path: root/drivers/video/am335x-fb.c

// 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 <dm.h>
#include <lcd.h>
#include <log.h>
#include <video.h>
#include <asm/arch/clock.h>
#include <asm/arch/hardware.h>
#include <asm/arch/omap.h>
#include <asm/arch/sys_proto.h>
#include <asm/io.h>
#include <asm/utils.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 */
};

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

DECLARE_GLOBAL_DATA_PTR;

/**
 * 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;
}

#if !CONFIG_IS_ENABLED(DM_VIDEO)

#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;
}

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;
}

#else /* CONFIG_DM_VIDEO */

#define FBSIZE(t, p)	(((t)->hactive.typ * (t)->vactive.typ * (p)->bpp) >> 3)

enum {
	LCD_MAX_WIDTH		= 2048,
	LCD_MAX_HEIGHT		= 2048,
	LCD_MAX_LOG2_BPP	= VIDEO_BPP32,
};

/**
 * tilcdc_panel_info: Panel parameters
 *
 * @ac_bias: AC Bias Pin Frequency
 * @ac_bias_intrpt: AC Bias Pin Transitions per Interrupt
 * @dma_burst_sz: DMA burst size
 * @bpp: Bits per pixel
 * @fdd: FIFO DMA Request Delay
 * @tft_alt_mode: TFT Alternative Signal Mapping (Only for active)
 * @invert_pxl_clk: Invert pixel clock
 * @sync_edge: Horizontal and Vertical Sync Edge: 0=rising 1=falling
 * @sync_ctrl: Horizontal and Vertical Sync: Control: 0=ignore
 * @raster_order: Raster Data Order Select: 1=Most-to-least 0=Least-to-most
 * @fifo_th: DMA FIFO threshold
 */
struct tilcdc_panel_info {
	u32 ac_bias;
	u32 ac_bias_intrpt;
	u32 dma_burst_sz;
	u32 bpp;
	u32 fdd;
	bool tft_alt_mode;
	bool invert_pxl_clk;
	u32 sync_edge;
	u32 sync_ctrl;
	u32 raster_order;
	u32 fifo_th;
};

struct am335x_fb_priv {
	struct am335x_lcdhw *regs;
	struct tilcdc_panel_info panel;
	struct display_timing timing;
};

static int am335x_fb_remove(struct udevice *dev)
{
	struct video_uc_platdata *uc_plat = dev_get_uclass_platdata(dev);

	uc_plat->base -= 0x20;
	uc_plat->size += 0x20;
	return 0;
}

static int am335x_fb_probe(struct udevice *dev)
{
	struct video_uc_platdata *uc_plat = dev_get_uclass_platdata(dev);
	struct video_priv *uc_priv = dev_get_uclass_priv(dev);
	struct am335x_fb_priv *priv = dev_get_priv(dev);
	struct am335x_lcdhw *regs = priv->regs;
	struct tilcdc_panel_info *panel = &priv->panel;
	struct display_timing *timing = &priv->timing;
	struct cm_dpll *const cmdpll = (struct cm_dpll *)CM_DPLL;
	u32 reg;

	/* Before relocation we don't need to do anything */
	if (!(gd->flags & GD_FLG_RELOC))
		return 0;

	am335x_fb_set_pixel_clk_rate(regs, timing->pixelclock.typ);

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

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

	writel(LCDC_CLKC_ENABLE_CORECLKEN | LCDC_CLKC_ENABLE_LIDDCLKEN |
	       LCDC_CLKC_ENABLE_DMACLKEN, &regs->clkc_enable);
	writel(0, &regs->raster_ctrl);

	reg = readl(&regs->ctrl) & LCDC_CTRL_CLK_DIVISOR_MASK;
	reg |= LCDC_CTRL_RASTER_MODE;
	writel(reg, &regs->ctrl);

	writel(uc_plat->base, &regs->lcddma_fb0_base);
	writel(uc_plat->base + FBSIZE(timing, panel),
	       &regs->lcddma_fb0_ceiling);
	writel(uc_plat->base, &regs->lcddma_fb1_base);
	writel(uc_plat->base + FBSIZE(timing, panel),
	       &regs->lcddma_fb1_ceiling);

