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1// SPDX-License-Identifier: GPL-2.02/*3 * Siemens SIMATIC IPC driver for CMOS battery monitoring4 *5 * Copyright (c) Siemens AG, 20236 *7 * Authors:8 * Gerd Haeussler <gerd.haeussler.ext@siemens.com>9 * Henning Schild <henning.schild@siemens.com>10 */11 12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt13 14#include <linux/delay.h>15#include <linux/io.h>16#include <linux/ioport.h>17#include <linux/gpio/machine.h>18#include <linux/gpio/consumer.h>19#include <linux/hwmon.h>20#include <linux/hwmon-sysfs.h>21#include <linux/jiffies.h>22#include <linux/kernel.h>23#include <linux/module.h>24#include <linux/platform_device.h>25#include <linux/platform_data/x86/simatic-ipc-base.h>26#include <linux/sizes.h>27 28#include "simatic-ipc-batt.h"29 30#define BATT_DELAY_MS (1000 * 60 * 60 * 24) /* 24 h delay */31 32#define SIMATIC_IPC_BATT_LEVEL_FULL 300033#define SIMATIC_IPC_BATT_LEVEL_CRIT 275034#define SIMATIC_IPC_BATT_LEVEL_EMPTY 035 36static struct simatic_ipc_batt {37 u8 devmode;38 long current_state;39 struct gpio_desc *gpios[3];40 unsigned long last_updated_jiffies;41} priv;42 43static long simatic_ipc_batt_read_gpio(void)44{45 long r = SIMATIC_IPC_BATT_LEVEL_FULL;46 47 if (priv.gpios[2]) {48 gpiod_set_value(priv.gpios[2], 1);49 msleep(150);50 }51 52 if (gpiod_get_value_cansleep(priv.gpios[0]))53 r = SIMATIC_IPC_BATT_LEVEL_EMPTY;54 else if (gpiod_get_value_cansleep(priv.gpios[1]))55 r = SIMATIC_IPC_BATT_LEVEL_CRIT;56 57 if (priv.gpios[2])58 gpiod_set_value(priv.gpios[2], 0);59 60 return r;61}62 63#define SIMATIC_IPC_BATT_PORT_BASE 0x404D64static struct resource simatic_ipc_batt_io_res =65 DEFINE_RES_IO_NAMED(SIMATIC_IPC_BATT_PORT_BASE, SZ_1, KBUILD_MODNAME);66 67static long simatic_ipc_batt_read_io(struct device *dev)68{69 long r = SIMATIC_IPC_BATT_LEVEL_FULL;70 struct resource *res = &simatic_ipc_batt_io_res;71 u8 val;72 73 if (!request_muxed_region(res->start, resource_size(res), res->name)) {74 dev_err(dev, "Unable to register IO resource at %pR\n", res);75 return -EBUSY;76 }77 78 val = inb(SIMATIC_IPC_BATT_PORT_BASE);79 release_region(simatic_ipc_batt_io_res.start, resource_size(&simatic_ipc_batt_io_res));80 81 if (val & (1 << 7))82 r = SIMATIC_IPC_BATT_LEVEL_EMPTY;83 else if (val & (1 << 6))84 r = SIMATIC_IPC_BATT_LEVEL_CRIT;85 86 return r;87}88 89static long simatic_ipc_batt_read_value(struct device *dev)90{91 unsigned long next_update;92 93 next_update = priv.last_updated_jiffies + msecs_to_jiffies(BATT_DELAY_MS);94 if (time_after(jiffies, next_update) || !priv.last_updated_jiffies) {95 if (priv.devmode == SIMATIC_IPC_DEVICE_227E)96 priv.current_state = simatic_ipc_batt_read_io(dev);97 else98 priv.current_state = simatic_ipc_batt_read_gpio();99 100 priv.last_updated_jiffies = jiffies;101 if (priv.current_state < SIMATIC_IPC_BATT_LEVEL_FULL)102 dev_warn(dev, "CMOS battery needs to be replaced.