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