atmel_lcdfb.c

Linux环境下视频显示卡设备的驱动程序源代码

/*
 *  Driver for AT91/AT32 LCD Controller
 *
 *  Copyright (C) 2007 Atmel Corporation
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file COPYING in the main directory of this archive for
 * more details.
 */

#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/clk.h>
#include <linux/fb.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/backlight.h>

#include <mach/board.h>
#include <mach/cpu.h>
#include <mach/gpio.h>

#include <video/atmel_lcdc.h>

#define lcdc_readl(sinfo, reg)		__raw_readl((sinfo)->mmio+(reg))
#define lcdc_writel(sinfo, reg, val)	__raw_writel((val), (sinfo)->mmio+(reg))

/* configurable parameters */
#define ATMEL_LCDC_CVAL_DEFAULT		0xc8
#define ATMEL_LCDC_DMA_BURST_LEN	8

#if defined(CONFIG_ARCH_AT91SAM9263) || defined(CONFIG_ARCH_AT91CAP9) || \
	defined(CONFIG_ARCH_AT91SAM9RL)
#define ATMEL_LCDC_FIFO_SIZE		2048
#else
#define ATMEL_LCDC_FIFO_SIZE		512
#endif

#if defined(CONFIG_ARCH_AT91)
#define	ATMEL_LCDFB_FBINFO_DEFAULT	(FBINFO_DEFAULT \
					 | FBINFO_PARTIAL_PAN_OK \
					 | FBINFO_HWACCEL_YPAN)

static inline void atmel_lcdfb_update_dma2d(struct atmel_lcdfb_info *sinfo,
					struct fb_var_screeninfo *var)
{

}
#elif defined(CONFIG_AVR32)
#define	ATMEL_LCDFB_FBINFO_DEFAULT	(FBINFO_DEFAULT \
					| FBINFO_PARTIAL_PAN_OK \
					| FBINFO_HWACCEL_XPAN \
					| FBINFO_HWACCEL_YPAN)

static void atmel_lcdfb_update_dma2d(struct atmel_lcdfb_info *sinfo,
				     struct fb_var_screeninfo *var)
{
	u32 dma2dcfg;
	u32 pixeloff;

	pixeloff = (var->xoffset * var->bits_per_pixel) & 0x1f;

	dma2dcfg = ((var->xres_virtual - var->xres) * var->bits_per_pixel) / 8;
	dma2dcfg |= pixeloff << ATMEL_LCDC_PIXELOFF_OFFSET;
	lcdc_writel(sinfo, ATMEL_LCDC_DMA2DCFG, dma2dcfg);

	/* Update configuration */
	lcdc_writel(sinfo, ATMEL_LCDC_DMACON,
		    lcdc_readl(sinfo, ATMEL_LCDC_DMACON)
		    | ATMEL_LCDC_DMAUPDT);
}
#endif

static const u32 contrast_ctr = ATMEL_LCDC_PS_DIV8
		| ATMEL_LCDC_POL_POSITIVE
		| ATMEL_LCDC_ENA_PWMENABLE;

#ifdef CONFIG_BACKLIGHT_ATMEL_LCDC

/* some bl->props field just changed */
static int atmel_bl_update_status(struct backlight_device *bl)
{
	struct atmel_lcdfb_info *sinfo = bl_get_data(bl);
	int			power = sinfo->bl_power;
	int			brightness = bl->props.brightness;

	/* REVISIT there may be a meaningful difference between
	 * fb_blank and power ... there seem to be some cases
	 * this doesn't handle correctly.
	 */
	if (bl->props.fb_blank != sinfo->bl_power)
		power = bl->props.fb_blank;
	else if (bl->props.power != sinfo->bl_power)
		power = bl->props.power;

	if (brightness < 0 && power == FB_BLANK_UNBLANK)
		brightness = lcdc_readl(sinfo, ATMEL_LCDC_CONTRAST_VAL);
	else if (power != FB_BLANK_UNBLANK)
		brightness = 0;

	lcdc_writel(sinfo, ATMEL_LCDC_CONTRAST_VAL, brightness);
	lcdc_writel(sinfo, ATMEL_LCDC_CONTRAST_CTR,
			brightness ? contrast_ctr : 0);

	bl->props.fb_blank = bl->props.power = sinfo->bl_power = power;

	return 0;
}

static int atmel_bl_get_brightness(struct backlight_device *bl)
{
	struct atmel_lcdfb_info *sinfo = bl_get_data(bl);

	return lcdc_readl(sinfo, ATMEL_LCDC_CONTRAST_VAL);
}

static struct backlight_ops atmel_lcdc_bl_ops = {
	.update_status = atmel_bl_update_status,
	.get_brightness = atmel_bl_get_brightness,
};

static void init_backlight(struct atmel_lcdfb_info *sinfo)
{
	struct backlight_device	*bl;

