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Message-ID: <f0aaa35c-ddda-a875-c6b0-9fded6114578@redhat.com>
Date:   Mon, 10 Jul 2023 15:34:00 +0200
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Subject: Re: [PATCH 2/2] platform/x86: add CMOS battery monitoring for simatic
 IPCs
Content-Language: en-US
To:     Henning Schild <henning.schild@siemens.com>,
        Mark Gross <markgross@kernel.org>,
        linux-kernel@vger.kernel.org, platform-driver-x86@vger.kernel.org
Cc:     Wim Van Sebroeck <wim@linux-watchdog.org>,
        Guenter Roeck <linux@roeck-us.net>,
        Jean Delvare <jdelvare@suse.com>,
        linux-watchdog@vger.kernel.org, linux-hwmon@vger.kernel.org,
        Tobias Schaffner <tobias.schaffner@siemens.com>,
        Gerd Haeussler <gerd.haeussler.ext@siemens.com>
References: <20230706154831.19100-1-henning.schild@siemens.com>
 <20230706154831.19100-3-henning.schild@siemens.com>
From:   Hans de Goede <hdegoede@redhat.com>
In-Reply-To: <20230706154831.19100-3-henning.schild@siemens.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk

Hi,

On 7/6/23 17:48, Henning Schild wrote:
> Siemens Simatic Industrial PCs can monitor the voltage of the CMOS
> battery with two bits that indicate low or empty state. This can be GPIO
> or PortIO based.
> Here we model that as a hwmon voltage. The core driver does the PortIO
> and provides boilerplate for the GPIO versions. Which are split out to
> model runtime dependencies while allowing fine-grained kernel
> configuration.
> 
> Signed-off-by: Henning Schild <henning.schild@siemens.com>

Thanks, patch looks good to me:

Reviewed-by: Hans de Goede <hdegoede@redhat.com>

Regards,

Hans


> ---
>  drivers/platform/x86/Kconfig                  |  48 ++++
>  drivers/platform/x86/Makefile                 |   6 +-
>  .../x86/simatic-ipc-batt-apollolake.c         |  51 ++++
>  .../x86/simatic-ipc-batt-elkhartlake.c        |  51 ++++
>  .../platform/x86/simatic-ipc-batt-f7188x.c    |  70 +++++
>  drivers/platform/x86/simatic-ipc-batt.c       | 250 ++++++++++++++++++
>  drivers/platform/x86/simatic-ipc-batt.h       |  20 ++
>  drivers/platform/x86/simatic-ipc.c            |  65 ++++-
>  .../platform_data/x86/simatic-ipc-base.h      |   1 +
>  9 files changed, 547 insertions(+), 15 deletions(-)
>  create mode 100644 drivers/platform/x86/simatic-ipc-batt-apollolake.c
>  create mode 100644 drivers/platform/x86/simatic-ipc-batt-elkhartlake.c
>  create mode 100644 drivers/platform/x86/simatic-ipc-batt-f7188x.c
>  create mode 100644 drivers/platform/x86/simatic-ipc-batt.c
>  create mode 100644 drivers/platform/x86/simatic-ipc-batt.h
> 
> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> index 49c2c4cd8d00..ad15063e1178 100644
> --- a/drivers/platform/x86/Kconfig
> +++ b/drivers/platform/x86/Kconfig
> @@ -1086,6 +1086,54 @@ config SIEMENS_SIMATIC_IPC
>  	  To compile this driver as a module, choose M here: the module
>  	  will be called simatic-ipc.
>  
> +config SIEMENS_SIMATIC_IPC_BATT
> +	tristate "CMOS battery driver for Siemens Simatic IPCs"
> +	depends on HWMON
> +	depends on SIEMENS_SIMATIC_IPC
> +	default SIEMENS_SIMATIC_IPC
> +	help
> +	  This option enables support for monitoring the voltage of the CMOS
> +	  batteries of several Industrial PCs from Siemens.
> +
> +	  To compile this driver as a module, choose M here: the module
> +	  will be called simatic-ipc-batt.
> +
> +config SIEMENS_SIMATIC_IPC_BATT_APOLLOLAKE
> +	tristate "CMOS Battery monitoring for Simatic IPCs based on Apollo Lake GPIO"
> +	depends on PINCTRL_BROXTON
> +	depends on SIEMENS_SIMATIC_IPC_BATT
> +	default SIEMENS_SIMATIC_IPC_BATT
> +	help
> +	  This option enables CMOS battery monitoring for Simatic Industrial PCs
> +	  from Siemens based on Apollo Lake GPIO.
