linux-kernel - [PATCH v1 4/6] mfd: max77620: Use power off call chain API

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Message-Id: <20211007060253.17049-5-digetx@gmail.com>
Date:   Thu,  7 Oct 2021 09:02:51 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Lee Jones <lee.jones@...aro.org>,
        "Rafael J . Wysocki" <rafael@...nel.org>,
        Mark Brown <broonie@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Guenter Roeck <linux@...ck-us.net>,
        Russell King <linux@...linux.org.uk>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Ulf Hansson <ulf.hansson@...aro.org>
Cc:     linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-tegra@...r.kernel.org
Subject: [PATCH v1 4/6] mfd: max77620: Use power off call chain API

Use new power off call chain API which allows multiple power off handlers
to coexist. Nexus 7 Android tablet can be powered off using MAX77663 PMIC
and using a special bootloader command. At first the bootloader option
should be tried, it will have a higher priority than the PMIC.

Signed-off-by: Dmitry Osipenko <digetx@...il.com>
---
 drivers/mfd/max77620.c       | 22 +++++++++++++++-------
 include/linux/mfd/max77620.h |  2 ++
 2 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/drivers/mfd/max77620.c b/drivers/mfd/max77620.c
index fec2096474ad..ad40eed1f0c6 100644
--- a/drivers/mfd/max77620.c
+++ b/drivers/mfd/max77620.c
@@ -31,11 +31,10 @@
 #include <linux/init.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/reboot.h>
 #include <linux/regmap.h>
 #include <linux/slab.h>
 
-static struct max77620_chip *max77620_scratch;
-
 static const struct resource gpio_resources[] = {
 	DEFINE_RES_IRQ(MAX77620_IRQ_TOP_GPIO),
 };
@@ -483,13 +482,17 @@ static int max77620_read_es_version(struct max77620_chip *chip)
 	return ret;
 }
 
-static void max77620_pm_power_off(void)
+static int max77620_pm_power_off(struct notifier_block *nb,
+				 unsigned long reboot_mode, void *data)
 {
-	struct max77620_chip *chip = max77620_scratch;
+	struct max77620_chip *chip = container_of(nb, struct max77620_chip,
+						  pm_off_nb);
 
 	regmap_update_bits(chip->rmap, MAX77620_REG_ONOFFCNFG1,
 			   MAX77620_ONOFFCNFG1_SFT_RST,
 			   MAX77620_ONOFFCNFG1_SFT_RST);
+
+	return NOTIFY_DONE;
 }
 
 static int max77620_probe(struct i2c_client *client,
@@ -566,9 +569,14 @@ static int max77620_probe(struct i2c_client *client,
 	}
 
 	pm_off = of_device_is_system_power_controller(client->dev.of_node);
-	if (pm_off && !pm_power_off) {
-		max77620_scratch = chip;
-		pm_power_off = max77620_pm_power_off;
+	if (pm_off) {
+		chip->pm_off_nb.notifier_call = max77620_pm_power_off;
+		chip->pm_off_nb.priority = 128;
+
+		ret = devm_register_poweroff_handler(chip->dev, &chip->pm_off_nb);
+		if (ret < 0)
+			dev_err(chip->dev,
+				"Failed to register poweroff handler: %d\n", ret);
 	}
 
 	return 0;
diff --git a/include/linux/mfd/max77620.h b/include/linux/mfd/max77620.h
index f552ef5b1100..99de4f8c9cbf 100644
--- a/include/linux/mfd/max77620.h
+++ b/include/linux/mfd/max77620.h
@@ -8,6 +8,7 @@
 #ifndef _MFD_MAX77620_H_
 #define _MFD_MAX77620_H_
 
+#include <linux/notifier.h>
 #include <linux/types.h>
 
 /* GLOBAL, PMIC, GPIO, FPS, ONOFFC, CID Registers */
@@ -327,6 +328,7 @@ enum max77620_chip_id {
 struct max77620_chip {
 	struct device *dev;
 	struct regmap *rmap;
+	struct notifier_block pm_off_nb;
 
 	int chip_irq;
 
-- 
2.32.0