\n");103 }104 105 return priv.current_state;106}107 108static int simatic_ipc_batt_read(struct device *dev, enum hwmon_sensor_types type,109 u32 attr, int channel, long *val)110{111 switch (attr) {112 case hwmon_in_input:113 *val = simatic_ipc_batt_read_value(dev);114 break;115 case hwmon_in_lcrit:116 *val = SIMATIC_IPC_BATT_LEVEL_CRIT;117 break;118 default:119 return -EOPNOTSUPP;120 }121 122 return 0;123}124 125static umode_t simatic_ipc_batt_is_visible(const void *data, enum hwmon_sensor_types type,126 u32 attr, int channel)127{128 if (attr == hwmon_in_input || attr == hwmon_in_lcrit)129 return 0444;130 131 return 0;132}133 134static const struct hwmon_ops simatic_ipc_batt_ops = {135 .is_visible = simatic_ipc_batt_is_visible,136 .read = simatic_ipc_batt_read,137};138 139static const struct hwmon_channel_info *simatic_ipc_batt_info[] = {140 HWMON_CHANNEL_INFO(in, HWMON_I_INPUT | HWMON_I_LCRIT),141 NULL142};143 144static const struct hwmon_chip_info simatic_ipc_batt_chip_info = {145 .ops = &simatic_ipc_batt_ops,146 .info = simatic_ipc_batt_info,147};148 149void simatic_ipc_batt_remove(struct platform_device *pdev, struct gpiod_lookup_table *table)150{151 gpiod_remove_lookup_table(table);152}153EXPORT_SYMBOL_GPL(simatic_ipc_batt_remove);154 155int simatic_ipc_batt_probe(struct platform_device *pdev, struct gpiod_lookup_table *table)156{157 struct simatic_ipc_platform *plat;158 struct device *dev = &pdev->dev;159 struct device *hwmon_dev;160 unsigned long flags;161 int err;162 163 plat = pdev->dev.platform_data;164 priv.devmode = plat->devmode;165 166 switch (priv.devmode) {167 case SIMATIC_IPC_DEVICE_127E:168 case SIMATIC_IPC_DEVICE_227G:169 case SIMATIC_IPC_DEVICE_BX_39A:170 case SIMATIC_IPC_DEVICE_BX_21A:171 case SIMATIC_IPC_DEVICE_BX_59A:172 table->dev_id = dev_name(dev);173 gpiod_add_lookup_table(table);174 break;175 case SIMATIC_IPC_DEVICE_227E:176 goto nogpio;177 default:178 return -ENODEV;179 }180 181 priv.gpios[0] = devm_gpiod_get_index(dev, "CMOSBattery empty", 0, GPIOD_IN);182 if (IS_ERR(priv.gpios[0])) {183 err = PTR_ERR(priv.gpios[0]);184 priv.gpios[0] = NULL;185 goto out;186 }187 priv.gpios[1] = devm_gpiod_get_index(dev, "CMOSBattery low", 1, GPIOD_IN);188 if (IS_ERR(priv.gpios[1])) {189 err = PTR_ERR(priv.gpios[1]);190 priv.gpios[1] = NULL;191 goto out;192 }193 194 if (table->table[2].key) {195 flags = GPIOD_OUT_HIGH;196 if (priv.devmode == SIMATIC_IPC_DEVICE_BX_21A ||197 priv.devmode == SIMATIC_IPC_DEVICE_BX_59A)198 flags = GPIOD_OUT_LOW;199 priv.gpios[2] = devm_gpiod_get_index(dev, "CMOSBattery meter", 2, flags);200 if (IS_ERR(priv.gpios[2])) {201 err = PTR_ERR(priv.gpios[2]);202 priv.gpios[2] = NULL;203 goto out;204 }205 } else {206 priv.gpios[2] = NULL;207 }208 209nogpio:210 hwmon_dev = devm_hwmon_device_register_with_info(dev, KBUILD_MODNAME,211 &priv,212 &simatic_ipc_batt_chip_info,213 NULL);214 if (IS_ERR(hwmon_dev)) {215 err = PTR_ERR(hwmon_dev);216 goto out;217 }218 219 /* warn about aging battery even if userspace never reads hwmon */220 simatic_ipc_batt_read_value(dev);221 222 return 0;223out:224 simatic_ipc_batt_remove(pdev, table);225 226 return err;227}228EXPORT_SYMBOL_GPL(simatic_ipc_batt_probe);229 230static void simatic_ipc_batt_io_remove(struct platform_device *pdev)231{232 simatic_ipc_batt_remove(pdev, NULL);233}234 235static int simatic_ipc_batt_io_probe(struct platform_device *pdev)236{237 return simatic_ipc_batt_probe(pdev, NULL);238}239 240static struct platform_driver simatic_ipc_batt_driver = {241 .probe = simatic_ipc_batt_io_probe,242 .remove_new = simatic_ipc_batt_io_remove,243 .driver = {244 .name = KBUILD_MODNAME,245 },246};247 248module_platform_driver(simatic_ipc_batt_driver);249 250MODULE_DESCRIPTION("CMOS core battery driver for Siemens Simatic IPCs");251MODULE_LICENSE("GPL");252MODULE_ALIAS("platform:" KBUILD_MODNAME);253MODULE_AUTHOR("Henning Schild <henning.schild@siemens.com>");254