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