Change V_VBAT_BKUP Configuration on an Intel® Edison Board

Documentation

Troubleshooting

000016246

07/12/2017

See the steps below to change the default settings of V_VBAT_BKUP on an Intel® Edison Board. The guide assumes you have an environment ready to build a standard Intel® Edison image. If your environment isn't ready, see the Intel® Edison Board Support Package.

In this example, the BBCHGRCFG register is set to 31, with a charge voltage of 3.3V, and charge current of 500 uA.

To change the default settings, follow these steps:

  1. Change directory:
    cd /meta-intel-edison/meta-intel-edison-bsp/recipes-kernel/linux/files/
  2. Create a file named intel_scu_pmic.patch with the following content:

    diff -urN a/drivers/platform/x86/intel_scu_pmic.c b/drivers/platform/x86/intel_scu_pmic.c
    --- a/drivers/platform/x86/intel_scu_pmic.c 2015-08-20 14:16:14.115259252 -0700
    +++ b/drivers/platform/x86/intel_scu_pmic.c 2015-08-20 14:15:11.823260500 -0700
    @@ -380,6 +380,8 @@

    static int pmic_rpmsg_probe(struct rpmsg_channel *rpdev)
    {
    + uint8_t bbchgrcfg_value;
    + int ret1;
    int ret = 0;

    if (rpdev == NULL) {
    @@ -415,6 +417,13 @@
    goto rpmsg_err;
    }

    + ret1 = intel_scu_ipc_ioread8(0x52, &bbchgrcfg_value);
    + printk(" ret=%d, reg=%d\n", ret1, bbchgrcfg_value);
    + ret1 = intel_scu_ipc_iowrite8(0x52, 31);
    + printk(" ret=%d\n", ret1);
    + ret1 = intel_scu_ipc_ioread8(0x52, &bbchgrcfg_value);
    + printk(" ret=%d, reg=%d\n", ret1, bbchgrcfg_value);
    +
    goto out;

    rpmsg_err:
    @@ -475,3 +484,4 @@
    MODULE_AUTHOR("Bin Yang");
    MODULE_DESCRIPTION("Intel PMIC Driver");
    MODULE_LICENSE("GPL v2");
    +

  3. Go back one level to this directory:
    cd /meta-intel-edison/meta-intel-edison-bsp/recipes-kernel/linux/
  4. Edit the linux-yocto_3.10.bbappend file and add this line:

    FILESEXTRAPATHS_prepend := "${THISDIR}/files:"

    COMPATIBLE_MACHINE = "edison"
    LINUX_VERSION = "3.10.17"
    SRCREV_machine = "c03195ed6e3066494e3fb4be69154a57066e845b"
    SRCREV_meta = "6ad20f049abd52b515a8e0a4664861cfd331f684"

    SRC_URI += "file://defconfig"
    SRC_URI += "file://upstream_to_edison.patch"
    SRC_URI += "file:// intel_scu_pmic.patch"
    PV = "${LINUX_VERSION}"

  5. Run the following command to clean the build:
    bitbake virtual/kernel –c cleanall
  6. Run the following command to build the kernel:
    bitbake virtual/kernel

After you successfully build the kernel, flash your new image to the Intel Edison Board. The V_VBAT_BKUP has the following configuration:

  • Register setting: BBCHGRCFG = 31
  • Voltage 3.3V
  • Current 500 uA