> +
> +	  To compile this driver as a module, choose M here: the module
> +	  will be called simatic-ipc-batt-apollolake.
> +
> +config SIEMENS_SIMATIC_IPC_BATT_ELKHARTLAKE
> +	tristate "CMOS Battery monitoring for Simatic IPCs based on Elkhart Lake GPIO"
> +	depends on PINCTRL_ELKHARTLAKE
> +	depends on SIEMENS_SIMATIC_IPC_BATT
> +	default SIEMENS_SIMATIC_IPC_BATT
> +	help
> +	  This option enables CMOS battery monitoring for Simatic Industrial PCs
> +	  from Siemens based on Elkhart Lake GPIO.
> +
> +	  To compile this driver as a module, choose M here: the module
> +	  will be called simatic-ipc-batt-elkhartlake.
> +
> +config SIEMENS_SIMATIC_IPC_BATT_F7188X
> +	tristate "CMOS Battery monitoring for Simatic IPCs based on Nuvoton GPIO"
> +	depends on GPIO_F7188X
> +	depends on SIEMENS_SIMATIC_IPC_BATT
> +	default SIEMENS_SIMATIC_IPC_BATT
> +	help
> +	  This option enables CMOS battery monitoring for Simatic Industrial PCs
> +	  from Siemens based on Nuvoton GPIO.
> +
> +	  To compile this driver as a module, choose M here: the module
> +	  will be called simatic-ipc-batt-elkhartlake.
> +
>  config WINMATE_FM07_KEYS
>  	tristate "Winmate FM07/FM07P front-panel keys driver"
>  	depends on INPUT
> diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
> index 52dfdf574ac2..522da0d1584d 100644
> --- a/drivers/platform/x86/Makefile
> +++ b/drivers/platform/x86/Makefile
> @@ -131,7 +131,11 @@ obj-$(CONFIG_INTEL_SCU_IPC_UTIL)	+= intel_scu_ipcutil.o
>  obj-$(CONFIG_X86_INTEL_LPSS)		+= pmc_atom.o
>  
>  # Siemens Simatic Industrial PCs
> -obj-$(CONFIG_SIEMENS_SIMATIC_IPC)	+= simatic-ipc.o
> +obj-$(CONFIG_SIEMENS_SIMATIC_IPC)			+= simatic-ipc.o
> +obj-$(CONFIG_SIEMENS_SIMATIC_IPC_BATT)			+= simatic-ipc-batt.o
> +obj-$(CONFIG_SIEMENS_SIMATIC_IPC_BATT_APOLLOLAKE)	+= simatic-ipc-batt-apollolake.o
> +obj-$(CONFIG_SIEMENS_SIMATIC_IPC_BATT_ELKHARTLAKE)	+= simatic-ipc-batt-elkhartlake.o
> +obj-$(CONFIG_SIEMENS_SIMATIC_IPC_BATT_F7188X)		+= simatic-ipc-batt-f7188x.o
>  
>  # Winmate
>  obj-$(CONFIG_WINMATE_FM07_KEYS)		+= winmate-fm07-keys.o
> diff --git a/drivers/platform/x86/simatic-ipc-batt-apollolake.c b/drivers/platform/x86/simatic-ipc-batt-apollolake.c
> new file mode 100644
> index 000000000000..0503cb89d8f8
> --- /dev/null
> +++ b/drivers/platform/x86/simatic-ipc-batt-apollolake.c
> @@ -0,0 +1,51 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Siemens SIMATIC IPC driver for CMOS battery monitoring
> + *
> + * Copyright (c) Siemens AG, 2023
> + *
> + * Authors:
> + *  Henning Schild <henning.schild@siemens.com>
> + */
> +
> +#include <linux/gpio/machine.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +
> +#include "simatic-ipc-batt.h"
> +
> +struct gpiod_lookup_table simatic_ipc_batt_gpio_table_127e = {
> +	.table = {
> +		GPIO_LOOKUP_IDX("apollolake-pinctrl.0", 55, NULL, 0, GPIO_ACTIVE_HIGH),
> +		GPIO_LOOKUP_IDX("apollolake-pinctrl.0", 61, NULL, 1, GPIO_ACTIVE_HIGH),
> +		GPIO_LOOKUP_IDX("apollolake-pinctrl.1", 41, NULL, 2, GPIO_ACTIVE_HIGH),
> +		{} /* Terminating entry */
> +	},
