linux-kernel - [PATCH v2 2/2] mfd: tps6586x: register restart handler

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Date:   Mon, 20 Mar 2023 23:03:45 +0100
From:   Benjamin Bara <bbara93@...il.com>
To:     lee@...nel.org
Cc:     dmitry.osipenko@...labora.com, jonathanh@...dia.com,
        treding@...dia.com, richard.leitner@...ux.dev,
        benjamin.bara@...data.com, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2 2/2] mfd: tps6586x: register restart handler

From: Benjamin Bara <benjamin.bara@...data.com>

The TPS658629-Q1 (unfortunately the only TPS6586x with public data sheet)
provides a SOFT RST bit in the SUPPLYENE reg to request a (cold) reboot.

Use it to implement and register a restart handler.

Tested on a TPS658640.

Signed-off-by: Benjamin Bara <benjamin.bara@...data.com>
---
 drivers/mfd/tps6586x.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/drivers/mfd/tps6586x.c b/drivers/mfd/tps6586x.c
index 4869155437cb..b46917231847 100644
--- a/drivers/mfd/tps6586x.c
+++ b/drivers/mfd/tps6586x.c
@@ -15,6 +15,7 @@
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/irqdomain.h>
+#include <linux/irqflags.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
@@ -30,6 +31,7 @@
 #include <linux/mfd/tps6586x.h>
 
 #define TPS6586X_SUPPLYENE	0x14
+#define SOFT_RST_BIT		BIT(0)
 #define EXITSLREQ_BIT		BIT(1)
 #define SLEEP_MODE_BIT		BIT(3)
 
@@ -470,6 +472,20 @@ static int tps6586x_power_off_handler(struct sys_off_data *data)
 	return tps6586x_set_bits(tps6586x_dev, TPS6586X_SUPPLYENE, SLEEP_MODE_BIT);
 }
 
+static int tps6586x_restart_handler(struct sys_off_data *data)
+{
+	unsigned long flags;
+	struct device *tps6586x_dev = (struct device *)data->cb_data;
+
+	/* bring pmic into HARD REBOOT state, enforce atomic i2c xfer */
+	local_irq_save(flags);
+	tps6586x_set_bits(tps6586x_dev, TPS6586X_SUPPLYENE, SOFT_RST_BIT);
+	local_irq_restore(flags);
+
+	mdelay(500);
+	return 0;
+}
+
 static void tps6586x_print_version(struct i2c_client *client, int version)
 {
 	const char *name;
@@ -570,6 +586,13 @@ static int tps6586x_i2c_probe(struct i2c_client *client)
 			dev_err(&client->dev, "register power off handler failed: %d\n", ret);
 			goto err_add_devs;
 		}
+
+		ret = devm_register_restart_handler(&client->dev, &tps6586x_restart_handler,
+						    &client->dev);
+		if (ret) {
+			dev_err(&client->dev, "register restart handler failed: %d\n", ret);
+			goto err_add_devs;
+		}
 	}
 
 	return 0;
-- 
2.34.1