Add support AGM1264K-FL monochrme display 128x64

[ololoshka2871]

This display contains two samsung ks0108 compatible controllers 64x64 pixels. Controllers are selected using the CS pins, others pins are common. Translating from RGB565 to 'bitmap' uses defusing error “Floyd-Steinberg” algorithm. My bord is Beaglebone Black

diff --git a/Kconfig b/Kconfig
index a4cb559..5d2fe7a 100644
--- a/Kconfig
+++ b/Kconfig
@@ -8,6 +8,12 @@ menuconfig FB_TFT
    select FB_DEFERRED_IO
    select FB_BACKLIGHT

+config FB_TFT_AGM1264K_FL
+   tristate "FB driver for the AGM1264K-FL LCD display"
+   depends on FB_TFT
+   help
+     Framebuffer support for the AGM1264K-FL LCD display (two Samsung KS0108 compatable chips)
+
 config FB_TFT_BD663474
    tristate "FB driver for the BD663474 LCD Controller"
    depends on FB_TFT
diff --git a/Makefile b/Makefile
index 54377d3..ac0afd3 100644
--- a/Makefile
+++ b/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_FB_TFT)             += fbtft.o
 fbtft-y                          += fbtft-core.o fbtft-sysfs.o fbtft-bus.o fbtft-io.o

 # drivers
+obj-$(CONFIG_FB_TFT_AGM1264K_FL) += fb_agm1264k-fl.o
 obj-$(CONFIG_FB_TFT_BD663474)    += fb_bd663474.o
 obj-$(CONFIG_FB_TFT_HX8340BN)    += fb_hx8340bn.o
 obj-$(CONFIG_FB_TFT_HX8347D)     += fb_hx8347d.o
diff --git a/fb_agm1264k-fl.c b/fb_agm1264k-fl.c
new file mode 100644
index 0000000..30a6895
--- /dev/null
+++ b/fb_agm1264k-fl.c
@@ -0,0 +1,463 @@
+/*
+ * FB driver for Two KS0108 LCD controllers in AGM1264K-FL display
+ *
+ * Copyright (C) 2014 ololoshka2871
+ *
+ * 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/delay.h>
+#include <linux/slab.h>
+
+#include "fbtft.h"
+
+/* Uncomment text line to use negative image on display */
+/*#define NEGATIVE*/
+
+#define WHITE      0xff
+#define BLACK      0
+
+#define DRVNAME        "fb_agm1264k-fl"
+#define WIDTH      64
+#define HEIGHT     64
+#define TOTALWIDTH (WIDTH * 2)  /* because 2 x ks0108 in one display */
+#define FPS            20
+
+#define EPIN       gpio.wr
+#define RS         gpio.dc
+#define RW         gpio.aux[2]
+#define CS0            gpio.aux[0]
+#define CS1            gpio.aux[1]
+
+
+/* diffusing error (“Floyd-Steinberg”) */
+#define DIFFUSING_MATRIX_WIDTH 2
+#define DIFFUSING_MATRIX_HEIGHT    2
+
+static const signed char
+diffusing_matrix[DIFFUSING_MATRIX_WIDTH][DIFFUSING_MATRIX_HEIGHT] = {
+   {-1, 3},
+   {3, 2},
+};
+
+static const unsigned char gamma_correction_table[] = {
+0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1,
+1, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 6,
+6, 6, 6, 7, 7, 7, 8, 8, 8, 9, 9, 9, 10, 10, 11, 11, 11, 12, 12, 13,
+13, 13, 14, 14, 15, 15, 16, 16, 17, 17, 18, 18, 19, 19, 20, 20, 21,
+22, 22, 23, 23, 24, 25, 25, 26, 26, 27, 28, 28, 29, 30, 30, 31, 32,
+33, 33, 34, 35, 35, 36, 37, 38, 39, 39, 40, 41, 42, 43, 43, 44, 45,
+46, 47, 48, 49, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61,
+62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 78, 79, 81,
+82, 83, 84, 85, 87, 88, 89, 90, 91, 93, 94, 95, 97, 98, 99, 100, 102,
+103, 105, 106, 107, 109, 110, 111, 113, 114, 116, 117, 119, 120, 121,
+123, 124, 126, 127, 129, 130, 132, 133, 135, 137, 138, 140, 141, 143,