> +};
> +
> +static int simatic_ipc_batt_apollolake_remove(struct platform_device *pdev)
> +{
> +	return simatic_ipc_batt_remove(pdev, &simatic_ipc_batt_gpio_table_127e);
> +}
> +
> +static int simatic_ipc_batt_apollolake_probe(struct platform_device *pdev)
> +{
> +	return simatic_ipc_batt_probe(pdev, &simatic_ipc_batt_gpio_table_127e);
> +}
> +
> +static struct platform_driver simatic_ipc_batt_driver = {
> +	.probe = simatic_ipc_batt_apollolake_probe,
> +	.remove = simatic_ipc_batt_apollolake_remove,
> +	.driver = {
> +		.name = KBUILD_MODNAME,
> +	},
> +};
> +
> +module_platform_driver(simatic_ipc_batt_driver);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:" KBUILD_MODNAME);
> +MODULE_SOFTDEP("pre: simatic-ipc-batt platform:apollolake-pinctrl");
> +MODULE_AUTHOR("Henning Schild <henning.schild@siemens.com>");
> diff --git a/drivers/platform/x86/simatic-ipc-batt-elkhartlake.c b/drivers/platform/x86/simatic-ipc-batt-elkhartlake.c
> new file mode 100644
> index 000000000000..ecf5ceb167f9
> --- /dev/null
> +++ b/drivers/platform/x86/simatic-ipc-batt-elkhartlake.c
> @@ -0,0 +1,51 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Siemens SIMATIC IPC driver for CMOS battery monitoring
> + *
> + * Copyright (c) Siemens AG, 2023
> + *
> + * Authors:
> + *  Henning Schild <henning.schild@siemens.com>
> + */
> +
> +#include <linux/gpio/machine.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +
> +#include "simatic-ipc-batt.h"
> +
> +struct gpiod_lookup_table simatic_ipc_batt_gpio_table_bx_21a = {
> +	.table = {
> +		GPIO_LOOKUP_IDX("INTC1020:04", 18, NULL, 0, GPIO_ACTIVE_HIGH),
> +		GPIO_LOOKUP_IDX("INTC1020:04", 19, NULL, 1, GPIO_ACTIVE_HIGH),
> +		GPIO_LOOKUP_IDX("INTC1020:01", 66, NULL, 2, GPIO_ACTIVE_HIGH),
> +		{} /* Terminating entry */
> +	},
> +};
> +
> +static int simatic_ipc_batt_elkhartlake_remove(struct platform_device *pdev)
> +{
> +	return simatic_ipc_batt_remove(pdev, &simatic_ipc_batt_gpio_table_bx_21a);
> +}
> +
> +static int simatic_ipc_batt_elkhartlake_probe(struct platform_device *pdev)
> +{
> +	return simatic_ipc_batt_probe(pdev, &simatic_ipc_batt_gpio_table_bx_21a);
> +}
> +
> +static struct platform_driver simatic_ipc_batt_driver = {
> +	.probe = simatic_ipc_batt_elkhartlake_probe,
> +	.remove = simatic_ipc_batt_elkhartlake_remove,
> +	.driver = {
> +		.name = KBUILD_MODNAME,
> +	},
> +};
> +
> +module_platform_driver(simatic_ipc_batt_driver);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:" KBUILD_MODNAME);
> +MODULE_SOFTDEP("pre: simatic-ipc-batt platform:elkhartlake-pinctrl");
> +MODULE_AUTHOR("Henning Schild <henning.schild@siemens.com>");
> diff --git a/drivers/platform/x86/simatic-ipc-batt-f7188x.c b/drivers/platform/x86/simatic-ipc-batt-f7188x.c
> new file mode 100644
> index 000000000000..a0189b9289f6
> --- /dev/null
> +++ b/drivers/platform/x86/simatic-ipc-batt-f7188x.c
> @@ -0,0 +1,70 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Siemens SIMATIC IPC driver for CMOS battery monitoring
> + *
> + * Copyright (c) Siemens AG, 2023
