drivers/video/ti/am335x-fb.c - platform/external/u-boot - Gitiles

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Copyright (C) 2013-2018 Hannes Schmelzer <oe5hpm@oevsv.at>
  * B&R Industrial Automation GmbH - http://www.br-automation.com
  * Copyright (C) 2020 Dario Binacchi <dariobin@libero.it>
  *
  * minimal framebuffer driver for TI's AM335x SoC to be compatible with
  * Wolfgang Denk's LCD-Framework (CONFIG_LCD, common/lcd.c)
  *
  * - supporting 16/24/32bit RGB/TFT raster Mode (not using palette)
  * - sets up LCD controller as in 'am335x_lcdpanel' struct given
  * - starts output DMA from gd->fb_base buffer
  */
 #include <common.h>
 #include <lcd.h>
 #include <log.h>
 #include <asm/arch/clock.h>
 #include <asm/arch/hardware.h>
 #include <asm/arch/omap.h>
 #include <asm/arch/sys_proto.h>
 #include <asm/global_data.h>
 #include <asm/io.h>
 #include <linux/delay.h>
 #include <linux/err.h>
 #include "am335x-fb.h"

 #define LCDC_FMAX				200000000

 /* LCD Control Register */
 #define LCDC_CTRL_CLK_DIVISOR_MASK		GENMASK(15, 8)
 #define LCDC_CTRL_RASTER_MODE			BIT(0)
 #define LCDC_CTRL_CLK_DIVISOR(x)		(((x) & GENMASK(7, 0)) << 8)
 /* LCD Clock Enable Register */
 #define LCDC_CLKC_ENABLE_CORECLKEN		BIT(0)
 #define LCDC_CLKC_ENABLE_LIDDCLKEN		BIT(1)
 #define LCDC_CLKC_ENABLE_DMACLKEN		BIT(2)
 /* LCD DMA Control Register */
 #define LCDC_DMA_CTRL_BURST_SIZE(x)		(((x) & GENMASK(2, 0)) << 4)
 #define LCDC_DMA_CTRL_BURST_1			0x0
 #define LCDC_DMA_CTRL_BURST_2			0x1
 #define LCDC_DMA_CTRL_BURST_4			0x2
 #define LCDC_DMA_CTRL_BURST_8			0x3
 #define LCDC_DMA_CTRL_BURST_16			0x4
 #define LCDC_DMA_CTRL_FIFO_TH(x)		(((x) & GENMASK(2, 0)) << 8)
 /* LCD Timing_0 Register */
 #define LCDC_RASTER_TIMING_0_HORMSB(x)	((((x) - 1) & BIT(10)) >> 7)
 #define LCDC_RASTER_TIMING_0_HORLSB(x) (((((x) >> 4) - 1) & GENMASK(5, 0)) << 4)
 #define LCDC_RASTER_TIMING_0_HSWLSB(x)	((((x) - 1) & GENMASK(5, 0)) << 10)
 #define LCDC_RASTER_TIMING_0_HFPLSB(x)	((((x) - 1) & GENMASK(7, 0)) << 16)
 #define LCDC_RASTER_TIMING_0_HBPLSB(x)	((((x) - 1) & GENMASK(7, 0)) << 24)
 /* LCD Timing_1 Register */
 #define LCDC_RASTER_TIMING_1_VERLSB(x)		(((x) - 1) & GENMASK(9, 0))
 #define LCDC_RASTER_TIMING_1_VSW(x)	((((x) - 1) & GENMASK(5, 0)) << 10)
 #define LCDC_RASTER_TIMING_1_VFP(x)		(((x) & GENMASK(7, 0)) << 16)
 #define LCDC_RASTER_TIMING_1_VBP(x)		(((x) & GENMASK(7, 0)) << 24)
 /* LCD Timing_2 Register */
 #define LCDC_RASTER_TIMING_2_HFPMSB(x)	((((x) - 1) & GENMASK(9, 8)) >> 8)
 #define LCDC_RASTER_TIMING_2_HBPMSB(x)	((((x) - 1) & GENMASK(9, 8)) >> 4)
 #define LCDC_RASTER_TIMING_2_ACB(x)		(((x) & GENMASK(7, 0)) << 8)
 #define LCDC_RASTER_TIMING_2_ACBI(x)		(((x) & GENMASK(3, 0)) << 16)
 #define LCDC_RASTER_TIMING_2_VSYNC_INVERT	BIT(20)
 #define LCDC_RASTER_TIMING_2_HSYNC_INVERT	BIT(21)
 #define LCDC_RASTER_TIMING_2_PXCLK_INVERT	BIT(22)
 #define LCDC_RASTER_TIMING_2_DE_INVERT		BIT(23)
 #define LCDC_RASTER_TIMING_2_HSVS_RISEFALL	BIT(24)
 #define LCDC_RASTER_TIMING_2_HSVS_CONTROL	BIT(25)
 #define LCDC_RASTER_TIMING_2_VERMSB(x)		((((x) - 1) & BIT(10)) << 16)
 #define LCDC_RASTER_TIMING_2_HSWMSB(x)	((((x) - 1) & GENMASK(9, 6)) << 21)
 /* LCD Raster Ctrl Register */
 #define LCDC_RASTER_CTRL_ENABLE			BIT(0)
 #define LCDC_RASTER_CTRL_TFT_MODE		BIT(7)
 #define LCDC_RASTER_CTRL_DATA_ORDER		BIT(8)
 #define LCDC_RASTER_CTRL_REQDLY(x)		(((x) & GENMASK(7, 0)) << 12)
 #define LCDC_RASTER_CTRL_PALMODE_RAWDATA	(0x02 << 20)
 #define LCDC_RASTER_CTRL_TFT_ALT_ENABLE		BIT(23)
 #define LCDC_RASTER_CTRL_TFT_24BPP_MODE		BIT(25)
 #define LCDC_RASTER_CTRL_TFT_24BPP_UNPACK	BIT(26)

