[U-Boot] [PATCH] board/freescale/vid: Add correction for ltc3882 read error.

[Priyanka Jain]

Voltage regulator LTC3882 device has 0.5% voltage read error.
So for NXP SoC devices this generally equates to 2mV

Update set_voltage_to_LTC for below:
1.Add coorection of upto 2mV in voltage comparison
to take care of voltage read error of voltage regulator
2.Add loop max count kept as 100 to avoid infinte loop.

Signed-off-by: Priyanka Jain <***@nxp.com>
---
board/freescale/common/vid.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/board/freescale/common/vid.c b/board/freescale/common/vid.c
index eb5cf88..db158cb 100644
--- a/board/freescale/common/vid.c
+++ b/board/freescale/common/vid.c
@@ -318,6 +318,7 @@ static int set_voltage_to_IR(int i2caddress, int vdd)
static int set_voltage_to_LTC(int i2caddress, int vdd)
{
int ret, vdd_last, vdd_target = vdd;
+ int count = 100, temp = 0;

/* Scale up to the LTC resolution is 1/4096V */
vdd = (vdd * 4096) / 1000;
@@ -343,7 +344,9 @@ static int set_voltage_to_LTC(int i2caddress, int vdd)
printf("VID: Couldn't read sensor abort VID adjust\n");
return -1;
}
- } while (vdd_last != vdd_target);
+ count--;
+ temp = vdd_last - vdd_target;
+ } while ((abs(temp) > 2) && (count > 0));

return vdd_last;
}

[York Sun]

Post by Priyanka Jain
Voltage regulator LTC3882 device has 0.5% voltage read error.
So for NXP SoC devices this generally equates to 2mV
1.Add coorection of upto 2mV in voltage comparison
to take care of voltage read error of voltage regulator
2.Add loop max count kept as 100 to avoid infinte loop.
---

Applied to fsl-qoriq master, awaiting upstream. Thanks.

York