> + *
> + * Authors:
> + *  Henning Schild <henning.schild@siemens.com>
> + */
> +
> +#include <linux/gpio/machine.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/platform_data/x86/simatic-ipc-base.h>
> +
> +#include "simatic-ipc-batt.h"
> +
> +struct gpiod_lookup_table simatic_ipc_batt_gpio_table_227g = {
> +	.table = {
> +		GPIO_LOOKUP_IDX("gpio-f7188x-7", 6, NULL, 0, GPIO_ACTIVE_HIGH),
> +		GPIO_LOOKUP_IDX("gpio-f7188x-7", 5, NULL, 1, GPIO_ACTIVE_HIGH),
> +		GPIO_LOOKUP_IDX("INTC1020:01",  66, NULL, 2, GPIO_ACTIVE_HIGH),
> +		{} /* Terminating entry */
> +	},
> +};
> +
> +struct gpiod_lookup_table simatic_ipc_batt_gpio_table_bx_39a = {
> +	.table = {
> +		GPIO_LOOKUP_IDX("gpio-f7188x-6", 4, NULL, 0, GPIO_ACTIVE_HIGH),
> +		GPIO_LOOKUP_IDX("gpio-f7188x-6", 3, NULL, 1, GPIO_ACTIVE_HIGH),
> +		{} /* Terminating entry */
> +	},
> +};
> +
> +static int simatic_ipc_batt_f7188x_remove(struct platform_device *pdev)
> +{
> +	const struct simatic_ipc_platform *plat = pdev->dev.platform_data;
> +
> +	if (plat->devmode == SIMATIC_IPC_DEVICE_227G)
> +		return simatic_ipc_batt_remove(pdev, &simatic_ipc_batt_gpio_table_227g);
> +
> +	return simatic_ipc_batt_remove(pdev, &simatic_ipc_batt_gpio_table_bx_39a);
> +}
> +
> +static int simatic_ipc_batt_f7188x_probe(struct platform_device *pdev)
> +{
> +	const struct simatic_ipc_platform *plat = pdev->dev.platform_data;
> +
> +	if (plat->devmode == SIMATIC_IPC_DEVICE_227G)
> +		return simatic_ipc_batt_probe(pdev, &simatic_ipc_batt_gpio_table_227g);
> +
> +	return simatic_ipc_batt_probe(pdev, &simatic_ipc_batt_gpio_table_bx_39a);
> +}
> +
> +static struct platform_driver simatic_ipc_batt_driver = {
> +	.probe = simatic_ipc_batt_f7188x_probe,
> +	.remove = simatic_ipc_batt_f7188x_remove,
> +	.driver = {
> +		.name = KBUILD_MODNAME,
> +	},
> +};
> +
> +module_platform_driver(simatic_ipc_batt_driver);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:" KBUILD_MODNAME);
> +MODULE_SOFTDEP("pre: simatic-ipc-batt gpio_f7188x platform:elkhartlake-pinctrl");
> +MODULE_AUTHOR("Henning Schild <henning.schild@siemens.com>");
> diff --git a/drivers/platform/x86/simatic-ipc-batt.c b/drivers/platform/x86/simatic-ipc-batt.c
> new file mode 100644
> index 000000000000..a83272475b9d
> --- /dev/null
> +++ b/drivers/platform/x86/simatic-ipc-batt.c
> @@ -0,0 +1,250 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Siemens SIMATIC IPC driver for CMOS battery monitoring
> + *
> + * Copyright (c) Siemens AG, 2023
> + *
> + * Authors:
> + *  Gerd Haeussler <gerd.haeussler.ext@siemens.com>
> + *  Henning Schild <henning.schild@siemens.com>
> + */
> +
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +
> +#include <linux/delay.h>
> +#include <linux/io.h>
> +#include <linux/ioport.h>
> +#include <linux/gpio/machine.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/hwmon.h>
> +#include <linux/hwmon-sysfs.h>
> +#include <linux/jiffies.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/platform_data/x86/simatic-ipc-base.h>
> +#include <linux/sizes.h>
> +
