1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * FB driver for the ST7789V LCD Controller
4 *
5 * Copyright (C) 2015 Dennis Menschel
6 */
7
8 #include <linux/bitops.h>
9 #include <linux/delay.h>
10 #include <linux/gpio/consumer.h>
11 #include <linux/init.h>
12 #include <linux/kernel.h>
13 #include <linux/interrupt.h>
14 #include <linux/completion.h>
15 #include <linux/module.h>
16
17 #include <video/mipi_display.h>
18
19 #include "fbtft.h"
20
21 #define DRVNAME "fb_st7789v"
22
23 #define DEFAULT_GAMMA \
24 "70 2C 2E 15 10 09 48 33 53 0B 19 18 20 25\n" \
25 "70 2C 2E 15 10 09 48 33 53 0B 19 18 20 25"
26
27 #define HSD20_IPS_GAMMA \
28 "D0 05 0A 09 08 05 2E 44 45 0F 17 16 2B 33\n" \
29 "D0 05 0A 09 08 05 2E 43 45 0F 16 16 2B 33"
30
31 #define HSD20_IPS 1
32
33 /**
34 * enum st7789v_command - ST7789V display controller commands
35 *
36 * @PORCTRL: porch setting
37 * @GCTRL: gate control
38 * @VCOMS: VCOM setting
39 * @VDVVRHEN: VDV and VRH command enable
40 * @VRHS: VRH set
41 * @VDVS: VDV set
42 * @VCMOFSET: VCOM offset set
43 * @PWCTRL1: power control 1
44 * @PVGAMCTRL: positive voltage gamma control
45 * @NVGAMCTRL: negative voltage gamma control
46 *
47 * The command names are the same as those found in the datasheet to ease
48 * looking up their semantics and usage.
49 *
50 * Note that the ST7789V display controller offers quite a few more commands
51 * which have been omitted from this list as they are not used at the moment.
52 * Furthermore, commands that are compliant with the MIPI DCS have been left
53 * out as well to avoid duplicate entries.
54 */
55 enum st7789v_command {
56 PORCTRL = 0xB2,
57 GCTRL = 0xB7,
58 VCOMS = 0xBB,
59 VDVVRHEN = 0xC2,
60 VRHS = 0xC3,
61 VDVS = 0xC4,
62 VCMOFSET = 0xC5,
63 PWCTRL1 = 0xD0,
64 PVGAMCTRL = 0xE0,
65 NVGAMCTRL = 0xE1,
66 };
67
68 #define MADCTL_BGR BIT(3) /* bitmask for RGB/BGR order */
69 #define MADCTL_MV BIT(5) /* bitmask for page/column order */
70 #define MADCTL_MX BIT(6) /* bitmask for column address order */
71 #define MADCTL_MY BIT(7) /* bitmask for page address order */
72
73 /* 60Hz for 16.6ms, configured as 2*16.6ms */
74 #define PANEL_TE_TIMEOUT_MS 33
75
76 static struct completion panel_te; /* completion for panel TE line */
77 static int irq_te; /* Linux IRQ for LCD TE line */
78
panel_te_handler(int irq,void * data)79 static irqreturn_t panel_te_handler(int irq, void *data)
80 {
81 complete(&panel_te);
82 return IRQ_HANDLED;
83 }
84
85 /*
86 * init_tearing_effect_line() - init tearing effect line.
87 * @par: FBTFT parameter object.
88 *
89 * Return: 0 on success, or a negative error code otherwise.
90 */
init_tearing_effect_line(struct fbtft_par * par)91 static int init_tearing_effect_line(struct fbtft_par *par)
92 {
93 struct device *dev = par->info->device;
94 struct gpio_desc *te;
95 int rc, irq;
96
97 te = gpiod_get_optional(dev, "te", GPIOD_IN);
98 if (IS_ERR(te))
99 return dev_err_probe(dev, PTR_ERR(te), "Failed to request te GPIO\n");
100
101 /* if te is NULL, indicating no configuration, directly return success */
102 if (!te) {
103 irq_te = 0;
104 return 0;
105 }
106
107 irq = gpiod_to_irq(te);
108
109 /* GPIO is locked as an IRQ, we may drop the reference */
110 gpiod_put(te);
111
112 if (irq < 0)
113 return irq;
114
115 irq_te = irq;
116 init_completion(&panel_te);
117
118 /* The effective state is high and lasts no more than 1000 microseconds */
119 rc = devm_request_irq(dev, irq_te, panel_te_handler,
120 IRQF_TRIGGER_RISING, "TE_GPIO", par);
121 if (rc)
122 return dev_err_probe(dev, rc, "TE IRQ request failed.\n");
123
124 disable_irq_nosync(irq_te);
125
126 return 0;
127 }
128
129 /**
130 * init_display() - initialize the display controller
131 *
132 * @par: FBTFT parameter object
133 *
134 * Most of the commands in this init function set their parameters to the
135 * same default values which are already in place after the display has been
136 * powered up. (The main exception to this rule is the pixel format which
137 * would default to 18 instead of 16 bit per pixel.)