+145, 146, 148, 149, 151, 153, 154, 156, 158, 159, 161, 163, 165, 166,
+168, 170, 172, 173, 175, 177, 179, 181, 182, 184, 186, 188, 190, 192,
+194, 196, 197, 199, 201, 203, 205, 207, 209, 211, 213, 215, 217, 219,
+221, 223, 225, 227, 229, 231, 234, 236, 238, 240, 242, 244, 246, 248,
+251, 253, 255
+};
+
+static int init_display(struct fbtft_par *par)
+{
+   u8 i;
+
+   fbtft_par_dbg(DEBUG_INIT_DISPLAY, par, "%s()\n", __func__);
+
+   par->fbtftops.reset(par);
+
+   for (i = 0; i < 2; ++i) {
+       write_reg(par, i, 0x3f); /* display on */
+       write_reg(par, i, 0x40); /* set x to 0 */
+       write_reg(par, i, 0xb0); /* set page to 0 */
+       write_reg(par, i, 0xc0); /* set start line to 0 */
+   }
+
+   return 0;
+}
+
+void reset(struct fbtft_par *par)
+{
+   if (par->gpio.reset == -1)
+       return;
+
+   fbtft_dev_dbg(DEBUG_RESET, par, par->info->device, "%s()\n", __func__);
+
+   gpio_set_value(par->gpio.reset, 0);
+   udelay(20);
+   gpio_set_value(par->gpio.reset, 1);
+   mdelay(120);
+}
+
+/* Check if all necessary GPIOS defined */
+static int verify_gpios(struct fbtft_par *par)
+{
+   int i;
+
+   fbtft_dev_dbg(DEBUG_VERIFY_GPIOS, par, par->info->device,
+       "%s()\n", __func__);
+
+   if (par->EPIN < 0) {
+       dev_err(par->info->device,
+           "Missing info about 'wr' (aka E) gpio. Aborting.\n");
+       return -EINVAL;
+   }
+   for (i = 0; i < 8; ++i) {
+       if (par->gpio.db[i] < 0) {
+           dev_err(par->info->device,
+               "Missing info about 'db[%i]' gpio. Aborting.\n",
+               i);
+           return -EINVAL;
+       }
+   }
+   if (par->CS0 < 0) {
+       dev_err(par->info->device,
+           "Missing info about 'cs0' gpio. Aborting.\n");
+       return -EINVAL;
+   }
+   if (par->CS1 < 0) {
+       dev_err(par->info->device,
+           "Missing info about 'cs1' gpio. Aborting.\n");
+       return -EINVAL;
+   }
+   if (par->RW < 0) {
+       dev_err(par->info->device,
+           "Missing info about 'rw' gpio. Aborting.\n");
+       return -EINVAL;
+   }
+
+   return 0;
+}
+
+static unsigned long
+request_gpios_match(struct fbtft_par *par, const struct fbtft_gpio *gpio)
+{
+   fbtft_dev_dbg(DEBUG_REQUEST_GPIOS_MATCH, par, par->info->device,
+       "%s('%s')\n", __func__, gpio->name);
+
+   if (strcasecmp(gpio->name, "wr") == 0) {
+       /* left ks0108 E pin */
+       par->EPIN = gpio->gpio;
+       return GPIOF_OUT_INIT_LOW;
+   } else if (strcasecmp(gpio->name, "cs0") == 0) {
+       /* left ks0108 controller pin */
+       par->CS0 = gpio->gpio;
+       return GPIOF_OUT_INIT_HIGH;
+   } else if (strcasecmp(gpio->name, "cs1") == 0) {
+       /* right ks0108 controller pin */
+       par->CS1 = gpio->gpio;
+       return GPIOF_OUT_INIT_HIGH;
+   }
+
+   /* if write (rw = 0) e(1->0) perform write */
+   /* if read (rw = 1) e(0->1) set data on D0-7*/
+   else if (strcasecmp(gpio->name, "rw") == 0) {
+       par->RW = gpio->gpio;
+       return GPIOF_OUT_INIT_LOW;
+   }
+
+   return FBTFT_GPIO_NO_MATCH;
+}
+
+/* This function oses to enter commands
+ * first byte - destination controller 0 or 1
+ * folowing - commands
+ */
+static void write_reg8_bus8(struct fbtft_par *par, int len, ...)
