linux-kernel - [PATCH v4 3/6] hwmon: (spd5118) Add suspend/resume support

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Date: Mon,  3 Jun 2024 21:02:34 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: linux-hwmon@...r.kernel.org
Cc: linux-i2c@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	devicetree@...r.kernel.org,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Wolfram Sang <wsa+renesas@...g-engineering.com>,
	René Rebe <rene@...ctcode.de>,
	Thomas Weißschuh <linux@...ssschuh.net>,
	Armin Wolf <W_Armin@....de>,
	Stephen Horvath <s.horvath@...look.com.au>,
	Guenter Roeck <linux@...ck-us.net>
Subject: [PATCH v4 3/6] hwmon: (spd5118) Add suspend/resume support

Add suspend/resume support to ensure that limit and configuration
registers are updated and synchronized after a suspend/resume cycle.

Cc: Armin Wolf <W_Armin@....de>
Cc: Stephen Horvath <s.horvath@...look.com.au>
Signed-off-by: Guenter Roeck <linux@...ck-us.net>
---
v4: Fix bug seen if the enable attribute was never read prior
    to a suspend/resume cycle.

v3: No change

v2: New patch

 drivers/hwmon/spd5118.c | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/drivers/hwmon/spd5118.c b/drivers/hwmon/spd5118.c
index d3fc0ae17743..d55c073ff5fd 100644
--- a/drivers/hwmon/spd5118.c
+++ b/drivers/hwmon/spd5118.c
@@ -20,6 +20,7 @@
 #include <linux/i2c.h>
 #include <linux/hwmon.h>
 #include <linux/module.h>
+#include <linux/pm.h>
 #include <linux/regmap.h>
 #include <linux/units.h>
 
@@ -432,6 +433,8 @@ static int spd5118_probe(struct i2c_client *client)
 	if (!spd5118_vendor_valid(bank, vendor))
 		return -ENODEV;
 
+	dev_set_drvdata(dev, regmap);
+
 	hwmon_dev = devm_hwmon_device_register_with_info(dev, "spd5118",
 							 regmap, &spd5118_chip_info,
 							 NULL);
@@ -449,6 +452,41 @@ static int spd5118_probe(struct i2c_client *client)
 	return 0;
 }
 
+static int spd5118_suspend(struct device *dev)
+{
+	struct regmap *regmap = dev_get_drvdata(dev);
+	u32 regval;
+	int err;
+
+	/*
+	 * Make sure the configuration register in the regmap cache is current
+	 * before bypassing it.
+	 */
+	err = regmap_read(regmap, SPD5118_REG_TEMP_CONFIG, &regval);
+	if (err < 0)
+		return err;
+
+	regcache_cache_bypass(regmap, true);
+	regmap_update_bits(regmap, SPD5118_REG_TEMP_CONFIG, SPD5118_TS_DISABLE,
+			   SPD5118_TS_DISABLE);
+	regcache_cache_bypass(regmap, false);
+
+	regcache_cache_only(regmap, true);
+	regcache_mark_dirty(regmap);
+
+	return 0;
+}
+
+static int spd5118_resume(struct device *dev)
+{
+	struct regmap *regmap = dev_get_drvdata(dev);
+
+	regcache_cache_only(regmap, false);
+	return regcache_sync(regmap);
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(spd5118_pm_ops, spd5118_suspend, spd5118_resume);
+
 static const struct i2c_device_id spd5118_id[] = {
 	{ "spd5118", 0 },
 	{ }
@@ -466,6 +504,7 @@ static struct i2c_driver spd5118_driver = {
 	.driver = {
 		.name	= "spd5118",
 		.of_match_table = spd5118_of_ids,
+		.pm = pm_sleep_ptr(&spd5118_pm_ops),
 	},
 	.probe		= spd5118_probe,
 	.id_table	= spd5118_id,
-- 
2.39.2