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.
21 #include <linux/module.h>
22 #include <linux/kernel.h>
23 #include <linux/init.h>
24 #include <linux/gpio.h>
25 #include <linux/spi/spi.h>
26 #include <linux/delay.h>
30 #define DRVNAME "fb_tls8204"
33 #define TXBUFLEN WIDTH
35 /* gamma is used to control contrast in this driver */
36 #define DEFAULT_GAMMA "40"
38 static unsigned int bs = 4;
39 module_param(bs, uint, 0);
40 MODULE_PARM_DESC(bs, "BS[2:0] Bias voltage level: 0-7 (default: 4)");
42 static int init_display(struct fbtft_par *par)
44 par->fbtftops.reset(par);
46 /* Enter extended command mode */
47 write_reg(par, 0x21); /* 5:1 1
48 * 2:0 PD - Powerdown control: chip is active
49 * 1:0 V - Entry mode: horizontal addressing
50 * 0:1 H - Extended instruction set control:
55 write_reg(par, 0x10 | (bs & 0x7));
58 * 2:x BS2 - Bias System
63 /* Set the address of the first display line. */
64 write_reg(par, 0x04 | (64 >> 6));
65 write_reg(par, 0x40 | (64 & 0x3F));
67 /* Enter H=0 standard command mode */
70 /* H=0 Display control */
71 write_reg(par, 0x08 | 4);
73 * 2:1 D - DE: 10=normal mode
81 static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
83 /* H=0 Set X address of RAM */
84 write_reg(par, 0x80); /* 7:1 1
88 /* H=0 Set Y address of RAM */
89 write_reg(par, 0x40); /* 7:0 0
95 static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
97 u16 *vmem16 = (u16 *)par->info->screen_buffer;
101 for (y = 0; y < HEIGHT / 8; y++) {
102 u8 *buf = par->txbuf.buf;
103 /* The display is 102x68 but the LCD is 84x48.
104 * Set the write pointer at the start of each row.
106 gpio_set_value(par->gpio.dc, 0);
107 write_reg(par, 0x80 | 0);
108 write_reg(par, 0x40 | y);
110 for (x = 0; x < WIDTH; x++) {
113 for (i = 0; i < 8 * WIDTH; i += WIDTH) {
115 if (vmem16[(y * 8 * WIDTH) + i + x])
121 gpio_set_value(par->gpio.dc, 1);
122 ret = par->fbtftops.write(par, par->txbuf.buf, WIDTH);
124 dev_err(par->info->device,
125 "write failed and returned: %d\n", ret);
133 static int set_gamma(struct fbtft_par *par, unsigned long *curves)
138 write_reg(par, 0x21); /* turn on extended instruction set */
139 write_reg(par, 0x80 | curves[0]);
140 write_reg(par, 0x20); /* turn off extended instruction set */
145 static struct fbtft_display display = {
149 .txbuflen = TXBUFLEN,
152 .gamma = DEFAULT_GAMMA,
154 .init_display = init_display,
155 .set_addr_win = set_addr_win,
156 .write_vmem = write_vmem,
157 .set_gamma = set_gamma,
162 FBTFT_REGISTER_DRIVER(DRVNAME, "teralane,tls8204", &display);
164 MODULE_ALIAS("spi:" DRVNAME);
165 MODULE_ALIAS("spi:tls8204");
167 MODULE_DESCRIPTION("FB driver for the TLS8204 LCD Controller");
168 MODULE_AUTHOR("Michael Hope");
169 MODULE_LICENSE("GPL");