1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Driver for the Solomon SSD1307 OLED controller
5 * Copyright 2012 Free Electrons
8 #include <linux/backlight.h>
9 #include <linux/delay.h>
11 #include <linux/gpio/consumer.h>
12 #include <linux/i2c.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/of_device.h>
16 #include <linux/of_gpio.h>
17 #include <linux/pwm.h>
18 #include <linux/uaccess.h>
19 #include <linux/regulator/consumer.h>
21 #define SSD1307FB_DATA 0x40
22 #define SSD1307FB_COMMAND 0x80
24 #define SSD1307FB_SET_ADDRESS_MODE 0x20
25 #define SSD1307FB_SET_ADDRESS_MODE_HORIZONTAL (0x00)
26 #define SSD1307FB_SET_ADDRESS_MODE_VERTICAL (0x01)
27 #define SSD1307FB_SET_ADDRESS_MODE_PAGE (0x02)
28 #define SSD1307FB_SET_COL_RANGE 0x21
29 #define SSD1307FB_SET_PAGE_RANGE 0x22
30 #define SSD1307FB_CONTRAST 0x81
31 #define SSD1307FB_CHARGE_PUMP 0x8d
32 #define SSD1307FB_SEG_REMAP_ON 0xa1
33 #define SSD1307FB_DISPLAY_OFF 0xae
34 #define SSD1307FB_SET_MULTIPLEX_RATIO 0xa8
35 #define SSD1307FB_DISPLAY_ON 0xaf
36 #define SSD1307FB_START_PAGE_ADDRESS 0xb0
37 #define SSD1307FB_SET_DISPLAY_OFFSET 0xd3
38 #define SSD1307FB_SET_CLOCK_FREQ 0xd5
39 #define SSD1307FB_SET_PRECHARGE_PERIOD 0xd9
40 #define SSD1307FB_SET_COM_PINS_CONFIG 0xda
41 #define SSD1307FB_SET_VCOMH 0xdb
43 #define MAX_CONTRAST 255
47 static u_int refreshrate = REFRESHRATE;
48 module_param(refreshrate, uint, 0);
52 struct ssd1307fb_deviceinfo {
60 struct ssd1307fb_par {
68 const struct ssd1307fb_deviceinfo *device_info;
69 struct i2c_client *client;
75 struct pwm_device *pwm;
77 struct gpio_desc *reset;
78 struct regulator *vbat_reg;
84 struct ssd1307fb_array {
89 static const struct fb_fix_screeninfo ssd1307fb_fix = {
90 .id = "Solomon SSD1307",
91 .type = FB_TYPE_PACKED_PIXELS,
92 .visual = FB_VISUAL_MONO10,
96 .accel = FB_ACCEL_NONE,
99 static const struct fb_var_screeninfo ssd1307fb_var = {
103 static struct ssd1307fb_array *ssd1307fb_alloc_array(u32 len, u8 type)
105 struct ssd1307fb_array *array;
107 array = kzalloc(sizeof(struct ssd1307fb_array) + len, GFP_KERNEL);
116 static int ssd1307fb_write_array(struct i2c_client *client,
117 struct ssd1307fb_array *array, u32 len)
121 len += sizeof(struct ssd1307fb_array);
123 ret = i2c_master_send(client, (u8 *)array, len);
125 dev_err(&client->dev, "Couldn't send I2C command.\n");
132 static inline int ssd1307fb_write_cmd(struct i2c_client *client, u8 cmd)
134 struct ssd1307fb_array *array;
137 array = ssd1307fb_alloc_array(1, SSD1307FB_COMMAND);
141 array->data[0] = cmd;
143 ret = ssd1307fb_write_array(client, array, 1);
149 static void ssd1307fb_update_display(struct ssd1307fb_par *par)
151 struct ssd1307fb_array *array;
152 u8 *vmem = par->info->screen_base;
155 array = ssd1307fb_alloc_array(par->width * par->height / 8,
161 * The screen is divided in pages, each having a height of 8
162 * pixels, and the width of the screen. When sending a byte of
163 * data to the controller, it gives the 8 bits for the current
164 * column. I.e, the first byte are the 8 bits of the first
165 * column, then the 8 bits for the second column, etc.
