Re: [PATCH v3 1/5] mfd: rk808: Add RK817 and RK809 support
From: tony
Date: Mon Oct 22 2018 - 23:20:44 EST
On Fri, 24 Aug 2018, Tony Xie wrote:
The rk809 and rk817 are a Power Management IC (PMIC) for multimedia
and handheld devices. It contains the following components:
- Regulators
- RTC
- Clocking
Both RK809 and RK817 chips are using a similar register map,
so we can reuse the RTC and Clocking and regulators functionality.
Signed-off-by: Tony Xie <tony.xie@xxxxxxxxxxxxxx>
---
drivers/mfd/Kconfig | 6 +-
drivers/mfd/rk808.c | 218 +++++++++++++++++++++++++++++++++++++++++++++-
include/linux/mfd/rk808.h | 172 ++++++++++++++++++++++++++++++++++++
kernel/reboot.c | 1 +
4 files changed, 391 insertions(+), 6 deletions(-)
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index b860eb5..84f2f22 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -967,14 +967,14 @@ config MFD_RC5T583
different functionality of the device.
config MFD_RK808
- tristate "Rockchip RK805/RK808/RK818 Power Management Chip"
+ tristate "Rockchip RK805/RK808/RK809/RK817/RK818 Power Management Chip"
depends on I2C && OF
select MFD_CORE
select REGMAP_I2C
select REGMAP_IRQ
help
- If you say yes here you get support for the RK805, RK808 and RK818
- Power Management chips.
+ If you say yes here you get support for the RK805, RK809 and RK817,
+ RK808 and RK818 Power Management chips.
Any reason why you've taken these out of order?
This driver provides common support for accessing the device
through I2C interface. The device supports multiple sub-devices
including interrupts, RTC, LDO & DCDC regulators, and onkey.
diff --git a/drivers/mfd/rk808.c b/drivers/mfd/rk808.c
index 216fbf6..62e2fe1 100644
--- a/drivers/mfd/rk808.c
+++ b/drivers/mfd/rk808.c
@@ -62,6 +62,29 @@ static bool rk808_is_volatile_reg(struct device *dev, unsigned int reg)
return false;
}
+static bool rk817_is_volatile_reg(struct device *dev, unsigned int reg)
+{
+ /*
+ * Notes:
+ * - Technically the ROUND_30s bit makes RTC_CTRL_REG volatile, but
+ * we don't use that feature. It's better to cache.
+ * - It's unlikely we care that RK808_DEVCTRL_REG is volatile since
+ * bits are cleared in case when we shutoff anyway, but better safe.
+ */
+
+ switch (reg) {
+ case RK817_SECONDS_REG ... RK817_WEEKS_REG:
+ case RK817_RTC_STATUS_REG:
+ case RK817_INT_STS_REG0:
+ case RK817_INT_STS_REG1:
+ case RK817_INT_STS_REG2:
+ case RK817_SYS_STS:
+ return true;
+ }
+
+ return true;
+}
+
static const struct regmap_config rk818_regmap_config = {
.reg_bits = 8,
.val_bits = 8,
@@ -86,6 +109,14 @@ static bool rk808_is_volatile_reg(struct device *dev, unsigned int reg)
.volatile_reg = rk808_is_volatile_reg,
};
+static const struct regmap_config rk817_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .max_register = RK817_GPIO_INT_CFG,
+ .cache_type = REGCACHE_NONE,
+ .volatile_reg = rk817_is_volatile_reg,
+};
+
static struct resource rtc_resources[] = {
{
.start = RK808_IRQ_RTC_ALARM,
@@ -94,6 +125,13 @@ static bool rk808_is_volatile_reg(struct device *dev, unsigned int reg)
}
};
+static struct resource rk817_rtc_resources[] = {
+ {
+ .start = RK817_IRQ_RTC_ALARM,
+ .end = RK817_IRQ_RTC_ALARM,
+ .flags = IORESOURCE_IRQ,
+ }
+};
static struct resource rk805_key_resources[] = {
{
.start = RK805_IRQ_PWRON_FALL,
@@ -107,6 +145,19 @@ static bool rk808_is_volatile_reg(struct device *dev, unsigned int reg)
