power: reset: Add poweroff driver for ATC260x PMICs

This driver provides poweroff and reboot support for a system through
the ATC2603C and ATC2609A chip variants of the Actions Semi ATC260x
family of PMICs.

Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@gmail.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

3 files changed, 270 insertions, 1 deletions

diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
index b22c4fdb2561..1737e227b16e 100644
--- a/drivers/power/reset/Kconfig
+++ b/drivers/power/reset/Kconfig
@@ -39,6 +39,13 @@ config POWER_RESET_AT91_SAMA5D2_SHDWC
 	  This driver supports the alternate shutdown controller for some Atmel
 	  SAMA5 SoCs. It is present for example on SAMA5D2 SoC.
 
+config POWER_RESET_ATC260X
+	tristate "Actions Semi ATC260x PMIC power-off driver"
+	depends on MFD_ATC260X
+	help
+	  This driver provides power-off and restart support for a system
+	  through Actions Semi ATC260x series PMICs.
+
 config POWER_RESET_AXXIA
 	bool "LSI Axxia reset driver"
 	depends on ARCH_AXXIA
@@ -292,4 +299,3 @@ config NVMEM_REBOOT_MODE
 	  action according to the mode.
 
 endif
-
diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
index 9dc49d3a57ff..b4601c0a96ed 100644
--- a/drivers/power/reset/Makefile
+++ b/drivers/power/reset/Makefile
@@ -3,6 +3,7 @@ obj-$(CONFIG_POWER_RESET_AS3722) += as3722-poweroff.o
 obj-$(CONFIG_POWER_RESET_AT91_POWEROFF) += at91-poweroff.o
 obj-$(CONFIG_POWER_RESET_AT91_RESET) += at91-reset.o
 obj-$(CONFIG_POWER_RESET_AT91_SAMA5D2_SHDWC) += at91-sama5d2_shdwc.o
+obj-$(CONFIG_POWER_RESET_ATC260X) += atc260x-poweroff.o
 obj-$(CONFIG_POWER_RESET_AXXIA) += axxia-reset.o
 obj-$(CONFIG_POWER_RESET_BRCMKONA) += brcm-kona-reset.o
 obj-$(CONFIG_POWER_RESET_BRCMSTB) += brcmstb-reboot.o
diff --git a/drivers/power/reset/atc260x-poweroff.c b/drivers/power/reset/atc260x-poweroff.c
new file mode 100644
index 000000000000..98f20251a6d1
--- /dev/null
+++ b/drivers/power/reset/atc260x-poweroff.c
@@ -0,0 +1,262 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Poweroff & reset driver for Actions Semi ATC260x PMICs
+ *
+ * Copyright (c) 2020 Cristian Ciocaltea <cristian.ciocaltea@gmail.com>
+ */
+
+#include <linux/delay.h>
+#include <linux/mfd/atc260x/core.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/power_supply.h>
+#include <linux/reboot.h>
+#include <linux/regmap.h>
+
+struct atc260x_pwrc {
+	struct device *dev;
+	struct regmap *regmap;
+	struct notifier_block restart_nb;
+	int (*do_poweroff)(const struct atc260x_pwrc *pwrc, bool restart);
+};
+
+/* Global variable needed only for pm_power_off */
+static struct atc260x_pwrc *atc260x_pwrc_data;
+
+static int atc2603c_do_poweroff(const struct atc260x_pwrc *pwrc, bool restart)
+{
+	int ret, deep_sleep = 0;
+	uint reg_mask, reg_val;
+
+	/* S4-Deep Sleep Mode is NOT available for WALL/USB power */
+	if (!restart && !power_supply_is_system_supplied()) {
+		deep_sleep = 1;
+		dev_info(pwrc->dev, "Enabling S4-Deep Sleep Mode");
+	}
+
+	/* Update wakeup sources */
