staging: fbtft: add fb_agm1264k-fl driver

This commit adds the fb_agm1264k-fl driver from the fbtft project at
https://github.com/notro/fbtft.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Noralf Tronnes <notro@tronnes.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 471 insertions, 0 deletions

diff --git a/drivers/staging/fbtft/Kconfig b/drivers/staging/fbtft/Kconfig
index 3d6598b31181..d552af657732 100644
--- a/drivers/staging/fbtft/Kconfig
+++ b/drivers/staging/fbtft/Kconfig
@@ -7,3 +7,9 @@ menuconfig FB_TFT
 	select FB_SYS_FOPS
 	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)
diff --git a/drivers/staging/fbtft/Makefile b/drivers/staging/fbtft/Makefile
index 9132dde4a152..eb13cc545747 100644
--- a/drivers/staging/fbtft/Makefile
+++ b/drivers/staging/fbtft/Makefile
@@ -1,3 +1,6 @@
 # Core module
 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
diff --git a/drivers/staging/fbtft/fb_agm1264k-fl.c b/drivers/staging/fbtft/fb_agm1264k-fl.c
new file mode 100644
index 000000000000..7fe4fa078200
--- /dev/null
+++ b/drivers/staging/fbtft/fb_agm1264k-fl.c
@@ -0,0 +1,462 @@
+/*
+ * 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");