 struct am335x_lcdhw {
 	unsigned int		pid;			/* 0x00 */
 	unsigned int		ctrl;			/* 0x04 */
 	unsigned int		gap0;			/* 0x08 */
 	unsigned int		lidd_ctrl;		/* 0x0C */
 	unsigned int		lidd_cs0_conf;		/* 0x10 */
 	unsigned int		lidd_cs0_addr;		/* 0x14 */
 	unsigned int		lidd_cs0_data;		/* 0x18 */
 	unsigned int		lidd_cs1_conf;		/* 0x1C */
 	unsigned int		lidd_cs1_addr;		/* 0x20 */
 	unsigned int		lidd_cs1_data;		/* 0x24 */
 	unsigned int		raster_ctrl;		/* 0x28 */
 	unsigned int		raster_timing0;		/* 0x2C */
 	unsigned int		raster_timing1;		/* 0x30 */
 	unsigned int		raster_timing2;		/* 0x34 */
 	unsigned int		raster_subpanel;	/* 0x38 */
 	unsigned int		raster_subpanel2;	/* 0x3C */
 	unsigned int		lcddma_ctrl;		/* 0x40 */
 	unsigned int		lcddma_fb0_base;	/* 0x44 */
 	unsigned int		lcddma_fb0_ceiling;	/* 0x48 */
 	unsigned int		lcddma_fb1_base;	/* 0x4C */
 	unsigned int		lcddma_fb1_ceiling;	/* 0x50 */
 	unsigned int		sysconfig;		/* 0x54 */
 	unsigned int		irqstatus_raw;		/* 0x58 */
 	unsigned int		irqstatus;		/* 0x5C */
 	unsigned int		irqenable_set;		/* 0x60 */
 	unsigned int		irqenable_clear;	/* 0x64 */
 	unsigned int		gap1;			/* 0x68 */
 	unsigned int		clkc_enable;		/* 0x6C */
 	unsigned int		clkc_reset;		/* 0x70 */
 };

 DECLARE_GLOBAL_DATA_PTR;

 #if !defined(LCD_CNTL_BASE)
 #error "hw-base address of LCD-Controller (LCD_CNTL_BASE) not defined!"
 #endif

 /* Macro definitions */
 #define FBSIZE(x)	(((x)->hactive * (x)->vactive * (x)->bpp) >> 3)

