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// SPDX-License-Identifier: GPL-2.0+
/*
* FB driver for the TLS8204 LCD Controller
*
* The display is monochrome and the video memory is RGB565.
* Any pixel value except 0 turns the pixel on.
*
* Copyright (C) 2013 Noralf Tronnes
* Copyright (C) 2014 Michael Hope (adapted for the TLS8204)
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/gpio/consumer.h>
#include <linux/spi/spi.h>
#include <linux/delay.h>
#include "fbtft.h"
#define DRVNAME "fb_tls8204"
#define WIDTH 84
#define HEIGHT 48
#define TXBUFLEN WIDTH
/* gamma is used to control contrast in this driver */
#define DEFAULT_GAMMA "40"
static unsigned int bs = 4;
module_param(bs, uint, 0000);
MODULE_PARM_DESC(bs, "BS[2:0] Bias voltage level: 0-7 (default: 4)");
static int init_display(struct fbtft_par *par)
{
par->fbtftops.reset(par);
/* Enter extended command mode */
write_reg(par, 0x21); /* 5:1 1
* 2:0 PD - Powerdown control: chip is active
* 1:0 V - Entry mode: horizontal addressing
* 0:1 H - Extended instruction set control:
* extended
*/
/* H=1 Bias system */
write_reg(par, 0x10 | (bs & 0x7));
/* 4:1 1
* 3:0 0
* 2:x BS2 - Bias System
* 1:x BS1
* 0:x BS0
*/
/* Set the address of the first display line. */
write_reg(par, 0x04 | (64 >> 6));
write_reg(par, 0x40 | (64 & 0x3F));
/* Enter H=0 standard command mode */
write_reg(par, 0x20);
/* H=0 Display control */
write_reg(par, 0x08 | 4);
/* 3:1 1
* 2:1 D - DE: 10=normal mode
* 1:0 0
* 0:0 E
*/
return 0;
}
static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
{
/* H=0 Set X address of RAM */
write_reg(par, 0x80); /* 7:1 1
* 6-0: X[6:0] - 0x00
*/
/* H=0 Set Y address of RAM */
write_reg(par, 0x40); /* 7:0 0
* 6:1 1
* 2-0: Y[2:0] - 0x0
*/
}
static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
{
u16 *vmem16 = (u16 *)par->info->screen_buffer;
int x, y, i;
int ret = 0;
for (y = 0; y < HEIGHT / 8; y++) {
u8 *buf = par->txbuf.buf;
/* The display is 102x68 but the LCD is 84x48.
* Set the write pointer at the start of each row.
*/
gpiod_set_value(par->gpio.dc, 0);
write_reg(par, 0x80 | 0);
write_reg(par, 0x40 | y);
for (x = 0; x < WIDTH; x++) {
u8 ch = 0;
for (i = 0; i < 8 * WIDTH; i += WIDTH) {
ch >>= 1;
if (vmem16[(y * 8 * WIDTH) + i + x])
ch |= 0x80;
}
*buf++ = ch;
}
/* Write the row */
gpiod_set_value(par->gpio.dc, 1);
ret = par->fbtftops.write(par, par->txbuf.buf, WIDTH);
if (ret < 0) {
dev_err(par->info->device,
"write failed and returned: %d\n", ret);
break;
}
}
return ret;
}
static int set_gamma(struct fbtft_par *par, u32 *curves)
{
/* apply mask */
curves[0] &= 0x7F;
write_reg(par, 0x21); /* turn on extended instruction set */
write_reg(par, 0x80 | curves[0]);
write_reg(par, 0x20); /* turn off extended instruction set */
return 0;
}
static struct fbtft_display display = {
.regwidth = 8,
.width = WIDTH,
.height = HEIGHT,
.txbuflen = TXBUFLEN,
.gamma_num = 1,
.gamma_len = 1,
.gamma = DEFAULT_GAMMA,
.fbtftops = {
.init_display = init_display,
.set_addr_win = set_addr_win,
.write_vmem = write_vmem,
.set_gamma = set_gamma,
},
.backlight = 1,
};
FBTFT_REGISTER_DRIVER(DRVNAME, "teralane,tls8204", &display);
MODULE_ALIAS("spi:" DRVNAME);
MODULE_ALIAS("spi:tls8204");
MODULE_DESCRIPTION("FB driver for the TLS8204 LCD Controller");
MODULE_AUTHOR("Michael Hope");
MODULE_LICENSE("GPL");
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