1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * FB driver for the Watterott LCD Controller
4 *
5 * Copyright (C) 2013 Noralf Tronnes
6 */
7
8 #include <linux/module.h>
9 #include <linux/kernel.h>
10 #include <linux/init.h>
11 #include <linux/gpio/consumer.h>
12 #include <linux/delay.h>
13
14 #include "fbtft.h"
15
16 #define DRVNAME "fb_watterott"
17 #define WIDTH 320
18 #define HEIGHT 240
19 #define FPS 5
20 #define TXBUFLEN 1024
21 #define DEFAULT_BRIGHTNESS 50
22
23 #define CMD_VERSION 0x01
24 #define CMD_LCD_LED 0x10
25 #define CMD_LCD_RESET 0x11
26 #define CMD_LCD_ORIENTATION 0x20
27 #define CMD_LCD_DRAWIMAGE 0x27
28 #define COLOR_RGB323 8
29 #define COLOR_RGB332 9
30 #define COLOR_RGB233 10
31 #define COLOR_RGB565 16
32
33 static short mode = 565;
34 module_param(mode, short, 0000);
35 MODULE_PARM_DESC(mode, "RGB color transfer mode: 332, 565 (default)");
36
write_reg8_bus8(struct fbtft_par * par,int len,...)37 static void write_reg8_bus8(struct fbtft_par *par, int len, ...)
38 {
39 va_list args;
40 int i, ret;
41 u8 *buf = par->buf;
42
43 va_start(args, len);
44 for (i = 0; i < len; i++)
45 *buf++ = (u8)va_arg(args, unsigned int);
46 va_end(args);
47
48 fbtft_par_dbg_hex(DEBUG_WRITE_REGISTER, par,
49 par->info->device, u8, par->buf,
50 len, "%s: ", __func__);
51
52 ret = par->fbtftops.write(par, par->buf, len);
53 if (ret < 0) {
54 dev_err(par->info->device,
55 "write() failed and returned %d\n", ret);
56 return;
57 }
58 }
59
write_vmem(struct fbtft_par * par,size_t offset,size_t len)60 static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
61 {
62 unsigned int start_line, end_line;
63 u16 *vmem16 = (u16 *)(par->info->screen_buffer + offset);
64 __be16 *pos = par->txbuf.buf + 1;
65 __be16 *buf16 = par->txbuf.buf + 10;
66 int i, j;
67 int ret = 0;
68
69 start_line = offset / par->info->fix.line_length;
70 end_line = start_line + (len / par->info->fix.line_length) - 1;
71
72 /* Set command header. pos: x, y, w, h */
73 ((u8 *)par->txbuf.buf)[0] = CMD_LCD_DRAWIMAGE;
74 pos[0] = 0;
75 pos[2] = cpu_to_be16(par->info->var.xres);
76 pos[3] = cpu_to_be16(1);
77 ((u8 *)par->txbuf.buf)[9] = COLOR_RGB565;
78
79 for (i = start_line; i <= end_line; i++) {
80 pos[1] = cpu_to_be16(i);
81 for (j = 0; j < par->info->var.xres; j++)
82 buf16[j] = cpu_to_be16(*vmem16++);
83 ret = par->fbtftops.write(par,
84 par->txbuf.buf, 10 + par->info->fix.line_length);
85 if (ret < 0)
86 return ret;
87 udelay(300);
88 }
89
90 return 0;
91 }
92
rgb565_to_rgb332(u16 c)93 static inline int rgb565_to_rgb332(u16 c)
94 {
95 return ((c & 0xE000) >> 8) | ((c & 000700) >> 6) | ((c & 0x0018) >> 3);
96 }
97
write_vmem_8bit(struct fbtft_par * par,size_t offset,size_t len)98 static int write_vmem_8bit(struct fbtft_par *par, size_t offset, size_t len)
99 {
100 unsigned int start_line, end_line;
101 u16 *vmem16 = (u16 *)(par->info->screen_buffer + offset);
102 __be16 *pos = par->txbuf.buf + 1;
103 u8 *buf8 = par->txbuf.buf + 10;
104 int i, j;
105 int ret = 0;
106
107 start_line = offset / par->info->fix.line_length;
108 end_line = start_line + (len / par->info->fix.line_length) - 1;
109
110 /* Set command header. pos: x, y, w, h */
111 ((u8 *)par->txbuf.buf)[0] = CMD_LCD_DRAWIMAGE;
112 pos[0] = 0;
113 pos[2] = cpu_to_be16(par->info->var.xres);
114 pos[3] = cpu_to_be16(1);
115 ((u8 *)par->txbuf.buf)[9] = COLOR_RGB332;
116
117 for (i = start_line; i <= end_line; i++) {
118 pos[1] = cpu_to_be16(i);
119 for (j = 0; j < par->info->var.xres; j++) {
120 buf8[j] = rgb565_to_rgb332(*vmem16);
121 vmem16++;
122 }
123 ret = par->fbtftops.write(par,
124 par->txbuf.buf, 10 + par->info->var.xres);
125 if (ret < 0)
126 return ret;
127 udelay(700);
128 }
129
130 return 0;
131 }
132
firmware_version(struct fbtft_par * par)133 static unsigned int firmware_version(struct fbtft_par *par)
134 {
135 u8 rxbuf[4] = {0, };
136
137 write_reg(par, CMD_VERSION);
138 par->fbtftops.read(par, rxbuf, 4);
139 if (rxbuf[1] != '.')
