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

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Message-ID: <59485024-f5d0-4553-b567-2a04ec3d2606@gmx.de>
Date: Fri, 7 Jun 2024 17:57:57 +0200
From: Armin Wolf <W_Armin@....de>
To: Guenter Roeck <linux@...ck-us.net>, 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>,
 Stephen Horvath <s.horvath@...look.com.au>
Subject: Re: [PATCH v4 3/6] hwmon: (spd5118) Add suspend/resume support

Am 04.06.24 um 06:02 schrieb Guenter Roeck:

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

Tested-by: Armin Wolf <W_Armin@....de>

>
> 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,