/*
* FB driver for the UltraChip UC1611 LCD controller
*
* The display is 4-bit grayscale (16 shades) 240x160.
*
* Copyright (C) 2015 Henri Chain
*
* 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_uc1611"
#define WIDTH 240
#define HEIGHT 160
#define BPP 8
#define FPS 40
/*
* LCD voltage is a combination of ratio, gain, pot and temp
*
* V_LCD = V_BIAS * ratio
* V_LCD = (C_V0 + C_PM × pot) * (1 + (T - 25) * temp)
* C_V0 and C_PM depend on ratio and gain
* T is ambient temperature
*/
/* BR -> actual ratio: 0-3 -> 5, 10, 11, 13 */
static unsigned ratio = 2;
module_param(ratio, uint, 0);
MODULE_PARM_DESC(ratio, "BR[1:0] Bias voltage ratio: 0-3 (default: 2)");
static unsigned gain = 3;
module_param(gain, uint, 0);
MODULE_PARM_DESC(gain, "GN[1:0] Bias voltage gain: 0-3 (default: 3)");
static unsigned pot = 16;
module_param(pot, uint, 0);
MODULE_PARM_DESC(pot, "PM[6:0] Bias voltage pot.: 0-63 (default: 16)");
/* TC -> % compensation per deg C: 0-3 -> -.05, -.10, -.015, -.20 */
static unsigned temp;
module_param(temp, uint, 0);
MODULE_PARM_DESC(temp, "TC[1:0] Temperature compensation: 0-3 (default: 0)");
/* PC[1:0] -> LCD capacitance: 0-3 -> <20nF, 20-28 nF, 29-40 nF, 40-56 nF */
static unsigned load = 1;
module_param(load, uint, 0);
MODULE_PARM_DESC(load, "PC[1:0] Panel Loading: 0-3 (default: 1)");
/* PC[3:2] -> V_LCD: 0, 1, 3 -> ext., int. with ratio = 5, int. standard */
static unsigned pump = 3;
module_param(pump, uint, 0);
MODULE_PARM_DESC(pump, "PC[3:2] Pump control: 0,1,3 (default: 3)");
static int init_display(struct fbtft_par *par)
{
int ret;
/* Set CS active high */
par->spi->mode |= SPI_CS_HIGH;
ret = spi_setup(par->spi);
if (ret) {
dev_err(par->info->device, "Could not set SPI_CS_HIGH\n");
return ret;
}
/* Reset controller */
write_reg(par, 0xE2);
/* Set bias ratio */
write_reg(par, 0xE8 | (ratio & 0x03));
/* Set bias gain and potentiometer */
write_reg(par, 0x81);
write_reg(par, (gain & 0x03) << 6 | (pot & 0x3F));
/* Set temperature compensation */
write_reg(par, 0x24 | (temp & 0x03));
/* Set panel loading */
write_reg(par, 0x28 | (load & 0x03));
/* Set pump control */
write_reg(par, 0x2C | (pump & 0x03));
/* Set inverse display */
write_reg(par, 0xA6 | (0x01 & 0x01));
/* Set 4-bit grayscale mode */
write_reg(par, 0xD0 | (0x02 & 0x03));
/* Set Display enable */
write_reg(par, 0xA8 | 0x07);
return 0;
}
static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
{
switch (par->info->var.rotate) {
case 90:
case 270:
/* Set column address */
write_reg(par, ys & 0x0F);
write_reg(par, 0x10 | (ys >> 4));
/* Set page address (divide xs by 2) (not used by driver) */
write_reg(par, 0x60 | ((xs >> 1) & 0x0F));
write_reg(par, 0x70 | (xs >> 5));
break;
default:
/* Set column address (not used by driver) */
write_reg(par, xs & 0x0F);
write_reg(par, 0x10 | (xs >> 4));
/* Set page address (divide ys by 2) */
write_reg(par, 0x60 | ((ys >> 1) & 0x0F));
write_reg(par, 0x70 | (ys >> 5));
break;
}
}
static int blank(struct fbtft_par *par, bool on)
{
fbtft_par_dbg(DEBUG_BLANK, par, "%s(blank=%s)\n",
__func__, on ? "true" : "false");
if (on)
write_reg(par, 0xA8 | 0x00);
else
write_reg(par, 0xA8 | 0x07);
return 0;
}
static int set_var(struct fbtft_par *par)
{
/* par->info->fix.visual = FB_VISUAL_PSEUDOCOLOR; */
par->info->var.grayscale = 1;
par->info->var.red.offset = 0;
par->info->var.red.length = 8;
par->info->var.green.offset = 0;
par->info->var.green.length = 8;
par->info->var.blue.offset = 0;
par->info->var.blue.length = 8;
par->info->var.transp.offset = 0;
par->info->var.transp.length = 0;
switch (par->info->var.rotate) {
case 90:
/* Set RAM address control */
write_reg(par, 0x88
| (0x0 & 0x1) << 2 /* Increment positively */
| (0x1 & 0x1) << 1 /* Increment page first */
