linux-kernel - [PATCH v2 3/3] mfd: tps6594: Add board power-off support

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Message-Id: <20250826134631.1499936-4-mwalle@kernel.org>
Date: Tue, 26 Aug 2025 15:46:31 +0200
From: Michael Walle <mwalle@...nel.org>
To: Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Lee Jones <lee@...nel.org>
Cc: jcormier@...ticallink.com,
	Job Sava <jsava@...ticallink.com>,
	linux-kernel@...r.kernel.org,
	linux-input@...r.kernel.org,
	Michael Walle <mwalle@...nel.org>
Subject: [PATCH v2 3/3] mfd: tps6594: Add board power-off support

Add a system level power-off handler if the "system-power-controller"
flag is set for this device in the device tree.

A power-off request is triggered by writing the TRIGGER_I2C_0 bit (which
is actually just a convention and really depends on the freely
programmable FSM).

Co-developed-by: Job Sava <jsava@...ticallink.com>
Signed-off-by: Job Sava <jsava@...ticallink.com>
Signed-off-by: Michael Walle <mwalle@...nel.org>
---
v2:
 - incoroprate feedback from Lee Jones.
 - use of_device_is_system_power_controller() instead of open coding it
 - handle errors in power_off handler
---
 drivers/mfd/tps6594-core.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/mfd/tps6594-core.c b/drivers/mfd/tps6594-core.c
index 9195c9059489..7127af7142f5 100644
--- a/drivers/mfd/tps6594-core.c
+++ b/drivers/mfd/tps6594-core.c
@@ -15,6 +15,7 @@
 #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>
@@ -688,6 +689,19 @@ static int tps6594_enable_crc(struct tps6594 *tps)
 	return ret;
 }
 
+static int tps6594_power_off_handler(struct sys_off_data *data)
+{
+	struct tps6594 *tps = data->cb_data;
+	int ret;
+
+	ret = regmap_update_bits(tps->regmap, TPS6594_REG_FSM_I2C_TRIGGERS,
+				 TPS6594_BIT_TRIGGER_I2C(0), TPS6594_BIT_TRIGGER_I2C(0));
+	if (ret)
+		return notifier_from_errno(ret);
+
+	return NOTIFY_DONE;
+}
+
 int tps6594_device_init(struct tps6594 *tps, bool enable_crc)
 {
 	struct device *dev = tps->dev;
@@ -770,6 +784,12 @@ int tps6594_device_init(struct tps6594 *tps, bool enable_crc)
 			return dev_err_probe(dev, ret, "Failed to add RTC child device\n");
 	}
 
+	if (of_device_is_system_power_controller(dev->of_node)) {
+		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);
-- 
2.39.5