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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"); |
398 |
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