cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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fb_pcd8544.c (3510B)

      1// SPDX-License-Identifier: GPL-2.0+
      2/*
      3 * FB driver for the PCD8544 LCD Controller
      4 *
      5 * The display is monochrome and the video memory is RGB565.
      6 * Any pixel value except 0 turns the pixel on.
      7 *
      8 * Copyright (C) 2013 Noralf Tronnes
      9 */
     10
     11#include <linux/module.h>
     12#include <linux/kernel.h>
     13#include <linux/init.h>
     14#include <linux/gpio/consumer.h>
     15#include <linux/spi/spi.h>
     16#include <linux/delay.h>
     17
     18#include "fbtft.h"
     19
     20#define DRVNAME	       "fb_pcd8544"
     21#define WIDTH          84
     22#define HEIGHT         48
     23#define TXBUFLEN       (84 * 6)
     24#define DEFAULT_GAMMA  "40" /* gamma controls the contrast in this driver */
     25
     26static unsigned int tc;
     27module_param(tc, uint, 0000);
     28MODULE_PARM_DESC(tc, "TC[1:0] Temperature coefficient: 0-3 (default: 0)");
     29
     30static unsigned int bs = 4;
     31module_param(bs, uint, 0000);
     32MODULE_PARM_DESC(bs, "BS[2:0] Bias voltage level: 0-7 (default: 4)");
     33
     34static int init_display(struct fbtft_par *par)
     35{
     36	par->fbtftops.reset(par);
     37
     38	/* Function set
     39	 *
     40	 * 5:1  1
     41	 * 2:0  PD - Powerdown control: chip is active
     42	 * 1:0  V  - Entry mode: horizontal addressing
     43	 * 0:1  H  - Extended instruction set control: extended
     44	 */
     45	write_reg(par, 0x21);
     46
     47	/* H=1 Temperature control
     48	 *
     49	 * 2:1  1
     50	 * 1:x  TC1 - Temperature Coefficient: 0x10
     51	 * 0:x  TC0
     52	 */
     53	write_reg(par, 0x04 | (tc & 0x3));
     54
     55	/* H=1 Bias system
     56	 *
     57	 * 4:1  1
     58	 * 3:0  0
     59	 * 2:x  BS2 - Bias System
     60	 * 1:x  BS1
     61	 * 0:x  BS0
     62	 */
     63	write_reg(par, 0x10 | (bs & 0x7));
     64
     65	/* Function set
     66	 *
     67	 * 5:1  1
     68	 * 2:0  PD - Powerdown control: chip is active
     69	 * 1:1  V  - Entry mode: vertical addressing
     70	 * 0:0  H  - Extended instruction set control: basic
     71	 */
     72	write_reg(par, 0x22);
     73
     74	/* H=0 Display control
     75	 *
     76	 * 3:1  1
     77	 * 2:1  D  - DE: 10=normal mode
     78	 * 1:0  0
     79	 * 0:0  E
     80	 */
     81	write_reg(par, 0x08 | 4);
     82
     83	return 0;
     84}
     85
     86static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
     87{
     88	/* H=0 Set X address of RAM
     89	 *
     90	 * 7:1  1
     91	 * 6-0: X[6:0] - 0x00
     92	 */
     93	write_reg(par, 0x80);
     94
     95	/* H=0 Set Y address of RAM
     96	 *
     97	 * 7:0  0
     98	 * 6:1  1
     99	 * 2-0: Y[2:0] - 0x0
    100	 */
    101	write_reg(par, 0x40);
    102}
    103
    104static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
    105{
    106	u16 *vmem16 = (u16 *)par->info->screen_buffer;
    107	u8 *buf = par->txbuf.buf;
    108	int x, y, i;
    109	int ret = 0;
    110
    111	for (x = 0; x < 84; x++) {
    112		for (y = 0; y < 6; y++) {
    113			*buf = 0x00;
    114			for (i = 0; i < 8; i++)
    115				*buf |= (vmem16[(y * 8 + i) * 84 + x] ?
    116					 1 : 0) << i;
    117			buf++;
    118		}
    119	}
    120
    121	/* Write data */
    122	gpiod_set_value(par->gpio.dc, 1);
    123	ret = par->fbtftops.write(par, par->txbuf.buf, 6 * 84);
    124	if (ret < 0)
    125		dev_err(par->info->device, "write failed and returned: %d\n",
    126			ret);
    127
    128	return ret;
    129}
    130
    131static int set_gamma(struct fbtft_par *par, u32 *curves)
    132{
    133	/* apply mask */
    134	curves[0] &= 0x7F;
    135
    136	write_reg(par, 0x23); /* turn on extended instruction set */
    137	write_reg(par, 0x80 | curves[0]);
    138	write_reg(par, 0x22); /* turn off extended instruction set */
    139
    140	return 0;
    141}
    142
    143static struct fbtft_display display = {
    144	.regwidth = 8,
    145	.width = WIDTH,
    146	.height = HEIGHT,
    147	.txbuflen = TXBUFLEN,
    148	.gamma_num = 1,
    149	.gamma_len = 1,
    150	.gamma = DEFAULT_GAMMA,
    151	.fbtftops = {
    152		.init_display = init_display,
    153		.set_addr_win = set_addr_win,
    154		.write_vmem = write_vmem,
    155		.set_gamma = set_gamma,
    156	},
    157	.backlight = 1,
    158};
    159
    160FBTFT_REGISTER_DRIVER(DRVNAME, "philips,pcd8544", &display);
    161
    162MODULE_ALIAS("spi:" DRVNAME);
    163MODULE_ALIAS("spi:pcd8544");
    164
    165MODULE_DESCRIPTION("FB driver for the PCD8544 LCD Controller");
    166MODULE_AUTHOR("Noralf Tronnes");
    167MODULE_LICENSE("GPL");