 page_length = SSD1307FB_WIDTH * i;
 146                                 u32 index = page_length + (SSD1307FB_WIDTH * k + j) / 8;
 147                                 u8 byte = *(vmem + index);
 148                                 u8 bit = byte & (1 << (j % 8));
 149                                 bit = bit >> (j % 8);
 150                                 buf |= bit << k;
 151                         }
 152                         ssd1307fb_write_data(par->client, buf);
 153                 }
 154         }
 155 }
 156
 157
 158 static ssize_t ssd1307fb_write(struct fb_info *info, const char __user *buf,
 159                 size_t count, loff_t *ppos)
 160 {
 161         struct ssd1307fb_par *par = info->par;
 162         unsigned long total_size;
 163         unsigned long p = *ppos;
 164         u8 __iomem *dst;
 165
 166         total_size = info->fix.smem_len;
 167
 168         if (p > total_size)
 169                 return -EINVAL;
 170
 171         if (count + p > total_size)
 172                 count = total_size - p;
 173
 174         if (!count)
 175                 return -EINVAL;
 176
 177         dst = (void __force *) (info->screen_base + p);
 178
 179         if (copy_from_user(dst, buf, count))
 180                 return -EFAULT;
 181
 182         ssd1307fb_update_display(par);
 183
 184         *ppos += count;
 185
 186         return count;
 187 }
 188
 189 static void ssd1307fb_fillrect(struct fb_info *info, const struct fb_fillrect *rect)
 190 {
 191         struct ssd1307fb_par *par = info->par;
 192         sys_fillrect(info, rect);
 193         ssd1307fb_update_display(par);
 194 }
 195
 196 static void ssd1307fb_copyarea(struct fb_info *info, const struct fb_copyarea *area)
 197 {
 198         struct ssd1307fb_par *par = info->par;
 199         sys_copyarea(info, area);
 200         ssd1307fb_update_display(par);
 201 }
 202
 203 static void ssd1307fb_imageblit(struct fb_info *info, const struct fb_image *image)
 204 {
 205         struct ssd1307fb_par *par = info->par;
 206         sys_imageblit(info, image);
 207         ssd1307fb_update_display(par);
 208 }
 209
 210 static struct fb_ops ssd1307fb_ops = {
 211         .owner          = THIS_MODULE,
 212         .fb_read        = fb_sys_read,
 213         .fb_write       = ssd1307fb_write,
 214         .fb_fillrect    = ssd1307fb_fillrect,
 215         .fb_copyarea    = ssd1307fb_copyarea,
 216         .fb_imageblit   = ssd1307fb_imageblit,
 217 };
 218
 219 static void ssd1307fb_deferred_io(struct fb_info *info,
 220                                 struct list_head *pagelist)
 221 {
 222         ssd1307fb_update_display(info->par);
 223 }
 224
 225 static struct fb_deferred_io ssd1307fb_defio = {
 226         .delay          = HZ,
 227         .deferred_io    = ssd1307fb_deferred_io,
 228 };
 229
 230 static int ssd1307fb_probe(struct i2c_client *client,
 231                            const struct i2c_device_id *id)
 232 {
 233         struct fb_info *info;
 234         u32 vmem_size = SSD1307FB_WIDTH * SSD1307FB_HEIGHT / 8;
 235         struct ssd1307fb_par *par;
 236         u8 *vmem;
 237         int ret;
 238
 239         if (!client->dev.of_node) {
 240                 dev_err(&client->dev, "No device tree data found!\n");
 241                 return -EINVAL;
 242         }
 243
 244         info = framebuffer_alloc(sizeof(struct ssd1307fb_par), &client->dev);
 245         if (!info) {
 246                 dev_err(&client->dev, "Couldn't allocate framebuffer.\n");
 247                 return -ENOMEM;
 248         }
 249
 250         vmem = devm_kzalloc(&client->dev, vmem_size, GFP_KERNEL);
 251         if (!vmem) {
 252                 dev_err(&client->dev, "Couldn't allocate graphical memory.\n");
 253                 ret = -ENOMEM;
 254                 goto fb_alloc_error;
 255         }
 256
 257         info->fbops = &ssd1307fb_ops;
 258         info->fix = ssd1307fb_fix;
 259         info->fbdefio = &ssd1307fb_defio;
 260
 261         info->var = ssd1307fb_var;
 262         info->var.red.length = 1;
 263         info->var.red.offset = 0;
 264         info->var.green.length = 1;
 265         info->var.green.offset = 0;
 266         info->var.blue.length = 1;
 267         info->var.blue.offset = 0;
 268
 269         info->screen_base = (u8 __force __iomem *)vmem;
 270         info->fix.smem_start = (unsigned long)vmem;
