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> 7 8 #include "fbtft.h" 9 10 #define DRVNAME "fb_ssd1351" 11 #define WIDTH 128 12 #define HEIGHT 128 13 #define GAMMA_NUM 1 14 #define GAMMA_LEN 63 15 #define DEFAULT_GAMMA "0 2 2 2 2 2 2 2 " \ 16 "2 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" \ 23 24 static void register_onboard_backlight(struct fbtft_par *par); 25 26 static int init_display(struct fbtft_par *par) 27 { 28 if (par->pdata && 29 par->pdata->display.backlight == FBTFT_ONBOARD_BACKLIGHT) { 30 /* module uses onboard GPIO for panel power */ 31 par->fbtftops.register_backlight = register_onboard_backlight; 32 } 33 34 par->fbtftops.reset(par); 35 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 */ 56 57 return 0; 58 } 59 60 static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye) 61 { 62 write_reg(par, 0x15, xs, xe); 63 write_reg(par, 0x75, ys, ye); 64 write_reg(par, 0x5c); 65 } 66 67 static int set_var(struct fbtft_par *par) 68 { 69 unsigned int remap; 70 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", 75 __func__); 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 */ 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 } 162 163 static int blank(struct fbtft_par *par, bool on) 164 { 165 fbtft_par_dbg(DEBUG_BLANK, par, "(%s=%s)\n", 166 __func__, on ? "true" : "false"); 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 }; 189 190 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, 196 "%s: power=%d, fb_blank=%d\n", 197 __func__, bd->props.power, bd->props.fb_blank); 198 199 on = !backlight_is_blank(bd); 200 /* Onboard backlight connected to GPIO0 on SSD1351, GPIO1 unused */ 201 write_reg(par, 0xB5, on ? 0x03 : 0x02); 202 203 return 0; 204 } 205 206 static const struct backlight_ops bl_ops = { 207 .update_status = update_onboard_backlight, 208 }; 209 210 static void register_onboard_backlight(struct fbtft_par *par) 211 { 212 struct backlight_device *bd; 213 struct backlight_properties bl_props = { 0, }; 214 215 bl_props.type = BACKLIGHT_RAW; 216 bl_props.power = FB_BLANK_POWERDOWN; 217 218 bd = backlight_device_register(dev_driver_string(par->info->device), 219 par->info->device, par, &bl_ops, 220 &bl_props); 221 if (IS_ERR(bd)) { 222 dev_err(par->info->device, 223 "cannot register backlight device (%ld)\n", 224 PTR_ERR(bd)); 225 return; 226 } 227 par->info->bl_dev = bd; 228 229 if (!par->fbtftops.unregister_backlight) 230 par->fbtftops.unregister_backlight = fbtft_unregister_backlight; 231 } 232 233 FBTFT_REGISTER_DRIVER(DRVNAME, "solomon,ssd1351", &display); 234 235 MODULE_ALIAS("spi:" DRVNAME); 236 MODULE_ALIAS("platform:" DRVNAME); 237 MODULE_ALIAS("spi:ssd1351"); 238 MODULE_ALIAS("platform:ssd1351"); 239 240 MODULE_DESCRIPTION("SSD1351 OLED Driver"); 241 MODULE_AUTHOR("James Davies"); 242 MODULE_LICENSE("GPL"); 243