138 * Nonetheless, this sequence can be used as a template for concrete
139 * displays which usually need some adjustments.
140 *
141 * Return: 0 on success, < 0 if error occurred.
142 */
init_display(struct fbtft_par * par)143 static int init_display(struct fbtft_par *par)
144 {
145 int rc;
146
147 par->fbtftops.reset(par);
148
149 rc = init_tearing_effect_line(par);
150 if (rc)
151 return rc;
152
153 /* turn off sleep mode */
154 write_reg(par, MIPI_DCS_EXIT_SLEEP_MODE);
155 mdelay(120);
156
157 /* set pixel format to RGB-565 */
158 write_reg(par, MIPI_DCS_SET_PIXEL_FORMAT, MIPI_DCS_PIXEL_FMT_16BIT);
159 if (HSD20_IPS)
160 write_reg(par, PORCTRL, 0x05, 0x05, 0x00, 0x33, 0x33);
161
162 else
163 write_reg(par, PORCTRL, 0x08, 0x08, 0x00, 0x22, 0x22);
164
165 /*
166 * VGH = 13.26V
167 * VGL = -10.43V
168 */
169 if (HSD20_IPS)
170 write_reg(par, GCTRL, 0x75);
171 else
172 write_reg(par, GCTRL, 0x35);
173
174 /*
175 * VDV and VRH register values come from command write
176 * (instead of NVM)
177 */
178 write_reg(par, VDVVRHEN, 0x01, 0xFF);
179
180 /*
181 * VAP = 4.1V + (VCOM + VCOM offset + 0.5 * VDV)
182 * VAN = -4.1V + (VCOM + VCOM offset + 0.5 * VDV)
183 */
184 if (HSD20_IPS)
185 write_reg(par, VRHS, 0x13);
186 else
187 write_reg(par, VRHS, 0x0B);
188
189 /* VDV = 0V */
190 write_reg(par, VDVS, 0x20);
191
192 /* VCOM = 0.9V */
193 if (HSD20_IPS)
194 write_reg(par, VCOMS, 0x22);
195 else
196 write_reg(par, VCOMS, 0x20);
197
198 /* VCOM offset = 0V */
199 write_reg(par, VCMOFSET, 0x20);
200
201 /*
202 * AVDD = 6.8V
203 * AVCL = -4.8V
204 * VDS = 2.3V
205 */
206 write_reg(par, PWCTRL1, 0xA4, 0xA1);
207
208 /* TE line output is off by default when powering on */
209 if (irq_te)
210 write_reg(par, MIPI_DCS_SET_TEAR_ON, 0x00);
211
212 write_reg(par, MIPI_DCS_SET_DISPLAY_ON);
213
214 if (HSD20_IPS)
215 write_reg(par, MIPI_DCS_ENTER_INVERT_MODE);
216
217 return 0;
218 }
219
220 /*
221 * write_vmem() - write data to display.
222 * @par: FBTFT parameter object.
223 * @offset: offset from screen_buffer.
224 * @len: the length of data to be writte.
225 *
226 * Return: 0 on success, or a negative error code otherwise.
227 */
write_vmem(struct fbtft_par * par,size_t offset,size_t len)228 static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
229 {
230 struct device *dev = par->info->device;
231 int ret;
232
233 if (irq_te) {
234 enable_irq(irq_te);
235 reinit_completion(&panel_te);
236 ret = wait_for_completion_timeout(&panel_te,
237 msecs_to_jiffies(PANEL_TE_TIMEOUT_MS));
238 if (ret == 0)
239 dev_err(dev, "wait panel TE timeout\n");
240
241 disable_irq(irq_te);
242 }
243
244 switch (par->pdata->display.buswidth) {
245 case 8:
246 ret = fbtft_write_vmem16_bus8(par, offset, len);
247 break;
248 case 9:
249 ret = fbtft_write_vmem16_bus9(par, offset, len);
250 break;
251 case 16:
252 ret = fbtft_write_vmem16_bus16(par, offset, len);
253 break;
254 default:
255 dev_err(dev, "Unsupported buswidth %d\n",
256 par->pdata->display.buswidth);
257 ret = 0;
258 break;
259 }
260
261 return ret;
262 }
263
264 /**
265 * set_var() - apply LCD properties like rotation and BGR mode
266 *
267 * @par: FBTFT parameter object
268 *
269 * Return: 0 on success, < 0 if error occurred.
