diff options
Diffstat (limited to 'drivers/staging/fbtft/fb_tls8204.c')
| -rw-r--r-- | drivers/staging/fbtft/fb_tls8204.c | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/drivers/staging/fbtft/fb_tls8204.c b/drivers/staging/fbtft/fb_tls8204.c new file mode 100644 index 000000000000..8738c7a7bfda --- /dev/null +++ b/drivers/staging/fbtft/fb_tls8204.c @@ -0,0 +1,176 @@ +/* + * FB driver for the TLS8204 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 + * Copyright (C) 2014 Michael Hope (adapted for the TLS8204) + * + * 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_tls8204" +#define WIDTH 84 +#define HEIGHT 48 +#define TXBUFLEN WIDTH +#define DEFAULT_GAMMA "40" /* gamma is used to control contrast in this driver */ + +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); + + /* Enter extended command mode */ + 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 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 + */ + + /* Set the address of the first display line. */ + write_reg(par, 0x04 | (64 >> 6)); + write_reg(par, 0x40 | (64 & 0x3F)); + + /* Enter H=0 standard command mode */ + write_reg(par, 0x20); + + /* 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; + int x, y, i; + int ret = 0; + + fbtft_par_dbg(DEBUG_WRITE_VMEM, par, "%s()\n", __func__); + + for (y = 0; y < HEIGHT/8; y++) { + u8 *buf = par->txbuf.buf; + /* The display is 102x68 but the LCD is 84x48. Set + the write pointer at the start of each row. */ + gpio_set_value(par->gpio.dc, 0); + write_reg(par, 0x80 | 0); + write_reg(par, 0x40 | y); + + for (x = 0; x < WIDTH; x++) { + u8 ch = 0; + for (i = 0; i < 8*WIDTH; i += WIDTH) { + ch >>= 1; + if (vmem16[(y*8*WIDTH)+i+x]) + ch |= 0x80; + } + *buf++ = ch; + } + /* Write the row */ + gpio_set_value(par->gpio.dc, 1); + ret = par->fbtftops.write(par, par->txbuf.buf, WIDTH); + if (ret < 0) { + dev_err(par->info->device, + "%s: write failed and returned: %d\n", __func__, ret); + break; + } + } + + 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, 0x21); /* turn on extended instruction set */ + write_reg(par, 0x80 | curves[0]); + write_reg(par, 0x20); /* 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, "teralane,tls8204", &display); + +MODULE_ALIAS("spi:" DRVNAME); +MODULE_ALIAS("spi:tls8204"); + +MODULE_DESCRIPTION("FB driver for the TLS8204 LCD Controller"); +MODULE_AUTHOR("Michael Hope"); +MODULE_LICENSE("GPL"); |