> +#define BATT_DELAY_MS	(1000 * 60 * 60 * 24)	/* 24 h delay */
> +
> +#define SIMATIC_IPC_BATT_LEVEL_FULL	3000
> +#define SIMATIC_IPC_BATT_LEVEL_CRIT	2750
> +#define SIMATIC_IPC_BATT_LEVEL_EMPTY	   0
> +
> +static struct simatic_ipc_batt {
> +	u8 devmode;
> +	long current_state;
> +	struct gpio_desc *gpios[3];
> +	unsigned long last_updated_jiffies;
> +} priv;
> +
> +static long simatic_ipc_batt_read_gpio(void)
> +{
> +	long r = SIMATIC_IPC_BATT_LEVEL_FULL;
> +
> +	if (priv.gpios[2]) {
> +		gpiod_set_value(priv.gpios[2], 1);
> +		msleep(150);
> +	}
> +
> +	if (gpiod_get_value_cansleep(priv.gpios[0]))
> +		r = SIMATIC_IPC_BATT_LEVEL_EMPTY;
> +	else if (gpiod_get_value_cansleep(priv.gpios[1]))
> +		r = SIMATIC_IPC_BATT_LEVEL_CRIT;
> +
> +	if (priv.gpios[2])
> +		gpiod_set_value(priv.gpios[2], 0);
> +
> +	return r;
> +}
> +
> +#define SIMATIC_IPC_BATT_PORT_BASE	0x404D
> +static struct resource simatic_ipc_batt_io_res =
> +	DEFINE_RES_IO_NAMED(SIMATIC_IPC_BATT_PORT_BASE, SZ_1, KBUILD_MODNAME);
> +
> +static long simatic_ipc_batt_read_io(struct device *dev)
> +{
> +	long r = SIMATIC_IPC_BATT_LEVEL_FULL;
> +	struct resource *res = &simatic_ipc_batt_io_res;
> +	u8 val;
> +
> +	if (!request_muxed_region(res->start, resource_size(res), res->name)) {
> +		dev_err(dev, "Unable to register IO resource at %pR\n", res);
> +		return -EBUSY;
> +	}
> +
> +	val = inb(SIMATIC_IPC_BATT_PORT_BASE);
> +	release_region(simatic_ipc_batt_io_res.start, resource_size(&simatic_ipc_batt_io_res));
> +
> +	if (val & (1 << 7))
> +		r = SIMATIC_IPC_BATT_LEVEL_EMPTY;
> +	else if (val & (1 << 6))
> +		r = SIMATIC_IPC_BATT_LEVEL_CRIT;
> +
> +	return r;
> +}
> +
> +static long simatic_ipc_batt_read_value(struct device *dev)
> +{
> +	unsigned long next_update;
> +
> +	next_update = priv.last_updated_jiffies + msecs_to_jiffies(BATT_DELAY_MS);
> +	if (time_after(jiffies, next_update) || !priv.last_updated_jiffies) {
> +		switch (priv.devmode) {
> +		case SIMATIC_IPC_DEVICE_127E:
> +		case SIMATIC_IPC_DEVICE_227G:
> +		case SIMATIC_IPC_DEVICE_BX_39A:
> +			priv.current_state = simatic_ipc_batt_read_gpio();
> +			break;
> +		case SIMATIC_IPC_DEVICE_227E:
> +			priv.current_state = simatic_ipc_batt_read_io(dev);
> +			break;
> +		}
> +		priv.last_updated_jiffies = jiffies;
> +		if (priv.current_state < SIMATIC_IPC_BATT_LEVEL_FULL)
> +			dev_warn(dev, "CMOS battery needs to be replaced.");
> +	}
> +
> +	return priv.current_state;
> +}
> +
> +static int simatic_ipc_batt_read(struct device *dev, enum hwmon_sensor_types type,
> +				 u32 attr, int channel, long *val)
> +{
> +	switch (attr) {
> +	case hwmon_in_input:
> +		*val = simatic_ipc_batt_read_value(dev);
> +		break;
> +	case hwmon_in_lcrit:
> +		*val = SIMATIC_IPC_BATT_LEVEL_CRIT;
> +		break;
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +
> +	return 0;
> +}
> +
> +static umode_t simatic_ipc_batt_is_visible(const void *data, enum hwmon_sensor_types type,
> +					   u32 attr, int channel)
> +{
> +	if (attr == hwmon_in_input || attr == hwmon_in_lcrit)
> +		return 0444;
> +
