1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Siemens SIMATIC IPC driver for CMOS battery monitoring
4 *
5 * Copyright (c) Siemens AG, 2023
6 *
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 ": " fmt
13
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 3000
33 #define SIMATIC_IPC_BATT_LEVEL_CRIT 2750
34 #define SIMATIC_IPC_BATT_LEVEL_EMPTY 0
35
36 static 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
simatic_ipc_batt_read_gpio(void)43 static 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 0x404D
64 static struct resource simatic_ipc_batt_io_res =
65 DEFINE_RES_IO_NAMED(SIMATIC_IPC_BATT_PORT_BASE, SZ_1, KBUILD_MODNAME);
66
simatic_ipc_batt_read_io(struct device * dev)67 static 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
simatic_ipc_batt_read_value(struct device * dev)89 static 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 else
98 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
simatic_ipc_batt_read(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long * val)108 static 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
simatic_ipc_batt_is_visible(const void * data,enum hwmon_sensor_types type,u32 attr,int channel)125 static 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
134 static const struct hwmon_ops simatic_ipc_batt_ops = {
135 .is_visible = simatic_ipc_batt_is_visible,
136 .read = simatic_ipc_batt_read,
137 };
138
139 static const struct hwmon_channel_info *simatic_ipc_batt_info[] = {
140 HWMON_CHANNEL_INFO(in, HWMON_I_INPUT | HWMON_I_LCRIT),
141 NULL
142 };
143
144 static const struct hwmon_chip_info simatic_ipc_batt_chip_info = {
145 .ops = &simatic_ipc_batt_ops,
146 .info = simatic_ipc_batt_info,
147 };
148
simatic_ipc_batt_remove(struct platform_device * pdev,struct gpiod_lookup_table * table)149 void simatic_ipc_batt_remove(struct platform_device *pdev, struct gpiod_lookup_table *table)
150 {
151 gpiod_remove_lookup_table(table);
152 }
153 EXPORT_SYMBOL_GPL(simatic_ipc_batt_remove);
154
simatic_ipc_batt_probe(struct platform_device * pdev,struct gpiod_lookup_table * table)155 int 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
209 nogpio:
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;
223 out:
224 simatic_ipc_batt_remove(pdev, table);
225
226 return err;
227 }
228 EXPORT_SYMBOL_GPL(simatic_ipc_batt_probe);
229
simatic_ipc_batt_io_remove(struct platform_device * pdev)230 static void simatic_ipc_batt_io_remove(struct platform_device *pdev)
231 {
232 simatic_ipc_batt_remove(pdev, NULL);
233 }
234
simatic_ipc_batt_io_probe(struct platform_device * pdev)235 static int simatic_ipc_batt_io_probe(struct platform_device *pdev)
236 {
237 return simatic_ipc_batt_probe(pdev, NULL);
238 }
239
240 static 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
248 module_platform_driver(simatic_ipc_batt_driver);
249
250 MODULE_DESCRIPTION("CMOS core battery driver for Siemens Simatic IPCs");
251 MODULE_LICENSE("GPL");
252 MODULE_ALIAS("platform:" KBUILD_MODNAME);
253 MODULE_AUTHOR("Henning Schild <henning.schild@siemens.com>");
254