arm: mx5: Add NAND clock handling

Augment the MX5 clock code with function to enable and configure
NFC clock. This is necessary to get NFC working on MX5.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
Cc: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Scott Wood <scottwood@freescale.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Tom Rini <trini@ti.com>

arch/arm/cpu/armv7/mx5/clock.c

@@ -739,10 +739,11 @@ static int config_core_clk(u32 ref, u32 freq)
 static int config_nfc_clk(u32 nfc_clk)
 {
 	u32 parent_rate = get_emi_slow_clk();
-	u32 div = parent_rate / nfc_clk;
+	u32 div;
 
-	if (nfc_clk <= 0)
+	if (nfc_clk == 0)
 		return -EINVAL;
+	div = parent_rate / nfc_clk;
 	if (div == 0)
 		div++;
 	if (parent_rate / div > NFC_CLK_MAX)
@@ -755,6 +756,15 @@ static int config_nfc_clk(u32 nfc_clk)
 	return 0;
 }
 
+void enable_nfc_clk(unsigned char enable)
+{
+	unsigned int cg = enable ? MXC_CCM_CCGR_CG_ON : MXC_CCM_CCGR_CG_OFF;
+
+	clrsetbits_le32(&mxc_ccm->CCGR5,
+		MXC_CCM_CCGR5_EMI_ENFC(MXC_CCM_CCGR_CG_MASK),
+		MXC_CCM_CCGR5_EMI_ENFC(cg));
+}
+
 /* Config main_bus_clock for periphs */
 static int config_periph_clk(u32 ref, u32 freq)
 {

arch/arm/include/asm/arch-mx5/clock.h

@@ -68,5 +68,6 @@ void set_usboh3_clk(void);
 void enable_usboh3_clk(unsigned char enable);
 void mxc_set_sata_internal_clock(void);
 int enable_i2c_clk(unsigned char enable, unsigned i2c_num);
+void enable_nfc_clk(unsigned char enable);
 
 #endif /* __ASM_ARCH_CLOCK_H */