168 * Representation of the screen, assuming it is 5 bits
169 * wide. Each letter-number combination is a bit that controls
181 * If you want to update this screen, you need to send 5 bytes:
182 * (1) A0 B0 C0 D0 E0 F0 G0 H0
183 * (2) A1 B1 C1 D1 E1 F1 G1 H1
184 * (3) A2 B2 C2 D2 E2 F2 G2 H2
185 * (4) A3 B3 C3 D3 E3 F3 G3 H3
186 * (5) A4 B4 C4 D4 E4 F4 G4 H4
189 for (i = 0; i < (par->height / 8); i++) {
190 for (j = 0; j < par->width; j++) {
191 u32 array_idx = i * par->width + j;
192 array->data[array_idx] = 0;
193 for (k = 0; k < 8; k++) {
194 u32 page_length = par->width * i;
195 u32 index = page_length + (par->width * k + j) / 8;
196 u8 byte = *(vmem + index);
197 u8 bit = byte & (1 << (j % 8));
198 bit = bit >> (j % 8);
199 array->data[array_idx] |= bit << k;
204 ssd1307fb_write_array(par->client, array, par->width * par->height / 8);
209 static ssize_t ssd1307fb_write(struct fb_info *info, const char __user *buf,
210 size_t count, loff_t *ppos)
212 struct ssd1307fb_par *par = info->par;
213 unsigned long total_size;
214 unsigned long p = *ppos;
217 total_size = info->fix.smem_len;
222 if (count + p > total_size)
223 count = total_size - p;
228 dst = (void __force *) (info->screen_base + p);
230 if (copy_from_user(dst, buf, count))
233 ssd1307fb_update_display(par);
240 static int ssd1307fb_blank(int blank_mode, struct fb_info *info)
242 struct ssd1307fb_par *par = info->par;
244 if (blank_mode != FB_BLANK_UNBLANK)
245 return ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_OFF);
247 return ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_ON);
250 static void ssd1307fb_fillrect(struct fb_info *info, const struct fb_fillrect *rect)
252 struct ssd1307fb_par *par = info->par;
253 sys_fillrect(info, rect);
254 ssd1307fb_update_display(par);
257 static void ssd1307fb_copyarea(struct fb_info *info, const struct fb_copyarea *area)
259 struct ssd1307fb_par *par = info->par;
260 sys_copyarea(info, area);
261 ssd1307fb_update_display(par);
264 static void ssd1307fb_imageblit(struct fb_info *info, const struct fb_image *image)
266 struct ssd1307fb_par *par = info->par;
267 sys_imageblit(info, image);
268 ssd1307fb_update_display(par);
271 static struct fb_ops ssd1307fb_ops = {
272 .owner = THIS_MODULE,
273 .fb_read = fb_sys_read,
274 .fb_write = ssd1307fb_write,
275 .fb_blank = ssd1307fb_blank,
276 .fb_fillrect = ssd1307fb_fillrect,
277 .fb_copyarea = ssd1307fb_copyarea,
278 .fb_imageblit = ssd1307fb_imageblit,
281 static void ssd1307fb_deferred_io(struct fb_info *info,
282 struct list_head *pagelist)
284 ssd1307fb_update_display(info->par);
287 static int ssd1307fb_init(struct ssd1307fb_par *par)
290 u32 precharge, dclk, com_invdir, compins;
291 struct pwm_args pargs;
293 if (par->device_info->need_pwm) {
294 par->pwm = pwm_get(&par->client->dev, NULL);
295 if (IS_ERR(par->pwm)) {
296 dev_err(&par->client->dev, "Could not get PWM from device tree!\n");
297 return PTR_ERR(par->pwm);
301 * FIXME: pwm_apply_args() should be removed when switching to
302 * the atomic PWM API.
