/*

* 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.

*

* You should have received a copy of the GNU General Public License

* along with this program; if not, write to the Free Software

* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#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 is used to control contrast in this driver */

static unsigned tc = 0;

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)

{

fbtft_par_dbg(DEBUG_INIT_DISPLAY, par, "%s()\n", __func__);

par->fbtftops.reset(par);

/* Function set */

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 Temperature control */

write_reg(par, 0x04 | (tc & 0x3)); /*

2:1 1

1:x TC1 - Temperature Coefficient: 0x10

0:x TC0

*/

/* 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

*/

/* Function set */

write_reg(par, 0x22); /* 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

*/

/* 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)

{

fbtft_par_dbg(DEBUG_SET_ADDR_WIN, par, "%s(xs=%d, ys=%d, xe=%d, ye=%d)\n", __func__, xs, ys, xe, 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_base;

u8 *buf = par->txbuf.buf;

int x, y, i;

int ret = 0;

fbtft_par_dbg(DEBUG_WRITE_VMEM, par, "%s()\n", __func__);

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, "%s: write failed and returned: %d\n", __func__, ret);

return ret;

}

static int set_gamma(struct fbtft_par *par, unsigned long *curves)

{

fbtft_par_dbg(DEBUG_INIT_DISPLAY, par, "%s()\n", __func__);

/* 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");