| // SPDX-License-Identifier: GPL-2.0+ |
| /* |
| * FB driver for the SSD1325 OLED Controller |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/kernel.h> |
| #include <linux/init.h> |
| #include <linux/gpio/consumer.h> |
| #include <linux/delay.h> |
| |
| #include "fbtft.h" |
| |
| #define DRVNAME "fb_ssd1325" |
| |
| #define WIDTH 128 |
| #define HEIGHT 64 |
| #define GAMMA_NUM 1 |
| #define GAMMA_LEN 15 |
| #define DEFAULT_GAMMA "7 1 1 1 1 2 2 3 3 4 4 5 5 6 6" |
| |
| /* |
| * 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) |
| { |
| par->fbtftops.reset(par); |
| |
| write_reg(par, 0xb3); |
| write_reg(par, 0xf0); |
| write_reg(par, 0xae); |
| write_reg(par, 0xa1); |
| write_reg(par, 0x00); |
| write_reg(par, 0xa8); |
| write_reg(par, 0x3f); |
| write_reg(par, 0xa0); |
| write_reg(par, 0x45); |
| write_reg(par, 0xa2); |
| write_reg(par, 0x40); |
| write_reg(par, 0x75); |
| write_reg(par, 0x00); |
| write_reg(par, 0x3f); |
| write_reg(par, 0x15); |
| write_reg(par, 0x00); |
| write_reg(par, 0x7f); |
| write_reg(par, 0xa4); |
| write_reg(par, 0xaf); |
| |
| return 0; |
| } |
| |
| static uint8_t rgb565_to_g16(u16 pixel) |
| { |
| u16 b = pixel & 0x1f; |
| u16 g = (pixel & (0x3f << 5)) >> 5; |
| u16 r = (pixel & (0x1f << (5 + 6))) >> (5 + 6); |
| |
| pixel = (299 * r + 587 * g + 114 * b) / 195; |
| if (pixel > 255) |
| pixel = 255; |
| return (uint8_t)pixel / 16; |
| } |
| |
| 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); |
| |
| write_reg(par, 0x75); |
| write_reg(par, 0x00); |
| write_reg(par, 0x3f); |
| write_reg(par, 0x15); |
| write_reg(par, 0x00); |
| write_reg(par, 0x7f); |
| } |
| |
| static int blank(struct fbtft_par *par, bool on) |
| { |
| fbtft_par_dbg(DEBUG_BLANK, par, "(%s=%s)\n", |
| __func__, on ? "true" : "false"); |
| |
| if (on) |
| write_reg(par, 0xAE); |
| else |
| write_reg(par, 0xAF); |
| return 0; |
| } |
| |
| /* |
| * Grayscale Lookup Table |
| * GS1 - GS15 |
| * The "Gamma curve" contains the relative values between the entries |
| * in the Lookup table. |
| * |
| * 0 = Setting of GS1 < Setting of GS2 < Setting of GS3.....< |
| * Setting of GS14 < Setting of GS15 |
| */ |
| static int set_gamma(struct fbtft_par *par, u32 *curves) |
| { |
| int i; |
| |
| fbtft_par_dbg(DEBUG_INIT_DISPLAY, par, "%s()\n", __func__); |
| |
| for (i = 0; i < GAMMA_LEN; i++) { |
| if (i > 0 && curves[i] < 1) { |
| dev_err(par->info->device, |
| "Illegal value in Grayscale Lookup Table at index %d.\n" |
| "Must be greater than 0\n", i); |
| return -EINVAL; |
| } |
| if (curves[i] > 7) { |
| dev_err(par->info->device, |
| "Illegal value(s) in Grayscale Lookup Table.\n" |
| "At index=%d, the accumulated value has exceeded 7\n", |
| i); |
| return -EINVAL; |
| } |
| } |
| write_reg(par, 0xB8); |
| for (i = 0; i < 8; i++) |
| write_reg(par, (curves[i] & 0xFF)); |
| return 0; |
| } |
| |
| 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; |
| u8 n1; |
| u8 n2; |
| int y, x; |
| int ret; |
| |
| for (x = 0; x < par->info->var.xres; x++) { |
| if (x % 2) |
| continue; |
| for (y = 0; y < par->info->var.yres; y++) { |
| n1 = rgb565_to_g16(vmem16[y * par->info->var.xres + x]); |
| n2 = rgb565_to_g16(vmem16 |
| [y * par->info->var.xres + x + 1]); |
| *buf = (n1 << 4) | n2; |
| buf++; |
| } |
| } |
| |
| gpiod_set_value(par->gpio.dc, 1); |
| |
| /* Write data */ |
| ret = par->fbtftops.write(par, par->txbuf.buf, |
| par->info->var.xres * par->info->var.yres / 2); |
| 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, |
| .txbuflen = WIDTH * HEIGHT / 2, |
| .gamma_num = GAMMA_NUM, |
| .gamma_len = GAMMA_LEN, |
| .gamma = DEFAULT_GAMMA, |
| .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,ssd1325", &display); |
| |
| MODULE_ALIAS("spi:" DRVNAME); |
| MODULE_ALIAS("platform:" DRVNAME); |
| MODULE_ALIAS("spi:ssd1325"); |
| MODULE_ALIAS("platform:ssd1325"); |
| |
| MODULE_DESCRIPTION("SSD1325 OLED Driver"); |
| MODULE_AUTHOR("Alexey Mednyy"); |
| MODULE_LICENSE("GPL"); |