304 pwm_apply_args(par->pwm);
306 pwm_get_args(par->pwm, &pargs);
308 par->pwm_period = pargs.period;
310 pwm_config(par->pwm, par->pwm_period / 2, par->pwm_period);
311 pwm_enable(par->pwm);
313 dev_dbg(&par->client->dev, "Using PWM%d with a %dns period.\n",
314 par->pwm->pwm, par->pwm_period);
317 /* Set initial contrast */
318 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CONTRAST);
322 ret = ssd1307fb_write_cmd(par->client, par->contrast);
326 /* Set segment re-map */
327 if (par->seg_remap) {
328 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SEG_REMAP_ON);
333 /* Set COM direction */
334 com_invdir = 0xc0 | (par->com_invdir & 0x1) << 3;
335 ret = ssd1307fb_write_cmd(par->client, com_invdir);
339 /* Set multiplex ratio value */
340 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_MULTIPLEX_RATIO);
344 ret = ssd1307fb_write_cmd(par->client, par->height - 1);
348 /* set display offset value */
349 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_DISPLAY_OFFSET);
353 ret = ssd1307fb_write_cmd(par->client, par->com_offset);
357 /* Set clock frequency */
358 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_CLOCK_FREQ);
362 dclk = ((par->dclk_div - 1) & 0xf) | (par->dclk_frq & 0xf) << 4;
363 ret = ssd1307fb_write_cmd(par->client, dclk);
367 /* Set precharge period in number of ticks from the internal clock */
368 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PRECHARGE_PERIOD);
372 precharge = (par->prechargep1 & 0xf) | (par->prechargep2 & 0xf) << 4;
373 ret = ssd1307fb_write_cmd(par->client, precharge);
377 /* Set COM pins configuration */
378 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COM_PINS_CONFIG);
382 compins = 0x02 | !(par->com_seq & 0x1) << 4
383 | (par->com_lrremap & 0x1) << 5;
384 ret = ssd1307fb_write_cmd(par->client, compins);
389 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_VCOMH);
393 ret = ssd1307fb_write_cmd(par->client, par->vcomh);
397 /* Turn on the DC-DC Charge Pump */
398 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CHARGE_PUMP);
402 ret = ssd1307fb_write_cmd(par->client,
403 BIT(4) | (par->device_info->need_chargepump ? BIT(2) : 0));
407 /* Switch to horizontal addressing mode */
408 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_ADDRESS_MODE);
412 ret = ssd1307fb_write_cmd(par->client,
413 SSD1307FB_SET_ADDRESS_MODE_HORIZONTAL);
417 /* Set column range */
418 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COL_RANGE);
422 ret = ssd1307fb_write_cmd(par->client, 0x0);
426 ret = ssd1307fb_write_cmd(par->client, par->width - 1);
431 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PAGE_RANGE);
435 ret = ssd1307fb_write_cmd(par->client, 0x0);
439 ret = ssd1307fb_write_cmd(par->client,
440 par->page_offset + (par->height / 8) - 1);
444 /* Clear the screen */
445 ssd1307fb_update_display(par);
447 /* Turn on the display */
448 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_ON);
455 static int ssd1307fb_update_bl(struct backlight_device *bdev)
457 struct ssd1307fb_par *par = bl_get_data(bdev);
459 int brightness = bdev->props.brightness;
461 par->contrast = brightness;
463 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CONTRAST);
466 ret = ssd1307fb_write_cmd(par->client, par->contrast);
472 static int ssd1307fb_get_brightness(struct backlight_device *bdev)
474 struct ssd1307fb_par *par = bl_get_data(bdev);
476 return par->contrast;
