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// SPDX-License-Identifier: GPL-2.0+
/*
* FB driver for the PCD8544 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
*/
#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_pcd8544"
#define WIDTH 84
#define HEIGHT 48
#define TXBUFLEN (84 * 6)
#define DEFAULT_GAMMA "40" /* gamma controls the contrast in this driver */
static unsigned int tc;
module_param(tc, uint, 0000);
MODULE_PARM_DESC(tc, "TC[1:0] Temperature coefficient: 0-3 (default: 0)");
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);
/* Function set
*
* 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
*/
write_reg(par, 0x21);
/* H=1 Temperature control
*
* 2:1 1
* 1:x TC1 - Temperature Coefficient: 0x10
* 0:x TC0
*/
write_reg(par, 0x04 | (tc & 0x3));
/* H=1 Bias system
*
* 4:1 1
* 3:0 0
* 2:x BS2 - Bias System
* 1:x BS1
* 0:x BS0
*/
write_reg(par, 0x10 | (bs & 0x7));
/* Function set
*
* 5:1 1
* 2:0 PD - Powerdown control: chip is active
* 1:1 V - Entry mode: vertical addressing
* 0:0 H - Extended instruction set control: basic
*/
write_reg(par, 0x22);
/* H=0 Display control
*
* 3:1 1
* 2:1 D - DE: 10=normal mode
* 1:0 0
* 0:0 E
*/
write_reg(par, 0x08 | 4);
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
*
* 7:1 1
* 6-0: X[6:0] - 0x00
*/
write_reg(par, 0x80);
/* H=0 Set Y address of RAM
*
* 7:0 0
* 6:1 1
* 2-0: Y[2:0] - 0x0
*/
write_reg(par, 0x40);
}
static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
{
u16 *vmem16 = (u16 *)par->info->screen_buffer;
u8 *buf = par->txbuf.buf;
int x, y, i;
int ret = 0;
for (x = 0; x < 84; x++) {
for (y = 0; y < 6; y++) {
*buf = 0x00;
for (i = 0; i < 8; i++)
*buf |= (vmem16[(y * 8 + i) * 84 + x] ?
1 : 0) << i;
buf++;
}
}
/* Write data */
gpiod_set_value(par->gpio.dc, 1);
ret = par->fbtftops.write(par, par->txbuf.buf, 6 * 84);
if (ret < 0)
dev_err(par->info->device, "write failed and returned: %d\n",
ret);
return ret;
}
static int set_gamma(struct fbtft_par *par, u32 *curves)
{
/* apply mask */
curves[0] &= 0x7F;
write_reg(par, 0x23); /* turn on extended instruction set */
write_reg(par, 0x80 | curves[0]);
write_reg(par, 0x22); /* 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, "philips,pdc8544", &display);
MODULE_ALIAS("spi:" DRVNAME);
MODULE_ALIAS("spi:pdc8544");
MODULE_DESCRIPTION("FB driver for the PCD8544 LCD Controller");
MODULE_AUTHOR("Noralf Tronnes");
MODULE_LICENSE("GPL");
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