linux-kernel - [PATCH 3/3] mfd: tps6594: Adds support for powering off the PMIC

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Message-Id: <20250520-linux-stable-tps6594-pwrbutton-v1-3-0cc5c6e0415c@criticallink.com>
Date: Tue, 20 May 2025 13:43:38 -0400
From: Job Sava <jsava@...ticallink.com>
To: Lee Jones <lee@...nel.org>, Rob Herring <robh@...nel.org>, 
 Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, Julien Panis <jpanis@...libre.com>, 
 Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc: devicetree@...r.kernel.org, linux-kernel@...r.kernel.org, 
 linux-input@...r.kernel.org, jcormier@...ticallink.com, 
 Job Sava <jsava@...ticallink.com>
Subject: [PATCH 3/3] mfd: tps6594: Adds support for powering off the PMIC

When the FSM_I2C_TRIGGER register's bit 0 is set it triggers TRIGGER_I2C_0
and the PMIC is transitioned to the STANDBY state
(table 6-18: SLVSGG7 – DECEMBER 2023).

An ON request is required to transition from STANDBY to ACTIVE.

Signed-off-by: Job Sava <jsava@...ticallink.com>
---
 drivers/mfd/tps6594-core.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/mfd/tps6594-core.c b/drivers/mfd/tps6594-core.c
index 1b0b3d1bf6c4..f4c434c0d87a 100644
--- a/drivers/mfd/tps6594-core.c
+++ b/drivers/mfd/tps6594-core.c
@@ -10,6 +10,7 @@
 #include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/reboot.h>
 
 #include <linux/mfd/core.h>
 #include <linux/mfd/tps6594.h>
@@ -615,6 +616,19 @@ static int tps6594_enable_crc(struct tps6594 *tps)
 	return ret;
 }
 
+static int tps6594_soft_shutdown(struct tps6594 *tps)
+{
+	return regmap_update_bits(tps->regmap, TPS6594_REG_FSM_I2C_TRIGGERS,
+				TPS6594_BIT_TRIGGER_I2C(0),
+				TPS6594_BIT_TRIGGER_I2C(0));
+}
+
+static int tps6594_power_off_handler(struct sys_off_data *data)
+{
+	tps6594_soft_shutdown(data->cb_data);
+	return NOTIFY_DONE;
+}
+
 int tps6594_device_init(struct tps6594 *tps, bool enable_crc)
 {
 	struct device *dev = tps->dev;
@@ -623,6 +637,7 @@ int tps6594_device_init(struct tps6594 *tps, bool enable_crc)
 	const struct mfd_cell *cells;
 	int n_cells;
 	bool pwr_button;
+	bool system_power_controller;
 
 	if (enable_crc) {
 		ret = tps6594_enable_crc(tps);
@@ -681,6 +696,15 @@ int tps6594_device_init(struct tps6594 *tps, bool enable_crc)
 			return dev_err_probe(dev, ret, "Failed to add RTC child device\n");
 	}
 
+	system_power_controller = of_property_read_bool(dev->of_node, "system-power-controller");
+	if (system_power_controller) {
+		ret = devm_register_power_off_handler(tps->dev,
+								tps6594_power_off_handler,
+								tps);
+		if (ret)
+			return dev_err_probe(dev, ret, "Failed to register power-off handler\n");
+	}
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(tps6594_device_init);

-- 
2.43.0