+	reg_val = ATC2603C_PMU_SYS_CTL0_ONOFF_LONG_WK_EN |
+		  (restart ? ATC2603C_PMU_SYS_CTL0_RESET_WK_EN
+			   : ATC2603C_PMU_SYS_CTL0_ONOFF_SHORT_WK_EN);
+
+	ret = regmap_update_bits(pwrc->regmap, ATC2603C_PMU_SYS_CTL0,
+				 ATC2603C_PMU_SYS_CTL0_WK_ALL, reg_val);
+	if (ret)
+		dev_warn(pwrc->dev, "failed to write SYS_CTL0: %d\n", ret);
+
+	/* Update power mode */
+	reg_mask = ATC2603C_PMU_SYS_CTL3_EN_S2 | ATC2603C_PMU_SYS_CTL3_EN_S3;
+
+	ret = regmap_update_bits(pwrc->regmap, ATC2603C_PMU_SYS_CTL3, reg_mask,
+				 deep_sleep ? 0 : ATC2603C_PMU_SYS_CTL3_EN_S3);
+	if (ret) {
+		dev_err(pwrc->dev, "failed to write SYS_CTL3: %d\n", ret);
+		return ret;
+	}
+
+	/* Trigger poweroff / restart sequence */
+	reg_mask = restart ? ATC2603C_PMU_SYS_CTL0_RESTART_EN
+			   : ATC2603C_PMU_SYS_CTL1_EN_S1;
+	reg_val = restart ? ATC2603C_PMU_SYS_CTL0_RESTART_EN : 0;
+
+	ret = regmap_update_bits(pwrc->regmap,
+				 restart ? ATC2603C_PMU_SYS_CTL0 : ATC2603C_PMU_SYS_CTL1,
+				 reg_mask, reg_val);
+	if (ret) {
+		dev_err(pwrc->dev, "failed to write SYS_CTL%d: %d\n",
+			restart ? 0 : 1, ret);
+		return ret;
+	}
+
+	/* Wait for trigger completion */
+	mdelay(200);
+
+	return 0;
+}
+
+static int atc2609a_do_poweroff(const struct atc260x_pwrc *pwrc, bool restart)
+{
+	int ret, deep_sleep = 0;
+	uint reg_mask, reg_val;
+
+	/* S4-Deep Sleep Mode is NOT available for WALL/USB power */
+	if (!restart && !power_supply_is_system_supplied()) {
+		deep_sleep = 1;
+		dev_info(pwrc->dev, "Enabling S4-Deep Sleep Mode");
+	}
+
+	/* Update wakeup sources */
+	reg_val = ATC2609A_PMU_SYS_CTL0_ONOFF_LONG_WK_EN |
+		  (restart ? ATC2609A_PMU_SYS_CTL0_RESET_WK_EN
+			   : ATC2609A_PMU_SYS_CTL0_ONOFF_SHORT_WK_EN);
+
+	ret = regmap_update_bits(pwrc->regmap, ATC2609A_PMU_SYS_CTL0,
+				 ATC2609A_PMU_SYS_CTL0_WK_ALL, reg_val);
+	if (ret)
+		dev_warn(pwrc->dev, "failed to write SYS_CTL0: %d\n", ret);
+
+	/* Update power mode */
+	reg_mask = ATC2609A_PMU_SYS_CTL3_EN_S2 | ATC2609A_PMU_SYS_CTL3_EN_S3;
+
+	ret = regmap_update_bits(pwrc->regmap, ATC2609A_PMU_SYS_CTL3, reg_mask,
+				 deep_sleep ? 0 : ATC2609A_PMU_SYS_CTL3_EN_S3);
+	if (ret) {
+		dev_err(pwrc->dev, "failed to write SYS_CTL3: %d\n", ret);
+		return ret;
+	}
+
+	/* Trigger poweroff / restart sequence */
+	reg_mask = restart ? ATC2609A_PMU_SYS_CTL0_RESTART_EN
+			   : ATC2609A_PMU_SYS_CTL1_EN_S1;
+	reg_val = restart ? ATC2609A_PMU_SYS_CTL0_RESTART_EN : 0;
+
+	ret = regmap_update_bits(pwrc->regmap,
+				 restart ? ATC2609A_PMU_SYS_CTL0 : ATC2609A_PMU_SYS_CTL1,
+				 reg_mask, reg_val);
+	if (ret) {
+		dev_err(pwrc->dev, "failed to write SYS_CTL%d: %d\n",
+			restart ? 0 : 1, ret);
+		return ret;
+	}
+
+	/* Wait for trigger completion */
+	mdelay(200);
+
+	return 0;
+}
+
+static int atc2603c_init(const struct atc260x_pwrc *pwrc)
+{
+	int ret;
+
+	/*
+	 * Delay transition from S2/S3 to S1 in order to avoid
+	 * DDR init failure in Bootloader.
+	 */
+	ret = regmap_update_bits(pwrc->regmap, ATC2603C_PMU_SYS_CTL3,
+				 ATC2603C_PMU_SYS_CTL3_S2S3TOS1_TIMER_EN,
