1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/module.h>
3 #include <linux/kernel.h>
4 #include <linux/init.h>
5 #include <linux/spi/spi.h>
6 #include <linux/delay.h>
10 #define DRVNAME "fb_ssd1351"
15 #define DEFAULT_GAMMA "0 2 2 2 2 2 2 2 " \
24 static void register_onboard_backlight(struct fbtft_par *par);
26 static int init_display(struct fbtft_par *par)
29 par->pdata->display.backlight == FBTFT_ONBOARD_BACKLIGHT) {
30 /* module uses onboard GPIO for panel power */
31 par->fbtftops.register_backlight = register_onboard_backlight;
34 par->fbtftops.reset(par);
36 write_reg(par, 0xfd, 0x12); /* Command Lock */
37 write_reg(par, 0xfd, 0xb1); /* Command Lock */
38 write_reg(par, 0xae); /* Display Off */
39 write_reg(par, 0xb3, 0xf1); /* Front Clock Div */
40 write_reg(par, 0xca, 0x7f); /* Set Mux Ratio */
41 write_reg(par, 0x15, 0x00, 0x7f); /* Set Column Address */
42 write_reg(par, 0x75, 0x00, 0x7f); /* Set Row Address */
43 write_reg(par, 0xa1, 0x00); /* Set Display Start Line */
44 write_reg(par, 0xa2, 0x00); /* Set Display Offset */
45 write_reg(par, 0xb5, 0x00); /* Set GPIO */
46 write_reg(par, 0xab, 0x01); /* Set Function Selection */
47 write_reg(par, 0xb1, 0x32); /* Set Phase Length */
48 write_reg(par, 0xb4, 0xa0, 0xb5, 0x55); /* Set Segment Low Voltage */
49 write_reg(par, 0xbb, 0x17); /* Set Precharge Voltage */
50 write_reg(par, 0xbe, 0x05); /* Set VComH Voltage */
51 write_reg(par, 0xc1, 0xc8, 0x80, 0xc8); /* Set Contrast */
52 write_reg(par, 0xc7, 0x0f); /* Set Master Contrast */
53 write_reg(par, 0xb6, 0x01); /* Set Second Precharge Period */
54 write_reg(par, 0xa6); /* Set Display Mode Reset */
55 write_reg(par, 0xaf); /* Set Sleep Mode Display On */
60 static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
62 write_reg(par, 0x15, xs, xe);
63 write_reg(par, 0x75, ys, ye);
67 static int set_var(struct fbtft_par *par)
71 if (par->fbtftops.init_display != init_display) {
72 /* don't risk messing up register A0h */
73 fbtft_par_dbg(DEBUG_INIT_DISPLAY, par,
74 "%s: skipping since custom init_display() is used\n",
79 remap = 0x60 | (par->bgr << 2); /* Set Colour Depth */
81 switch (par->info->var.rotate) {
83 write_reg(par, 0xA0, remap | 0x00 | BIT(4));
86 write_reg(par, 0xA0, remap | 0x03 | BIT(4));
89 write_reg(par, 0xA0, remap | 0x02);
92 write_reg(par, 0xA0, remap | 0x01);
100 * Grayscale Lookup Table
102 * The driver Gamma curve contains the relative values between the entries
103 * in the Lookup table.
106 * 8.8 Gray Scale Decoder
108 * there are total 180 Gamma Settings (Setting 0 to Setting 180)
109 * available for the Gray Scale table.