+{
+   va_list args;
+   int i, ret;
+   u8 *buf = (u8 *)par->buf;
+
+   if (unlikely(par->debug & DEBUG_WRITE_REGISTER)) {
+       va_start(args, len);
+       for (i = 0; i < len; i++)
+           buf[i] = (u8)va_arg(args, unsigned int);
+
+       va_end(args);
+       fbtft_par_dbg_hex(DEBUG_WRITE_REGISTER, par,
+           par->info->device, u8, buf, len, "%s: ", __func__);
+   }
+
+   va_start(args, len);
+
+   *buf = (u8)va_arg(args, unsigned int);
+
+   if (*buf > 1) {
+       va_end(args);
+       dev_err(par->info->device, "%s: Incorrect chip sellect request (%d)\n",
+           __func__, *buf);
+       return;
+   }
+
+   /* select chip */
+   if (*buf) {
+       /* cs1 */
+       gpio_set_value(par->CS0, 1);
+       gpio_set_value(par->CS1, 0);
+   } else {
+       /* cs0 */
+       gpio_set_value(par->CS0, 0);
+       gpio_set_value(par->CS1, 1);
+   }
+
+   gpio_set_value(par->RS, 0); /* RS->0 (command mode) */
+   len--;
+
+   if (len) {
+       i = len;
+       while (i--)
+           *buf++ = (u8)va_arg(args, unsigned int);
+       ret = par->fbtftops.write(par, par->buf, len * (sizeof(u8)));
+       if (ret < 0) {
+           va_end(args);
+           dev_err(par->info->device, "%s: write() failed and returned %d\n",
+               __func__, ret);
+           return;
+       }
+   }
+
+   va_end(args);
+}
+
+static struct
+{
+   int xs, ys_page, xe, ye_page;
+} addr_win;
+
+/* save display writing zone */
+static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
+{
+   addr_win.xs = xs;
+   addr_win.ys_page = ys / 8;
+   addr_win.xe = xe;
+   addr_win.ye_page = ye / 8;
+
+   fbtft_par_dbg(DEBUG_SET_ADDR_WIN, par,
+       "%s(xs=%d, ys_page=%d, xe=%d, ye_page=%d)\n", __func__,
+       addr_win.xs, addr_win.ys_page, addr_win.xe, addr_win.ye_page);
+}
+
+static void
+construct_line_bitmap(struct fbtft_par *par, u8 *dest, signed short *src,
+                       int xs, int xe, int y)
+{
+   int x, i;
+
+   for (x = xs; x < xe; ++x) {
+       u8 res = 0;
+
+       for (i = 0; i < 8; i++)
+           if (src[(y * 8 + i) * par->info->var.xres + x])
+               res |= 1 << i;
+#ifdef NEGATIVE
+       *dest++ = res;
+#else
+       *dest++ = ~res;
+#endif
+   }
+}
+
+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;
+   int ret = 0;
+
+   /* buffer to convert RGB565 -> grayscale16 -> Ditherd image 1bpp */
+   signed short *convert_buf = kmalloc(par->info->var.xres *
+       par->info->var.yres * sizeof(signed short), GFP_NOIO);
+
+   fbtft_par_dbg(DEBUG_WRITE_VMEM, par, "%s()\n", __func__);
+
+   /* converting to grayscale16 */
+   for (x = 0; x < par->info->var.xres; ++x)
+       for (y = 0; y < par->info->var.yres; ++y) {
+           u16 pixel = vmem16[y *  par->info->var.xres + x];
+           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) / 200;
+           if (pixel > 255)
+               pixel = 255;
+
+           /* gamma-correction by table */
+           convert_buf[y *  par->info->var.xres + x] =
+               (signed short)gamma_correction_table[pixel];
+       }
+
+   /* Image Dithering */
+   for (x = 0; x < par->info->var.xres; ++x)
+       for (y = 0; y < par->info->var.yres; ++y) {
+           signed short pixel =