+				 ATC2603C_PMU_SYS_CTL3_S2S3TOS1_TIMER_EN);
+	if (ret)
+		dev_warn(pwrc->dev, "failed to write SYS_CTL3: %d\n", ret);
+
+	/* Set wakeup sources */
+	ret = regmap_update_bits(pwrc->regmap, ATC2603C_PMU_SYS_CTL0,
+				 ATC2603C_PMU_SYS_CTL0_WK_ALL,
+				 ATC2603C_PMU_SYS_CTL0_HDSW_WK_EN |
+				 ATC2603C_PMU_SYS_CTL0_ONOFF_LONG_WK_EN);
+	if (ret)
+		dev_warn(pwrc->dev, "failed to write SYS_CTL0: %d\n", ret);
+
+	return ret;
+}
+
+static int atc2609a_init(const struct atc260x_pwrc *pwrc)
+{
+	int ret;
+
+	/* Set wakeup sources */
+	ret = regmap_update_bits(pwrc->regmap, ATC2609A_PMU_SYS_CTL0,
+				 ATC2609A_PMU_SYS_CTL0_WK_ALL,
+				 ATC2609A_PMU_SYS_CTL0_HDSW_WK_EN |
+				 ATC2609A_PMU_SYS_CTL0_ONOFF_LONG_WK_EN);
+	if (ret)
+		dev_warn(pwrc->dev, "failed to write SYS_CTL0: %d\n", ret);
+
+	return ret;
+}
+
+static void atc260x_pwrc_pm_handler(void)
+{
+	atc260x_pwrc_data->do_poweroff(atc260x_pwrc_data, false);
+
+	WARN_ONCE(1, "Unable to power off system\n");
+}
+
+static int atc260x_pwrc_restart_handler(struct notifier_block *nb,
+					unsigned long mode, void *cmd)
+{
+	struct atc260x_pwrc *pwrc = container_of(nb, struct atc260x_pwrc,
+						 restart_nb);
+	pwrc->do_poweroff(pwrc, true);
+
+	return NOTIFY_DONE;
+}
+
+static int atc260x_pwrc_probe(struct platform_device *pdev)
+{
+	struct atc260x *atc260x = dev_get_drvdata(pdev->dev.parent);
+	struct atc260x_pwrc *priv;
+	int ret;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->dev = &pdev->dev;
+	priv->regmap = atc260x->regmap;
+	priv->restart_nb.notifier_call = atc260x_pwrc_restart_handler;
+	priv->restart_nb.priority = 192;
+
+	switch (atc260x->ic_type) {
+	case ATC2603C:
+		priv->do_poweroff = atc2603c_do_poweroff;
+		ret = atc2603c_init(priv);
+		break;
+	case ATC2609A:
+		priv->do_poweroff = atc2609a_do_poweroff;
+		ret = atc2609a_init(priv);
+		break;
+	default:
+		dev_err(priv->dev,
+			"Poweroff not supported for ATC260x PMIC type: %u\n",
+			atc260x->ic_type);
+		return -EINVAL;
+	}
+
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, priv);
+
+	if (!pm_power_off) {
+		atc260x_pwrc_data = priv;
+		pm_power_off = atc260x_pwrc_pm_handler;
+	} else {
+		dev_warn(priv->dev, "Poweroff callback already assigned\n");
+	}
+
+	ret = register_restart_handler(&priv->restart_nb);
+	if (ret)
+		dev_err(priv->dev, "failed to register restart handler: %d\n",
+			ret);
+
+	return ret;
+}
+
+static int atc260x_pwrc_remove(struct platform_device *pdev)
+{
+	struct atc260x_pwrc *priv = platform_get_drvdata(pdev);
+
+	if (atc260x_pwrc_data == priv) {
+		pm_power_off = NULL;
+		atc260x_pwrc_data = NULL;
+	}
+
+	unregister_restart_handler(&priv->restart_nb);
+
+	return 0;
+}
+
+static struct platform_driver atc260x_pwrc_driver = {
+	.probe = atc260x_pwrc_probe,
+	.remove = atc260x_pwrc_remove,
+	.driver = {
+		.name = "atc260x-pwrc",
+	},
+};
+
+module_platform_driver(atc260x_pwrc_driver);
+
+MODULE_DESCRIPTION("Poweroff & reset driver for ATC260x PMICs");
+MODULE_AUTHOR("Cristian Ciocaltea <cristian.ciocaltea@gmail.com>");
+MODULE_LICENSE("GPL");