	reg = LCDC_DMA_CTRL_FIFO_TH(panel->fifo_th);
	switch (panel->dma_burst_sz) {
	case 1:
		reg |= LCDC_DMA_CTRL_BURST_SIZE(LCDC_DMA_CTRL_BURST_1);
		break;
	case 2:
		reg |= LCDC_DMA_CTRL_BURST_SIZE(LCDC_DMA_CTRL_BURST_2);
		break;
	case 4:
		reg |= LCDC_DMA_CTRL_BURST_SIZE(LCDC_DMA_CTRL_BURST_4);
		break;
	case 8:
		reg |= LCDC_DMA_CTRL_BURST_SIZE(LCDC_DMA_CTRL_BURST_8);
		break;
	case 16:
		reg |= LCDC_DMA_CTRL_BURST_SIZE(LCDC_DMA_CTRL_BURST_16);
		break;
	}

	writel(reg, &regs->lcddma_ctrl);

	writel(LCDC_RASTER_TIMING_0_HORLSB(timing->hactive.typ) |
	       LCDC_RASTER_TIMING_0_HORMSB(timing->hactive.typ) |
	       LCDC_RASTER_TIMING_0_HFPLSB(timing->hfront_porch.typ) |
	       LCDC_RASTER_TIMING_0_HBPLSB(timing->hback_porch.typ) |
	       LCDC_RASTER_TIMING_0_HSWLSB(timing->hsync_len.typ),
	       &regs->raster_timing0);

	writel(LCDC_RASTER_TIMING_1_VBP(timing->vback_porch.typ) |
	       LCDC_RASTER_TIMING_1_VFP(timing->vfront_porch.typ) |
	       LCDC_RASTER_TIMING_1_VSW(timing->vsync_len.typ) |
	       LCDC_RASTER_TIMING_1_VERLSB(timing->vactive.typ),
	       &regs->raster_timing1);

	reg = LCDC_RASTER_TIMING_2_ACB(panel->ac_bias) |
		LCDC_RASTER_TIMING_2_ACBI(panel->ac_bias_intrpt) |
		LCDC_RASTER_TIMING_2_HSWMSB(timing->hsync_len.typ) |
		LCDC_RASTER_TIMING_2_VERMSB(timing->vactive.typ) |
		LCDC_RASTER_TIMING_2_HBPMSB(timing->hback_porch.typ) |
		LCDC_RASTER_TIMING_2_HFPMSB(timing->hfront_porch.typ);

	if (timing->flags & DISPLAY_FLAGS_VSYNC_LOW)
		reg |= LCDC_RASTER_TIMING_2_VSYNC_INVERT;

	if (timing->flags & DISPLAY_FLAGS_HSYNC_LOW)
		reg |= LCDC_RASTER_TIMING_2_HSYNC_INVERT;

	if (panel->invert_pxl_clk)
		reg |= LCDC_RASTER_TIMING_2_PXCLK_INVERT;

	if (panel->sync_edge)
		reg |= LCDC_RASTER_TIMING_2_HSVS_RISEFALL;

	if (panel->sync_ctrl)
		reg |= LCDC_RASTER_TIMING_2_HSVS_CONTROL;

	writel(reg, &regs->raster_timing2);

	reg = LCDC_RASTER_CTRL_PALMODE_RAWDATA | LCDC_RASTER_CTRL_TFT_MODE |
		LCDC_RASTER_CTRL_ENABLE | LCDC_RASTER_CTRL_REQDLY(panel->fdd);

	if (panel->tft_alt_mode)
		reg |= LCDC_RASTER_CTRL_TFT_ALT_ENABLE;

	if (panel->bpp == 24)
		reg |= LCDC_RASTER_CTRL_TFT_24BPP_MODE;
	else if (panel->bpp == 32)
		reg |= LCDC_RASTER_CTRL_TFT_24BPP_MODE |
			LCDC_RASTER_CTRL_TFT_24BPP_UNPACK;

	if (panel->raster_order)
		reg |= LCDC_RASTER_CTRL_DATA_ORDER;

	writel(reg, &regs->raster_ctrl);

	uc_priv->xsize = timing->hactive.typ;
	uc_priv->ysize = timing->vactive.typ;
	uc_priv->bpix = log_2_n_round_up(panel->bpp);
	return 0;
}

static int am335x_fb_ofdata_to_platdata(struct udevice *dev)
{
	struct am335x_fb_priv *priv = dev_get_priv(dev);
	struct tilcdc_panel_info *panel = &priv->panel;
	struct display_timing *timing = &priv->timing;
	ofnode node;
	int err;

	node = ofnode_by_compatible(ofnode_null(), "ti,am33xx-tilcdc");
	if (!ofnode_valid(node)) {
		dev_err(dev, "missing 'ti,am33xx-tilcdc' node\n");
		return -ENXIO;
	}

