Complete Rockchip RK808 PMIC Guide: Pins, Sequencing, DTS, Power and Debugging

Chinese source V1.0.1, kernel scope 3.10 / 4.4 / 4.19. The technical preface introduces RK808 submodule concepts, functions, DTS configuration and troubleshooting; the full technical body is retained. No English PDF is available. All four languages use Chinese-PDF original figures, some already bearing English labels. Platform reference only: verify the actual ArmSoM PMIC, SoC, power tree, pins, SDK/BSP and kernel. Not a claim of support on every ArmSoM board; no hardware testing was performed.

Voltage, pin-mode and register writes can power off or damage hardware; these are unexecuted source examples. Source 0.737.5, differences between voltage/sequence tables, regulator-ramp-delay 12500 versus example 6001, and the claimed four functions versus actual list count are retained without guessing corrections. Verify the pin-table default active-high INT versus active-low prose, VCC11 supply in the VCC10 row, OSC32KOUT type I and incomplete VCCA description against the datasheet. LDO7 sequence value 1.8/OFF omits V in the source.

ArmSoM Docs · Rockchip kernel

1. Basics

1.1 Overview

RK808 is a high-performance PMIC integrating 4 high-current DCDCs, 8 LDOs, 2 SWITCH outputs, 1 RTC and adjustable power-up sequencing. System power rails are generally divided into DCDC and LDO types. Their general characteristics follow; consult further references for details.

1. DCDC: efficient at a large input/output voltage difference, but with relatively high ripple and cost; therefore used for large voltage drops and high-current loads. Two common modes are PWM, with good ripple/transient response but lower efficiency, and PFM, with higher efficiency but weaker load capability.

2. LDO: low efficiency at a large input/output voltage difference, but low cost. Optimize the system to improve conversion efficiency: for a 1.1V LDO output, its input can be supplied by the VCCIO_3.3V DCDC. Where the circuit permits, connect the LDO input to a DCDC output, taking power-up sequencing into account.

1.2 Functions

From the user perspective, RK808 functions are described as four parts:

1. regulator: controls the state of individual DCDC and LDO supplies.

2. rtc: provides clockkeeping, timing and related functions.

3. clk: two 32.768KHZ clock outputs; one is always on and cannot be controlled, while the other is software-controlled.

1.3 Pin functions

Chinese PDF original · p5

Pay particular attention to the SLEEP and INT pins in the following descriptions.

Chinese PDF original · p6

Chinese PDF original · p7

Chinese PDF original · p8

Chinese PDF original · p9

Editable transcription of the original tables above.

1.4 Important concepts

I2C address: 7-bit slave address 0x1b. The PMIC has three operating modes.

1. PMIC normal mode: during normal system operation the PMIC is in normal mode and pmic_sleep is low.

2. PMIC sleep mode: the PMIC enters sleep to reduce its own consumption when the system suspends. Usually some outputs are reduced or disabled, configurable for the product. Raising pmic_sleep during standby enters sleep; when the SoC wakes, pmic_sleep returns low and the PMIC exits sleep.

3. PMIC shutdown mode: during system shutdown, the PMIC powers down the entire system. The AP configures pmic_sleep for shutdown over I2C, then raises pmic_sleep to enter shutdown.

pmic_sleep pin:

Normally low, keeping the PMIC in normal mode; raising it switches to sleep or shutdown.

pmic_int: normally high; an interrupt drives it low, and it stays low until the interrupt is handled.

pmic_pwron: connect the hardware power key to this pin; the driver detects press/release through it.

DCDC modes: besides PWM (force PWM) and PFM, AUTO dynamically switches between PWM and PFM. The PMIC supports PWM and AUTO PWM/PFM. AUTO has higher efficiency but poorer ripple/transient response. For stability, use PWM during operation and switch to AUTO PWM/PFM during suspend.

DCDC3 voltage: this special rail cannot change voltage through registers; external divider resistors set it. Change the external hardware to change voltage. Rockchip designs generally use it for VCC_DDR.

Runtime voltage adjustment ranges of DCDC and LDO:

1. Continuous DCDC voltage ranges:

1. Continuous LDO voltages:

1.5 Power-on conditions and sequence

1. Power-on conditions: any one of the following powers on the PMIC:

• EN transitions from low to high.
• EN remains high and an RTC alarm interrupt occurs.
• EN remains high and the PWRON key is pressed.

