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