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
39 /* gamma is used to control contrast in this driver */
40 #define DEFAULT_GAMMA "40"
42 static unsigned bs = 4;
43 module_param(bs, uint, 0);
44 MODULE_PARM_DESC(bs, "BS[2:0] Bias voltage level: 0-7 (default: 4)");
46 static int init_display(struct fbtft_par *par)
48 fbtft_par_dbg(DEBUG_INIT_DISPLAY, par, "%s()\n", __func__);
50 par->fbtftops.reset(par);
52 /* Enter extended command mode */
53 write_reg(par, 0x21); /* 5:1 1
54 2:0 PD - Powerdown control: chip is active
55 1:0 V - Entry mode: horizontal addressing
56 0:1 H - Extended instruction set control:
61 write_reg(par, 0x10 | (bs & 0x7)); /*
69 /* Set the address of the first display line. */
70 write_reg(par, 0x04 | (64 >> 6));
71 write_reg(par, 0x40 | (64 & 0x3F));
73 /* Enter H=0 standard command mode */
76 /* H=0 Display control */
77 write_reg(par, 0x08 | 4); /*
79 2:1 D - DE: 10=normal mode
87 static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
89 fbtft_par_dbg(DEBUG_SET_ADDR_WIN, par,
90 "%s(xs=%d, ys=%d, xe=%d, ye=%d)\n",
91 __func__, xs, ys, xe, ye);
93 /* H=0 Set X address of RAM */
94 write_reg(par, 0x80); /* 7:1 1
98 /* H=0 Set Y address of RAM */
99 write_reg(par, 0x40); /* 7:0 0
105 static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
107 u16 *vmem16 = (u16 *)par->info->screen_base;
111 fbtft_par_dbg(DEBUG_WRITE_VMEM, par, "%s()\n", __func__);
113 for (y = 0; y < HEIGHT/8; y++) {
114 u8 *buf = par->txbuf.buf;
115 /* The display is 102x68 but the LCD is 84x48. Set
116 the write pointer at the start of each row. */
117 gpio_set_value(par->gpio.dc, 0);
118 write_reg(par, 0x80 | 0);
119 write_reg(par, 0x40 | y);
121 for (x = 0; x < WIDTH; x++) {
124 for (i = 0; i < 8*WIDTH; i += WIDTH) {
126 if (vmem16[(y*8*WIDTH)+i+x])
132 gpio_set_value(par->gpio.dc, 1);
133 ret = par->fbtftops.write(par, par->txbuf.buf, WIDTH);
135 dev_err(par->info->device,
136 "write failed and returned: %d\n", ret);
144 static int set_gamma(struct fbtft_par *par, unsigned long *curves)
146 fbtft_par_dbg(DEBUG_INIT_DISPLAY, par, "%s()\n", __func__);
151 write_reg(par, 0x21); /* turn on extended instruction set */
152 write_reg(par, 0x80 | curves[0]);
153 write_reg(par, 0x20); /* turn off extended instruction set */
159 static struct fbtft_display display = {
163 .txbuflen = TXBUFLEN,
166 .gamma = DEFAULT_GAMMA,
168 .init_display = init_display,
169 .set_addr_win = set_addr_win,
170 .write_vmem = write_vmem,
171 .set_gamma = set_gamma,
175 FBTFT_REGISTER_DRIVER(DRVNAME, "teralane,tls8204", &display);
177 MODULE_ALIAS("spi:" DRVNAME);
178 MODULE_ALIAS("spi:tls8204");
180 MODULE_DESCRIPTION("FB driver for the TLS8204 LCD Controller");
181 MODULE_AUTHOR("Michael Hope");
182 MODULE_LICENSE("GPL");