1// SPDX-License-Identifier: GPL-2.0
2
3#include <linux/backlight.h>
4#include <linux/module.h>
5#include <linux/kernel.h>
6#include <linux/init.h>
7#include <linux/spi/spi.h>
8#include <linux/delay.h>
9
10#include "fbtft.h"
11
12#define DRVNAME "fb_ssd1351"
13#define WIDTH 128
14#define HEIGHT 128
15#define GAMMA_NUM 1
16#define GAMMA_LEN 63
17#define DEFAULT_GAMMA "0 2 2 2 2 2 2 2 " \
18 "2 2 2 2 2 2 2 2 " \
19 "2 2 2 2 2 2 2 2 " \
20 "2 2 2 2 2 2 2 2 " \
21 "2 2 2 2 2 2 2 2 " \
22 "2 2 2 2 2 2 2 2 " \
23 "2 2 2 2 2 2 2 2 " \
24 "2 2 2 2 2 2 2" \
25
26static void register_onboard_backlight(struct fbtft_par *par);
27
28static int init_display(struct fbtft_par *par)
29{
30 if (par->pdata &&
31 par->pdata->display.backlight == FBTFT_ONBOARD_BACKLIGHT) {
32 /* module uses onboard GPIO for panel power */
33 par->fbtftops.register_backlight = register_onboard_backlight;
34 }
35
36 par->fbtftops.reset(par);
37
38 write_reg(par, 0xfd, 0x12); /* Command Lock */
39 write_reg(par, 0xfd, 0xb1); /* Command Lock */
40 write_reg(par, 0xae); /* Display Off */
41 write_reg(par, 0xb3, 0xf1); /* Front Clock Div */
42 write_reg(par, 0xca, 0x7f); /* Set Mux Ratio */
43 write_reg(par, 0x15, 0x00, 0x7f); /* Set Column Address */
44 write_reg(par, 0x75, 0x00, 0x7f); /* Set Row Address */
45 write_reg(par, 0xa1, 0x00); /* Set Display Start Line */
46 write_reg(par, 0xa2, 0x00); /* Set Display Offset */
47 write_reg(par, 0xb5, 0x00); /* Set GPIO */
48 write_reg(par, 0xab, 0x01); /* Set Function Selection */
49 write_reg(par, 0xb1, 0x32); /* Set Phase Length */
50 write_reg(par, 0xb4, 0xa0, 0xb5, 0x55); /* Set Segment Low Voltage */
51 write_reg(par, 0xbb, 0x17); /* Set Precharge Voltage */
52 write_reg(par, 0xbe, 0x05); /* Set VComH Voltage */
53 write_reg(par, 0xc1, 0xc8, 0x80, 0xc8); /* Set Contrast */
54 write_reg(par, 0xc7, 0x0f); /* Set Master Contrast */
55 write_reg(par, 0xb6, 0x01); /* Set Second Precharge Period */
56 write_reg(par, 0xa6); /* Set Display Mode Reset */
57 write_reg(par, 0xaf); /* Set Sleep Mode Display On */
58
59 return 0;
60}
61
62static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
63{
64 write_reg(par, 0x15, xs, xe);
65 write_reg(par, 0x75, ys, ye);
66 write_reg(par, 0x5c);
67}
68
69static int set_var(struct fbtft_par *par)
70{
71 unsigned int remap;
72
73 if (par->fbtftops.init_display != init_display) {
74 /* don't risk messing up register A0h */
75 fbtft_par_dbg(DEBUG_INIT_DISPLAY, par,
76 "%s: skipping since custom init_display() is used\n",
77 __func__);
78 return 0;
79 }
80
81 remap = 0x60 | (par->bgr << 2); /* Set Colour Depth */
82
83 switch (par->info->var.rotate) {
84 case 0:
85 write_reg(par, 0xA0, remap | 0x00 | BIT(4));
86 break;
87 case 270:
88 write_reg(par, 0xA0, remap | 0x03 | BIT(4));
89 break;
90 case 180:
91 write_reg(par, 0xA0, remap | 0x02);
92 break;
93 case 90:
94 write_reg(par, 0xA0, remap | 0x01);
95 break;
96 }
97
98 return 0;
99}
100
101/*
102 * Grayscale Lookup Table
103 * GS1 - GS63
104 * The driver Gamma curve contains the relative values between the entries
105 * in the Lookup table.
106 *
107 * From datasheet:
108 * 8.8 Gray Scale Decoder
109 *
110 * there are total 180 Gamma Settings (Setting 0 to Setting 180)
111 * available for the Gray Scale table.
