// SPDX-License-Identifier: GPL-2.0+
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/*
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* FB driver for the PCD8544 LCD Controller
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*
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* The display is monochrome and the video memory is RGB565.
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* Any pixel value except 0 turns the pixel on.
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*
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* Copyright (C) 2013 Noralf Tronnes
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/gpio/consumer.h>
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#include <linux/spi/spi.h>
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#include <linux/delay.h>
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#include "fbtft.h"
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#define DRVNAME "fb_pcd8544"
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#define WIDTH 84
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#define HEIGHT 48
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#define TXBUFLEN (84 * 6)
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#define DEFAULT_GAMMA "40" /* gamma controls the contrast in this driver */
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static unsigned int tc;
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module_param(tc, uint, 0000);
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MODULE_PARM_DESC(tc, "TC[1:0] Temperature coefficient: 0-3 (default: 0)");
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static unsigned int bs = 4;
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module_param(bs, uint, 0000);
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MODULE_PARM_DESC(bs, "BS[2:0] Bias voltage level: 0-7 (default: 4)");
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static int init_display(struct fbtft_par *par)
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{
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par->fbtftops.reset(par);
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/* Function set
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*
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* 5:1 1
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* 2:0 PD - Powerdown control: chip is active
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* 1:0 V - Entry mode: horizontal addressing
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* 0:1 H - Extended instruction set control: extended
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*/
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write_reg(par, 0x21);
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/* H=1 Temperature control
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*
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* 2:1 1
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* 1:x TC1 - Temperature Coefficient: 0x10
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* 0:x TC0
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*/
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write_reg(par, 0x04 | (tc & 0x3));
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/* H=1 Bias system
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*
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* 4:1 1
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* 3:0 0
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* 2:x BS2 - Bias System
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* 1:x BS1
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* 0:x BS0
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*/
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write_reg(par, 0x10 | (bs & 0x7));
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/* Function set
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*
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* 5:1 1
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* 2:0 PD - Powerdown control: chip is active
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* 1:1 V - Entry mode: vertical addressing
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* 0:0 H - Extended instruction set control: basic
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*/
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write_reg(par, 0x22);
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/* H=0 Display control
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*
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* 3:1 1
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* 2:1 D - DE: 10=normal mode
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* 1:0 0
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* 0:0 E
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*/
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write_reg(par, 0x08 | 4);
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return 0;
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}
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static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
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{
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/* H=0 Set X address of RAM
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*
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* 7:1 1
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* 6-0: X[6:0] - 0x00
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*/
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write_reg(par, 0x80);
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/* H=0 Set Y address of RAM
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*
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* 7:0 0
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* 6:1 1
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* 2-0: Y[2:0] - 0x0
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*/
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write_reg(par, 0x40);
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}
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static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
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{
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u16 *vmem16 = (u16 *)par->info->screen_buffer;
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u8 *buf = par->txbuf.buf;
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int x, y, i;
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int ret = 0;
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for (x = 0; x < 84; x++) {
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for (y = 0; y < 6; y++) {
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*buf = 0x00;
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for (i = 0; i < 8; i++)
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*buf |= (vmem16[(y * 8 + i) * 84 + x] ?
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1 : 0) << i;
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buf++;
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}
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}
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/* Write data */
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gpiod_set_value(par->gpio.dc, 1);
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ret = par->fbtftops.write(par, par->txbuf.buf, 6 * 84);
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if (ret < 0)
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dev_err(par->info->device, "write failed and returned: %d\n",
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ret);
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return ret;
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}
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static int set_gamma(struct fbtft_par *par, u32 *curves)
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{
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/* apply mask */
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curves[0] &= 0x7F;
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write_reg(par, 0x23); /* turn on extended instruction set */
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write_reg(par, 0x80 | curves[0]);
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write_reg(par, 0x22); /* turn off extended instruction set */
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return 0;
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}
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static struct fbtft_display display = {
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.regwidth = 8,
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.width = WIDTH,
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.height = HEIGHT,
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.txbuflen = TXBUFLEN,
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.gamma_num = 1,
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.gamma_len = 1,
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.gamma = DEFAULT_GAMMA,
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.fbtftops = {
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.init_display = init_display,
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.set_addr_win = set_addr_win,
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.write_vmem = write_vmem,
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.set_gamma = set_gamma,
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},
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.backlight = 1,
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};
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FBTFT_REGISTER_DRIVER(DRVNAME, "philips,pcd8544", &display);
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MODULE_ALIAS("spi:" DRVNAME);
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MODULE_ALIAS("spi:pcd8544");
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MODULE_DESCRIPTION("FB driver for the PCD8544 LCD Controller");
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MODULE_AUTHOR("Noralf Tronnes");
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MODULE_LICENSE("GPL");
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