270 */
set_var(struct fbtft_par * par)271 static int set_var(struct fbtft_par *par)
272 {
273 u8 madctl_par = 0;
274
275 if (par->bgr)
276 madctl_par |= MADCTL_BGR;
277 switch (par->info->var.rotate) {
278 case 0:
279 break;
280 case 90:
281 madctl_par |= (MADCTL_MV | MADCTL_MY);
282 break;
283 case 180:
284 madctl_par |= (MADCTL_MX | MADCTL_MY);
285 break;
286 case 270:
287 madctl_par |= (MADCTL_MV | MADCTL_MX);
288 break;
289 default:
290 return -EINVAL;
291 }
292 write_reg(par, MIPI_DCS_SET_ADDRESS_MODE, madctl_par);
293 return 0;
294 }
295
296 /**
297 * set_gamma() - set gamma curves
298 *
299 * @par: FBTFT parameter object
300 * @curves: gamma curves
301 *
302 * Before the gamma curves are applied, they are preprocessed with a bitmask
303 * to ensure syntactically correct input for the display controller.
304 * This implies that the curves input parameter might be changed by this
305 * function and that illegal gamma values are auto-corrected and not
306 * reported as errors.
307 *
308 * Return: 0 on success, < 0 if error occurred.
309 */
set_gamma(struct fbtft_par * par,u32 * curves)310 static int set_gamma(struct fbtft_par *par, u32 *curves)
311 {
312 int i;
313 int j;
314 int c; /* curve index offset */
315
316 /*
317 * Bitmasks for gamma curve command parameters.
318 * The masks are the same for both positive and negative voltage
319 * gamma curves.
320 */
321 static const u8 gamma_par_mask[] = {
322 0xFF, /* V63[3:0], V0[3:0]*/
323 0x3F, /* V1[5:0] */
324 0x3F, /* V2[5:0] */
325 0x1F, /* V4[4:0] */
326 0x1F, /* V6[4:0] */
327 0x3F, /* J0[1:0], V13[3:0] */
328 0x7F, /* V20[6:0] */
329 0x77, /* V36[2:0], V27[2:0] */
330 0x7F, /* V43[6:0] */
331 0x3F, /* J1[1:0], V50[3:0] */
332 0x1F, /* V57[4:0] */
333 0x1F, /* V59[4:0] */
334 0x3F, /* V61[5:0] */
335 0x3F, /* V62[5:0] */
336 };
337
338 for (i = 0; i < par->gamma.num_curves; i++) {
339 c = i * par->gamma.num_values;
340 for (j = 0; j < par->gamma.num_values; j++)
341 curves[c + j] &= gamma_par_mask[j];
342 write_reg(par, PVGAMCTRL + i,
343 curves[c + 0], curves[c + 1], curves[c + 2],
344 curves[c + 3], curves[c + 4], curves[c + 5],
345 curves[c + 6], curves[c + 7], curves[c + 8],
346 curves[c + 9], curves[c + 10], curves[c + 11],
347 curves[c + 12], curves[c + 13]);
348 }
349 return 0;
350 }
351
352 /**
353 * blank() - blank the display
354 *
355 * @par: FBTFT parameter object
356 * @on: whether to enable or disable blanking the display
357 *
358 * Return: 0 on success, < 0 if error occurred.
359 */
blank(struct fbtft_par * par,bool on)360 static int blank(struct fbtft_par *par, bool on)
361 {
362 if (on)
363 write_reg(par, MIPI_DCS_SET_DISPLAY_OFF);
364 else
365 write_reg(par, MIPI_DCS_SET_DISPLAY_ON);
366 return 0;
367 }
368
369 static struct fbtft_display display = {
370 .regwidth = 8,
371 .width = 240,
372 .height = 320,
373 .gamma_num = 2,
374 .gamma_len = 14,
375 .gamma = HSD20_IPS_GAMMA,
376 .fbtftops = {
377 .init_display = init_display,
378 .write_vmem = write_vmem,
379 .set_var = set_var,
380 .set_gamma = set_gamma,
381 .blank = blank,
382 },
383 };
384
385 FBTFT_REGISTER_DRIVER(DRVNAME, "sitronix,st7789v", &display);
386
387 MODULE_ALIAS("spi:" DRVNAME);
388 MODULE_ALIAS("platform:" DRVNAME);
389 MODULE_ALIAS("spi:st7789v");
390 MODULE_ALIAS("platform:st7789v");
391
392 MODULE_DESCRIPTION("FB driver for the ST7789V LCD Controller");
393 MODULE_AUTHOR("Dennis Menschel");
394 MODULE_LICENSE("GPL");
395