linux-kernel - Re: [PATCH RFT v3 3/4] hwmon: (spd5118) Add suspend/resume support

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Date: Sat, 1 Jun 2024 21:17:41 +0200
From: Armin Wolf <W_Armin@....de>
To: Guenter Roeck <linux@...ck-us.net>, linux-hwmon@...r.kernel.org
Cc: devicetree@...r.kernel.org, Rob Herring <robh@...nel.org>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
 <conor+dt@...nel.org>, linux-kernel@...r.kernel.org,
 Thomas Weißschuh <linux@...ssschuh.net>,
 René Rebe <rene@...ctcode.de>,
 Wolfram Sang <wsa+renesas@...g-engineering.com>
Subject: Re: [PATCH RFT v3 3/4] hwmon: (spd5118) Add suspend/resume support

Am 01.06.24 um 01:05 schrieb Guenter Roeck:

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

Hi,

it seems that 6.10.0-rc1 cannot suspend/resume on my machine. Kernel 6.9.1 however
can successfully enter and leave S3 and S4, so i tested the driver on this kernel
version.

In both cases, the driver was successfully preserving the settings, so:

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

> Cc: Armin Wolf <W_Armin@....de>
> Signed-off-by: Guenter Roeck <linux@...ck-us.net>
> ---
> v3: No change
>
> v2: New patch
>
> RFT: I tested the patch through a suspend/resume cycle, and it seems
>       to work, but I am not sure if that had any effect because,
>       after all, the memory is still active during suspend/resume.
>       I was unable to test a hibernation cycle with my system.
>
>   drivers/hwmon/spd5118.c | 29 +++++++++++++++++++++++++++++
>   1 file changed, 29 insertions(+)
>
> diff --git a/drivers/hwmon/spd5118.c b/drivers/hwmon/spd5118.c
> index d3fc0ae17743..baa315172298 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 +452,31 @@ static int spd5118_probe(struct i2c_client *client)
>   	return 0;
>   }
>
> +static int spd5118_suspend(struct device *dev)
> +{
> +	struct regmap *regmap = dev_get_drvdata(dev);
> +
> +	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 +494,7 @@ 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,