 #define LCDC_RASTER_TIMING_2_INVMASK(x)		((x) & GENMASK(25, 20))

 static struct am335x_lcdhw *lcdhw = (void *)LCD_CNTL_BASE;

 int lcd_get_size(int *line_length)
 {
 	*line_length = (panel_info.vl_col * NBITS(panel_info.vl_bpix)) / 8;
 	return *line_length * panel_info.vl_row + 0x20;
 }

 struct dpll_data {
 	unsigned long rounded_rate;
 	u16 rounded_m;
 	u8 rounded_n;
 	u8 rounded_div;
 };

 /**
  * am335x_dpll_round_rate() - Round a target rate for an OMAP DPLL
  *
  * @dpll_data: struct dpll_data pointer for the DPLL
  * @rate:      New DPLL clock rate
  * @return rounded rate and the computed m, n and div values in the dpll_data
  *         structure, or -ve error code.
  */
 static ulong am335x_dpll_round_rate(struct dpll_data *dd, ulong rate)
 {
 	unsigned int m, n, d;
 	unsigned long rounded_rate;
 	int err, err_r;

 	dd->rounded_rate = -EFAULT;
 	err = rate;
 	err_r = err;

 	for (d = 2; err && d < 255; d++) {
 		for (m = 2; m < 2047; m++) {
 			if ((V_OSCK * m) < (rate * d))
 				continue;

 			n = (V_OSCK * m) / (rate * d);
 			if (n > 127)
 				break;

 			if (((V_OSCK * m) / n) > LCDC_FMAX)
 				break;

 			rounded_rate = (V_OSCK * m) / n / d;
 			err = abs(rounded_rate - rate);
 			if (err < err_r) {
 				err_r = err;
 				dd->rounded_rate = rounded_rate;
 				dd->rounded_m = m;
 				dd->rounded_n = n;
 				dd->rounded_div = d;
 				if (err == 0)
 					break;
 			}
 		}
 	}

 	debug("DPLL display: best error %d Hz (M %d, N %d, DIV %d)\n",
 	      err_r, dd->rounded_m, dd->rounded_n, dd->rounded_div);

 	return dd->rounded_rate;
 }

 /**
  * am335x_fb_set_pixel_clk_rate() - Set pixel clock rate.
  *
  * @am335x_lcdhw: Base address of the LCD controller registers.
  * @rate:         New clock rate in Hz.
  * @return new rate, or -ve error code.
  */
 static ulong am335x_fb_set_pixel_clk_rate(struct am335x_lcdhw *regs, ulong rate)
 {
 	struct dpll_params dpll_disp = { 1, 0, 1, -1, -1, -1, -1 };
 	struct dpll_data dd;
 	ulong round_rate;
 	u32 reg;

 	round_rate = am335x_dpll_round_rate(&dd, rate);
 	if (IS_ERR_VALUE(round_rate))
 		return round_rate;

 	dpll_disp.m = dd.rounded_m;
 	dpll_disp.n = dd.rounded_n;
 	do_setup_dpll(&dpll_disp_regs, &dpll_disp);

 	reg = readl(&regs->ctrl) & ~LCDC_CTRL_CLK_DIVISOR_MASK;
 	reg |= LCDC_CTRL_CLK_DIVISOR(dd.rounded_div);
 	writel(reg, &regs->ctrl);
 	return round_rate;
 }

 int am335xfb_init(struct am335x_lcdpanel *panel)
 {
 	u32 raster_ctrl = 0;
 	struct cm_dpll *const cmdpll = (struct cm_dpll *)CM_DPLL;
 	ulong rate;
 	u32 reg;

 	if (gd->fb_base == 0) {
 		printf("ERROR: no valid fb_base stored in GLOBAL_DATA_PTR!\n");
 		return -1;
 	}
 	if (panel == NULL) {
 		printf("ERROR: missing ptr to am335x_lcdpanel!\n");
 		return -1;
 	}

 	/* We can already set the bits for the raster_ctrl in this check */
 	switch (panel->bpp) {
 	case 16:
 		break;
 	case 32:
 		raster_ctrl |= LCDC_RASTER_CTRL_TFT_24BPP_UNPACK;
 		/* fallthrough */
 	case 24:
 		raster_ctrl |= LCDC_RASTER_CTRL_TFT_24BPP_MODE;
 		break;
 	default:
 		pr_err("am335x-fb: invalid bpp value: %d\n", panel->bpp);
 		return -1;
 	}