1. Power-up sequencing: SoC platforms can require different rail sequences. The current sequences are shown below; consult the latest applicable datasheet for specifics.

Chinese PDF original · p11

Sequence table transcribed from the original image; blanks, x, OTP and ON/OFF are retained.

2. Configuration

2.1 Drivers and menuconfig

2.1.1 3.10 kernelConfiguration

RK808 driver files:

drivers/mfd/rk808.c
drivers/mfd/rk808-irq.c
drivers/rtc/rtc-rk808.c

Reference RK808 DTS file:

arch/arm/boot/dts/rk808.dtsi
arch/arm/boot/dts/rk3288-evb-android-rk808-edp.dts

Corresponding menuconfig symbols:

CONFIG_MFD_RK808
CONFIG_RTC_RK808

2.1.2 4.4 kernelConfiguration

RK808 driver files:

drivers/mfd/rk808.c
drivers/rtc/rtc-rk808.c
drivers/regulator/rk808-regulator.c
drivers/clk/clk-rk808.c

Reference RK808 DTS file:

arch/arm64/boot/dts/rockchip/rk3399-evb-rev3.dtsi

Corresponding menuconfig symbols:

CONFIG_MFD_RK808
CONFIG_RTC_RK808
CONFIG_REGULATOR_RK808
CONFIG_COMMON_CLK_RK808

2.1.3 4.19 kernelConfiguration

RK808 driver files:

drivers/mfd/rk808.c
drivers/rtc/rtc-rk808.c
drivers/regulator/rk808-regulator.c     // 跟4.4内核不同
drivers/clk/clk-rk808.c

Corresponding menuconfig symbols:

CONFIG_MFD_RK808
CONFIG_RTC_RK808
CONFIG_REGULATOR_RK808
CONFIG_COMMON_CLK_RK808

2.2 DTS configuration

2.2.1 3.10 kernel DTS configuration

DTS configuration consists of I2C attachment, main properties, regulator, rtc and poweroff sections.

&i2c1 {
    rk808: rk808@1b {
        reg = <0x1b>;
        status = "okay";
    };
};

/include/ "rk808.dtsi"
&rk808 {
    gpios = <&gpio0 GPIO_A4 GPIO_ACTIVE_HIGH>,
            <&gpio0 GPIO_B3 GPIO_ACTIVE_LOW>;
    rk808,system-power-controller;

    rtc {
        status = "disabled";
    };

    regulators {
        rk808_dcdc1_reg: regulator@0 {
            regulator-always-on;
            regulator-boot-on;
            regulator-min-microvolt = <750000>;
            regulator-max-microvolt = <1400000>;
            regulator-init-microvolt = <1300000>;
            regulator-name = "vdd_arm";
            regulator-state-mem {
                regulator-off-in-suspend;
            };
        };
        rk808_dcdc2_reg: regulator@1 {
                    .............
        };
        rk808_dcdc3_reg: regulator@2 {
                    .............
        };
        .................................
    };
};

1. I2C attachment: place the complete RK808 node under the appropriate i2c node and set status = "okay";.

2. Main properties — do not change the following:

rk808,system-power-controller: declares that RK808 manages system power-off.

Configurable: gpios specifies pmic_int first and pmic_sleep second.

1. regulator

• regulator-name: Supply name; match the schematic. regulator_get uses this name.

• regulator-min-microvolt: Minimum adjustable voltage during operation.

• regulator-max-microvolt: Maximum adjustable voltage during operation.

• regulator-initial-mode: DCDC runtime mode, normally 1: 1 = force PWM; 2 = auto PWM/PFM.

• regulator-state-mode: DCDC suspend mode, normally 2: 1 = force PWM; 2 = auto PWM/PFM.

• regulator-initial-state: Suspend state; must be 3.

• regulator-boot-on: Enable the rail when registering the regulator.

• regulator-always-on: Disallow disabling the rail during operation and enable it at registration.

• regulator-state-enabled: Keep powered during suspend; replace with regulator-state-disabled to power off.

• regulator-state-uv: Standby voltage when the rail remains powered.

Notes:

When regulator-min-microvolt equals regulator-max-microvolt, the framework sets that voltage and enables the rail at registration, without user intervention.

With regulator-boot-on or regulator-always-on present, the framework enables the rail at registration. If the minimum and maximum voltages are equal, it sets that voltage. If they differ, the rail remains at the PMIC hardware-default power-up voltage.