}
};
+static struct resource rk817_pwrkey_resources[] = {
+ {
+ .start = RK817_IRQ_PWRON_RISE,
+ .end = RK817_IRQ_PWRON_RISE,
+ .flags = IORESOURCE_IRQ,
+ },
+ {
+ .start = RK817_IRQ_PWRON_FALL,
+ .end = RK817_IRQ_PWRON_FALL,
+ .flags = IORESOURCE_IRQ,
+ },
+};
+
static const struct mfd_cell rk805s[] = {
{ .name = "rk808-clkout", },
{ .name = "rk808-regulator", },
@@ -132,6 +183,21 @@ static bool rk808_is_volatile_reg(struct device *dev, unsigned int reg)
},
};
+static const struct mfd_cell rk817s[] = {
+ { .name = "rk808-clkout",},
+ { .name = "rk808-regulator",},
+ {
+ .name = "rk8xx-pwrkey",
+ .num_resources = ARRAY_SIZE(rk817_pwrkey_resources),
+ .resources = &rk817_pwrkey_resources[0],
+ },
+ {
+ .name = "rk808-rtc",
+ .num_resources = ARRAY_SIZE(rk817_rtc_resources),
+ .resources = &rk817_rtc_resources[0],
+ },
+};
+
static const struct mfd_cell rk818s[] = {
{ .name = "rk808-clkout", },
{ .name = "rk808-regulator", },
@@ -167,6 +233,13 @@ static bool rk808_is_volatile_reg(struct device *dev, unsigned int reg)
VB_LO_SEL_3500MV },
};
+static const struct rk808_reg_data rk817_pre_init_reg[] = {
+ {RK817_RTC_CTRL_REG, RTC_STOP, RTC_STOP},
+ {RK817_GPIO_INT_CFG, RK817_INT_POL_MSK, RK817_INT_POL_H},
+ {RK817_SYS_CFG(1), RK817_HOTDIE_TEMP_MSK | RK817_TSD_TEMP_MSK,
+ RK817_HOTDIE_105 | RK817_TSD_140},
+};
+
static const struct rk808_reg_data rk818_pre_init_reg[] = {
/* improve efficiency */
{ RK818_BUCK2_CONFIG_REG, BUCK2_RATE_MASK, BUCK_ILMIN_250MA },
@@ -332,6 +405,39 @@ static bool rk808_is_volatile_reg(struct device *dev, unsigned int reg)
},
};
+#define REGMAP_IRQ_M(_id) \
+ [_id] = { \
+ .mask = BIT(((_id) % 8)), \
+ .reg_offset = ((_id) / 8), \
+ }
If this is helpful for you, it will be helpful for others.
Please submit this to the Regmap subsystem.
See: include/linux/regmap.h
+static const struct regmap_irq rk817_irqs[RK817_IRQ_END] = {
+ REGMAP_IRQ_M(0),
+ REGMAP_IRQ_M(1),
+ REGMAP_IRQ_M(2),
+ REGMAP_IRQ_M(3),
+ REGMAP_IRQ_M(4),
+ REGMAP_IRQ_M(5),
+ REGMAP_IRQ_M(6),
+ REGMAP_IRQ_M(7),
+ REGMAP_IRQ_M(8),
+ REGMAP_IRQ_M(9),
+ REGMAP_IRQ_M(10),
+ REGMAP_IRQ_M(11),
+ REGMAP_IRQ_M(12),
+ REGMAP_IRQ_M(13),
+ REGMAP_IRQ_M(14),
+ REGMAP_IRQ_M(15),
+ REGMAP_IRQ_M(16),
+ REGMAP_IRQ_M(17),
+ REGMAP_IRQ_M(18),
+ REGMAP_IRQ_M(19),
+ REGMAP_IRQ_M(20),
+ REGMAP_IRQ_M(21),
+ REGMAP_IRQ_M(22),
+ REGMAP_IRQ_M(23)
+};
+
static struct regmap_irq_chip rk805_irq_chip = {
.name = "rk805",
.irqs = rk805_irqs,
@@ -355,6 +461,18 @@ static bool rk808_is_volatile_reg(struct device *dev, unsigned int reg)
.init_ack_masked = true,
};
+static struct regmap_irq_chip rk817_irq_chip = {
+ .name = "rk817",
+ .irqs = rk817_irqs,
+ .num_irqs = ARRAY_SIZE(rk817_irqs),
+ .num_regs = 3,
+ .irq_reg_stride = 2,
+ .status_base = RK817_INT_STS_REG0,
+ .mask_base = RK817_INT_STS_MSK_REG0,
+ .ack_base = RK817_INT_STS_REG0,
+ .init_ack_masked = true,
+};
+
static const struct regmap_irq_chip rk818_irq_chip = {
.name = "rk818",
.irqs = rk818_irqs,
@@ -423,9 +541,39 @@ static void rk818_device_shutdown(void)
dev_err(&rk808_i2c_client->dev, "power off error!\n");
}
+static void rk8xx_device_shutdown_prepare(void)
+{
+ int ret;
+ struct rk808 *rk808 = i2c_get_clientdata(rk808_i2c_client);
+
+ if (!rk808) {
+ dev_warn(&rk808_i2c_client->dev,
+ "have no rk808, so do nothing here\n");
This isn't a good warning to an end user.