	priv->regs = (struct am335x_lcdhw *)ofnode_get_addr(node);
	dev_dbg(dev, "LCD: base address=0x%x\n", (unsigned int)priv->regs);

	err = ofnode_decode_display_timing(dev_ofnode(dev), 0, timing);
	if (err) {
		dev_err(dev, "failed to get display timing\n");
		return err;
	}

	if (timing->pixelclock.typ > (LCDC_FMAX / 2)) {
		dev_err(dev, "invalid display clock-frequency: %d Hz\n",
			timing->pixelclock.typ);
		return -EINVAL;
	}

	if (timing->hactive.typ > LCD_MAX_WIDTH)
		timing->hactive.typ = LCD_MAX_WIDTH;

	if (timing->vactive.typ > LCD_MAX_HEIGHT)
		timing->vactive.typ = LCD_MAX_HEIGHT;

	node = ofnode_find_subnode(dev_ofnode(dev), "panel-info");
	if (!ofnode_valid(node)) {
		dev_err(dev, "missing 'panel-info' node\n");
		return -ENXIO;
	}

	err |= ofnode_read_u32(node, "ac-bias", &panel->ac_bias);
	err |= ofnode_read_u32(node, "ac-bias-intrpt", &panel->ac_bias_intrpt);
	err |= ofnode_read_u32(node, "dma-burst-sz", &panel->dma_burst_sz);
	err |= ofnode_read_u32(node, "bpp", &panel->bpp);
	err |= ofnode_read_u32(node, "fdd", &panel->fdd);
	err |= ofnode_read_u32(node, "sync-edge", &panel->sync_edge);
	err |= ofnode_read_u32(node, "sync-ctrl", &panel->sync_ctrl);
	err |= ofnode_read_u32(node, "raster-order", &panel->raster_order);
	err |= ofnode_read_u32(node, "fifo-th", &panel->fifo_th);
	if (err) {
		dev_err(dev, "failed to get panel info\n");
		return err;
	}

	switch (panel->bpp) {
	case 16:
	case 24:
	case 32:
		break;
	default:
		dev_err(dev, "invalid seting, bpp: %d\n", panel->bpp);
		return -EINVAL;
	}

	switch (panel->dma_burst_sz) {
	case 1:
	case 2:
	case 4:
	case 8:
	case 16:
		break;
	default:
		dev_err(dev, "invalid setting, dma-burst-sz: %d\n",
			panel->dma_burst_sz);
		return -EINVAL;
	}

	/* optional */
	panel->tft_alt_mode = ofnode_read_bool(node, "tft-alt-mode");
	panel->invert_pxl_clk = ofnode_read_bool(node, "invert-pxl-clk");

	dev_dbg(dev, "LCD: %dx%d, bpp=%d, clk=%d Hz\n", timing->hactive.typ,
		timing->vactive.typ, panel->bpp, timing->pixelclock.typ);
	dev_dbg(dev, "     hbp=%d, hfp=%d, hsw=%d\n", timing->hback_porch.typ,
		timing->hfront_porch.typ, timing->hsync_len.typ);
	dev_dbg(dev, "     vbp=%d, vfp=%d, vsw=%d\n", timing->vback_porch.typ,
		timing->vfront_porch.typ, timing->vsync_len.typ);

	return 0;
}

static int am335x_fb_bind(struct udevice *dev)
{
	struct video_uc_platdata *uc_plat = dev_get_uclass_platdata(dev);

	uc_plat->size = ((LCD_MAX_WIDTH * LCD_MAX_HEIGHT *
			  (1 << LCD_MAX_LOG2_BPP)) >> 3) + 0x20;

	dev_dbg(dev, "frame buffer size 0x%x\n", uc_plat->size);
	return 0;
}

static const struct udevice_id am335x_fb_ids[] = {
	{ .compatible = "ti,tilcdc,panel" },
	{ }
};

U_BOOT_DRIVER(am335x_fb) = {
	.name = "am335x_fb",
	.id = UCLASS_VIDEO,
	.of_match = am335x_fb_ids,
	.bind = am335x_fb_bind,
	.ofdata_to_platdata = am335x_fb_ofdata_to_platdata,
	.probe = am335x_fb_probe,
	.remove = am335x_fb_remove,
	.priv_auto	= sizeof(struct am335x_fb_priv),
};

#endif /* CONFIG_DM_VIDEO */