	sinfo->bl_power = FB_BLANK_UNBLANK;

	if (sinfo->backlight)
		return;

	bl = backlight_device_register("backlight", &sinfo->pdev->dev,
			sinfo, &atmel_lcdc_bl_ops);
	if (IS_ERR(bl)) {
		dev_err(&sinfo->pdev->dev, "error %ld on backlight register\n",
				PTR_ERR(bl));
		return;
	}
	sinfo->backlight = bl;

	bl->props.power = FB_BLANK_UNBLANK;
	bl->props.fb_blank = FB_BLANK_UNBLANK;
	bl->props.max_brightness = 0xff;
	bl->props.brightness = atmel_bl_get_brightness(bl);
}

static void exit_backlight(struct atmel_lcdfb_info *sinfo)
{
	if (sinfo->backlight)
		backlight_device_unregister(sinfo->backlight);
}

#else

static void init_backlight(struct atmel_lcdfb_info *sinfo)
{
	dev_warn(&sinfo->pdev->dev, "backlight control is not available\n");
}

static void exit_backlight(struct atmel_lcdfb_info *sinfo)
{
}

#endif

static void init_contrast(struct atmel_lcdfb_info *sinfo)
{
	/* have some default contrast/backlight settings */
	lcdc_writel(sinfo, ATMEL_LCDC_CONTRAST_CTR, contrast_ctr);
	lcdc_writel(sinfo, ATMEL_LCDC_CONTRAST_VAL, ATMEL_LCDC_CVAL_DEFAULT);

	if (sinfo->lcdcon_is_backlight)
		init_backlight(sinfo);
}


static struct fb_fix_screeninfo atmel_lcdfb_fix __initdata = {
	.type		= FB_TYPE_PACKED_PIXELS,
	.visual		= FB_VISUAL_TRUECOLOR,
	.xpanstep	= 0,
	.ypanstep	= 1,
	.ywrapstep	= 0,
	.accel		= FB_ACCEL_NONE,
};

static unsigned long compute_hozval(unsigned long xres, unsigned long lcdcon2)
{
	unsigned long value;

	if (!(cpu_is_at91sam9261() || cpu_is_at32ap7000()))
		return xres;

	value = xres;
	if ((lcdcon2 & ATMEL_LCDC_DISTYPE) != ATMEL_LCDC_DISTYPE_TFT) {
		/* STN display */
		if ((lcdcon2 & ATMEL_LCDC_DISTYPE) == ATMEL_LCDC_DISTYPE_STNCOLOR) {
			value *= 3;
		}
		if ( (lcdcon2 & ATMEL_LCDC_IFWIDTH) == ATMEL_LCDC_IFWIDTH_4
		   || ( (lcdcon2 & ATMEL_LCDC_IFWIDTH) == ATMEL_LCDC_IFWIDTH_8
		      && (lcdcon2 & ATMEL_LCDC_SCANMOD) == ATMEL_LCDC_SCANMOD_DUAL ))
			value = DIV_ROUND_UP(value, 4);
		else
			value = DIV_ROUND_UP(value, 8);
	}

	return value;
}

static void atmel_lcdfb_stop_nowait(struct atmel_lcdfb_info *sinfo)
{
	/* Turn off the LCD controller and the DMA controller */
	lcdc_writel(sinfo, ATMEL_LCDC_PWRCON,
			sinfo->guard_time << ATMEL_LCDC_GUARDT_OFFSET);

	/* Wait for the LCDC core to become idle */
	while (lcdc_readl(sinfo, ATMEL_LCDC_PWRCON) & ATMEL_LCDC_BUSY)
		msleep(10);

	lcdc_writel(sinfo, ATMEL_LCDC_DMACON, 0);
}

static void atmel_lcdfb_stop(struct atmel_lcdfb_info *sinfo)
{
	atmel_lcdfb_stop_nowait(sinfo);

	/* Wait for DMA engine to become idle... */
	while (lcdc_readl(sinfo, ATMEL_LCDC_DMACON) & ATMEL_LCDC_DMABUSY)
		msleep(10);
}

static void atmel_lcdfb_start(struct atmel_lcdfb_info *sinfo)
{
	lcdc_writel(sinfo, ATMEL_LCDC_DMACON, sinfo->default_dmacon);
	lcdc_writel(sinfo, ATMEL_LCDC_PWRCON,
		(sinfo->guard_time << ATMEL_LCDC_GUARDT_OFFSET)
		| ATMEL_LCDC_PWR);
}

static void atmel_lcdfb_update_dma(struct fb_info *info,
			       struct fb_var_screeninfo *var)
{
	struct atmel_lcdfb_info *sinfo = info->par;
	struct fb_fix_screeninfo *fix = &info->fix;
	unsigned long dma_addr;

	dma_addr = (fix->smem_start + var->yoffset * fix->line_length
		    + var->xoffset * var->bits_per_pixel / 8);

	dma_addr &= ~3UL;

