extra voltage for imx6 sabresd - will it cause issue for derivative boards?

[abraham_v]

Looking over the android BSP provided by freescale for the imx6q sabresd board, I find that the VGEN3 output is increased from 2.5 to 2.8v and VGEN5 output increased from 2.8 to 3.0v in uboot. This file;

board/freescale/mx6q_sabresd/mx6q_sabresd.c  { funciton "static int setup_pmic_voltages(void)" }

The comments in code provide the following explanation;

        /*For camera streaks issue,swap VGEN5 and VGEN3 to power camera.
        *sperate VDDHIGH_IN and camera 2.8V power supply, after switch:
        *VGEN5 for VDDHIGH_IN and increase to 3V to align with datasheet
        *VGEN3 for camera 2.8V power supply
        */
        /*increase VGEN3 from 2.5 to 2.8V*/
        if (i2c_read(0x8, 0x6e, 1, &value, 1)) {
            printf("Read VGEN3 error!\n");
            return -1;
        }
        value &= ~0xf;
        value |= 0xa;
        if (i2c_write(0x8, 0x6e, 1, &value, 1)) {
            printf("Set VGEN3 error!\n");
            return -1;
        }
        /*increase VGEN5 from 2.8 to 3V*/
        if (i2c_read(0x8, 0x70, 1, &value, 1)) {
            printf("Read VGEN5 error!\n");
            return -1;
        }
        value &= ~0xf;
        value |= 0xc;
        if (i2c_write(0x8, 0x70, 1, &value, 1)) {
            printf("Set VGEN5 error!\n");
            return -1;
        }

My question is this - I have a derivative iMX6 dual core board without a camera. VGEN3 and VGEN5 are only used to power the processor (similar design on sabresd). Will the above setting create problems? Or should I remove it and revert VGEN3 and VGEN5 to their default values?

Amusingly enough, when I cross-checked the sabresd schematics, it states that VGEN3 should be 2.5v and VGEN5 should be 3v.

Curious,

Abraham V.

[Yuri]

On the SDP design VGEN3 (from PF0100) may be selected (via R85) to provide supply voltage
GEN_2V5 for i.MX6 SATA, HDMI, MIPI, PCIe, LVDS modules.

Strictly speaking, according to the i.MX6 Datasheet, corresponding voltages should be in
range 2.25 (2.325) - 2.75 V. Therefore 2.8V is out of specified range. 

But resistor R85 is not populated by default, therefore such option (VGEN3 -> GEN_2V5) really is not used.

  For customer’s designs it may be recommended to double check if  VDDHIGH_CAP feeds GEN_2V5,
as on the SDP.