1. rtc: if RTC is not needed (for example on a box product), add the node shown above and explicitly set status = "disabled". To enable RTC, remove the entire RTC node or set status = "okay".

2. poweroff: the RK808 driver intercepts shutdown and writes over I2C to turn off PMIC outputs. rk808_shutdown is registered as syscore shutdown for preparatory work, such as printing shutdown voltages and disabling RTC interrupts.

static void rk808_shutdown(void)
{
    int ret,i,val;
    u16 reg = 0;
    struct rk808 *rk808 = g_rk808;

    printk("%s\n",__func__);
    /***************get dc1\dc2 voltage *********************/
    for(i=0;i<2;i++){
    reg = rk808_reg_read(rk808,rk808_BUCK_SET_VOL_REG(i));
    reg &= BUCK_VOL_MASK;
    val = 712500 + reg * 12500;
    printk("%s,line=%d dc[%d]= %d\n", __func__,__LINE__,(i+1),val);
    }
    /*****************************************************/
    ret = rk808_set_bits(rk808, RK808_INT_STS_MSK_REG1,(0x3<<5),(0x3<<5));
//close rtc int when power off
    ret = rk808_clear_bits(rk808, RK808_RTC_INT_REG,(0x3<<2)); //close rtc int when power off
    mutex_lock(&rk808->io_lock);
    mdelay(100);
}

static struct syscore_ops rk808_syscore_ops = {
    .shutdown = rk808_shutdown,
};

rk808_device_shutdown performs the actual I2C writes to switch off PMIC outputs.

static void rk808_device_shutdown(void)
{
    int ret,i;
    u8 reg = 0;
    struct rk808 *rk808 = g_rk808;
    for(i=0;i < 10;i++){
        printk("%s\n",__func__);
        ret = rk808_i2c_read(rk808,RK808_DEVCTRL_REG,1,&reg);
        if(ret < 0)
            continue;
        ret = rk808_i2c_write(rk808, RK808_DEVCTRL_REG, 1,(reg |(0x1 <<3)));
        if (ret < 0) {
            printk("rk808 power off error!\n");
            continue;
        }
    }
    while(1)wfi();
}
EXPORT_SYMBOL_GPL(rk808_device_shutdown);

2.2.2 4.4 kernel DTS configuration

DTS includes i2c attachment, main properties, rtc, clk and regulator sections.

&i2c1 {
    status = "okay";
    rk808: pmic@1b {
        compatible = "rockchip,rk808";
        reg = <0x1b>;
        interrupt-parent = <&gpio1>;
        interrupts = <21 IRQ_TYPE_LEVEL_LOW>;
        pinctrl-names = "default";
        pinctrl-0 = <&pmic_int_l &pmic_dvs2>;
        rockchip,system-power-controller;
        wakeup-source;
        #clock-cells = <1>;
        clock-output-names = "rk808-clkout1", "rk808-clkout2";

        vcc1-supply = <&vcc3v3_sys>;
        vcc2-supply = <&vcc3v3_sys>;
        vcc3-supply = <&vcc3v3_sys>;
        vcc4-supply = <&vcc3v3_sys>;
        vcc6-supply = <&vcc3v3_sys>;
        vcc7-supply = <&vcc3v3_sys>;
        vcc8-supply = <&vcc3v3_sys>;
        vcc9-supply = <&vcc3v3_sys>;
        vcc10-supply = <&vcc3v3_sys>;
        vcc11-supply = <&vcc3v3_sys>;
        vcc12-supply = <&vcc3v3_sys>;
        vddio-supply = <&vcc1v8_pmu>;

        regulators {
            vdd_log: DCDC_REG1 {
                regulator-always-on;
                regulator-boot-on;
                regulator-min-microvolt = <750000>;
                regulator-max-microvolt = <1350000>;
                regulator-ramp-delay = <6001>;
                regulator-name = "vdd_log";
                regulator-state-mem {
                    regulator-on-in-suspend;
                    regulator-suspend-microvolt = <900000>;
                };
            };
            vdd_cpu_l: DCDC_REG2 {
                regulator-always-on;
                regulator-boot-on;
                regulator-min-microvolt = <750000>;
                regulator-max-microvolt = <1350000>;
                regulator-ramp-delay = <6001>;
                regulator-name = "vdd_cpu_l";
                regulator-state-mem {
                    regulator-off-in-suspend;
                };
            };
            vcc_ddr: DCDC_REG3 {
                .................
            };
            .............................
        };
    };
};

1. i2c attachment: place the complete RK808 node under the corresponding i2c node and set status = "okay";.

