staging: fbtft: add fb_st7735r driver

This commit adds the fb_st7735r 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>

drivers/staging/fbtft/Kconfig

@@ -121,3 +121,9 @@ config FB_TFT_SSD1351
 	depends on FB_TFT
 	help
 	  Framebuffer support for SSD1351
+
+config FB_TFT_ST7735R
+	tristate "FB driver for the ST7735R LCD Controller"
+	depends on FB_TFT
+	help
+	  Generic Framebuffer support for ST7735R

drivers/staging/fbtft/Makefile

@@ -22,3 +22,4 @@ obj-$(CONFIG_FB_TFT_SSD1289)     += fb_ssd1289.o
 obj-$(CONFIG_FB_TFT_SSD1306)     += fb_ssd1306.o
 obj-$(CONFIG_FB_TFT_SSD1331)     += fb_ssd1331.o
 obj-$(CONFIG_FB_TFT_SSD1351)     += fb_ssd1351.o
+obj-$(CONFIG_FB_TFT_ST7735R)     += fb_st7735r.o

drivers/staging/fbtft/fb_st7735r.c

+/*
+ * FB driver for the ST7735R LCD 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 "fbtft.h"
+
+#define DRVNAME "fb_st7735r"
+#define DEFAULT_GAMMA "0F 1A 0F 18 2F 28 20 22 1F 1B 23 37 00 07 02 10\n" \
+                      "0F 1B 0F 17 33 2C 29 2E 30 30 39 3F 00 07 03 10"
+
+
+static int default_init_sequence[] = {
+	/* SWRESET - Software reset */
+	-1, 0x01,                                
+	-2, 150,                               /* delay */
+
+	/* SLPOUT - Sleep out & booster on */
+	-1, 0x11,                          
+	-2, 500,                               /* delay */
+
+	/* FRMCTR1 - frame rate control: normal mode
+	     frame rate = fosc / (1 x 2 + 40) * (LINE + 2C + 2D) */
+	-1, 0xB1, 0x01, 0x2C, 0x2D, 
+
+	/* FRMCTR2 - frame rate control: idle mode
+	     frame rate = fosc / (1 x 2 + 40) * (LINE + 2C + 2D) */
+	-1, 0xB2, 0x01, 0x2C, 0x2D, 
+
+	/* FRMCTR3 - frame rate control - partial mode
+	     dot inversion mode, line inversion mode */
+	-1, 0xB3, 0x01, 0x2C, 0x2D, 0x01, 0x2C, 0x2D,
+
+	/* INVCTR - display inversion control
+	     no inversion */
+	-1, 0xB4, 0x07,
+
+	/* PWCTR1 - Power Control
+	     -4.6V, AUTO mode */
+	-1, 0xC0, 0xA2, 0x02, 0x84,
+
+	/* PWCTR2 - Power Control
+	     VGH25 = 2.4C VGSEL = -10 VGH = 3 * AVDD */
+	-1, 0xC1, 0xC5,
+
+	/* PWCTR3 - Power Control
+	     Opamp current small, Boost frequency */
+	-1, 0xC2, 0x0A, 0x00,
+
+	/* PWCTR4 - Power Control
+	     BCLK/2, Opamp current small & Medium low */
+	-1, 0xC3,0x8A,0x2A,
+
+	/* PWCTR5 - Power Control */
+	-1, 0xC4, 0x8A, 0xEE,
+
+	/* VMCTR1 - Power Control */
+	-1, 0xC5, 0x0E,
+
+	/* INVOFF - Display inversion off */
+	-1, 0x20,
+
+	/* COLMOD - Interface pixel format */
+	-1, 0x3A, 0x05,
+
+	/* DISPON - Display On */
+	-1, 0x29,
+	-2, 100,                               /* delay */
+
+	/* NORON - Partial off (Normal) */
+	-1, 0x13,
+	-2, 10,                               /* delay */