+               convert_buf[y *  par->info->var.xres + x];
+           signed short error_b = pixel - BLACK;
+           signed short error_w = pixel - WHITE;
+           signed short error;
+           u16 i, j;
+
+           /* what color close? */
+           if (abs(error_b) >= abs(error_w)) {
+               /* white */
+               error = error_w;
+               pixel = 0xff;
+           } else {
+               /* black */
+               error = error_b;
+               pixel = 0;
+           }
+
+           error /= 8;
+
+           /* diffusion matrix row */
+           for (i = 0; i < DIFFUSING_MATRIX_WIDTH; ++i)
+               /* diffusion matrix column */
+               for (j = 0; j < DIFFUSING_MATRIX_HEIGHT; ++j) {
+                   signed short *write_pos;
+                   signed char coeff;
+
+                   /* skip pixels out of zone */
+                   if (x + i < 0 ||
+                       x + i >= par->info->var.xres
+                       || y + j >= par->info->var.yres)
+                       continue;
+                   write_pos = &convert_buf[
+                       (y + j) * par->info->var.xres +
+                       x + i];
+                   coeff = diffusing_matrix[i][j];
+                   if (coeff == -1)
+                       /* pixel itself */
+                       *write_pos = pixel;
+                   else {
+                       signed short p = *write_pos +
+                           error * coeff;
+
+                       if (p > WHITE)
+                           p = WHITE;
+                       if (p < BLACK)
+                           p = BLACK;
+                       *write_pos = p;
+                   }
+               }
+       }
+
+    /* 1 string = 2 pages */
+    for (y = addr_win.ys_page; y <= addr_win.ye_page; ++y) {
+       /* left half of display */
+       if (addr_win.xs < par->info->var.xres / 2) {
+           construct_line_bitmap(par, buf, convert_buf,
+               addr_win.xs, par->info->var.xres / 2, y);
+
+           len = par->info->var.xres / 2 - addr_win.xs;
+
+           /* select left side (sc0)
+            * set addr
+            */
+           write_reg(par, 0x00, (1 << 6) | (u8)addr_win.xs);
+           write_reg(par, 0x00, (0x17 << 3) | (u8)y);
+
+           /* write bitmap */
+           gpio_set_value(par->RS, 1); /* RS->1 (data mode) */
+           ret = par->fbtftops.write(par, buf, len);
+           if (ret < 0)
+               dev_err(par->info->device,
+                   "%s: write failed and returned: %d\n",
+                   __func__, ret);
+       }
+       /* right half of display */
+       if (addr_win.xe >= par->info->var.xres / 2) {
+           construct_line_bitmap(par, buf,
+               convert_buf, par->info->var.xres / 2,
+               addr_win.xe + 1, y);
+
+           len = addr_win.xe + 1 - par->info->var.xres / 2;
+
+           /* select right side (sc1)
+            * set addr
+            */
+           write_reg(par, 0x01, (1 << 6));
+           write_reg(par, 0x01, (0x17 << 3) | (u8)y);
+
+           /* write bitmap */
+           gpio_set_value(par->RS, 1); /* RS->1 (data mode) */