Where is "here"?
Please provide something a little more forthcoming/descriptive.
+ return;
+ }
+
+ switch (rk808->variant) {
+ case RK809_ID:
+ case RK817_ID:
+ ret = regmap_update_bits(rk808->regmap,
+ RK817_SYS_CFG(3),
+ RK817_SLPPIN_FUNC_MSK,
+ SLPPIN_DN_FUN);
+ if (ret) {
+ dev_warn(&rk808_i2c_client->dev,
+ "switch pin func to power down error!\n");
Again, what does this mean to an end user? Probably very little.
+ }
+ break;
+ default:
+ break;
+ }
+}
+
static const struct of_device_id rk808_of_match[] = {
{ .compatible = "rockchip,rk805" },
{ .compatible = "rockchip,rk808" },
+ { .compatible = "rockchip,rk809" },
+ { .compatible = "rockchip,rk817" },
{ .compatible = "rockchip,rk818" },
{ },
};
@@ -438,10 +586,11 @@ static int rk808_probe(struct i2c_client *client,
struct rk808 *rk808;
const struct rk808_reg_data *pre_init_reg;
const struct mfd_cell *cells;
- void (*pm_pwroff_fn)(void);
+ void (*pm_pwroff_fn)(void) = NULL;
int nr_pre_init_regs;
int nr_cells;
int pm_off = 0, msb, lsb;
+ unsigned char pmic_id_msb = RK808_ID_MSB, pmic_id_lsb = RK808_ID_LSB;
Please place these on separate lines.
int ret;
int i;
@@ -449,15 +598,20 @@ static int rk808_probe(struct i2c_client *client,
if (!rk808)
return -ENOMEM;
+ if (of_device_is_compatible(np, "rockchip,rk817") ||
+ of_device_is_compatible(np, "rockchip,rk809")) {
+ pmic_id_msb = RK817_ID_MSB;
+ pmic_id_lsb = RK817_ID_LSB;
+ }
Rather than pre-assign default values at declaration, I think it would
be cleaner to have an else here.
