MIPS: BCM63XX: add and use a clock for PCIe

Add a PCIe clock and use that instead of directly touching the clock
control register. While at it, fail if there is no such clock.

Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
Acked-by: Florian Fainelli <florian@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/4452
Signed-off-by: John Crispin <blogic@openwrt.org>

arch/mips/bcm63xx/clk.c

@@ -252,6 +252,19 @@ static struct clk clk_ipsec = {
 	.set	= ipsec_set,
 };
 
+/*
+ * PCIe clock
+ */
+
+static void pcie_set(struct clk *clk, int enable)
+{
+	bcm_hwclock_set(CKCTL_6328_PCIE_EN, enable);
+}
+
+static struct clk clk_pcie = {
+	.set	= pcie_set,
+};
+
 /*
  * Internal peripheral clock
  */
@@ -313,6 +326,8 @@ struct clk *clk_get(struct device *dev, const char *id)
 		return &clk_pcm;
 	if (BCMCPU_IS_6368() && !strcmp(id, "ipsec"))
 		return &clk_ipsec;
+	if (BCMCPU_IS_6328() && !strcmp(id, "pcie"))
+		return &clk_pcie;
 	return ERR_PTR(-ENOENT);
 }