 271         info->fix.smem_len = vmem_size;
 272
 273         fb_deferred_io_init(info);
 274
 275         par = info->par;
 276         par->info = info;
 277         par->client = client;
 278
 279         par->reset = of_get_named_gpio(client->dev.of_node,
 280                                          "reset-gpios", 0);
 281         if (!gpio_is_valid(par->reset)) {
 282                 ret = -EINVAL;
 283                 goto reset_oled_error;
 284         }
 285
 286         ret = devm_gpio_request_one(&client->dev, par->reset,
 287                                     GPIOF_OUT_INIT_HIGH,
 288                                     "oled-reset");
 289         if (ret) {
 290                 dev_err(&client->dev,
 291                         "failed to request gpio %d: %d\n",
 292                         par->reset, ret);
 293                 goto reset_oled_error;
 294         }
 295
 296         par->pwm = pwm_get(&client->dev, NULL);
 297         if (IS_ERR(par->pwm)) {
 298                 dev_err(&client->dev, "Could not get PWM from device tree!\n");
 299                 ret = PTR_ERR(par->pwm);
 300                 goto pwm_error;
 301         }
 302
 303         par->pwm_period = pwm_get_period(par->pwm);
 304
 305         dev_dbg(&client->dev, "Using PWM%d with a %dns period.\n", par->pwm->pwm, par->pwm_period);
 306
 307         ret = register_framebuffer(info);
 308         if (ret) {
 309                 dev_err(&client->dev, "Couldn't register the framebuffer\n");
 310                 goto fbreg_error;
 311         }
 312
 313         i2c_set_clientdata(client, info);
 314
 315         /* Reset the screen */
 316         gpio_set_value(par->reset, 0);
 317         udelay(4);
 318         gpio_set_value(par->reset, 1);
 319         udelay(4);
 320
 321         /* Enable the PWM */
 322         pwm_config(par->pwm, par->pwm_period / 2, par->pwm_period);
 323         pwm_enable(par->pwm);
 324
 325         /* Map column 127 of the OLED to segment 0 */
 326         ret = ssd1307fb_write_cmd(client, SSD1307FB_SEG_REMAP_ON);
 327         if (ret < 0) {
 328                 dev_err(&client->dev, "Couldn't remap the screen.\n");
 329                 goto remap_error;
 330         }
 331
 332         /* Turn on the display */
 333         ret = ssd1307fb_write_cmd(client, SSD1307FB_DISPLAY_ON);
 334         if (ret < 0) {
 335                 dev_err(&client->dev, "Couldn't turn the display on.\n");
 336                 goto remap_error;
 337         }
 338
 339         dev_info(&client->dev, "fb%d: %s framebuffer device registered, using %d bytes of video memory\n", info->node, info->fix.id, vmem_size);
 340
 341         return 0;
 342
 343 remap_error:
 344         unregister_framebuffer(info);
 345         pwm_disable(par->pwm);
 346 fbreg_error:
 347         pwm_put(par->pwm);
 348 pwm_error:
 349 reset_oled_error:
 350         fb_deferred_io_cleanup(info);
 351 fb_alloc_error:
 352         framebuffer_release(info);
 353         return ret;
 354 }
 355
 356 static int ssd1307fb_remove(struct i2c_client *client)
 357 {
 358         struct fb_info *info = i2c_get_clientdata(client);
 359         struct ssd1307fb_par *par = info->par;
 360
 361         unregister_framebuffer(info);
 362         pwm_disable(par->pwm);
 363         pwm_put(par->pwm);
 364         fb_deferred_io_cleanup(info);
 365         framebuffer_release(info);
 366
 367         return 0;
 368 }
 369
 370 static const struct i2c_device_id ssd1307fb_i2c_id[] = {
 371         { "ssd1307fb", 0 },
 372         { }
 373 };
 374 MODULE_DEVICE_TABLE(i2c, ssd1307fb_i2c_id);
 375
 376 static const struct of_device_id ssd1307fb_of_match[] = {
 377         { .compatible = "solomon,ssd1307fb-i2c" },
 378         {},
 379 };
 380 MODULE_DEVICE_TABLE(of, ssd1307fb_of_match);
 381
 382 static struct i2c_driver ssd1307fb_driver = {
 383         .probe = ssd1307fb_probe,
 384         .remove = ssd1307fb_remove,
 385         .id_table = ssd1307fb_i2c_id,
 386         .driver = {
 387                 .name = "ssd1307fb",
 388                 .of_match_table = of_match_ptr(ssd1307fb_of_match),
 389                 .owner = THIS_MODULE,
 390         },
 391 };
 392
 393 module_i2c_driver(ssd1307fb_driver);
 394
 395 MODULE_DESCRIPTION("FB driver for the Solomon SSD1307 OLED controller");
 396 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
 397 MODULE_LICENSE("GPL");