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
26 static void register_onboard_backlight(struct fbtft_par *par);
27
init_display(struct fbtft_par * par)28 static 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
set_addr_win(struct fbtft_par * par,int xs,int ys,int xe,int ye)62 static 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
set_var(struct fbtft_par * par)69 static 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 return 0;
76 }
77
78 remap = 0x60 | (par->bgr << 2); /* Set Colour Depth */
79
80 switch (par->info->var.rotate) {
81 case 0:
82 write_reg(par, 0xA0, remap | 0x00 | BIT(4));
83 break;
84 case 270:
85 write_reg(par, 0xA0, remap | 0x03 | BIT(4));
86 break;
87 case 180:
88 write_reg(par, 0xA0, remap | 0x02);
89 break;
90 case 90:
91 write_reg(par, 0xA0, remap | 0x01);
92 break;
93 }
94
95 return 0;
96 }
97
98 /*
99 * Grayscale Lookup Table
100 * GS1 - GS63
101 * The driver Gamma curve contains the relative values between the entries
102 * in the Lookup table.
103 *
104 * From datasheet:
105 * 8.8 Gray Scale Decoder
106 *
107 * there are total 180 Gamma Settings (Setting 0 to Setting 180)
108 * available for the Gray Scale table.
109 *
110 * The gray scale is defined in incremental way, with reference
111 * to the length of previous table entry:
112 * Setting of GS1 has to be >= 0
113 * Setting of GS2 has to be > Setting of GS1 +1
114 * Setting of GS3 has to be > Setting of GS2 +1
115 * :
116 * Setting of GS63 has to be > Setting of GS62 +1
117 *
118 */
set_gamma(struct fbtft_par * par,u32 * curves)119 static int set_gamma(struct fbtft_par *par, u32 *curves)
120 {
121 unsigned long tmp[GAMMA_NUM * GAMMA_LEN];
122 int i, acc = 0;
123
124 for (i = 0; i < 63; i++) {
125 if (i > 0 && curves[i] < 2) {
126 dev_err(par->info->device,
127 "Illegal value in Grayscale Lookup Table at index %d : %d. Must be greater than 1\n",
128 i, curves[i]);
129 return -EINVAL;
130 }
131 acc += curves[i];
132 tmp[i] = acc;
133 if (acc > 180) {
134 dev_err(par->info->device,
135 "Illegal value(s) in Grayscale Lookup Table. At index=%d : %d, the accumulated value has exceeded 180\n",
136 i, acc);
137 return -EINVAL;
138 }
139 }
140
141 write_reg(par, 0xB8,
142 tmp[0], tmp[1], tmp[2], tmp[3],
143 tmp[4], tmp[5], tmp[6], tmp[7],
144 tmp[8], tmp[9], tmp[10], tmp[11],
145 tmp[12], tmp[13], tmp[14], tmp[15],
146 tmp[16], tmp[17], tmp[18], tmp[19],
147 tmp[20], tmp[21], tmp[22], tmp[23],
148 tmp[24], tmp[25], tmp[26], tmp[27],
149 tmp[28], tmp[29], tmp[30], tmp[31],
150 tmp[32], tmp[33], tmp[34], tmp[35],
151 tmp[36], tmp[37], tmp[38], tmp[39],
152 tmp[40], tmp[41], tmp[42], tmp[43],
153 tmp[44], tmp[45], tmp[46], tmp[47],
154 tmp[48], tmp[49], tmp[50], tmp[51],
155 tmp[52], tmp[53], tmp[54], tmp[55],
156 tmp[56], tmp[57], tmp[58], tmp[59],
157 tmp[60], tmp[61], tmp[62]);
158
159 return 0;
160 }
161
blank(struct fbtft_par * par,bool on)162 static int blank(struct fbtft_par *par, bool on)
163 {
164 fbtft_par_dbg(DEBUG_BLANK, par, "(%s=%s)\n",
165 __func__, on ? "true" : "false");
166 if (on)
167 write_reg(par, 0xAE);
168 else
169 write_reg(par, 0xAF);
170 return 0;
171 }
172
173 static struct fbtft_display display = {
174 .regwidth = 8,
175 .width = WIDTH,
176 .height = HEIGHT,
177 .gamma_num = GAMMA_NUM,
178 .gamma_len = GAMMA_LEN,
179 .gamma = DEFAULT_GAMMA,
180 .fbtftops = {
181 .init_display = init_display,
182 .set_addr_win = set_addr_win,
183 .set_var = set_var,
184 .set_gamma = set_gamma,
185 .blank = blank,
186 },
187 };
188
update_onboard_backlight(struct backlight_device * bd)189 static int update_onboard_backlight(struct backlight_device *bd)
190 {
191 struct fbtft_par *par = bl_get_data(bd);
192 bool on;
193
194 fbtft_par_dbg(DEBUG_BACKLIGHT, par, "%s: power=%d\n", __func__, bd->props.power);
195
196 on = !backlight_is_blank(bd);
197 /* Onboard backlight connected to GPIO0 on SSD1351, GPIO1 unused */
198 write_reg(par, 0xB5, on ? 0x03 : 0x02);
199
200 return 0;
201 }
202
203 static const struct backlight_ops bl_ops = {
204 .update_status = update_onboard_backlight,
205 };
206
register_onboard_backlight(struct fbtft_par * par)207 static void register_onboard_backlight(struct fbtft_par *par)
208 {
209 struct backlight_device *bd;
210 struct backlight_properties bl_props = { 0, };
211
212 bl_props.type = BACKLIGHT_RAW;
213 bl_props.power = BACKLIGHT_POWER_OFF;
214
215 bd = backlight_device_register(dev_driver_string(par->info->device),
216 par->info->device, par, &bl_ops,
217 &bl_props);
218 if (IS_ERR(bd)) {
219 dev_err(par->info->device,
220 "cannot register backlight device (%ld)\n",
221 PTR_ERR(bd));
222 return;
223 }
224 par->info->bl_dev = bd;
225
226 if (!par->fbtftops.unregister_backlight)
227 par->fbtftops.unregister_backlight = fbtft_unregister_backlight;
228 }
229
230 FBTFT_REGISTER_DRIVER(DRVNAME, "solomon,ssd1351", &display);
231
232 MODULE_ALIAS("spi:" DRVNAME);
233 MODULE_ALIAS("platform:" DRVNAME);
234 MODULE_ALIAS("spi:ssd1351");
235 MODULE_ALIAS("platform:ssd1351");
236
237 MODULE_DESCRIPTION("SSD1351 OLED Driver");
238 MODULE_AUTHOR("James Davies");
239 MODULE_LICENSE("GPL");
240