 	/* check given clock-frequency */
 	if (panel->pxl_clk > (LCDC_FMAX / 2)) {
 		pr_err("am335x-fb: requested pxl-clk: %d not supported!\n",
 		       panel->pxl_clk);
 		return -1;
 	}

 	debug("setting up LCD-Controller for %dx%dx%d (hfp=%d,hbp=%d,hsw=%d / ",
 	      panel->hactive, panel->vactive, panel->bpp,
 	      panel->hfp, panel->hbp, panel->hsw);
 	debug("vfp=%d,vbp=%d,vsw=%d / clk=%d)\n",
 	      panel->vfp, panel->vfp, panel->vsw, panel->pxl_clk);
 	debug("using frambuffer at 0x%08x with size %d.\n",
 	      (unsigned int)gd->fb_base, FBSIZE(panel));

 	rate = am335x_fb_set_pixel_clk_rate(lcdhw, panel->pxl_clk);
 	if (IS_ERR_VALUE(rate))
 		return rate;

 	/* clock source for LCDC from dispPLL M2 */
 	writel(0x0, &cmdpll->clklcdcpixelclk);

 	/* palette default entry */
 	memset((void *)gd->fb_base, 0, 0x20);
 	*(unsigned int *)gd->fb_base = 0x4000;
 	/* point fb behind palette */
 	gd->fb_base += 0x20;

 	/* turn ON display through powercontrol function if accessible */
 	if (panel->panel_power_ctrl != NULL)
 		panel->panel_power_ctrl(1);

 	debug("am335x-fb: wait for stable power ...\n");
 	mdelay(panel->pup_delay);
 	lcdhw->clkc_enable = LCDC_CLKC_ENABLE_CORECLKEN |
 		LCDC_CLKC_ENABLE_LIDDCLKEN | LCDC_CLKC_ENABLE_DMACLKEN;
 	lcdhw->raster_ctrl = 0;

 	reg = lcdhw->ctrl & LCDC_CTRL_CLK_DIVISOR_MASK;
 	reg |= LCDC_CTRL_RASTER_MODE;
 	lcdhw->ctrl = reg;

 	lcdhw->lcddma_fb0_base = gd->fb_base;
 	lcdhw->lcddma_fb0_ceiling = gd->fb_base + FBSIZE(panel);
 	lcdhw->lcddma_fb1_base = gd->fb_base;
 	lcdhw->lcddma_fb1_ceiling = gd->fb_base + FBSIZE(panel);
 	lcdhw->lcddma_ctrl = LCDC_DMA_CTRL_BURST_SIZE(LCDC_DMA_CTRL_BURST_16);

 	lcdhw->raster_timing0 = LCDC_RASTER_TIMING_0_HORLSB(panel->hactive) |
 				LCDC_RASTER_TIMING_0_HORMSB(panel->hactive) |
 				LCDC_RASTER_TIMING_0_HFPLSB(panel->hfp) |
 				LCDC_RASTER_TIMING_0_HBPLSB(panel->hbp) |
 				LCDC_RASTER_TIMING_0_HSWLSB(panel->hsw);
 	lcdhw->raster_timing1 = LCDC_RASTER_TIMING_1_VBP(panel->vbp) |
 				LCDC_RASTER_TIMING_1_VFP(panel->vfp) |
 				LCDC_RASTER_TIMING_1_VSW(panel->vsw) |
 				LCDC_RASTER_TIMING_1_VERLSB(panel->vactive);
 	lcdhw->raster_timing2 = LCDC_RASTER_TIMING_2_HSWMSB(panel->hsw) |
 				LCDC_RASTER_TIMING_2_VERMSB(panel->vactive) |
 				LCDC_RASTER_TIMING_2_INVMASK(panel->pol) |
 				LCDC_RASTER_TIMING_2_HBPMSB(panel->hbp) |
 				LCDC_RASTER_TIMING_2_HFPMSB(panel->hfp) |
 				0x0000FF00;	/* clk cycles for ac-bias */
 	lcdhw->raster_ctrl =	raster_ctrl |
 				LCDC_RASTER_CTRL_PALMODE_RAWDATA |
 				LCDC_RASTER_CTRL_TFT_MODE |
 				LCDC_RASTER_CTRL_ENABLE;