> +	return 0;
> +}
> +
> +static const struct hwmon_ops simatic_ipc_batt_ops = {
> +	.is_visible = simatic_ipc_batt_is_visible,
> +	.read = simatic_ipc_batt_read,
> +};
> +
> +static const struct hwmon_channel_info *simatic_ipc_batt_info[] = {
> +	HWMON_CHANNEL_INFO(in, HWMON_I_INPUT | HWMON_I_LCRIT),
> +	NULL
> +};
> +
> +static const struct hwmon_chip_info simatic_ipc_batt_chip_info = {
> +	.ops = &simatic_ipc_batt_ops,
> +	.info = simatic_ipc_batt_info,
> +};
> +
> +int simatic_ipc_batt_remove(struct platform_device *pdev, struct gpiod_lookup_table *table)
> +{
> +	gpiod_remove_lookup_table(table);
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(simatic_ipc_batt_remove);
> +
> +int simatic_ipc_batt_probe(struct platform_device *pdev, struct gpiod_lookup_table *table)
> +{
> +	struct simatic_ipc_platform *plat;
> +	struct device *dev = &pdev->dev;
> +	struct device *hwmon_dev;
> +	int err;
> +
> +	plat = pdev->dev.platform_data;
> +	priv.devmode = plat->devmode;
> +
> +	switch (priv.devmode) {
> +	case SIMATIC_IPC_DEVICE_127E:
> +	case SIMATIC_IPC_DEVICE_227G:
> +	case SIMATIC_IPC_DEVICE_BX_39A:
> +	case SIMATIC_IPC_DEVICE_BX_21A:
> +		table->dev_id = dev_name(dev);
> +		gpiod_add_lookup_table(table);
> +		break;
> +	case SIMATIC_IPC_DEVICE_227E:
> +		goto nogpio;
> +	default:
> +		return -ENODEV;
> +	}
> +
> +	priv.gpios[0] = devm_gpiod_get_index(dev, "CMOSBattery empty", 0, GPIOD_IN);
> +	if (IS_ERR(priv.gpios[0])) {
> +		err = PTR_ERR(priv.gpios[0]);
> +		priv.gpios[0] = NULL;
> +		goto out;
> +	}
> +	priv.gpios[1] = devm_gpiod_get_index(dev, "CMOSBattery low", 1, GPIOD_IN);
> +	if (IS_ERR(priv.gpios[1])) {
> +		err = PTR_ERR(priv.gpios[1]);
> +		priv.gpios[1] = NULL;
> +		goto out;
> +	}
> +
> +	if (table->table[2].key) {
> +		priv.gpios[2] = devm_gpiod_get_index(dev, "CMOSBattery meter", 2, GPIOD_OUT_HIGH);
> +		if (IS_ERR(priv.gpios[2])) {
> +			err = PTR_ERR(priv.gpios[1]);
> +			priv.gpios[2] = NULL;
> +			goto out;
> +		}
> +	} else {
> +		priv.gpios[2] = NULL;
> +	}
> +
> +nogpio:
> +	hwmon_dev = devm_hwmon_device_register_with_info(dev, KBUILD_MODNAME,
> +							 &priv,
> +							 &simatic_ipc_batt_chip_info,
> +							 NULL);
> +	if (IS_ERR(hwmon_dev)) {
> +		err = PTR_ERR(hwmon_dev);
> +		goto out;
> +	}
> +
> +	/* warn about aging battery even if userspace never reads hwmon */
> +	simatic_ipc_batt_read_value(dev);
> +
> +	return 0;
> +out:
> +	simatic_ipc_batt_remove(pdev, table);
> +
> +	return err;
> +}
> +EXPORT_SYMBOL_GPL(simatic_ipc_batt_probe);
> +
> +static int simatic_ipc_batt_io_remove(struct platform_device *pdev)
> +{
> +	return simatic_ipc_batt_remove(pdev, NULL);
> +}
> +
> +static int simatic_ipc_batt_io_probe(struct platform_device *pdev)
> +{
> +	return simatic_ipc_batt_probe(pdev, NULL);
> +}
> +
> +static struct platform_driver simatic_ipc_batt_driver = {
> +	.probe = simatic_ipc_batt_io_probe,
> +	.remove = simatic_ipc_batt_io_remove,
> +	.driver = {
> +		.name = KBUILD_MODNAME,
> +	},
> +};
> +
