2 * FB driver for the TLS8204 LCD Controller
4 * The display is monochrome and the video memory is RGB565.
5 * Any pixel value except 0 turns the pixel on.
7 * Copyright (C) 2013 Noralf Tronnes
8 * Copyright (C) 2014 Michael Hope (adapted for the TLS8204)
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
25 #include <linux/module.h>
26 #include <linux/kernel.h>
27 #include <linux/init.h>
28 #include <linux/gpio.h>
29 #include <linux/spi/spi.h>
30 #include <linux/delay.h>
34 #define DRVNAME "fb_tls8204"
37 #define TXBUFLEN WIDTH
38 #define DEFAULT_GAMMA "40" /* gamma is used to control contrast in this driver */
40 static unsigned bs = 4;
41 module_param(bs, uint, 0);
42 MODULE_PARM_DESC(bs, "BS[2:0] Bias voltage level: 0-7 (default: 4)");
44 static int init_display(struct fbtft_par *par)
46 fbtft_par_dbg(DEBUG_INIT_DISPLAY, par, "%s()\n", __func__);
48 par->fbtftops.reset(par);
50 /* Enter extended command mode */
51 write_reg(par, 0x21); /* 5:1 1
52 2:0 PD - Powerdown control: chip is active
53 1:0 V - Entry mode: horizontal addressing
54 0:1 H - Extended instruction set control: extended
58 write_reg(par, 0x10 | (bs & 0x7)); /*
66 /* Set the address of the first display line. */
67 write_reg(par, 0x04 | (64 >> 6));
68 write_reg(par, 0x40 | (64 & 0x3F));
70 /* Enter H=0 standard command mode */
73 /* H=0 Display control */
74 write_reg(par, 0x08 | 4); /*
76 2:1 D - DE: 10=normal mode
84 static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
86 fbtft_par_dbg(DEBUG_SET_ADDR_WIN, par, "%s(xs=%d, ys=%d, xe=%d, ye=%d)\n", __func__, xs, ys, xe, ye);
88 /* H=0 Set X address of RAM */
89 write_reg(par, 0x80); /* 7:1 1
93 /* H=0 Set Y address of RAM */
94 write_reg(par, 0x40); /* 7:0 0
100 static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
102 u16 *vmem16 = (u16 *)par->info->screen_base;
106 fbtft_par_dbg(DEBUG_WRITE_VMEM, par, "%s()\n", __func__);
108 for (y = 0; y < HEIGHT/8; y++) {
109 u8 *buf = par->txbuf.buf;
110 /* The display is 102x68 but the LCD is 84x48. Set
111 the write pointer at the start of each row. */
112 gpio_set_value(par->gpio.dc, 0);
113 write_reg(par, 0x80 | 0);
114 write_reg(par, 0x40 | y);
116 for (x = 0; x < WIDTH; x++) {
118 for (i = 0; i < 8*WIDTH; i += WIDTH) {
120 if (vmem16[(y*8*WIDTH)+i+x])
126 gpio_set_value(par->gpio.dc, 1);
127 ret = par->fbtftops.write(par, par->txbuf.buf, WIDTH);
129 dev_err(par->info->device,
130 "write failed and returned: %d\n", ret);
138 static int set_gamma(struct fbtft_par *par, unsigned long *curves)
140 fbtft_par_dbg(DEBUG_INIT_DISPLAY, par, "%s()\n", __func__);
145 write_reg(par, 0x21); /* turn on extended instruction set */
146 write_reg(par, 0x80 | curves[0]);
147 write_reg(par, 0x20); /* turn off extended instruction set */
153 static struct fbtft_display display = {
157 .txbuflen = TXBUFLEN,
160 .gamma = DEFAULT_GAMMA,
162 .init_display = init_display,
163 .set_addr_win = set_addr_win,
164 .write_vmem = write_vmem,
165 .set_gamma = set_gamma,
169 FBTFT_REGISTER_DRIVER(DRVNAME, "teralane,tls8204", &display);
171 MODULE_ALIAS("spi:" DRVNAME);
172 MODULE_ALIAS("spi:tls8204");
174 MODULE_DESCRIPTION("FB driver for the TLS8204 LCD Controller");
175 MODULE_AUTHOR("Michael Hope");
176 MODULE_LICENSE("GPL");