/* Read chip variant */
- msb = i2c_smbus_read_byte_data(client, RK808_ID_MSB);
+ msb = i2c_smbus_read_byte_data(client, pmic_id_msb);
if (msb < 0) {
dev_err(&client->dev, "failed to read the chip id at 0x%x\n",
RK808_ID_MSB);
return msb;
}
- lsb = i2c_smbus_read_byte_data(client, RK808_ID_LSB);
+ lsb = i2c_smbus_read_byte_data(client, pmic_id_lsb);
if (lsb < 0) {
dev_err(&client->dev, "failed to read the chip id at 0x%x\n",
RK808_ID_LSB);
@@ -495,6 +649,16 @@ static int rk808_probe(struct i2c_client *client,
nr_cells = ARRAY_SIZE(rk818s);
pm_pwroff_fn = rk818_device_shutdown;
break;
+ case RK809_ID:
+ case RK817_ID:
+ rk808->regmap_cfg = &rk817_regmap_config;
+ rk808->regmap_irq_chip = &rk817_irq_chip;
+ pre_init_reg = rk817_pre_init_reg;
+ nr_pre_init_regs = ARRAY_SIZE(rk817_pre_init_reg);
+ cells = rk817s;
+ nr_cells = ARRAY_SIZE(rk817s);
+ pm_power_off_prepare = rk8xx_device_shutdown_prepare;
+ break;
default:
dev_err(&client->dev, "Unsupported RK8XX ID %lu\n",
rk808->variant);
@@ -568,9 +732,56 @@ static int rk808_remove(struct i2c_client *client)
return 0;
}
+static int rk8xx_suspend(struct device *dev)
+{
+ int ret = 0;
+ struct rk808 *rk808 = i2c_get_clientdata(rk808_i2c_client);
+
+ switch (rk808->variant) {
+ case RK809_ID:
+ case RK817_ID:
+ ret = regmap_update_bits(rk808->regmap,
+ RK817_SYS_CFG(3),
+ RK817_SLPPIN_FUNC_MSK,
+ SLPPIN_SLP_FUN);
+ break;
+ default:
+ break;
+ }
+
+ return ret;
+}
+
+static int rk8xx_resume(struct device *dev)
+{
+ int ret = 0;
+ struct rk808 *rk808 = i2c_get_clientdata(rk808_i2c_client);
+
+ switch (rk808->variant) {
+ case RK809_ID:
+ case RK817_ID:
+ ret = regmap_update_bits(rk808->regmap,
+ RK817_SYS_CFG(3),
+ RK817_SLPPIN_FUNC_MSK,
+ SLPPIN_NULL_FUN);
+ break;
+ default:
+ break;
+ }
+
+ return ret;
+}
+
+static const struct dev_pm_ops rk8xx_pm_ops = {
+ .suspend = rk8xx_suspend,
+ .resume = rk8xx_resume,
+};
Looks like you want SIMPLE_DEV_PM_OPS() here.
static const struct i2c_device_id rk808_ids[] = {
{ "rk805" },
{ "rk808" },
+ { "rk809" },
+ { "rk817" },
{ "rk818" },
{ },
};
I don't think this table is required anymore.
Try removing it.
@@ -580,6 +791,7 @@ static int rk808_remove(struct i2c_client *client)
.driver = {
.name = "rk808",
.of_match_table = rk808_of_match,
+ .pm = &rk8xx_pm_ops,
},
.probe = rk808_probe,
.remove = rk808_remove,
diff --git a/include/linux/mfd/rk808.h b/include/linux/mfd/rk808.h
index d315659..b973b0a 100644
--- a/include/linux/mfd/rk808.h
+++ b/include/linux/mfd/rk808.h
@@ -382,6 +382,7 @@ enum rk805_reg {
#define SWITCH1_EN BIT(5)
#define DEV_OFF_RST BIT(3)
#define DEV_OFF BIT(0)
+#define RTC_STOP BIT(0)
#define VB_LO_ACT BIT(4)
#define VB_LO_SEL_3500MV (7 << 0)
@@ -396,6 +397,175 @@ enum rk805_reg {
#define SLEEP_FUN (0x1 << 2)
#define RK8XX_ID_MSK 0xfff0