+           par->fbtftops.write(par, buf, len);
+           if (ret < 0)
+               dev_err(par->info->device,
+                   "%s: write failed and returned: %d\n",
+                   __func__, ret);
+       }
+   }
+   kfree(convert_buf);
+
+   gpio_set_value(par->CS0, 1);
+   gpio_set_value(par->CS1, 1);
+
+   return ret;
+}
+
+static int write(struct fbtft_par *par, void *buf, size_t len)
+{
+   fbtft_par_dbg_hex(DEBUG_WRITE, par, par->info->device, u8, buf, len,
+       "%s(len=%d): ", __func__, len);
+
+   gpio_set_value(par->RW, 0); /* set write mode */
+
+
+   while (len--) {
+       u8 i, data;
+
+       data = *(u8 *) buf++;
+
+       /* set data bus */
+       for (i = 0; i < 8; ++i)
+           gpio_set_value(par->gpio.db[i], data & (1 << i));
+       /* set E */
+       gpio_set_value(par->EPIN, 1);
+       udelay(5);
+       /* unset E - write */
+       gpio_set_value(par->EPIN, 0);
+       udelay(1);
+   }
+
+   return 0;
+}
+
+static struct fbtft_display display = {
+   .regwidth = 8,
+   .width = TOTALWIDTH,
+   .height = HEIGHT,
+   .fps = FPS,
+   .fbtftops = {
+       .init_display = init_display,
+       .set_addr_win = set_addr_win,
+       .verify_gpios = verify_gpios,
+       .request_gpios_match = request_gpios_match,
+       .reset = reset,
+       .write = write,
+       .write_register = write_reg8_bus8,
+       .write_vmem = write_vmem,
+   },
+};
+FBTFT_REGISTER_DRIVER(DRVNAME, "displaytronic,fb_agm1264k-fl", &display);
+
+MODULE_ALIAS("platform:" DRVNAME);
+
+MODULE_DESCRIPTION("Two KS0108 LCD controllers in AGM1264K-FL display");
+MODULE_AUTHOR("ololoshka2871");
+MODULE_LICENSE("GPL");
+
diff --git a/fbtft_device.c b/fbtft_device.c
index 19ddd8f..7396a0a 100644
--- a/fbtft_device.c
+++ b/fbtft_device.c
@@ -286,6 +286,39 @@ static struct fbtft_device_display displays[] = {
            }
        }
    }, {
+       .name = "agm1264k-fl",
+       .pdev = &(struct platform_device) {
+           .name = "fb_agm1264k-fl",
+           .id = 0,
+           .dev = {
+           .release = fbtft_device_pdev_release,
+           .platform_data = &(struct fbtft_platform_data) {
+               .display = {
+                   .buswidth = 8,
+                   .backlight = FBTFT_ONBOARD_BACKLIGHT,
+               },
+               .gpios = (const struct fbtft_gpio []) {
+                   /* for my Beaglebone Black
+                   { "reset", 48 },
+                   { "wr", 60 },  // aka E
+                   { "dc", 112 }, // aka D/I
+                   { "rw", 113 },
+                   { "cs0", 49 },
+                   { "cs1", 117 },
+                   { "db00", 66 },
+                   { "db01", 69 },
+                   { "db02", 45 },
+                   { "db03", 67 },
+                   { "db04", 68 },
+                   { "db05", 44 },
+                   { "db06", 26 },
+                   { "db07", 65 },*/
+                   {},
+               },
+           },
+           }
+       }
+   }, {
        .name = "er_tftm050_2",
        .spi = &(struct spi_board_info) {
            .modalias = "fb_ra8875",

[notro]

Committted, thanks: https://github.com/notro/fbtft/commit/de1c2adfbb7b04b90a02d0e4cf6d7d923bab3656