| (0x1 & 0x1)); /* Wrap around (default) */
/* Set LCD mapping */
write_reg(par, 0xC0
| (0x0 & 0x1) << 2 /* Mirror Y OFF */
| (0x0 & 0x1) << 1 /* Mirror X OFF */
| (0x0 & 0x1)); /* MS nibble last (default) */
break;
case 180:
/* Set RAM address control */
write_reg(par, 0x88
| (0x0 & 0x1) << 2 /* Increment positively */
| (0x0 & 0x1) << 1 /* Increment column first */
| (0x1 & 0x1)); /* Wrap around (default) */
/* Set LCD mapping */
write_reg(par, 0xC0
| (0x1 & 0x1) << 2 /* Mirror Y ON */
| (0x0 & 0x1) << 1 /* Mirror X OFF */
| (0x0 & 0x1)); /* MS nibble last (default) */
break;
case 270:
/* Set RAM address control */
write_reg(par, 0x88
| (0x0 & 0x1) << 2 /* Increment positively */
| (0x1 & 0x1) << 1 /* Increment page first */
| (0x1 & 0x1)); /* Wrap around (default) */
/* Set LCD mapping */
write_reg(par, 0xC0
| (0x1 & 0x1) << 2 /* Mirror Y ON */
| (0x1 & 0x1) << 1 /* Mirror X ON */
| (0x0 & 0x1)); /* MS nibble last (default) */
break;
default:
/* Set RAM address control */
write_reg(par, 0x88
| (0x0 & 0x1) << 2 /* Increment positively */
| (0x0 & 0x1) << 1 /* Increment column first */
| (0x1 & 0x1)); /* Wrap around (default) */
/* Set LCD mapping */
write_reg(par, 0xC0
| (0x0 & 0x1) << 2 /* Mirror Y OFF */
| (0x1 & 0x1) << 1 /* Mirror X ON */
| (0x0 & 0x1)); /* MS nibble last (default) */
break;
}
return 0;
}
static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
{
u8 *vmem8 = (u8 *)(par->info->screen_buffer);
u8 *buf8 = (u8 *)(par->txbuf.buf);
u16 *buf16 = (u16 *)(par->txbuf.buf);
int line_length = par->info->fix.line_length;
int y_start = (offset / line_length);
int y_end = (offset + len - 1) / line_length;
int x, y, i;
int ret = 0;
switch (par->pdata->display.buswidth) {
case 8:
switch (par->info->var.rotate) {
case 90:
case 270:
i = y_start * line_length;
for (y = y_start; y <= y_end; y++) {
for (x = 0; x < line_length; x += 2) {
*buf8 = vmem8[i] >> 4;
*buf8 |= vmem8[i + 1] & 0xF0;
buf8++;
i += 2;
}
}
break;
default:
/* Must be even because pages are two lines */
y_start &= 0xFE;
i = y_start * line_length;
for (y = y_start; y <= y_end; y += 2) {
for (x = 0; x < line_length; x++) {
*buf8 = vmem8[i] >> 4;
*buf8 |= vmem8[i + line_length] & 0xF0;
buf8++;
i++;
}
i += line_length;
}
break;
}
gpio_set_value(par->gpio.dc, 1);
/* Write data */
ret = par->fbtftops.write(par, par->txbuf.buf, len / 2);
break;
case 9:
switch (par->info->var.rotate) {
case 90:
case 270:
i = y_start * line_length;
for (y = y_start; y <= y_end; y++) {
for (x = 0; x < line_length; x += 2) {
*buf16 = 0x100;
*buf16 |= vmem8[i] >> 4;
*buf16 |= vmem8[i + 1] & 0xF0;
buf16++;
i += 2;
}
}
break;
default:
/* Must be even because pages are two lines */
y_start &= 0xFE;
i = y_start * line_length;
for (y = y_start; y <= y_end; y += 2) {
for (x = 0; x < line_length; x++) {
*buf16 = 0x100;
*buf16 |= vmem8[i] >> 4;
*buf16 |= vmem8[i + line_length] & 0xF0;
buf16++;
i++;
}
i += line_length;
}
break;
}
/* Write data */
ret = par->fbtftops.write(par, par->txbuf.buf, len);
break;
default:
dev_err(par->info->device, "unsupported buswidth %d\n",
par->pdata->display.buswidth);
}
if (ret < 0)
dev_err(par->info->device, "write failed and returned: %d\n",
ret);
return ret;
}
static struct fbtft_display display = {
.txbuflen = -1,
.regwidth = 8,
.width = WIDTH,
.height = HEIGHT,
.bpp = BPP,
.fps = FPS,
.fbtftops = {
.write_vmem = write_vmem,
.init_display = init_display,
.set_addr_win = set_addr_win,
.set_var = set_var,
.blank = blank,
},
};
FBTFT_REGISTER_DRIVER(DRVNAME, "ultrachip,uc1611", &display);
MODULE_ALIAS("spi:" DRVNAME);
MODULE_ALIAS("platform:" DRVNAME);
MODULE_ALIAS("spi:uc1611");
MODULE_ALIAS("platform:uc1611");
MODULE_DESCRIPTION("FB driver for the UC1611 LCD controller");
MODULE_AUTHOR("Henri Chain");
MODULE_LICENSE("GPL");