/*
 * FB driver for the ILI9325 LCD Controller
 *
 * Copyright (C) 2013 Noralf Tronnes
 *
 * Based on ili9325.c by Jeroen Domburg
 *
 * 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_ili9325"
#define WIDTH		240
#define HEIGHT		320
#define BPP		16
#define FPS		20
#define DEFAULT_GAMMA	"0F 00 7 2 0 0 6 5 4 1\n" \
			"04 16 2 7 6 3 2 1 7 7"

static unsigned bt = 6; /* VGL=Vci*4 , VGH=Vci*4 */
module_param(bt, uint, 0);
MODULE_PARM_DESC(bt, "Sets the factor used in the step-up circuits");

static unsigned vc = 0x03; /* Vci1=Vci*0.80 */
module_param(vc, uint, 0);
MODULE_PARM_DESC(vc,
"Sets the ratio factor of Vci to generate the reference voltages Vci1");

static unsigned vrh = 0x0d; /* VREG1OUT=Vci*1.85 */
module_param(vrh, uint, 0);
MODULE_PARM_DESC(vrh,
"Set the amplifying rate (1.6 ~ 1.9) of Vci applied to output the VREG1OUT");

static unsigned vdv = 0x12; /* VCOMH amplitude=VREG1OUT*0.98 */
module_param(vdv, uint, 0);
MODULE_PARM_DESC(vdv,
"Select the factor of VREG1OUT to set the amplitude of Vcom");

static unsigned vcm = 0x0a; /* VCOMH=VREG1OUT*0.735 */
module_param(vcm, uint, 0);
MODULE_PARM_DESC(vcm, "Set the internal VcomH voltage");

/*
 * Verify that this configuration is within the Voltage limits
 *
 * Display module configuration: Vcc = IOVcc = Vci = 3.3V
 *
 * Voltages
 * ----------
 * Vci                                =   3.3
 * Vci1           =  Vci * 0.80       =   2.64
 * DDVDH          =  Vci1 * 2         =   5.28
 * VCL            = -Vci1             =  -2.64
 * VREG1OUT       =  Vci * 1.85       =   4.88
 * VCOMH          =  VREG1OUT * 0.735 =   3.59
 * VCOM amplitude =  VREG1OUT * 0.98  =   4.79
 * VGH            =  Vci * 4          =  13.2
 * VGL            = -Vci * 4          = -13.2
 *
 * Limits
 * --------
 * Power supplies
 * 1.65 < IOVcc < 3.30   =>  1.65 < 3.3 < 3.30
 * 2.40 < Vcc   < 3.30   =>  2.40 < 3.3 < 3.30
 * 2.50 < Vci   < 3.30   =>  2.50 < 3.3 < 3.30
 *
 * Source/VCOM power supply voltage
 *  4.50 < DDVDH < 6.0   =>  4.50 <  5.28 <  6.0
 * -3.0  < VCL   < -2.0  =>  -3.0 < -2.64 < -2.0
 * VCI - VCL < 6.0       =>  5.94 < 6.0
 *
 * Gate driver output voltage
 *  10  < VGH   < 20     =>   10 <  13.2  < 20
 * -15  < VGL   < -5     =>  -15 < -13.2  < -5
 * VGH - VGL < 32        =>   26.4 < 32
 *
 * VCOM driver output voltage
 * VCOMH - VCOML < 6.0   =>  4.79 < 6.0
 */

static int init_display(struct fbtft_par *par)
{
	par->fbtftops.reset(par);

	if (par->gpio.cs != -1)
		gpio_set_value(par->gpio.cs, 0);  /* Activate chip */

	bt &= 0x07;
	vc &= 0x07;
	vrh &= 0x0f;
	vdv &= 0x1f;
	vcm &= 0x3f;

