i2c-omap: Use I2C interface clock also on OMAP16xx CPUs

Create and use a virtual i2c_ick clock which prevents its parent clock
ARMPER_CK from being stopped during MPU idle whenever i2c_ick is enabled.
Otherwise we end up losing IRQs if ARMPER_CK would otherwise idle.
Signed-off-by: Jarkko Nikula <jarkko.nikula@nokia.com>
Signed-off-by: Juha Yrjola <juha.yrjola@nokia.com>

arch/arm/mach-omap1/clock.h

@@ -741,6 +741,18 @@ static struct clk i2c_fck = {
 	.disable	= &omap1_clk_disable_generic,
 };
 
+static struct clk i2c_ick = {
+	.name		= "i2c_ick",
+	.id		= 1,
+	.flags		= CLOCK_IN_OMAP16XX |
+			  VIRTUAL_CLOCK | CLOCK_NO_IDLE_PARENT |
+			  ALWAYS_ENABLED,
+	.parent		= &armper_ck.clk,
+	.recalc		= &followparent_recalc,
+	.enable		= &omap1_clk_enable_generic,
+	.disable	= &omap1_clk_disable_generic,
+};
+
 static struct clk * onchip_clks[] = {
 	/* non-ULPD clocks */
 	&ck_ref,
@@ -790,6 +802,7 @@ static struct clk * onchip_clks[] = {
 	/* Virtual clocks */
 	&virtual_ck_mpu,
 	&i2c_fck,
+	&i2c_ick,
 };
 
 #endif

drivers/i2c/busses/i2c-omap.c

@@ -163,21 +163,16 @@ static inline u16 omap_i2c_read_reg(struct omap_i2c_dev *i2c_dev, int reg)
 
 static int omap_i2c_get_clocks(struct omap_i2c_dev *dev)
 {
-	if (cpu_is_omap24xx()) {
+	if (cpu_is_omap16xx() || cpu_is_omap24xx()) {
 		dev->iclk = clk_get(dev->dev, "i2c_ick");
-		if (IS_ERR(dev->iclk)) {
+		if (IS_ERR(dev->iclk))
 			return -ENODEV;
 	}
-		dev->fclk = clk_get(dev->dev, "i2c_fck");
-		if (IS_ERR(dev->fclk)) {
-			clk_put(dev->fclk);
-			return -ENODEV;
-		}
-	}
 
-	if (cpu_class_is_omap1()) {
 	dev->fclk = clk_get(dev->dev, "i2c_fck");
-		if (IS_ERR(dev->fclk))
+	if (IS_ERR(dev->fclk)) {
+		if (dev->iclk != NULL)
+			clk_put(dev->iclk);
 		return -ENODEV;
 	}