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// 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>
#include "simatic-ipc-batt.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) {
if (priv.devmode == SIMATIC_IPC_DEVICE_227E)
priv.current_state = simatic_ipc_batt_read_io(dev);
else
priv.current_state = simatic_ipc_batt_read_gpio();
priv.last_updated_jiffies = jiffies;
if (priv.current_state < SIMATIC_IPC_BATT_LEVEL_FULL)
dev_warn(dev, "CMOS battery needs to be replaced.\n");
}
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,
};
void simatic_ipc_batt_remove(struct platform_device *pdev, struct gpiod_lookup_table *table)
{
gpiod_remove_lookup_table(table);
}
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;
unsigned long flags;
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:
case SIMATIC_IPC_DEVICE_BX_59A:
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) {
flags = GPIOD_OUT_HIGH;
if (priv.devmode == SIMATIC_IPC_DEVICE_BX_21A ||
priv.devmode == SIMATIC_IPC_DEVICE_BX_59A)
flags = GPIOD_OUT_LOW;
priv.gpios[2] = devm_gpiod_get_index(dev, "CMOSBattery meter", 2, flags);
if (IS_ERR(priv.gpios[2])) {
err = PTR_ERR(priv.gpios[2]);
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 void simatic_ipc_batt_io_remove(struct platform_device *pdev)
{
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_new = simatic_ipc_batt_io_remove,
.driver = {
.name = KBUILD_MODNAME,
},
};
module_platform_driver(simatic_ipc_batt_driver);
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" KBUILD_MODNAME);
MODULE_AUTHOR("Henning Schild <henning.schild@siemens.com>");
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