#define FPWM_MODE BIT(7)
+enum rk817_reg_id {
+ RK817_ID_DCDC1 = 0,
+ RK817_ID_DCDC2,
+ RK817_ID_DCDC3,
+ RK817_ID_DCDC4,
+ RK817_ID_LDO1,
+ RK817_ID_LDO2,
+ RK817_ID_LDO3,
+ RK817_ID_LDO4,
+ RK817_ID_LDO5,
+ RK817_ID_LDO6,
+ RK817_ID_LDO7,
+ RK817_ID_LDO8,
+ RK817_ID_LDO9,
+ RK817_ID_BOOST,
+ RK817_ID_BOOST_OTG_SW,
+ RK817_NUM_REGULATORS
+};
+
+enum rk809_reg_id {
+ RK809_ID_DCDC5 = RK817_ID_BOOST,
+ RK809_ID_SW1,
+ RK809_ID_SW2,
+ RK809_NUM_REGULATORS
+};
+
+#define RK817_SECONDS_REG 0x00
+#define RK817_MINUTES_REG 0x01
+#define RK817_HOURS_REG 0x02
+#define RK817_DAYS_REG 0x03
+#define RK817_MONTHS_REG 0x04
+#define RK817_YEARS_REG 0x05
+#define RK817_WEEKS_REG 0x06
+#define RK817_ALARM_SECONDS_REG 0x07
+#define RK817_ALARM_MINUTES_REG 0x08
+#define RK817_ALARM_HOURS_REG 0x09
+#define RK817_ALARM_DAYS_REG 0x0a
+#define RK817_ALARM_MONTHS_REG 0x0b
+#define RK817_ALARM_YEARS_REG 0x0c
+#define RK817_RTC_CTRL_REG 0xd
+#define RK817_RTC_STATUS_REG 0xe
+#define RK817_RTC_INT_REG 0xf
+#define RK817_RTC_COMP_LSB_REG 0x10
+#define RK817_RTC_COMP_MSB_REG 0x11
+
+#define RK817_POWER_EN_REG(i) (0xb1 + (i))
+#define RK817_POWER_SLP_EN_REG(i) (0xb5 + (i))
+
+#define RK817_POWER_CONFIG (0xb9)
+
+#define RK817_BUCK_CONFIG_REG(i) (0xba + (i) * 3)
+
+#define RK817_BUCK1_ON_VSEL_REG 0xBB
+#define RK817_BUCK1_SLP_VSEL_REG 0xBC
+
+#define RK817_BUCK2_CONFIG_REG 0xBD
+#define RK817_BUCK2_ON_VSEL_REG 0xBE
+#define RK817_BUCK2_SLP_VSEL_REG 0xBF
+
+#define RK817_BUCK3_CONFIG_REG 0xC0
+#define RK817_BUCK3_ON_VSEL_REG 0xC1
+#define RK817_BUCK3_SLP_VSEL_REG 0xC2
+
+#define RK817_BUCK4_CONFIG_REG 0xC3
+#define RK817_BUCK4_ON_VSEL_REG 0xC4
+#define RK817_BUCK4_SLP_VSEL_REG 0xC5
+
+#define RK817_LDO_ON_VSEL_REG(idx) (0xcc + (idx) * 2)
+#define RK817_BOOST_OTG_CFG (0xde)
+
+#define RK817_ID_MSB 0xed
+#define RK817_ID_LSB 0xee
+
+#define RK817_SYS_STS 0xf0
+#define RK817_SYS_CFG(i) (0xf1 + (i))
+
+#define RK817_ON_SOURCE_REG 0xf5
+#define RK817_OFF_SOURCE_REG 0xf6
+
+/* INTERRUPT REGISTER */
+#define RK817_INT_STS_REG0 0xf8
+#define RK817_INT_STS_MSK_REG0 0xf9
+#define RK817_INT_STS_REG1 0xfa
+#define RK817_INT_STS_MSK_REG1 0xfb
+#define RK817_INT_STS_REG2 0xfc
+#define RK817_INT_STS_MSK_REG2 0xfd
+#define RK817_GPIO_INT_CFG 0xfe
+
+/* IRQ Definitions */
+#define RK817_IRQ_PWRON_FALL 0
+#define RK817_IRQ_PWRON_RISE 1
+#define RK817_IRQ_PWRON 2
+#define RK817_IRQ_PWMON_LP 3
+#define RK817_IRQ_HOTDIE 4
+#define RK817_IRQ_RTC_ALARM 5
+#define RK817_IRQ_RTC_PERIOD 6
+#define RK817_IRQ_VB_LO 7
+#define RK817_IRQ_PLUG_IN (8 + 0)
+#define RK817_IRQ_PLUG_OUT (8 + 1)
+#define RK817_IRQ_CHRG_TERM (8 + 2)
+#define RK817_IRQ_CHRG_TIME (8 + 3)
+#define RK817_IRQ_CHRG_TS (8 + 4)
+#define RK817_IRQ_USB_OV (8 + 5)
+#define RK817_IRQ_CHRG_IN_CLMP (8 + 6)
+#define RK817_IRQ_BAT_DIS_ILIM (8 + 7)