 	debug("am335x-fb: waiting picture to be stable.\n.");
 	mdelay(panel->pon_delay);

 	return 0;
 }
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* Copyright (C) 2013-2018 Hannes Schmelzer <oe5hpm@oevsv.at>
	* B&R Industrial Automation GmbH - http://www.br-automation.com
	* Copyright (C) 2020 Dario Binacchi <dariobin@libero.it>
	*
	* minimal framebuffer driver for TI's AM335x SoC to be compatible with
	* Wolfgang Denk's LCD-Framework (CONFIG_LCD, common/lcd.c)
	*
	* - supporting 16/24/32bit RGB/TFT raster Mode (not using palette)
	* - sets up LCD controller as in 'am335x_lcdpanel' struct given
	* - starts output DMA from gd->fb_base buffer
	*/
	#include <common.h>
	#include <lcd.h>
	#include <log.h>
	#include <asm/arch/clock.h>
	#include <asm/arch/hardware.h>
	#include <asm/arch/omap.h>
	#include <asm/arch/sys_proto.h>
	#include <asm/global_data.h>
	#include <asm/io.h>
	#include <linux/delay.h>
	#include <linux/err.h>
	#include "am335x-fb.h"

	#define LCDC_FMAX 200000000

	/* LCD Control Register */
	#define LCDC_CTRL_CLK_DIVISOR_MASK GENMASK(15, 8)
	#define LCDC_CTRL_RASTER_MODE BIT(0)
	#define LCDC_CTRL_CLK_DIVISOR(x) (((x) & GENMASK(7, 0)) << 8)
	/* LCD Clock Enable Register */
	#define LCDC_CLKC_ENABLE_CORECLKEN BIT(0)
	#define LCDC_CLKC_ENABLE_LIDDCLKEN BIT(1)
	#define LCDC_CLKC_ENABLE_DMACLKEN BIT(2)
	/* LCD DMA Control Register */
	#define LCDC_DMA_CTRL_BURST_SIZE(x) (((x) & GENMASK(2, 0)) << 4)
	#define LCDC_DMA_CTRL_BURST_1 0x0
	#define LCDC_DMA_CTRL_BURST_2 0x1
	#define LCDC_DMA_CTRL_BURST_4 0x2
	#define LCDC_DMA_CTRL_BURST_8 0x3
	#define LCDC_DMA_CTRL_BURST_16 0x4
	#define LCDC_DMA_CTRL_FIFO_TH(x) (((x) & GENMASK(2, 0)) << 8)
	/* LCD Timing_0 Register */
	#define LCDC_RASTER_TIMING_0_HORMSB(x) ((((x) - 1) & BIT(10)) >> 7)
	#define LCDC_RASTER_TIMING_0_HORLSB(x) (((((x) >> 4) - 1) & GENMASK(5, 0)) << 4)
	#define LCDC_RASTER_TIMING_0_HSWLSB(x) ((((x) - 1) & GENMASK(5, 0)) << 10)
	#define LCDC_RASTER_TIMING_0_HFPLSB(x) ((((x) - 1) & GENMASK(7, 0)) << 16)
	#define LCDC_RASTER_TIMING_0_HBPLSB(x) ((((x) - 1) & GENMASK(7, 0)) << 24)
	/* LCD Timing_1 Register */
	#define LCDC_RASTER_TIMING_1_VERLSB(x) (((x) - 1) & GENMASK(9, 0))
	#define LCDC_RASTER_TIMING_1_VSW(x) ((((x) - 1) & GENMASK(5, 0)) << 10)
	#define LCDC_RASTER_TIMING_1_VFP(x) (((x) & GENMASK(7, 0)) << 16)
	#define LCDC_RASTER_TIMING_1_VBP(x) (((x) & GENMASK(7, 0)) << 24)
	/* LCD Timing_2 Register */
	#define LCDC_RASTER_TIMING_2_HFPMSB(x) ((((x) - 1) & GENMASK(9, 8)) >> 8)
	#define LCDC_RASTER_TIMING_2_HBPMSB(x) ((((x) - 1) & GENMASK(9, 8)) >> 4)
	#define LCDC_RASTER_TIMING_2_ACB(x) (((x) & GENMASK(7, 0)) << 8)
	#define LCDC_RASTER_TIMING_2_ACBI(x) (((x) & GENMASK(3, 0)) << 16)
	#define LCDC_RASTER_TIMING_2_VSYNC_INVERT BIT(20)
	#define LCDC_RASTER_TIMING_2_HSYNC_INVERT BIT(21)
	#define LCDC_RASTER_TIMING_2_PXCLK_INVERT BIT(22)
	#define LCDC_RASTER_TIMING_2_DE_INVERT BIT(23)
	#define LCDC_RASTER_TIMING_2_HSVS_RISEFALL BIT(24)
	#define LCDC_RASTER_TIMING_2_HSVS_CONTROL BIT(25)
	#define LCDC_RASTER_TIMING_2_VERMSB(x) ((((x) - 1) & BIT(10)) << 16)
	#define LCDC_RASTER_TIMING_2_HSWMSB(x) ((((x) - 1) & GENMASK(9, 6)) << 21)
	/* LCD Raster Ctrl Register */
	#define LCDC_RASTER_CTRL_ENABLE BIT(0)
	#define LCDC_RASTER_CTRL_TFT_MODE BIT(7)
	#define LCDC_RASTER_CTRL_DATA_ORDER BIT(8)
	#define LCDC_RASTER_CTRL_REQDLY(x) (((x) & GENMASK(7, 0)) << 12)
	#define LCDC_RASTER_CTRL_PALMODE_RAWDATA (0x02 << 20)
	#define LCDC_RASTER_CTRL_TFT_ALT_ENABLE BIT(23)
	#define LCDC_RASTER_CTRL_TFT_24BPP_MODE BIT(25)
	#define LCDC_RASTER_CTRL_TFT_24BPP_UNPACK BIT(26)