> +module_platform_driver(simatic_ipc_batt_driver);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:" KBUILD_MODNAME);
> +MODULE_AUTHOR("Henning Schild <henning.schild@siemens.com>");
> diff --git a/drivers/platform/x86/simatic-ipc-batt.h b/drivers/platform/x86/simatic-ipc-batt.h
> new file mode 100644
> index 000000000000..4545cd3e3026
> --- /dev/null
> +++ b/drivers/platform/x86/simatic-ipc-batt.h
> @@ -0,0 +1,20 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Siemens SIMATIC IPC driver for CMOS battery monitoring
> + *
> + * Copyright (c) Siemens AG, 2023
> + *
> + * Author:
> + *  Henning Schild <henning.schild@siemens.com>
> + */
> +
> +#ifndef _SIMATIC_IPC_BATT_H
> +#define _SIMATIC_IPC_BATT_H
> +
> +int simatic_ipc_batt_probe(struct platform_device *pdev,
> +			   struct gpiod_lookup_table *table);
> +
> +int simatic_ipc_batt_remove(struct platform_device *pdev,
> +			    struct gpiod_lookup_table *table);
> +
> +#endif /* _SIMATIC_IPC_BATT_H */
> diff --git a/drivers/platform/x86/simatic-ipc.c b/drivers/platform/x86/simatic-ipc.c
> index 4402cd354104..6d2c94c17414 100644
> --- a/drivers/platform/x86/simatic-ipc.c
> +++ b/drivers/platform/x86/simatic-ipc.c
> @@ -21,6 +21,7 @@
>  
>  static struct platform_device *ipc_led_platform_device;
>  static struct platform_device *ipc_wdt_platform_device;
> +static struct platform_device *ipc_batt_platform_device;
>  
>  static const struct dmi_system_id simatic_ipc_whitelist[] = {
>  	{
> @@ -37,38 +38,71 @@ static struct {
>  	u32 station_id;
>  	u8 led_mode;
>  	u8 wdt_mode;
> +	u8 batt_mode;
>  } device_modes[] = {
> -	{SIMATIC_IPC_IPC127E, SIMATIC_IPC_DEVICE_127E, SIMATIC_IPC_DEVICE_NONE},
> -	{SIMATIC_IPC_IPC227D, SIMATIC_IPC_DEVICE_227D, SIMATIC_IPC_DEVICE_NONE},
> -	{SIMATIC_IPC_IPC227E, SIMATIC_IPC_DEVICE_427E, SIMATIC_IPC_DEVICE_227E},
> -	{SIMATIC_IPC_IPC227G, SIMATIC_IPC_DEVICE_227G, SIMATIC_IPC_DEVICE_227G},
> -	{SIMATIC_IPC_IPC277E, SIMATIC_IPC_DEVICE_NONE, SIMATIC_IPC_DEVICE_227E},
> -	{SIMATIC_IPC_IPC427D, SIMATIC_IPC_DEVICE_427E, SIMATIC_IPC_DEVICE_NONE},
> -	{SIMATIC_IPC_IPC427E, SIMATIC_IPC_DEVICE_427E, SIMATIC_IPC_DEVICE_427E},
> -	{SIMATIC_IPC_IPC477E, SIMATIC_IPC_DEVICE_NONE, SIMATIC_IPC_DEVICE_427E},
> -	{SIMATIC_IPC_IPCBX_39A, SIMATIC_IPC_DEVICE_227G, SIMATIC_IPC_DEVICE_227G},
> -	{SIMATIC_IPC_IPCPX_39A, SIMATIC_IPC_DEVICE_NONE, SIMATIC_IPC_DEVICE_227G},
> -	{SIMATIC_IPC_IPCBX_21A, SIMATIC_IPC_DEVICE_BX_21A, SIMATIC_IPC_DEVICE_NONE},
> +	{SIMATIC_IPC_IPC127E,
> +		SIMATIC_IPC_DEVICE_127E, SIMATIC_IPC_DEVICE_NONE, SIMATIC_IPC_DEVICE_127E},
> +	{SIMATIC_IPC_IPC227D,
> +		SIMATIC_IPC_DEVICE_227D, SIMATIC_IPC_DEVICE_NONE, SIMATIC_IPC_DEVICE_NONE},
> +	{SIMATIC_IPC_IPC227E,
> +		SIMATIC_IPC_DEVICE_427E, SIMATIC_IPC_DEVICE_227E, SIMATIC_IPC_DEVICE_227E},
> +	{SIMATIC_IPC_IPC227G,
> +		SIMATIC_IPC_DEVICE_227G, SIMATIC_IPC_DEVICE_227G, SIMATIC_IPC_DEVICE_227G},
> +	{SIMATIC_IPC_IPC277E,
> +		SIMATIC_IPC_DEVICE_NONE, SIMATIC_IPC_DEVICE_227E, SIMATIC_IPC_DEVICE_227E},
> +	{SIMATIC_IPC_IPC427D,
> +		SIMATIC_IPC_DEVICE_427E, SIMATIC_IPC_DEVICE_NONE, SIMATIC_IPC_DEVICE_NONE},