+
+	/* end marker */
+	-3                                  
+};
+
+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);
+
+	/* Column address */
+	write_reg(par, 0x2A, xs >> 8, xs & 0xFF, xe >> 8, xe & 0xFF);
+
+	/* Row adress */
+	write_reg(par, 0x2B, ys >> 8, ys & 0xFF, ye >> 8, ye & 0xFF);
+
+	/* Memory write */
+	write_reg(par, 0x2C);
+}
+
+#define MY (1 << 7)
+#define MX (1 << 6)
+#define MV (1 << 5)
+static int set_var(struct fbtft_par *par)
+{
+	fbtft_par_dbg(DEBUG_INIT_DISPLAY, par, "%s()\n", __func__);
+
+	/* MADCTL - Memory data access control
+	     RGB/BGR:
+	     1. Mode selection pin SRGB
+	        RGB H/W pin for color filter setting: 0=RGB, 1=BGR
+	     2. MADCTL RGB bit
+	        RGB-BGR ORDER color filter panel: 0=RGB, 1=BGR */
+	switch (par->info->var.rotate) {
+	case 0:
+		write_reg(par, 0x36, MX | MY | (par->bgr << 3));
+		break;
+	case 270:
+		write_reg(par, 0x36, MY | MV | (par->bgr << 3));
+		break;
+	case 180:
+		write_reg(par, 0x36, (par->bgr << 3));
+		break;
+	case 90:
+		write_reg(par, 0x36, MX | MV | (par->bgr << 3));
+		break;
+	}
+
+	return 0;
+}
+
+/*
+  Gamma string format:
+    VRF0P VOS0P PK0P PK1P PK2P PK3P PK4P PK5P PK6P PK7P PK8P PK9P SELV0P SELV1P SELV62P SELV63P
+    VRF0N VOS0N PK0N PK1N PK2N PK3N PK4N PK5N PK6N PK7N PK8N PK9N SELV0N SELV1N SELV62N SELV63N
+*/
+#define CURVE(num, idx)  curves[num*par->gamma.num_values + idx]
+static int set_gamma(struct fbtft_par *par, unsigned long *curves)
+{
+	int i,j;
+
+	fbtft_par_dbg(DEBUG_INIT_DISPLAY, par, "%s()\n", __func__);
+
+	/* apply mask */
+	for (i = 0; i < par->gamma.num_curves; i++)
+		for (j = 0; j < par->gamma.num_values; j++)
+			CURVE(i,j) &= 0b111111;
+
+	for (i = 0; i < par->gamma.num_curves; i++)
+		write_reg(par, 0xE0 + i,
+			CURVE(i, 0), CURVE(i, 1), CURVE(i, 2), CURVE(i, 3),
+			CURVE(i, 4), CURVE(i, 5), CURVE(i, 6), CURVE(i, 7),
+			CURVE(i, 8), CURVE(i, 9), CURVE(i, 10), CURVE(i, 11),
+			CURVE(i, 12), CURVE(i, 13), CURVE(i, 14), CURVE(i,15));
+
+	return 0;
+}
+#undef CURVE
+
+
+static struct fbtft_display display = {
+	.regwidth = 8,
+	.width = 128,
+	.height = 160,
+	.init_sequence = default_init_sequence,
+	.gamma_num = 2,
+	.gamma_len = 16,
+	.gamma = DEFAULT_GAMMA,
+	.fbtftops = {
+		.set_addr_win = set_addr_win,
+		.set_var = set_var,
+		.set_gamma = set_gamma,
+	},
+};
+FBTFT_REGISTER_DRIVER(DRVNAME, "sitronix,st7735r", &display);
+
+MODULE_ALIAS("spi:" DRVNAME);
+MODULE_ALIAS("platform:" DRVNAME);
+MODULE_ALIAS("spi:st7735r");
+MODULE_ALIAS("platform:st7735r");
+
+MODULE_DESCRIPTION("FB driver for the ST7735R LCD Controller");
+MODULE_AUTHOR("Noralf Tronnes");
+MODULE_LICENSE("GPL");