	struct am335x_lcdhw {
	unsigned int pid; /* 0x00 */
	unsigned int ctrl; /* 0x04 */
	unsigned int gap0; /* 0x08 */
	unsigned int lidd_ctrl; /* 0x0C */
	unsigned int lidd_cs0_conf; /* 0x10 */
	unsigned int lidd_cs0_addr; /* 0x14 */
	unsigned int lidd_cs0_data; /* 0x18 */
	unsigned int lidd_cs1_conf; /* 0x1C */
	unsigned int lidd_cs1_addr; /* 0x20 */
	unsigned int lidd_cs1_data; /* 0x24 */
	unsigned int raster_ctrl; /* 0x28 */
	unsigned int raster_timing0; /* 0x2C */
	unsigned int raster_timing1; /* 0x30 */
	unsigned int raster_timing2; /* 0x34 */
	unsigned int raster_subpanel; /* 0x38 */
	unsigned int raster_subpanel2; /* 0x3C */
	unsigned int lcddma_ctrl; /* 0x40 */
	unsigned int lcddma_fb0_base; /* 0x44 */
	unsigned int lcddma_fb0_ceiling; /* 0x48 */
	unsigned int lcddma_fb1_base; /* 0x4C */
	unsigned int lcddma_fb1_ceiling; /* 0x50 */
	unsigned int sysconfig; /* 0x54 */
	unsigned int irqstatus_raw; /* 0x58 */
	unsigned int irqstatus; /* 0x5C */
	unsigned int irqenable_set; /* 0x60 */
	unsigned int irqenable_clear; /* 0x64 */
	unsigned int gap1; /* 0x68 */
	unsigned int clkc_enable; /* 0x6C */
	unsigned int clkc_reset; /* 0x70 */
	};

	DECLARE_GLOBAL_DATA_PTR;

	#if !defined(LCD_CNTL_BASE)
	#error "hw-base address of LCD-Controller (LCD_CNTL_BASE) not defined!"
	#endif

	/* Macro definitions */
	#define FBSIZE(x) (((x)->hactive * (x)->vactive * (x)->bpp) >> 3)

