2 * FB driver for the SSD1306 OLED Controller
4 * Copyright (C) 2013 Noralf Tronnes
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 #include <linux/module.h>
22 #include <linux/kernel.h>
23 #include <linux/init.h>
24 #include <linux/gpio.h>
25 #include <linux/delay.h>
29 #define DRVNAME "fb_ssd1306"
37 This doesn't work because D/C has to be LOW for both values:
38 write_reg(par, val1, val2);
45 /* Init sequence taken from the Adafruit SSD1306 Arduino library */
46 static int init_display(struct fbtft_par *par)
48 fbtft_par_dbg(DEBUG_INIT_DISPLAY, par, "%s()\n", __func__);
50 par->fbtftops.reset(par);
52 if (par->gamma.curves[0] == 0) {
53 mutex_lock(&par->gamma.lock);
54 if (par->info->var.yres == 64)
55 par->gamma.curves[0] = 0xCF;
57 par->gamma.curves[0] = 0x8F;
58 mutex_unlock(&par->gamma.lock);
64 /* Set Display Clock Divide Ratio/ Oscillator Frequency */
68 /* Set Multiplex Ratio */
70 if (par->info->var.yres == 64)
75 /* Set Display Offset */
79 /* Set Display Start Line */
80 write_reg(par, 0x40 | 0x0);
82 /* Charge Pump Setting */
84 /* A[2] = 1b, Enable charge pump during display on */
87 /* Set Memory Addressing Mode */
89 /* Vertical addressing mode */
92 /*Set Segment Re-map */
93 /* column address 127 is mapped to SEG0 */
94 write_reg(par, 0xA0 | 0x1);
96 /* Set COM Output Scan Direction */
97 /* remapped mode. Scan from COM[N-1] to COM0 */
100 /* Set COM Pins Hardware Configuration */
101 write_reg(par, 0xDA);
102 if (par->info->var.yres == 64)
103 /* A[4]=1b, Alternative COM pin configuration */
104 write_reg(par, 0x12);
106 /* A[4]=0b, Sequential COM pin configuration */
107 write_reg(par, 0x02);
109 /* Set Pre-charge Period */
110 write_reg(par, 0xD9);
111 write_reg(par, 0xF1);
113 /* Set VCOMH Deselect Level */
114 write_reg(par, 0xDB);
115 /* according to the datasheet, this value is out of bounds */
116 write_reg(par, 0x40);
118 /* Entire Display ON */
119 /* Resume to RAM content display. Output follows RAM content */
120 write_reg(par, 0xA4);
122 /* Set Normal Display
123 0 in RAM: OFF in display panel
124 1 in RAM: ON in display panel */
125 write_reg(par, 0xA6);
128 write_reg(par, 0xAF);
133 static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
135 fbtft_par_dbg(DEBUG_SET_ADDR_WIN, par,
136 "%s(xs=%d, ys=%d, xe=%d, ye=%d)\n", __func__, xs, ys, xe, ye);
138 /* Set Lower Column Start Address for Page Addressing Mode */
139 write_reg(par, 0x00 | 0x0);
140 /* Set Higher Column Start Address for Page Addressing Mode */
141 write_reg(par, 0x10 | 0x0);
142 /* Set Display Start Line */
143 write_reg(par, 0x40 | 0x0);
146 static int blank(struct fbtft_par *par, bool on)
148 fbtft_par_dbg(DEBUG_BLANK, par, "%s(blank=%s)\n",
149 __func__, on ? "true" : "false");
152 write_reg(par, 0xAE);
154 write_reg(par, 0xAF);
158 /* Gamma is used to control Contrast */
159 static int set_gamma(struct fbtft_par *par, unsigned long *curves)
161 fbtft_par_dbg(DEBUG_INIT_DISPLAY, par, "%s()\n", __func__);
166 /* Set Contrast Control for BANK0 */
167 write_reg(par, 0x81);
168 write_reg(par, curves[0]);
173 static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
175 u16 *vmem16 = (u16 *)par->info->screen_base;
176 u8 *buf = par->txbuf.buf;
180 fbtft_par_dbg(DEBUG_WRITE_VMEM, par, "%s()\n", __func__);
182 for (x = 0; x < par->info->var.xres; x++) {
183 for (y = 0; y < par->info->var.yres/8; y++) {
185 for (i = 0; i < 8; i++)
186 *buf |= (vmem16[(y*8+i)*par->info->var.xres+x] ? 1 : 0) << i;
192 gpio_set_value(par->gpio.dc, 1);
193 ret = par->fbtftops.write(par, par->txbuf.buf,
194 par->info->var.xres*par->info->var.yres/8);
196 dev_err(par->info->device, "write failed and returned: %d\n",
203 static struct fbtft_display display = {
211 .write_vmem = write_vmem,
212 .init_display = init_display,
213 .set_addr_win = set_addr_win,
215 .set_gamma = set_gamma,
220 FBTFT_REGISTER_DRIVER(DRVNAME, "solomon,ssd1306", &display);
222 MODULE_ALIAS("spi:" DRVNAME);
223 MODULE_ALIAS("platform:" DRVNAME);
224 MODULE_ALIAS("spi:ssd1306");
225 MODULE_ALIAS("platform:ssd1306");
227 MODULE_DESCRIPTION("SSD1306 OLED Driver");
228 MODULE_AUTHOR("Noralf Tronnes");
229 MODULE_LICENSE("GPL");