	/* Set framebuffer DMA base address and pixel offset */
	lcdc_writel(sinfo, ATMEL_LCDC_DMABADDR1, dma_addr);

	atmel_lcdfb_update_dma2d(sinfo, var);
}

static inline void atmel_lcdfb_free_video_memory(struct atmel_lcdfb_info *sinfo)
{
	struct fb_info *info = sinfo->info;

	dma_free_writecombine(info->device, info->fix.smem_len,
				info->screen_base, info->fix.smem_start);
}

/**
 *	atmel_lcdfb_alloc_video_memory - Allocate framebuffer memory
 *	@sinfo: the frame buffer to allocate memory for
 */
static int atmel_lcdfb_alloc_video_memory(struct atmel_lcdfb_info *sinfo)
{
	struct fb_info *info = sinfo->info;
	struct fb_var_screeninfo *var = &info->var;
	unsigned int smem_len;

	smem_len = (var->xres_virtual * var->yres_virtual
		    * ((var->bits_per_pixel + 7) / 8));
	info->fix.smem_len = max(smem_len, sinfo->smem_len);

	info->screen_base = dma_alloc_writecombine(info->device, info->fix.smem_len,
					(dma_addr_t *)&info->fix.smem_start, GFP_KERNEL);

	if (!info->screen_base) {
		return -ENOMEM;
	}

	memset(info->screen_base, 0, info->fix.smem_len);

	return 0;
}

static const struct fb_videomode *atmel_lcdfb_choose_mode(struct fb_var_screeninfo *var,
						     struct fb_info *info)
{
	struct fb_videomode varfbmode;
	const struct fb_videomode *fbmode = NULL;

	fb_var_to_videomode(&varfbmode, var);
	fbmode = fb_find_nearest_mode(&varfbmode, &info->modelist);
	if (fbmode)
		fb_videomode_to_var(var, fbmode);
	return fbmode;
}


/**
 *      atmel_lcdfb_check_var - Validates a var passed in.
 *      @var: frame buffer variable screen structure
 *      @info: frame buffer structure that represents a single frame buffer
 *
 *	Checks to see if the hardware supports the state requested by
 *	var passed in. This function does not alter the hardware
 *	state!!!  This means the data stored in struct fb_info and
 *	struct atmel_lcdfb_info do not change. This includes the var
 *	inside of struct fb_info.  Do NOT change these. This function
 *	can be called on its own if we intent to only test a mode and
 *	not actually set it. The stuff in modedb.c is a example of
 *	this. If the var passed in is slightly off by what the
 *	hardware can support then we alter the var PASSED in to what
 *	we can do. If the hardware doesn't support mode change a
 *	-EINVAL will be returned by the upper layers. You don't need
 *	to implement this function then. If you hardware doesn't
 *	support changing the resolution then this function is not
 *	needed. In this case the driver would just provide a var that
 *	represents the static state the screen is in.
 *
 *	Returns negative errno on error, or zero on success.
 */
static int atmel_lcdfb_check_var(struct fb_var_screeninfo *var,
			     struct fb_info *info)
{
	struct device *dev = info->device;
	struct atmel_lcdfb_info *sinfo = info->par;
	unsigned long clk_value_khz;

	clk_value_khz = clk_get_rate(sinfo->lcdc_clk) / 1000;

	dev_dbg(dev, "%s:\n", __func__);

	if (!(var->pixclock && var->bits_per_pixel)) {
		/* choose a suitable mode if possible */
		if (!atmel_lcdfb_choose_mode(var, info)) {
			dev_err(dev, "needed value not specified\n");
			return -EINVAL;
		}
	}

	dev_dbg(dev, "  resolution: %ux%u\n", var->xres, var->yres);
	dev_dbg(dev, "  pixclk:     %lu KHz\n", PICOS2KHZ(var->pixclock));
	dev_dbg(dev, "  bpp:        %u\n", var->bits_per_pixel);
	dev_dbg(dev, "  clk:        %lu KHz\n", clk_value_khz);

	if ((PICOS2KHZ(var->pixclock) * var->bits_per_pixel / 8) > clk_value_khz) {
		dev_err(dev, "%lu KHz pixel clock is too fast\n", PICOS2KHZ(var->pixclock));
		return -EINVAL;
	}

	/* Do not allow to have real resoulution larger than virtual */
	if (var->xres > var->xres_virtual)
		var->xres_virtual = var->xres;

	if (var->yres > var->yres_virtual)
		var->yres_virtual = var->yres;

	/* Force same alignment for each line */
	var->xres = (var->xres + 3) & ~3UL;
	var->xres_virtual = (var->xres_virtual + 3) & ~3UL;

	var->red.msb_right = var->green.msb_right = var->blue.msb_right = 0;
	var->transp.msb_right = 0;