drivers: at91: clean up peripheral clock code

Due to introducing the new peripheral clock handle functions,
use these functions to reduce the duplicated code.

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Tested-by: Heiko Schocher <hs@denx.de>
[fixup for missing clk.h in at91_emac.c]
Signed-off-by: Andreas Bießmann <andreas.devel@googlemail.com>
diff --git a/drivers/usb/host/ehci-atmel.c b/drivers/usb/host/ehci-atmel.c
index 9a8f004..a33fb49 100644
--- a/drivers/usb/host/ehci-atmel.c
+++ b/drivers/usb/host/ehci-atmel.c
@@ -40,11 +40,7 @@
 	}
 
 	/* Enable USB Host clock */
-#ifdef CPU_HAS_PCR
 	at91_periph_clk_enable(ATMEL_ID_UHPHS);
-#else
-	writel(1 << ATMEL_ID_UHPHS, &pmc->pcer);
-#endif
 
 	*hccr = (struct ehci_hccr *)ATMEL_BASE_EHCI;
 	*hcor = (struct ehci_hcor *)((uint32_t)*hccr +
@@ -59,11 +55,7 @@
 	ulong start_time, tmp_time;
 
 	/* Disable USB Host Clock */
-#ifdef CPU_HAS_PCR
 	at91_periph_clk_disable(ATMEL_ID_UHPHS);
-#else
-	writel(1 << ATMEL_ID_UHPHS, &pmc->pcdr);
-#endif
 
 	start_time = get_timer(0);
 	/* Disable UTMI PLL */
diff --git a/drivers/usb/host/ohci-at91.c b/drivers/usb/host/ohci-at91.c
index 820e2e5..da85111 100644
--- a/drivers/usb/host/ohci-at91.c
+++ b/drivers/usb/host/ohci-at91.c
@@ -37,17 +37,11 @@
 	writel(AT91_PMC_USBS_USB_UPLL | AT91_PMC_USBDIV_10, &pmc->usb);
 #endif
 
-	/* Enable USB host clock. */
-#ifdef CPU_HAS_PCR
 	at91_periph_clk_enable(ATMEL_ID_UHP);
-#else
-	writel(1 << ATMEL_ID_UHP, &pmc->pcer);
-#endif
 
+	at91_system_clk_enable(ATMEL_PMC_UHP);
 #if defined(CONFIG_AT91SAM9261) || defined(CONFIG_AT91SAM9G10)
-	writel(ATMEL_PMC_UHP | AT91_PMC_HCK0, &pmc->scer);
-#else
-	writel(ATMEL_PMC_UHP, &pmc->scer);
+	at91_system_clk_enable(AT91_PMC_HCK0);
 #endif
 
 	return 0;
@@ -57,17 +51,11 @@
 {
 	at91_pmc_t *pmc	= (at91_pmc_t *)ATMEL_BASE_PMC;
 
-	/* Disable USB host clock. */
-#ifdef CPU_HAS_PCR
 	at91_periph_clk_disable(ATMEL_ID_UHP);
-#else
-	writel(1 << ATMEL_ID_UHP, &pmc->pcdr);
-#endif
 
+	at91_system_clk_disable(ATMEL_PMC_UHP);
 #if defined(CONFIG_AT91SAM9261) || defined(CONFIG_AT91SAM9G10)
-	writel(ATMEL_PMC_UHP | AT91_PMC_HCK0, &pmc->scdr);
-#else
-	writel(ATMEL_PMC_UHP, &pmc->scdr);
+	at91_system_clk_disable(AT91_PMC_HCK0);
 #endif
 
 #ifdef CONFIG_USB_ATMEL_CLK_SEL_PLLB