> +	{SIMATIC_IPC_IPC427E,
> +		SIMATIC_IPC_DEVICE_427E, SIMATIC_IPC_DEVICE_427E, SIMATIC_IPC_DEVICE_NONE},
> +	{SIMATIC_IPC_IPC477E,
> +		SIMATIC_IPC_DEVICE_NONE, SIMATIC_IPC_DEVICE_427E, SIMATIC_IPC_DEVICE_NONE},
> +	{SIMATIC_IPC_IPCBX_39A,
> +		SIMATIC_IPC_DEVICE_227G, SIMATIC_IPC_DEVICE_227G, SIMATIC_IPC_DEVICE_BX_39A},
> +	{SIMATIC_IPC_IPCPX_39A,
> +		SIMATIC_IPC_DEVICE_NONE, SIMATIC_IPC_DEVICE_227G, SIMATIC_IPC_DEVICE_BX_39A},
> +	{SIMATIC_IPC_IPCBX_21A,
> +		SIMATIC_IPC_DEVICE_BX_21A, SIMATIC_IPC_DEVICE_NONE, SIMATIC_IPC_DEVICE_BX_21A},
>  };
>  
>  static int register_platform_devices(u32 station_id)
>  {
>  	u8 ledmode = SIMATIC_IPC_DEVICE_NONE;
>  	u8 wdtmode = SIMATIC_IPC_DEVICE_NONE;
> -	char *pdevname = KBUILD_MODNAME "_leds";
> +	u8 battmode = SIMATIC_IPC_DEVICE_NONE;
> +	char *pdevname;
>  	int i;
>  
> -	platform_data.devmode = SIMATIC_IPC_DEVICE_NONE;
> -
>  	for (i = 0; i < ARRAY_SIZE(device_modes); i++) {
>  		if (device_modes[i].station_id == station_id) {
>  			ledmode = device_modes[i].led_mode;
>  			wdtmode = device_modes[i].wdt_mode;
> +			battmode = device_modes[i].batt_mode;
>  			break;
>  		}
>  	}
>  
> +	if (battmode != SIMATIC_IPC_DEVICE_NONE) {
> +		pdevname = KBUILD_MODNAME "_batt";
> +		if (battmode == SIMATIC_IPC_DEVICE_127E)
> +			pdevname = KBUILD_MODNAME "_batt_apollolake";
> +		if (battmode == SIMATIC_IPC_DEVICE_BX_21A)
> +			pdevname = KBUILD_MODNAME "_batt_elkhartlake";
> +		if (battmode == SIMATIC_IPC_DEVICE_227G || battmode == SIMATIC_IPC_DEVICE_BX_39A)
> +			pdevname = KBUILD_MODNAME "_batt_f7188x";
> +		platform_data.devmode = battmode;
> +		ipc_batt_platform_device =
> +			platform_device_register_data(NULL, pdevname,
> +				PLATFORM_DEVID_NONE, &platform_data,
> +				sizeof(struct simatic_ipc_platform));
> +		if (IS_ERR(ipc_batt_platform_device))
> +			return PTR_ERR(ipc_batt_platform_device);
> +
> +		pr_debug("device=%s created\n",
> +			 ipc_batt_platform_device->name);
> +	}
> +
>  	if (ledmode != SIMATIC_IPC_DEVICE_NONE) {
> +		pdevname = KBUILD_MODNAME "_leds";
>  		if (ledmode == SIMATIC_IPC_DEVICE_127E)
>  			pdevname = KBUILD_MODNAME "_leds_gpio_apollolake";
>  		if (ledmode == SIMATIC_IPC_DEVICE_227G)
> @@ -144,6 +178,9 @@ static void __exit simatic_ipc_exit_module(void)
>  
>  	platform_device_unregister(ipc_wdt_platform_device);
>  	ipc_wdt_platform_device = NULL;
> +
> +	platform_device_unregister(ipc_batt_platform_device);
> +	ipc_batt_platform_device = NULL;
>  }
>  
>  module_init(simatic_ipc_init_module);
> diff --git a/include/linux/platform_data/x86/simatic-ipc-base.h b/include/linux/platform_data/x86/simatic-ipc-base.h
> index 00bf18ecb160..1ba47dd6939e 100644
> --- a/include/linux/platform_data/x86/simatic-ipc-base.h
> +++ b/include/linux/platform_data/x86/simatic-ipc-base.h
> @@ -21,6 +21,7 @@
>  #define SIMATIC_IPC_DEVICE_227E 4
>  #define SIMATIC_IPC_DEVICE_227G 5
>  #define SIMATIC_IPC_DEVICE_BX_21A 6
> +#define SIMATIC_IPC_DEVICE_BX_39A 7
>  
>  struct simatic_ipc_platform {
>  	u8	devmode;