112 *
113 * The gray scale is defined in incremental way, with reference
114 * to the length of previous table entry:
115 * Setting of GS1 has to be >= 0
116 * Setting of GS2 has to be > Setting of GS1 +1
117 * Setting of GS3 has to be > Setting of GS2 +1
118 * :
119 * Setting of GS63 has to be > Setting of GS62 +1
120 *
121 */
122static int set_gamma(struct fbtft_par *par, u32 *curves)
123{
124 unsigned long tmp[GAMMA_NUM * GAMMA_LEN];
125 int i, acc = 0;
126
127 for (i = 0; i < 63; i++) {
128 if (i > 0 && curves[i] < 2) {
129 dev_err(par->info->device,
130 "Illegal value in Grayscale Lookup Table at index %d : %d. Must be greater than 1\n",
131 i, curves[i]);
132 return -EINVAL;
133 }
134 acc += curves[i];
135 tmp[i] = acc;
136 if (acc > 180) {
137 dev_err(par->info->device,
138 "Illegal value(s) in Grayscale Lookup Table. At index=%d : %d, the accumulated value has exceeded 180\n",
139 i, acc);
140 return -EINVAL;
141 }
142 }
143
144 write_reg(par, 0xB8,
145 tmp[0], tmp[1], tmp[2], tmp[3],
146 tmp[4], tmp[5], tmp[6], tmp[7],
147 tmp[8], tmp[9], tmp[10], tmp[11],
148 tmp[12], tmp[13], tmp[14], tmp[15],
149 tmp[16], tmp[17], tmp[18], tmp[19],
150 tmp[20], tmp[21], tmp[22], tmp[23],
151 tmp[24], tmp[25], tmp[26], tmp[27],
152 tmp[28], tmp[29], tmp[30], tmp[31],
153 tmp[32], tmp[33], tmp[34], tmp[35],
154 tmp[36], tmp[37], tmp[38], tmp[39],
155 tmp[40], tmp[41], tmp[42], tmp[43],
156 tmp[44], tmp[45], tmp[46], tmp[47],
157 tmp[48], tmp[49], tmp[50], tmp[51],
158 tmp[52], tmp[53], tmp[54], tmp[55],
159 tmp[56], tmp[57], tmp[58], tmp[59],
160 tmp[60], tmp[61], tmp[62]);
161
162 return 0;
163}
164
165static int blank(struct fbtft_par *par, bool on)
166{
167 fbtft_par_dbg(DEBUG_BLANK, par, "(%s=%s)\n",
168 __func__, on ? "true" : "false");
169 if (on)
170 write_reg(par, 0xAE);
171 else
172 write_reg(par, 0xAF);
173 return 0;
174}
175
176static struct fbtft_display display = {
177 .regwidth = 8,
178 .width = WIDTH,
179 .height = HEIGHT,
180 .gamma_num = GAMMA_NUM,
181 .gamma_len = GAMMA_LEN,
182 .gamma = DEFAULT_GAMMA,
183 .fbtftops = {
184 .init_display = init_display,
185 .set_addr_win = set_addr_win,
186 .set_var = set_var,
187 .set_gamma = set_gamma,
188 .blank = blank,
189 },
190};
191
192static int update_onboard_backlight(struct backlight_device *bd)
193{
194 struct fbtft_par *par = bl_get_data(bl_dev: bd);
195 bool on;
196
197 fbtft_par_dbg(DEBUG_BACKLIGHT, par,
198 "%s: power=%d, fb_blank=%d\n",
199 __func__, bd->props.power, bd->props.fb_blank);
200
201 on = !backlight_is_blank(bd);
202 /* Onboard backlight connected to GPIO0 on SSD1351, GPIO1 unused */
203 write_reg(par, 0xB5, on ? 0x03 : 0x02);
204
205 return 0;
206}
207
208static const struct backlight_ops bl_ops = {
209 .update_status = update_onboard_backlight,
210};
211
212static void register_onboard_backlight(struct fbtft_par *par)
213{
214 struct backlight_device *bd;
215 struct backlight_properties bl_props = { 0, };
216
217 bl_props.type = BACKLIGHT_RAW;
218 bl_props.power = FB_BLANK_POWERDOWN;
219
220 bd = backlight_device_register(name: dev_driver_string(dev: par->info->device),
221 dev: par->info->device, devdata: par, ops: &bl_ops,
222 props: &bl_props);
223 if (IS_ERR(ptr: bd)) {
224 dev_err(par->info->device,
225 "cannot register backlight device (%ld)\n",
226 PTR_ERR(bd));
227 return;
228 }
229 par->info->bl_dev = bd;
230
231 if (!par->fbtftops.unregister_backlight)
232 par->fbtftops.unregister_backlight = fbtft_unregister_backlight;
233}
234
235FBTFT_REGISTER_DRIVER(DRVNAME, "solomon,ssd1351", &display);
236
237MODULE_ALIAS("spi:" DRVNAME);
238MODULE_ALIAS("platform:" DRVNAME);
239MODULE_ALIAS("spi:ssd1351");
240MODULE_ALIAS("platform:ssd1351");
241
242MODULE_DESCRIPTION("SSD1351 OLED Driver");
243MODULE_AUTHOR("James Davies");
244MODULE_LICENSE("GPL");
245

source code of linux/drivers/staging/fbtft/fb_ssd1351.c