	/* Initialization sequence from ILI9325 Application Notes */

	/* ----------- Start Initial Sequence ----------- */
	write_reg(par, 0x00E3, 0x3008); /* Set internal timing */
	write_reg(par, 0x00E7, 0x0012); /* Set internal timing */
	write_reg(par, 0x00EF, 0x1231); /* Set internal timing */
	write_reg(par, 0x0001, 0x0100); /* set SS and SM bit */
	write_reg(par, 0x0002, 0x0700); /* set 1 line inversion */
	write_reg(par, 0x0004, 0x0000); /* Resize register */
	write_reg(par, 0x0008, 0x0207); /* set the back porch and front porch */
	write_reg(par, 0x0009, 0x0000); /* set non-display area refresh cycle */
	write_reg(par, 0x000A, 0x0000); /* FMARK function */
	write_reg(par, 0x000C, 0x0000); /* RGB interface setting */
	write_reg(par, 0x000D, 0x0000); /* Frame marker Position */
	write_reg(par, 0x000F, 0x0000); /* RGB interface polarity */

	/* ----------- Power On sequence ----------- */
	write_reg(par, 0x0010, 0x0000); /* SAP, BT[3:0], AP, DSTB, SLP, STB */
	write_reg(par, 0x0011, 0x0007); /* DC1[2:0], DC0[2:0], VC[2:0] */
	write_reg(par, 0x0012, 0x0000); /* VREG1OUT voltage */
	write_reg(par, 0x0013, 0x0000); /* VDV[4:0] for VCOM amplitude */
	mdelay(200); /* Dis-charge capacitor power voltage */
	write_reg(par, 0x0010, /* SAP, BT[3:0], AP, DSTB, SLP, STB */
		(1 << 12) | (bt << 8) | (1 << 7) | (0x01 << 4));
	write_reg(par, 0x0011, 0x220 | vc); /* DC1[2:0], DC0[2:0], VC[2:0] */
	mdelay(50); /* Delay 50ms */
	write_reg(par, 0x0012, vrh); /* Internal reference voltage= Vci; */
	mdelay(50); /* Delay 50ms */
	write_reg(par, 0x0013, vdv << 8); /* Set VDV[4:0] for VCOM amplitude */
	write_reg(par, 0x0029, vcm); /* Set VCM[5:0] for VCOMH */
	write_reg(par, 0x002B, 0x000C); /* Set Frame Rate */
	mdelay(50); /* Delay 50ms */
	write_reg(par, 0x0020, 0x0000); /* GRAM horizontal Address */
	write_reg(par, 0x0021, 0x0000); /* GRAM Vertical Address */

	/*------------------ Set GRAM area --------------- */
	write_reg(par, 0x0050, 0x0000); /* Horizontal GRAM Start Address */
	write_reg(par, 0x0051, 0x00EF); /* Horizontal GRAM End Address */
	write_reg(par, 0x0052, 0x0000); /* Vertical GRAM Start Address */
	write_reg(par, 0x0053, 0x013F); /* Vertical GRAM Start Address */
	write_reg(par, 0x0060, 0xA700); /* Gate Scan Line */
	write_reg(par, 0x0061, 0x0001); /* NDL,VLE, REV */
	write_reg(par, 0x006A, 0x0000); /* set scrolling line */

	/*-------------- Partial Display Control --------- */
	write_reg(par, 0x0080, 0x0000);
	write_reg(par, 0x0081, 0x0000);
	write_reg(par, 0x0082, 0x0000);
	write_reg(par, 0x0083, 0x0000);
	write_reg(par, 0x0084, 0x0000);
	write_reg(par, 0x0085, 0x0000);

