| /* |
| * 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 |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/kernel.h> |
| #include <linux/init.h> |
| #include <linux/gpio.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 tc; |
| module_param(tc, uint, 0); |
| MODULE_PARM_DESC(tc, "TC[1:0] Temperature coefficient: 0-3 (default: 0)"); |
| |
| static unsigned bs = 4; |
| module_param(bs, uint, 0); |
| 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 */ |
| gpio_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, unsigned long *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"); |