Hi all,
we have an issue/doubt about u-boot for our i.MX6ULL processor.
Now our GA BSP has an old u-boot without the patch below, where the 6–4 REFTOP_VBGADJ field is set to 0x6 as constant.
Migrating to a new u-boot where the patch below is applied we are experiencing a great temperature increasing on the processor.
When the patch is applied the REFTOP_VBGADJ field is set to 0x0.. and the temperature reading goes up more than 10°C.
Measuring the case temperature, we don't see a so big change between the two configurations, but cat /sys/class/thermal/thermal_zon0/temp reads more than 10°C above...
The patch reads a value from eFuse to setup the bandgap. Does NXP write this eFuse field during production?.. or we need to perform a calibration on our side?
Many thanks for your help.
---
arch/arm/cpu/armv7/mx6/soc.c | 31 ++++++++++++++++++++++++++-----
arch/arm/include/asm/arch-mx6/crm_regs.h | 1 +
2 files changed, 27 insertions(+), 5 deletions(-)
diff --git a/arch/arm/cpu/armv7/mx6/soc.c b/arch/arm/cpu/armv7/mx6/soc.c
index 7b53bfd..dd94797 100644
--- a/arch/arm/cpu/armv7/mx6/soc.c
+++ b/arch/arm/cpu/armv7/mx6/soc.c
@@ -300,9 +300,17 @@ static void clear_mmdc_ch_mask(void)
writel(reg, &mxc_ccm->ccdr);
}
+#define OCOTP_MEM0_REFTOP_TRIM_SHIFT 8
+
static void init_bandgap(void)
{
struct anatop_regs *anatop = (struct anatop_regs *)ANATOP_BASE_ADDR;
+ struct ocotp_regs *ocotp = (struct ocotp_regs *)OCOTP_BASE_ADDR;
+ struct fuse_bank *bank = &ocotp->bank[1];
+ struct fuse_bank1_regs *fuse =
+ (struct fuse_bank1_regs *)bank->fuse_regs;
+ uint32_t val;
+
/*
* Ensure the bandgap has stabilized.
*/
@@ -315,13 +323,26 @@ static void init_bandgap(void)
*/
writel(BM_ANADIG_ANA_MISC0_REFTOP_SELBIASOFF, &anatop->ana_misc0_set);
/*
- * On i.MX6ULL, the LDO 1.2V bandgap voltage is 30mV higher. so set
- * VBGADJ bits to 2b'110 to adjust it.
+ * On i.MX6ULL,we need to set VBGADJ bits according to the
+ * REFTOP_TRIM[3:0] in fuse table
+ * 000 - set REFTOP_VBGADJ[2:0] to 3b'110,
+ * 110 - set REFTOP_VBGADJ[2:0] to 3b'000,
+ * 001 - set REFTOP_VBGADJ[2:0] to 3b'001,
+ * 010 - set REFTOP_VBGADJ[2:0] to 3b'010,
+ * 011 - set REFTOP_VBGADJ[2:0] to 3b'011,
+ * 100 - set REFTOP_VBGADJ[2:0] to 3b'100,
+ * 101 - set REFTOP_VBGADJ[2:0] to 3b'101,
+ * 111 - set REFTOP_VBGADJ[2:0] to 3b'111,
*/
- if (is_mx6ull())
- writel(BM_ANADIG_ANA_MISC0_REFTOP_VBGADJ, &anatop->ana_misc0_set);
-}
+ if (is_mx6ull()) {
+ val = readl(&fuse->mem0);
+ val >>= OCOTP_MEM0_REFTOP_TRIM_SHIFT;
+ val &= 0x7;
+ writel(val << BM_ANADIG_ANA_MISC0_REFTOP_VBGADJ_SHIFT,
+ &anatop->ana_misc0_set);
+ }
+}
