Staging: fbtft: add ssd1305 controller support

That patch adds support for SSD1305 controller.
That is monochrome OLED display controller present in several
displays eq: Winstar WEX012864
Signed-off-by: Alexey Mednyy <swexru@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/fbtft/Kconfig

@@ -117,6 +117,12 @@ config FB_TFT_SSD1289
 	help
 	  Framebuffer support for SSD1289
 
+config FB_TFT_SSD1305
+        tristate "FB driver for the SSD1305 OLED Controller"
+        depends on FB_TFT
+        help
+          Framebuffer support for SSD1305
+
 config FB_TFT_SSD1306
 	tristate "FB driver for the SSD1306 OLED Controller"
 	depends on FB_TFT

drivers/staging/fbtft/Makefile

@@ -21,6 +21,7 @@ obj-$(CONFIG_FB_TFT_RA8875)      += fb_ra8875.o
 obj-$(CONFIG_FB_TFT_S6D02A1)     += fb_s6d02a1.o
 obj-$(CONFIG_FB_TFT_S6D1121)     += fb_s6d1121.o
 obj-$(CONFIG_FB_TFT_SSD1289)     += fb_ssd1289.o
+obj-$(CONFIG_FB_TFT_SSD1305)     += fb_ssd1305.o
 obj-$(CONFIG_FB_TFT_SSD1306)     += fb_ssd1306.o
 obj-$(CONFIG_FB_TFT_SSD1331)     += fb_ssd1331.o
 obj-$(CONFIG_FB_TFT_SSD1351)     += fb_ssd1351.o

drivers/staging/fbtft/fb_ssd1305.c

+/*
+ * FB driver for the SSD1305 OLED Controller
+ *
+ * based on SSD1306 driver by 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.
+ */
+
+#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_ssd1305"
+
+#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)
+{
+	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 | ((par->info->var.rotate == 180) ? 0x0 : 0x1));
+
+	/*
+	 * Set COM Output Scan Direction
+	 * remapped mode. Scan from COM[N-1] to COM0
+	 */
+	write_reg(par, ((par->info->var.rotate == 180) ? 0xC8 : 0xC0));
+
+	/* 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);
+
+	/*
+	 * 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)
+{
+	/* Set Lower Column Start Address for Page Addressing Mode */
+	write_reg(par, 0x00 | ((par->info->var.rotate == 180) ? 0x0 : 0x4));
+	/* 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)
+{
+	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)
+{
+	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_buffer;
+	u8 *buf = par->txbuf.buf;
+	int x, y, i;
+	int ret;
+
+	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, "write failed and returned: %d\n",
+			ret);
+	return ret;
+}
+
+static struct fbtft_display display = {
+	.regwidth = 8,
+	.width = WIDTH,
+	.height = HEIGHT,
+	.txbuflen = WIDTH * HEIGHT / 8,
+	.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,ssd1305", &display);
+
+MODULE_ALIAS("spi:" DRVNAME);
+MODULE_ALIAS("platform:" DRVNAME);
+MODULE_ALIAS("spi:ssd1305");
+MODULE_ALIAS("platform:ssd1305");
+
+MODULE_DESCRIPTION("SSD1305 OLED Driver");
+MODULE_AUTHOR("Alexey Mednyy");
+MODULE_LICENSE("GPL");