2. Main properties

Do not modify:

compatible = "rockchip,rk808";
reg = <0x1b>;
rockchip,system-power-controller;
wakeup-source;
#clock-cells = <1>;

Configurable according to pinctrl rules:

• interrupt-parent: GPIO controller owning pmic_int.
• interrupts: pin index and polarity of pmic_int on that controller.
• pinctrl-names: do not modify; fixed as “default”.
• pinctrl-0: reference to the pmic_int pin defined in pinctrl.

1. rtc: if selected in menuconfig but not needed, add an rtc node in DTS and explicitly set status = "disabled". The driver will not be enabled; error logs at boot can be ignored in this case. To enable it, remove the node or set status = "okay".

2. regulator

• regulator-compatible: Name required for driver matching; changing it causes loading to fail.

• regulator-name: Supply name; match the schematic. regulator_get uses this name.

• regulator-init-microvolt: Initial voltage in U-Boot; ineffective in the kernel.

• regulator-min-microvolt: Minimum adjustable voltage during operation.

• regulator-max-microvolt: Maximum adjustable voltage during operation.

• regulator-initial-mode: DCDC runtime mode, normally 1: 1 = force PWM; 2 = auto PWM/PFM.

• regulator-mode: DCDC suspend mode, normally 2: 1 = force PWM; 2 = auto PWM/PFM.

• regulator-initial-state: Suspend state; must be 3.

• regulator-boot-on: Enable the rail when registering the regulator.

• regulator-always-on: Disallow disabling the rail during operation and enable it at registration.

• regulator-ramp-delay: DCDC voltage rise time; source fixed value 12500.

• regulator-on-in-suspend: Keep powered during suspend; replace with regulator-off-in-suspend to power off.

• regulator-suspend-microvolt: Standby voltage when the rail remains powered.

1. poweroff

Kernel 4.4 uses pm_power_off_prepare for preparatory actions such as disabling RTC interrupts and configuring special registers. The registered syscore shutdown performs the actual PMIC power-off.

1. clk: a node using a RK808 clock references it as follows:

clocks = <&rk808 1>;

First argument: &rk808, fixed. Second argument: clock index, only 0 or 1; 0 = rk808-clkout1, 1 = rk808-clkout2.

2.2.3 4.19 kernel DTS configuration

See the kernel 4.4 DTS configuration. Difference: kernel 4.19 no longer needs a gpio child node, but other modules still reference RK808 pins using gpios = <&rk808 0 GPIO_ACTIVE_LOW>;.

2.3 Function interfaces

The following interfaces cover common regulator operations: enable, disable, set voltage and get voltage.

1. Get a regulator:

struct regulator *regulator_get(struct device *dev, const char *id)

Use NULL for dev by default; id matches regulator-name in DTS.

1. Release regulator:

void regulator_put(struct regulator *regulator)

1. Enable regulator:

int regulator_enable(struct regulator *regulator)

1. Disable regulator:

int regulator_disable(struct regulator *regulator)

1. Get voltage regulator:

int regulator_get_voltage(struct regulator *regulator)

1. Set regulator voltage:

int regulator_set_voltage(struct regulator *regulator, int min_uV, int max_uV)

The caller must ensure min_uV = max_uV.

1. Example

struct regulator *rdev_logic;

rdev_logic = regulator_get(NULL, "vdd_logic");          // 获取vdd_logic
regulator_enable(rdev_logic);                           // 使能vdd_logic
regulator_set_voltage(rdev_logic, 1100000, 1100000);    // 设置电压1.1v
regulator_disable(rdev_logic);                          // 关闭vdd_logic
regulator_put(rdev_logic);                              // 释放vdd_logic

Kernel 4.4 and 4.19 also provide regulator interfaces prefixed devm_ to manage allocated resources for developers.

3. Debug

3.1 3.10 kernel

PMIC driver logic is relatively simple; final register settings are the main focus. A common debug method is to inspect RK808 registers through /sys/rk808/rk808_test.

Read: echo r [addr] > /sys/rk808/rk808_test

Write: echo w [addr] [value] > /sys/rk808/rk808_test

After a write, read back to verify success.

3.2 4.4 kernel

Command format is unchanged from kernel 3.10; only the path differs. Kernel 4.4 uses /sys/rk8xx/rk8xx_dbg.

3.3 4.19 kernel

Refer to the kernel 4.4 commands.