+#define RK817_IRQ_GATE_GPIO (16 + 0)
+#define RK817_IRQ_TS_GPIO (16 + 1)
+#define RK817_IRQ_CODEC_PD (16 + 2)
+#define RK817_IRQ_CODEC_PO (16 + 3)
+#define RK817_IRQ_CLASSD_MUTE_DONE (16 + 4)
+#define RK817_IRQ_CLASSD_OCP (16 + 5)
+#define RK817_IRQ_BAT_OVP (16 + 6)
+#define RK817_IRQ_CHRG_BAT_HI (16 + 7)
+#define RK817_IRQ_END (RK817_IRQ_CHRG_BAT_HI + 1)
+
+/*
+ * rtc_ctrl 0xd
+ * same as 808, except bit4
+ */
+#define RK817_RTC_CTRL_RSV4 BIT(4)
+
+/* power config 0xb9 */
+#define RK817_BUCK3_FB_RES_MSK BIT(6)
+#define RK817_BUCK3_FB_RES_INTER BIT(6)
+#define RK817_BUCK3_FB_RES_EXT 0
+
+/* buck config 0xba */
+#define RK817_RAMP_RATE_OFFSET 6
+#define RK817_RAMP_RATE_MASK (0x3 << RK817_RAMP_RATE_OFFSET)
+#define RK817_RAMP_RATE_3MV_PER_US (0x0 << RK817_RAMP_RATE_OFFSET)
+#define RK817_RAMP_RATE_6_3MV_PER_US (0x1 << RK817_RAMP_RATE_OFFSET)
+#define RK817_RAMP_RATE_12_5MV_PER_US (0x2 << RK817_RAMP_RATE_OFFSET)
+#define RK817_RAMP_RATE_25MV_PER_US (0x3 << RK817_RAMP_RATE_OFFSET)
+
+/* sys_cfg1 0xf2 */
+#define RK817_HOTDIE_TEMP_MSK (0x3 << 4)
+#define RK817_HOTDIE_85 (0x0 << 4)
+#define RK817_HOTDIE_95 (0x1 << 4)
+#define RK817_HOTDIE_105 (0x2 << 4)
+#define RK817_HOTDIE_115 (0x3 << 4)
+
+#define RK817_TSD_TEMP_MSK BIT(6)
+#define RK817_TSD_140 0
+#define RK817_TSD_160 BIT(6)
+
+#define RK817_CLK32KOUT2_EN BIT(7)
+
+/* sys_cfg3 0xf4 */
+#define RK817_SLPPIN_FUNC_MSK (0x3 << 3)
+#define SLPPIN_NULL_FUN (0x0 << 3)
+#define SLPPIN_SLP_FUN (0x1 << 3)
+#define SLPPIN_DN_FUN (0x2 << 3)
+#define SLPPIN_RST_FUN (0x3 << 3)
+
+#define RK817_RST_FUNC_MSK (0x3 << 6)
+#define RK817_RST_FUNC_SFT (6)
+#define RK817_RST_FUNC_CNT (3)
+#define RK817_RST_FUNC_DEV (0) /* reset the dev */
+#define RK817_RST_FUNC_REG (0x1 << 6) /* reset the reg only */
+
+#define RK817_SLPPOL_MSK BIT(5)
+#define RK817_SLPPOL_H BIT(5)
+#define RK817_SLPPOL_L (0)
+
+/* gpio&int 0xfe */
+#define RK817_INT_POL_MSK BIT(1)
+#define RK817_INT_POL_H BIT(1)
+#define RK817_INT_POL_L 0
+#define RK809_BUCK5_CONFIG(i) (RK817_BOOST_OTG_CFG + (i) * 1)
enum {
BUCK_ILMIN_50MA,
@@ -443,6 +613,8 @@ enum {
enum {
RK805_ID = 0x8050,
RK808_ID = 0x0000,
+ RK809_ID = 0x8090,
+ RK817_ID = 0x8170,
RK818_ID = 0x8181,
};
diff --git a/kernel/reboot.c b/kernel/reboot.c
index e4ced88..83810d7 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -49,6 +49,7 @@
*/
void (*pm_power_off_prepare)(void);
+EXPORT_SYMBOL_GPL(pm_power_off_prepare);
Why do you need this where no other driver in the kernel does?
ÂÂÂ There is a gpio_slp pin for RK809 and RK817ïthis pin has
resetãpower down and sleep functionsïso
ÂÂÂ when system is going to power down, this pin is needed to switch to
power down functionïand then we just only control
ÂÂÂ this pin to high to power down the system in atf at lastã
/**
* emergency_restart - reboot the system