479 static int ssd1307fb_check_fb(struct backlight_device *bdev,
480 struct fb_info *info)
482 return (info->bl_dev == bdev);
485 static const struct backlight_ops ssd1307fb_bl_ops = {
486 .options = BL_CORE_SUSPENDRESUME,
487 .update_status = ssd1307fb_update_bl,
488 .get_brightness = ssd1307fb_get_brightness,
489 .check_fb = ssd1307fb_check_fb,
492 static struct ssd1307fb_deviceinfo ssd1307fb_ssd1305_deviceinfo = {
493 .default_vcomh = 0x34,
494 .default_dclk_div = 1,
495 .default_dclk_frq = 7,
498 static struct ssd1307fb_deviceinfo ssd1307fb_ssd1306_deviceinfo = {
499 .default_vcomh = 0x20,
500 .default_dclk_div = 1,
501 .default_dclk_frq = 8,
502 .need_chargepump = 1,
505 static struct ssd1307fb_deviceinfo ssd1307fb_ssd1307_deviceinfo = {
506 .default_vcomh = 0x20,
507 .default_dclk_div = 2,
508 .default_dclk_frq = 12,
512 static struct ssd1307fb_deviceinfo ssd1307fb_ssd1309_deviceinfo = {
513 .default_vcomh = 0x34,
514 .default_dclk_div = 1,
515 .default_dclk_frq = 10,
518 static const struct of_device_id ssd1307fb_of_match[] = {
520 .compatible = "solomon,ssd1305fb-i2c",
521 .data = (void *)&ssd1307fb_ssd1305_deviceinfo,
524 .compatible = "solomon,ssd1306fb-i2c",
525 .data = (void *)&ssd1307fb_ssd1306_deviceinfo,
528 .compatible = "solomon,ssd1307fb-i2c",
529 .data = (void *)&ssd1307fb_ssd1307_deviceinfo,
532 .compatible = "solomon,ssd1309fb-i2c",
533 .data = (void *)&ssd1307fb_ssd1309_deviceinfo,
537 MODULE_DEVICE_TABLE(of, ssd1307fb_of_match);
539 static int ssd1307fb_probe(struct i2c_client *client,
540 const struct i2c_device_id *id)
542 struct backlight_device *bl;
544 struct fb_info *info;
545 struct device_node *node = client->dev.of_node;
546 struct fb_deferred_io *ssd1307fb_defio;
548 struct ssd1307fb_par *par;
553 dev_err(&client->dev, "No device tree data found!\n");
557 info = framebuffer_alloc(sizeof(struct ssd1307fb_par), &client->dev);
559 dev_err(&client->dev, "Couldn't allocate framebuffer.\n");
565 par->client = client;
567 par->device_info = of_device_get_match_data(&client->dev);
569 par->reset = devm_gpiod_get_optional(&client->dev, "reset",
571 if (IS_ERR(par->reset)) {
572 dev_err(&client->dev, "failed to get reset gpio: %ld\n",
573 PTR_ERR(par->reset));
574 ret = PTR_ERR(par->reset);
578 par->vbat_reg = devm_regulator_get_optional(&client->dev, "vbat");
579 if (IS_ERR(par->vbat_reg)) {
580 ret = PTR_ERR(par->vbat_reg);
581 if (ret == -ENODEV) {
582 par->vbat_reg = NULL;
584 dev_err(&client->dev, "failed to get VBAT regulator: %d\n",
590 if (of_property_read_u32(node, "solomon,width", &par->width))
593 if (of_property_read_u32(node, "solomon,height", &par->height))
596 if (of_property_read_u32(node, "solomon,page-offset", &par->page_offset))
597 par->page_offset = 1;
599 if (of_property_read_u32(node, "solomon,com-offset", &par->com_offset))
602 if (of_property_read_u32(node, "solomon,prechargep1", &par->prechargep1))
603 par->prechargep1 = 2;
605 if (of_property_read_u32(node, "solomon,prechargep2", &par->prechargep2))
606 par->prechargep2 = 2;
608 par->seg_remap = !of_property_read_bool(node, "solomon,segment-no-remap");
609 par->com_seq = of_property_read_bool(node, "solomon,com-seq");
610 par->com_lrremap = of_property_read_bool(node, "solomon,com-lrremap");
611 par->com_invdir = of_property_read_bool(node, "solomon,com-invdir");
614 par->vcomh = par->device_info->default_vcomh;
616 /* Setup display timing */