111 * The gray scale is defined in incremental way, with reference
112 * to the length of previous table entry:
113 * Setting of GS1 has to be >= 0
114 * Setting of GS2 has to be > Setting of GS1 +1
115 * Setting of GS3 has to be > Setting of GS2 +1
117 * Setting of GS63 has to be > Setting of GS62 +1
120 static int set_gamma(struct fbtft_par *par, u32 *curves)
122 unsigned long tmp[GAMMA_NUM * GAMMA_LEN];
125 for (i = 0; i < 63; i++) {
126 if (i > 0 && curves[i] < 2) {
127 dev_err(par->info->device,
128 "Illegal value in Grayscale Lookup Table at index %d : %d. Must be greater than 1\n",
135 dev_err(par->info->device,
136 "Illegal value(s) in Grayscale Lookup Table. At index=%d : %d, the accumulated value has exceeded 180\n",
143 tmp[0], tmp[1], tmp[2], tmp[3],
144 tmp[4], tmp[5], tmp[6], tmp[7],
145 tmp[8], tmp[9], tmp[10], tmp[11],
146 tmp[12], tmp[13], tmp[14], tmp[15],
147 tmp[16], tmp[17], tmp[18], tmp[19],
148 tmp[20], tmp[21], tmp[22], tmp[23],
149 tmp[24], tmp[25], tmp[26], tmp[27],
150 tmp[28], tmp[29], tmp[30], tmp[31],
151 tmp[32], tmp[33], tmp[34], tmp[35],
152 tmp[36], tmp[37], tmp[38], tmp[39],
153 tmp[40], tmp[41], tmp[42], tmp[43],
154 tmp[44], tmp[45], tmp[46], tmp[47],
155 tmp[48], tmp[49], tmp[50], tmp[51],
156 tmp[52], tmp[53], tmp[54], tmp[55],
157 tmp[56], tmp[57], tmp[58], tmp[59],
158 tmp[60], tmp[61], tmp[62]);
163 static int blank(struct fbtft_par *par, bool on)
165 fbtft_par_dbg(DEBUG_BLANK, par, "(%s=%s)\n",
166 __func__, on ? "true" : "false");
168 write_reg(par, 0xAE);
170 write_reg(par, 0xAF);
174 static struct fbtft_display display = {
178 .gamma_num = GAMMA_NUM,
179 .gamma_len = GAMMA_LEN,
180 .gamma = DEFAULT_GAMMA,
182 .init_display = init_display,
183 .set_addr_win = set_addr_win,
185 .set_gamma = set_gamma,
190 #ifdef CONFIG_FB_BACKLIGHT
191 static int update_onboard_backlight(struct backlight_device *bd)
193 struct fbtft_par *par = bl_get_data(bd);
196 fbtft_par_dbg(DEBUG_BACKLIGHT, par,
197 "%s: power=%d, fb_blank=%d\n",
198 __func__, bd->props.power, bd->props.fb_blank);
200 on = (bd->props.power == FB_BLANK_UNBLANK) &&
201 (bd->props.fb_blank == FB_BLANK_UNBLANK);
202 /* Onboard backlight connected to GPIO0 on SSD1351, GPIO1 unused */
203 write_reg(par, 0xB5, on ? 0x03 : 0x02);
208 static const struct backlight_ops bl_ops = {
209 .update_status = update_onboard_backlight,
212 static void register_onboard_backlight(struct fbtft_par *par)
214 struct backlight_device *bd;
215 struct backlight_properties bl_props = { 0, };
217 bl_props.type = BACKLIGHT_RAW;
218 bl_props.power = FB_BLANK_POWERDOWN;
220 bd = backlight_device_register(dev_driver_string(par->info->device),
221 par->info->device, par, &bl_ops,
224 dev_err(par->info->device,
225 "cannot register backlight device (%ld)\n",
229 par->info->bl_dev = bd;
231 if (!par->fbtftops.unregister_backlight)
232 par->fbtftops.unregister_backlight = fbtft_unregister_backlight;
235 static void register_onboard_backlight(struct fbtft_par *par) { };
238 FBTFT_REGISTER_DRIVER(DRVNAME, "solomon,ssd1351", &display);
240 MODULE_ALIAS("spi:" DRVNAME);
241 MODULE_ALIAS("platform:" DRVNAME);
242 MODULE_ALIAS("spi:ssd1351");
243 MODULE_ALIAS("platform:ssd1351");
245 MODULE_DESCRIPTION("SSD1351 OLED Driver");
246 MODULE_AUTHOR("James Davies");
247 MODULE_LICENSE("GPL");