ARM: 6124/1: ep93xx: SPI driver platform support code

This patch adds platform side support code for the EP93xx SPI
driver. This includes clock, resources and muxing. There is a new
function: ep93xx_register_spi() which can be used by board support
code to register new SPI devices for the board.

This patch depends on patch
  5998/1 ep93xx: added chip revision reading function

Cc: Ryan Mallon <ryan@bluewatersys.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Mika Westerberg <mika.westerberg@iki.fi>
Acked-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: Martin Guy <martinwguy@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mach-ep93xx/clock.c b/arch/arm/mach-ep93xx/clock.c
index 5f80092..e29bdef 100644
--- a/arch/arm/mach-ep93xx/clock.c
+++ b/arch/arm/mach-ep93xx/clock.c
@@ -96,6 +96,10 @@
 	.enable_mask	= EP93XX_SYSCON_KEYTCHCLKDIV_KEN,
 	.set_rate	= set_keytchclk_rate,
 };
+static struct clk clk_spi = {
+	.parent		= &clk_xtali,
+	.rate		= EP93XX_EXT_CLK_RATE,
+};
 static struct clk clk_pwm = {
 	.parent		= &clk_xtali,
 	.rate		= EP93XX_EXT_CLK_RATE,
@@ -186,6 +190,7 @@
 	INIT_CK("ep93xx-ohci",		NULL,		&clk_usb_host),
 	INIT_CK("ep93xx-keypad",	NULL,		&clk_keypad),
 	INIT_CK("ep93xx-fb",		NULL,		&clk_video),
+	INIT_CK("ep93xx-spi.0",		NULL,		&clk_spi),
 	INIT_CK(NULL,			"pwm_clk",	&clk_pwm),
 	INIT_CK(NULL,			"m2p0",		&clk_m2p0),
 	INIT_CK(NULL,			"m2p1",		&clk_m2p1),
@@ -473,6 +478,14 @@
 	/* Initialize the pll2 derived clocks */
 	clk_usb_host.rate = clk_pll2.rate / (((value >> 28) & 0xf) + 1);
 
+	/*
+	 * EP93xx SSP clock rate was doubled in version E2. For more information
+	 * see:
+	 *     http://www.cirrus.com/en/pubs/appNote/AN273REV4.pdf
+	 */
+	if (ep93xx_chip_revision() < EP93XX_CHIP_REV_E2)
+		clk_spi.rate /= 2;
+
 	pr_info("PLL1 running at %ld MHz, PLL2 at %ld MHz\n",
 		clk_pll1.rate / 1000000, clk_pll2.rate / 1000000);
 	pr_info("FCLK %ld MHz, HCLK %ld MHz, PCLK %ld MHz\n",