Framebuffer support for the Silicon Motion SM501
multi-function chip.

This driver provides a pair of framebuffer interfaces
for the CRT and LCD panel interfaces, and some basic
acceleration for the cursor.

The patch has been updated slightly from the previous
version to including being able to pass an initial
video mode through via the platform data.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Vincent Sanders <redacted>

+ *
+ * Converts a period in picoseconds to Hz.
+ *
+ * Note, we try to keep this in Hz to minimise rounding with
+ * the limited PLL settings on the SM501.
+*/
+
+static unsigned long sm501fb_ps_to_hz(unsigned long psvalue)
+{
+	unsigned long long numerator=1000000000000ULL;
+
+	/* 10^12 / picosecond period gives frequency in Hz */
+	do_div(numerator, psvalue);
+	return (unsigned long)numerator;
+}
+
+/* sm501fb_hz_to_ps is identical to the oposite transform */
+
+#define sm501fb_hz_to_ps(x) sm501fb_ps_to_hz(x)

You really need it down to the Hz? 

+/* sm501fb_validate_pan
+ *
+ * check panning on a var
+*/
+
+static inline int sm501fb_validate_pan(struct fb_var_screeninfo *var)
+{
+	if (var->xoffset < 0 || var->yoffset < 0)
+		return 0;
+
+	if (var->xoffset > (var->xres_virtual - var->xres) ||
+	    var->yoffset > (var->yres_virtual - var->yres))
+		return 0;
+
+	return 1;
+}

Not needed. fb_pan_display in fbmem.c does this check for you :-)

+/* framebuffer ops */
+
+static struct fb_ops sm501fb_ops_crt = {
+	.owner		= THIS_MODULE,
+	.fb_check_var	= sm501fb_check_var_crt,
+	.fb_set_par	= sm501fb_set_par_crt,
+	.fb_blank	= sm501fb_blank_crt,
+	.fb_setcolreg	= sm501fb_setcolreg,
+	.fb_pan_display	= sm501fb_pan_crt,
+	.fb_cursor	= sm501fb_cursor,
+	.fb_fillrect	= cfb_fillrect,
+	.fb_copyarea	= cfb_copyarea,
+	.fb_imageblit	= cfb_imageblit,
+};
+
+static struct fb_ops sm501fb_ops_pnl = {
+	.owner		= THIS_MODULE,
+	.fb_check_var	= sm501fb_check_var_pnl,
+	.fb_set_par	= sm501fb_set_par_pnl,
+	.fb_pan_display	= sm501fb_pan_pnl,
+	.fb_blank	= sm501fb_blank_pnl,
+	.fb_setcolreg	= sm501fb_setcolreg,
+	.fb_cursor	= sm501fb_cursor,
+	.fb_fillrect	= cfb_fillrect,
+	.fb_copyarea	= cfb_copyarea,
+	.fb_imageblit	= cfb_imageblit,
+};

Many cards require a fb_sync function after/before they do a drawing 
operation. I notice you don't have one. Is sm501fb_sync_regs equivalent to 
that?

Other than that the driver looks great. Thank you.