617 par->dclk_div = par->device_info->default_dclk_div;
618 par->dclk_frq = par->device_info->default_dclk_frq;
620 vmem_size = par->width * par->height / 8;
622 vmem = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
623 get_order(vmem_size));
625 dev_err(&client->dev, "Couldn't allocate graphical memory.\n");
630 ssd1307fb_defio = devm_kzalloc(&client->dev, sizeof(*ssd1307fb_defio),
632 if (!ssd1307fb_defio) {
633 dev_err(&client->dev, "Couldn't allocate deferred io.\n");
638 ssd1307fb_defio->delay = HZ / refreshrate;
639 ssd1307fb_defio->deferred_io = ssd1307fb_deferred_io;
641 info->fbops = &ssd1307fb_ops;
642 info->fix = ssd1307fb_fix;
643 info->fix.line_length = par->width / 8;
644 info->fbdefio = ssd1307fb_defio;
646 info->var = ssd1307fb_var;
647 info->var.xres = par->width;
648 info->var.xres_virtual = par->width;
649 info->var.yres = par->height;
650 info->var.yres_virtual = par->height;
652 info->var.red.length = 1;
653 info->var.red.offset = 0;
654 info->var.green.length = 1;
655 info->var.green.offset = 0;
656 info->var.blue.length = 1;
657 info->var.blue.offset = 0;
659 info->screen_base = (u8 __force __iomem *)vmem;
660 info->fix.smem_start = __pa(vmem);
661 info->fix.smem_len = vmem_size;
663 fb_deferred_io_init(info);
665 i2c_set_clientdata(client, info);
668 /* Reset the screen */
669 gpiod_set_value_cansleep(par->reset, 1);
671 gpiod_set_value_cansleep(par->reset, 0);
676 ret = regulator_enable(par->vbat_reg);
678 dev_err(&client->dev, "failed to enable VBAT: %d\n",
680 goto reset_oled_error;
684 ret = ssd1307fb_init(par);
686 goto regulator_enable_error;
688 ret = register_framebuffer(info);
690 dev_err(&client->dev, "Couldn't register the framebuffer\n");
691 goto panel_init_error;
694 snprintf(bl_name, sizeof(bl_name), "ssd1307fb%d", info->node);
695 bl = backlight_device_register(bl_name, &client->dev, par,
696 &ssd1307fb_bl_ops, NULL);
699 dev_err(&client->dev, "unable to register backlight device: %d\n",
704 bl->props.brightness = par->contrast;
705 bl->props.max_brightness = MAX_CONTRAST;
708 dev_info(&client->dev, "fb%d: %s framebuffer device registered, using %d bytes of video memory\n", info->node, info->fix.id, vmem_size);
713 unregister_framebuffer(info);
715 if (par->device_info->need_pwm) {
716 pwm_disable(par->pwm);
719 regulator_enable_error:
721 regulator_disable(par->vbat_reg);
723 fb_deferred_io_cleanup(info);
725 framebuffer_release(info);
729 static int ssd1307fb_remove(struct i2c_client *client)
731 struct fb_info *info = i2c_get_clientdata(client);
732 struct ssd1307fb_par *par = info->par;
734 ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_OFF);
736 backlight_device_unregister(info->bl_dev);
738 unregister_framebuffer(info);
739 if (par->device_info->need_pwm) {
740 pwm_disable(par->pwm);
743 fb_deferred_io_cleanup(info);
744 __free_pages(__va(info->fix.smem_start), get_order(info->fix.smem_len));
745 framebuffer_release(info);
750 static const struct i2c_device_id ssd1307fb_i2c_id[] = {
757 MODULE_DEVICE_TABLE(i2c, ssd1307fb_i2c_id);
759 static struct i2c_driver ssd1307fb_driver = {
760 .probe = ssd1307fb_probe,
761 .remove = ssd1307fb_remove,
762 .id_table = ssd1307fb_i2c_id,
765 .of_match_table = ssd1307fb_of_match,
769 module_i2c_driver(ssd1307fb_driver);
771 MODULE_DESCRIPTION("FB driver for the Solomon SSD1307 OLED controller");
772 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
773 MODULE_LICENSE("GPL");