	/*-------------- Panel Control ------------------- */
	write_reg(par, 0x0090, 0x0010);
	write_reg(par, 0x0092, 0x0600);
	write_reg(par, 0x0007, 0x0133); /* 262K color and display ON */

	return 0;
}

static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
{
	switch (par->info->var.rotate) {
	/* R20h = Horizontal GRAM Start Address */
	/* R21h = Vertical GRAM Start Address */
	case 0:
		write_reg(par, 0x0020, xs);
		write_reg(par, 0x0021, ys);
		break;
	case 180:
		write_reg(par, 0x0020, WIDTH - 1 - xs);
		write_reg(par, 0x0021, HEIGHT - 1 - ys);
		break;
	case 270:
		write_reg(par, 0x0020, WIDTH - 1 - ys);
		write_reg(par, 0x0021, xs);
		break;
	case 90:
		write_reg(par, 0x0020, ys);
		write_reg(par, 0x0021, HEIGHT - 1 - xs);
		break;
	}
	write_reg(par, 0x0022); /* Write Data to GRAM */
}

static int set_var(struct fbtft_par *par)
{
	switch (par->info->var.rotate) {
	/* AM: GRAM update direction */
	case 0:
		write_reg(par, 0x03, 0x0030 | (par->bgr << 12));
		break;
	case 180:
		write_reg(par, 0x03, 0x0000 | (par->bgr << 12));
		break;
	case 270:
		write_reg(par, 0x03, 0x0028 | (par->bgr << 12));
		break;
	case 90:
		write_reg(par, 0x03, 0x0018 | (par->bgr << 12));
		break;
	}

	return 0;
}

/*
 * Gamma string format:
 *  VRP0 VRP1 RP0 RP1 KP0 KP1 KP2 KP3 KP4 KP5
 *  VRN0 VRN1 RN0 RN1 KN0 KN1 KN2 KN3 KN4 KN5
 */
#define CURVE(num, idx)  curves[num * par->gamma.num_values + idx]
static int set_gamma(struct fbtft_par *par, unsigned long *curves)
{
	unsigned long mask[] = {
		0x1f, 0x1f, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07,
		0x1f, 0x1f, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07,
	};
	int i, j;

	/* apply mask */
	for (i = 0; i < 2; i++)
		for (j = 0; j < 10; j++)
			CURVE(i, j) &= mask[i * par->gamma.num_values + j];

	write_reg(par, 0x0030, CURVE(0, 5) << 8 | CURVE(0, 4));
	write_reg(par, 0x0031, CURVE(0, 7) << 8 | CURVE(0, 6));
	write_reg(par, 0x0032, CURVE(0, 9) << 8 | CURVE(0, 8));
	write_reg(par, 0x0035, CURVE(0, 3) << 8 | CURVE(0, 2));
	write_reg(par, 0x0036, CURVE(0, 1) << 8 | CURVE(0, 0));

	write_reg(par, 0x0037, CURVE(1, 5) << 8 | CURVE(1, 4));
	write_reg(par, 0x0038, CURVE(1, 7) << 8 | CURVE(1, 6));
	write_reg(par, 0x0039, CURVE(1, 9) << 8 | CURVE(1, 8));
	write_reg(par, 0x003C, CURVE(1, 3) << 8 | CURVE(1, 2));
	write_reg(par, 0x003D, CURVE(1, 1) << 8 | CURVE(1, 0));

	return 0;
}

#undef CURVE

static struct fbtft_display display = {
	.regwidth = 16,
	.width = WIDTH,
	.height = HEIGHT,
	.bpp = BPP,
	.fps = FPS,
	.gamma_num = 2,
	.gamma_len = 10,
	.gamma = DEFAULT_GAMMA,
	.fbtftops = {
		.init_display = init_display,
		.set_addr_win = set_addr_win,
		.set_var = set_var,
		.set_gamma = set_gamma,
	},
};

FBTFT_REGISTER_DRIVER(DRVNAME, "ilitek,ili9325", &display);

MODULE_ALIAS("spi:" DRVNAME);
MODULE_ALIAS("platform:" DRVNAME);
MODULE_ALIAS("spi:ili9325");
MODULE_ALIAS("platform:ili9325");

MODULE_DESCRIPTION("FB driver for the ILI9325 LCD Controller");
MODULE_AUTHOR("Noralf Tronnes");
MODULE_LICENSE("GPL");