	#define LCDC_RASTER_TIMING_2_INVMASK(x) ((x) & GENMASK(25, 20))

	static struct am335x_lcdhw lcdhw = (void )LCD_CNTL_BASE;

	int lcd_get_size(int *line_length)
	{
	line_length = (panel_info.vl_col NBITS(panel_info.vl_bpix)) / 8;
	return line_length panel_info.vl_row + 0x20;
	}

	struct dpll_data {
	unsigned long rounded_rate;
	u16 rounded_m;
	u8 rounded_n;
	u8 rounded_div;
	};

	/**
	* am335x_dpll_round_rate() - Round a target rate for an OMAP DPLL
	*
	* @dpll_data: struct dpll_data pointer for the DPLL
	* @rate: New DPLL clock rate
	* @return rounded rate and the computed m, n and div values in the dpll_data
	* structure, or -ve error code.
	*/
	static ulong am335x_dpll_round_rate(struct dpll_data *dd, ulong rate)
	{
	unsigned int m, n, d;
	unsigned long rounded_rate;
	int err, err_r;

	dd->rounded_rate = -EFAULT;
	err = rate;
	err_r = err;

	for (d = 2; err && d < 255; d++) {
	for (m = 2; m < 2047; m++) {
	if ((V_OSCK * m) < (rate * d))
	continue;

	n = (V_OSCK * m) / (rate * d);
	if (n > 127)
	break;

	if (((V_OSCK * m) / n) > LCDC_FMAX)
	break;

	rounded_rate = (V_OSCK * m) / n / d;
	err = abs(rounded_rate - rate);
	if (err < err_r) {
	err_r = err;
	dd->rounded_rate = rounded_rate;
	dd->rounded_m = m;
	dd->rounded_n = n;
	dd->rounded_div = d;
	if (err == 0)
	break;
	}
	}
	}

	debug("DPLL display: best error %d Hz (M %d, N %d, DIV %d)\n",
	err_r, dd->rounded_m, dd->rounded_n, dd->rounded_div);

	return dd->rounded_rate;
	}

	/**
	* am335x_fb_set_pixel_clk_rate() - Set pixel clock rate.
	*
	* @am335x_lcdhw: Base address of the LCD controller registers.
	* @rate: New clock rate in Hz.
	* @return new rate, or -ve error code.
	*/
	static ulong am335x_fb_set_pixel_clk_rate(struct am335x_lcdhw *regs, ulong rate)
	{
	struct dpll_params dpll_disp = { 1, 0, 1, -1, -1, -1, -1 };
	struct dpll_data dd;
	ulong round_rate;
	u32 reg;

	round_rate = am335x_dpll_round_rate(&dd, rate);
	if (IS_ERR_VALUE(round_rate))
	return round_rate;

	dpll_disp.m = dd.rounded_m;
	dpll_disp.n = dd.rounded_n;
	do_setup_dpll(&dpll_disp_regs, &dpll_disp);

	reg = readl(&regs->ctrl) & ~LCDC_CTRL_CLK_DIVISOR_MASK;
	reg \|= LCDC_CTRL_CLK_DIVISOR(dd.rounded_div);
	writel(reg, &regs->ctrl);
	return round_rate;
	}

	int am335xfb_init(struct am335x_lcdpanel *panel)
	{
	u32 raster_ctrl = 0;
	struct cm_dpll const cmdpll = (struct cm_dpll )CM_DPLL;
	ulong rate;
	u32 reg;

	if (gd->fb_base == 0) {
	printf("ERROR: no valid fb_base stored in GLOBAL_DATA_PTR!\n");
	return -1;
	}
	if (panel == NULL) {
	printf("ERROR: missing ptr to am335x_lcdpanel!\n");
	return -1;
	}

	/* We can already set the bits for the raster_ctrl in this check */
	switch (panel->bpp) {
	case 16:
	break;
	case 32:
	raster_ctrl \|= LCDC_RASTER_CTRL_TFT_24BPP_UNPACK;
	/* fallthrough */
	case 24:
	raster_ctrl \|= LCDC_RASTER_CTRL_TFT_24BPP_MODE;
	break;
	default:
	pr_err("am335x-fb: invalid bpp value: %d\n", panel->bpp);
	return -1;
	}

