imx6: clock: Enable External Memory Interface [EIM] clock (eim_slow_clock)

This patch extends the imx6 clock code to enable or disable the EIM
slow clock, which in necessary when one wants to use EIM interface t
o read/write from external memory (e.g. NOR).

Signed-off-by: Lukasz Majewski <l.majewski@majess.pl>

arch/arm/cpu/armv7/mx6/clock.c

@@ -1384,6 +1384,20 @@ void select_ldb_di_clock_source(enum ldb_di_clock clk)
 }
 #endif
 
+#ifndef CONFIG_SYS_NO_FLASH
+void enable_eim_clk(unsigned char enable)
+{
+	u32 reg;
+
+	reg = __raw_readl(&imx_ccm->CCGR6);
+	if (enable)
+		reg |= MXC_CCM_CCGR6_EMI_SLOW_MASK;
+	else
+		reg &= ~MXC_CCM_CCGR6_EMI_SLOW_MASK;
+	__raw_writel(reg, &imx_ccm->CCGR6);
+}
+#endif
+
 /***************************************************/
 
 U_BOOT_CMD(

arch/arm/include/asm/arch-mx6/clock.h

@@ -79,4 +79,5 @@ void enable_qspi_clk(int qspi_num);
 void enable_thermal_clk(void);
 void mxs_set_lcdclk(u32 base_addr, u32 freq);
 void select_ldb_di_clock_source(enum ldb_di_clock clk);
+void enable_eim_clk(unsigned char enable);
 #endif /* __ASM_ARCH_CLOCK_H */