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authorFabio Estevam <fabio.estevam@freescale.com>2013-12-26 14:51:34 -0200
committerStefano Babic <sbabic@denx.de>2014-01-02 17:16:51 +0100
commit39f0ac9347ed825089181c4b57ea9326332e66c3 (patch)
tree9444a3c24804dfe4de65e9db9a0646aec4bc5dc6 /arch
parent3d622b78bdd6832f6fa8599aaf31de541bf04ea8 (diff)
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mx6: soc: Add the required LDO ramp up delay
When changing LDO voltages we need to wait for the required amount of time for the voltage to settle. Also, as the timer is still not available when arch_cpu_init() is called, we need to call it later at board_postclk_init() phase. Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm/cpu/armv7/mx6/soc.c22
1 files changed, 19 insertions, 3 deletions
diff --git a/arch/arm/cpu/armv7/mx6/soc.c b/arch/arm/cpu/armv7/mx6/soc.c
index d8ccf3a..0208cba 100644
--- a/arch/arm/cpu/armv7/mx6/soc.c
+++ b/arch/arm/cpu/armv7/mx6/soc.c
@@ -124,7 +124,7 @@ static void clear_ldo_ramp(void)
static int set_ldo_voltage(enum ldo_reg ldo, u32 mv)
{
struct anatop_regs *anatop = (struct anatop_regs *)ANATOP_BASE_ADDR;
- u32 val, reg = readl(&anatop->reg_core);
+ u32 val, step, old, reg = readl(&anatop->reg_core);
u8 shift;
if (mv < 725)
@@ -150,9 +150,20 @@ static int set_ldo_voltage(enum ldo_reg ldo, u32 mv)
return -EINVAL;
}
+ old = (reg & (0x1F << shift)) >> shift;
+ step = abs(val - old);
+ if (step == 0)
+ return 0;
+
reg = (reg & ~(0x1F << shift)) | (val << shift);
writel(reg, &anatop->reg_core);
+ /*
+ * The LDO ramp-up is based on 64 clock cycles of 24 MHz = 2.6 us per
+ * step
+ */
+ udelay(3 * step);
+
return 0;
}
@@ -170,8 +181,6 @@ int arch_cpu_init(void)
{
init_aips();
- set_ldo_voltage(LDO_SOC, 1175); /* Set VDDSOC to 1.175V */
-
imx_set_wdog_powerdown(false); /* Disable PDE bit of WMCR register */
#ifdef CONFIG_APBH_DMA
@@ -182,6 +191,13 @@ int arch_cpu_init(void)
return 0;
}
+int board_postclk_init(void)
+{
+ set_ldo_voltage(LDO_SOC, 1175); /* Set VDDSOC to 1.175V */
+
+ return 0;
+}
+
#ifndef CONFIG_SYS_DCACHE_OFF
void enable_caches(void)
{