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 */
55enum 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
76static struct completion panel_te; /* completion for panel TE line */
77static int irq_te; /* Linux IRQ for LCD TE line */
78
79static 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 */
91static 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 */
143static 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 */
228static 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 */
271static 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 */
310static 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 */
360static 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
369static 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
385FBTFT_REGISTER_DRIVER(DRVNAME, "sitronix,st7789v", &display);
386
387MODULE_ALIAS("spi:" DRVNAME);
388MODULE_ALIAS("platform:" DRVNAME);
389MODULE_ALIAS("spi:st7789v");
390MODULE_ALIAS("platform:st7789v");
391
392MODULE_DESCRIPTION("FB driver for the ST7789V LCD Controller");
393MODULE_AUTHOR("Dennis Menschel");
394MODULE_LICENSE("GPL");
395