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[karo-tx-linux.git] / drivers / video / ssd1307fb.c
1 /*
2  * Driver for the Solomon SSD1307 OLED controler
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 controler");
396 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
397 MODULE_LICENSE("GPL");