diff options
Diffstat (limited to 'drivers/staging/fbtft/fb_ssd1306.c')
| -rw-r--r-- | drivers/staging/fbtft/fb_ssd1306.c | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/drivers/staging/fbtft/fb_ssd1306.c b/drivers/staging/fbtft/fb_ssd1306.c new file mode 100644 index 000000000000..5ea195b0de1b --- /dev/null +++ b/drivers/staging/fbtft/fb_ssd1306.c @@ -0,0 +1,229 @@ +/* + * FB driver for the SSD1306 OLED Controller + * + * 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/delay.h> + +#include "fbtft.h" + +#define DRVNAME "fb_ssd1306" +#define WIDTH 128 +#define HEIGHT 64 + + +/* + write_reg() caveat: + + This doesn't work because D/C has to be LOW for both values: + write_reg(par, val1, val2); + + Do it like this: + write_reg(par, val1); + write_reg(par, val2); +*/ + +/* Init sequence taken from the Adafruit SSD1306 Arduino library */ +static int init_display(struct fbtft_par *par) +{ + fbtft_par_dbg(DEBUG_INIT_DISPLAY, par, "%s()\n", __func__); + + par->fbtftops.reset(par); + + if (par->gamma.curves[0] == 0) { + mutex_lock(&par->gamma.lock); + if (par->info->var.yres == 64) + par->gamma.curves[0] = 0xCF; + else + par->gamma.curves[0] = 0x8F; + mutex_unlock(&par->gamma.lock); + } + + /* Set Display OFF */ + write_reg(par, 0xAE); + + /* Set Display Clock Divide Ratio/ Oscillator Frequency */ + write_reg(par, 0xD5); + write_reg(par, 0x80); + + /* Set Multiplex Ratio */ + write_reg(par, 0xA8); + if (par->info->var.yres == 64) + write_reg(par, 0x3F); + else + write_reg(par, 0x1F); + + /* Set Display Offset */ + write_reg(par, 0xD3); + write_reg(par, 0x0); + + /* Set Display Start Line */ + write_reg(par, 0x40 | 0x0); + + /* Charge Pump Setting */ + write_reg(par, 0x8D); + /* A[2] = 1b, Enable charge pump during display on */ + write_reg(par, 0x14); + + /* Set Memory Addressing Mode */ + write_reg(par, 0x20); + /* Vertical addressing mode */ + write_reg(par, 0x01); + + /*Set Segment Re-map */ + /* column address 127 is mapped to SEG0 */ + write_reg(par, 0xA0 | 0x1); + + /* Set COM Output Scan Direction */ + /* remapped mode. Scan from COM[N-1] to COM0 */ + write_reg(par, 0xC8); + + /* Set COM Pins Hardware Configuration */ + write_reg(par, 0xDA); + if (par->info->var.yres == 64) + /* A[4]=1b, Alternative COM pin configuration */ + write_reg(par, 0x12); + else + /* A[4]=0b, Sequential COM pin configuration */ + write_reg(par, 0x02); + + /* Set Pre-charge Period */ + write_reg(par, 0xD9); + write_reg(par, 0xF1); + + /* Set VCOMH Deselect Level */ + write_reg(par, 0xDB); + /* according to the datasheet, this value is out of bounds */ + write_reg(par, 0x40); + + /* Entire Display ON */ + /* Resume to RAM content display. Output follows RAM content */ + write_reg(par, 0xA4); + + /* Set Normal Display + 0 in RAM: OFF in display panel + 1 in RAM: ON in display panel */ + write_reg(par, 0xA6); + + /* Set Display ON */ + write_reg(par, 0xAF); + + 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); + + /* Set Lower Column Start Address for Page Addressing Mode */ + write_reg(par, 0x00 | 0x0); + /* Set Higher Column Start Address for Page Addressing Mode */ + write_reg(par, 0x10 | 0x0); + /* Set Display Start Line */ + write_reg(par, 0x40 | 0x0); +} + +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, 0xAE); + else + write_reg(par, 0xAF); + return 0; +} + +/* Gamma is used to control Contrast */ +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] &= 0xFF; + + /* Set Contrast Control for BANK0 */ + write_reg(par, 0x81); + write_reg(par, curves[0]); + + return 0; +} + +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 < par->info->var.xres; x++) { + for (y = 0; y < par->info->var.yres/8; y++) { + *buf = 0x00; + for (i = 0; i < 8; i++) + *buf |= (vmem16[(y*8+i)*par->info->var.xres+x] ? 1 : 0) << i; + buf++; + } + } + + /* Write data */ + gpio_set_value(par->gpio.dc, 1); + ret = par->fbtftops.write(par, par->txbuf.buf, + par->info->var.xres*par->info->var.yres/8); + if (ret < 0) + dev_err(par->info->device, + "%s: write failed and returned: %d\n", __func__, ret); + + return ret; +} + + +static struct fbtft_display display = { + .regwidth = 8, + .width = WIDTH, + .height = HEIGHT, + .gamma_num = 1, + .gamma_len = 1, + .gamma = "00", + .fbtftops = { + .write_vmem = write_vmem, + .init_display = init_display, + .set_addr_win = set_addr_win, + .blank = blank, + .set_gamma = set_gamma, + }, +}; + + +FBTFT_REGISTER_DRIVER(DRVNAME, "solomon,ssd1306", &display); + +MODULE_ALIAS("spi:" DRVNAME); +MODULE_ALIAS("platform:" DRVNAME); +MODULE_ALIAS("spi:ssd1306"); +MODULE_ALIAS("platform:ssd1306"); + +MODULE_DESCRIPTION("SSD1306 OLED Driver"); +MODULE_AUTHOR("Noralf Tronnes"); +MODULE_LICENSE("GPL"); |