	/* check given clock-frequency */
	if (panel->pxl_clk > (LCDC_FMAX / 2)) {
	pr_err("am335x-fb: requested pxl-clk: %d not supported!\n",
	panel->pxl_clk);
	return -1;
	}

	debug("setting up LCD-Controller for %dx%dx%d (hfp=%d,hbp=%d,hsw=%d / ",
	panel->hactive, panel->vactive, panel->bpp,
	panel->hfp, panel->hbp, panel->hsw);
	debug("vfp=%d,vbp=%d,vsw=%d / clk=%d)\n",
	panel->vfp, panel->vfp, panel->vsw, panel->pxl_clk);
	debug("using frambuffer at 0x%08x with size %d.\n",
	(unsigned int)gd->fb_base, FBSIZE(panel));

	rate = am335x_fb_set_pixel_clk_rate(lcdhw, panel->pxl_clk);
	if (IS_ERR_VALUE(rate))
	return rate;

	/* clock source for LCDC from dispPLL M2 */
	writel(0x0, &cmdpll->clklcdcpixelclk);

	/* palette default entry */
	memset((void *)gd->fb_base, 0, 0x20);
	(unsigned int )gd->fb_base = 0x4000;
	/* point fb behind palette */
	gd->fb_base += 0x20;

	/* turn ON display through powercontrol function if accessible */
	if (panel->panel_power_ctrl != NULL)
	panel->panel_power_ctrl(1);

	debug("am335x-fb: wait for stable power ...\n");
	mdelay(panel->pup_delay);
	lcdhw->clkc_enable = LCDC_CLKC_ENABLE_CORECLKEN \|
	LCDC_CLKC_ENABLE_LIDDCLKEN \| LCDC_CLKC_ENABLE_DMACLKEN;
	lcdhw->raster_ctrl = 0;

	reg = lcdhw->ctrl & LCDC_CTRL_CLK_DIVISOR_MASK;
	reg \|= LCDC_CTRL_RASTER_MODE;
	lcdhw->ctrl = reg;

	lcdhw->lcddma_fb0_base = gd->fb_base;
	lcdhw->lcddma_fb0_ceiling = gd->fb_base + FBSIZE(panel);
	lcdhw->lcddma_fb1_base = gd->fb_base;
	lcdhw->lcddma_fb1_ceiling = gd->fb_base + FBSIZE(panel);
	lcdhw->lcddma_ctrl = LCDC_DMA_CTRL_BURST_SIZE(LCDC_DMA_CTRL_BURST_16);

	lcdhw->raster_timing0 = LCDC_RASTER_TIMING_0_HORLSB(panel->hactive) \|
	LCDC_RASTER_TIMING_0_HORMSB(panel->hactive) \|
	LCDC_RASTER_TIMING_0_HFPLSB(panel->hfp) \|
	LCDC_RASTER_TIMING_0_HBPLSB(panel->hbp) \|
	LCDC_RASTER_TIMING_0_HSWLSB(panel->hsw);
	lcdhw->raster_timing1 = LCDC_RASTER_TIMING_1_VBP(panel->vbp) \|
	LCDC_RASTER_TIMING_1_VFP(panel->vfp) \|
	LCDC_RASTER_TIMING_1_VSW(panel->vsw) \|
	LCDC_RASTER_TIMING_1_VERLSB(panel->vactive);
	lcdhw->raster_timing2 = LCDC_RASTER_TIMING_2_HSWMSB(panel->hsw) \|
	LCDC_RASTER_TIMING_2_VERMSB(panel->vactive) \|
	LCDC_RASTER_TIMING_2_INVMASK(panel->pol) \|
	LCDC_RASTER_TIMING_2_HBPMSB(panel->hbp) \|
	LCDC_RASTER_TIMING_2_HFPMSB(panel->hfp) \|
	0x0000FF00; /* clk cycles for ac-bias */
	lcdhw->raster_ctrl = raster_ctrl \|
	LCDC_RASTER_CTRL_PALMODE_RAWDATA \|
	LCDC_RASTER_CTRL_TFT_MODE \|
	LCDC_RASTER_CTRL_ENABLE;

	debug("am335x-fb: waiting picture to be stable.\n.");
	mdelay(panel->pon_delay);

	return 0;
	}