140 return 0;
141
142 return (rxbuf[0] - '0') << 8 | (rxbuf[2] - '0') << 4 | (rxbuf[3] - '0');
143 }
144
init_display(struct fbtft_par * par)145 static int init_display(struct fbtft_par *par)
146 {
147 int ret;
148 unsigned int version;
149 u8 save_mode;
150
151 /* enable SPI interface by having CS and MOSI low during reset */
152 save_mode = par->spi->mode;
153 /*
154 * Set CS active inverse polarity: just setting SPI_CS_HIGH does not
155 * work with GPIO based chip selects that are logically active high
156 * but inverted inside the GPIO library, so enforce inverted
157 * semantics.
158 */
159 par->spi->mode ^= SPI_CS_HIGH;
160 ret = spi_setup(par->spi);
161 if (ret) {
162 dev_err(par->info->device,
163 "Could not set inverse CS polarity\n");
164 return ret;
165 }
166 write_reg(par, 0x00); /* make sure mode is set */
167
168 mdelay(50);
169 par->fbtftops.reset(par);
170 mdelay(1000);
171 par->spi->mode = save_mode;
172 ret = spi_setup(par->spi);
173 if (ret) {
174 dev_err(par->info->device, "Could not restore SPI mode\n");
175 return ret;
176 }
177 write_reg(par, 0x00);
178
179 version = firmware_version(par);
180 fbtft_par_dbg(DEBUG_INIT_DISPLAY, par, "Firmware version: %x.%02x\n",
181 version >> 8, version & 0xFF);
182
183 if (mode == 332)
184 par->fbtftops.write_vmem = write_vmem_8bit;
185 return 0;
186 }
187
set_addr_win(struct fbtft_par * par,int xs,int ys,int xe,int ye)188 static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
189 {
190 /* not used on this controller */
191 }
192
set_var(struct fbtft_par * par)193 static int set_var(struct fbtft_par *par)
194 {
195 u8 rotate;
196
197 /* this controller rotates clock wise */
198 switch (par->info->var.rotate) {
199 case 90:
200 rotate = 27;
201 break;
202 case 180:
203 rotate = 18;
204 break;
205 case 270:
206 rotate = 9;
207 break;
208 default:
209 rotate = 0;
210 }
211 write_reg(par, CMD_LCD_ORIENTATION, rotate);
212
213 return 0;
214 }
215
verify_gpios(struct fbtft_par * par)216 static int verify_gpios(struct fbtft_par *par)
217 {
218 if (!par->gpio.reset) {
219 dev_err(par->info->device, "Missing 'reset' gpio. Aborting.\n");
220 return -EINVAL;
221 }
222 return 0;
223 }
224
225 #ifdef CONFIG_FB_BACKLIGHT
backlight_chip_update_status(struct backlight_device * bd)226 static int backlight_chip_update_status(struct backlight_device *bd)
227 {
228 struct fbtft_par *par = bl_get_data(bd);
229 int brightness = bd->props.brightness;
230
231 fbtft_par_dbg(DEBUG_BACKLIGHT, par,
232 "%s: brightness=%d, power=%d, fb_blank=%d\n", __func__,
233 bd->props.brightness, bd->props.power,
234 bd->props.fb_blank);
235
236 if (bd->props.power != FB_BLANK_UNBLANK)
237 brightness = 0;
238
239 if (bd->props.fb_blank != FB_BLANK_UNBLANK)
240 brightness = 0;
241
242 write_reg(par, CMD_LCD_LED, brightness);
243
244 return 0;
245 }
246
247 static const struct backlight_ops bl_ops = {
248 .update_status = backlight_chip_update_status,
249 };
250
register_chip_backlight(struct fbtft_par * par)251 static void register_chip_backlight(struct fbtft_par *par)
252 {
253 struct backlight_device *bd;
254 struct backlight_properties bl_props = { 0, };
255
256 bl_props.type = BACKLIGHT_RAW;
257 bl_props.power = FB_BLANK_POWERDOWN;
258 bl_props.max_brightness = 100;
259 bl_props.brightness = DEFAULT_BRIGHTNESS;
260
261 bd = backlight_device_register(dev_driver_string(par->info->device),
262 par->info->device, par, &bl_ops,
263 &bl_props);
264 if (IS_ERR(bd)) {
265 dev_err(par->info->device,
266 "cannot register backlight device (%ld)\n",
267 PTR_ERR(bd));
268 return;
269 }
270 par->info->bl_dev = bd;
271
272 if (!par->fbtftops.unregister_backlight)
273 par->fbtftops.unregister_backlight = fbtft_unregister_backlight;
274 }
275 #else
276 #define register_chip_backlight NULL
277 #endif
278
279 static struct fbtft_display display = {
280 .regwidth = 8,
281 .buswidth = 8,
282 .width = WIDTH,
283 .height = HEIGHT,
284 .fps = FPS,
285 .txbuflen = TXBUFLEN,
286 .fbtftops = {
287 .write_register = write_reg8_bus8,
288 .write_vmem = write_vmem,
289 .init_display = init_display,
290 .set_addr_win = set_addr_win,
291 .set_var = set_var,
292 .verify_gpios = verify_gpios,
293 .register_backlight = register_chip_backlight,
294 },
295 };
296
297 FBTFT_REGISTER_DRIVER(DRVNAME, "watterott,openlcd", &display);
298
299 MODULE_ALIAS("spi:" DRVNAME);
300
301 MODULE_DESCRIPTION("FB driver for the Watterott LCD Controller");
302 MODULE_AUTHOR("Noralf Tronnes");
303 MODULE_LICENSE("GPL");
304
