1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * An I2C driver for the Intersil ISL 12022
4 *
5 * Author: Roman Fietze <roman.fietze@telemotive.de>
6 *
7 * Based on the Philips PCF8563 RTC
8 * by Alessandro Zummo <a.zummo@towertech.it>.
9 */
10
11#include <linux/bcd.h>
12#include <linux/bitfield.h>
13#include <linux/clk-provider.h>
14#include <linux/err.h>
15#include <linux/hwmon.h>
16#include <linux/i2c.h>
17#include <linux/module.h>
18#include <linux/regmap.h>
19#include <linux/rtc.h>
20#include <linux/slab.h>
21
22#include <asm/byteorder.h>
23
24/* ISL register offsets */
25#define ISL12022_REG_SC 0x00
26#define ISL12022_REG_MN 0x01
27#define ISL12022_REG_HR 0x02
28#define ISL12022_REG_DT 0x03
29#define ISL12022_REG_MO 0x04
30#define ISL12022_REG_YR 0x05
31#define ISL12022_REG_DW 0x06
32
33#define ISL12022_REG_SR 0x07
34#define ISL12022_REG_INT 0x08
35
36#define ISL12022_REG_PWR_VBAT 0x0a
37
38#define ISL12022_REG_BETA 0x0d
39#define ISL12022_REG_TEMP_L 0x28
40
41/* ISL register bits */
42#define ISL12022_HR_MIL (1 << 7) /* military or 24 hour time */
43
44#define ISL12022_SR_LBAT85 (1 << 2)
45#define ISL12022_SR_LBAT75 (1 << 1)
46
47#define ISL12022_INT_WRTC (1 << 6)
48#define ISL12022_INT_FO_MASK GENMASK(3, 0)
49#define ISL12022_INT_FO_OFF 0x0
50#define ISL12022_INT_FO_32K 0x1
51
52#define ISL12022_REG_VB85_MASK GENMASK(5, 3)
53#define ISL12022_REG_VB75_MASK GENMASK(2, 0)
54
55#define ISL12022_BETA_TSE (1 << 7)
56
57static umode_t isl12022_hwmon_is_visible(const void *data,
58 enum hwmon_sensor_types type,
59 u32 attr, int channel)
60{
61 if (type == hwmon_temp && attr == hwmon_temp_input)
62 return 0444;
63
64 return 0;
65}
66
67/*
68 * A user-initiated temperature conversion is not started by this function,
69 * so the temperature is updated once every ~60 seconds.
70 */
71static int isl12022_hwmon_read_temp(struct device *dev, long *mC)
72{
73 struct regmap *regmap = dev_get_drvdata(dev);
74 int temp, ret;
75 __le16 buf;
76
77 ret = regmap_bulk_read(map: regmap, ISL12022_REG_TEMP_L, val: &buf, val_count: sizeof(buf));
78 if (ret)
79 return ret;
80 /*
81 * Temperature is represented as a 10-bit number, unit half-Kelvins.
82 */
83 temp = le16_to_cpu(buf);
84 temp *= 500;
85 temp -= 273000;
86
87 *mC = temp;
88
89 return 0;
90}
91
92static int isl12022_hwmon_read(struct device *dev,
93 enum hwmon_sensor_types type,
94 u32 attr, int channel, long *val)
95{
96 if (type == hwmon_temp && attr == hwmon_temp_input)
97 return isl12022_hwmon_read_temp(dev, mC: val);
98
99 return -EOPNOTSUPP;
100}
101
102static const struct hwmon_channel_info * const isl12022_hwmon_info[] = {
103 HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
104 NULL
105};
106
107static const struct hwmon_ops isl12022_hwmon_ops = {
108 .is_visible = isl12022_hwmon_is_visible,
109 .read = isl12022_hwmon_read,
110};
111
112static const struct hwmon_chip_info isl12022_hwmon_chip_info = {
113 .ops = &isl12022_hwmon_ops,
114 .info = isl12022_hwmon_info,
115};
116
117static void isl12022_hwmon_register(struct device *dev)
118{
119 struct regmap *regmap = dev_get_drvdata(dev);
120 struct device *hwmon;
121 int ret;
122
123 if (!IS_REACHABLE(CONFIG_HWMON))
124 return;
125
126 ret = regmap_update_bits(map: regmap, ISL12022_REG_BETA,
127 ISL12022_BETA_TSE, ISL12022_BETA_TSE);
128 if (ret) {
129 dev_warn(dev, "unable to enable temperature sensor\n");
130 return;
131 }
132
133 hwmon = devm_hwmon_device_register_with_info(dev, name: "isl12022", drvdata: regmap,
134 info: &isl12022_hwmon_chip_info,
135 NULL);
136 if (IS_ERR(ptr: hwmon))
137 dev_warn(dev, "unable to register hwmon device: %pe\n", hwmon);
138}
139
140/*
141 * In the routines that deal directly with the isl12022 hardware, we use
142 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
143 */
144static int isl12022_rtc_read_time(struct device *dev, struct rtc_time *tm)
145{
146 struct regmap *regmap = dev_get_drvdata(dev);
147 uint8_t buf[ISL12022_REG_INT + 1];
148 int ret;
149
150 ret = regmap_bulk_read(map: regmap, ISL12022_REG_SC, val: buf, val_count: sizeof(buf));
151 if (ret)
152 return ret;
153
154 dev_dbg(dev,
155 "raw data is sec=%02x, min=%02x, hr=%02x, mday=%02x, mon=%02x, year=%02x, wday=%02x, sr=%02x, int=%02x",
156 buf[ISL12022_REG_SC],
157 buf[ISL12022_REG_MN],
158 buf[ISL12022_REG_HR],
159 buf[ISL12022_REG_DT],
160 buf[ISL12022_REG_MO],
161 buf[ISL12022_REG_YR],
162 buf[ISL12022_REG_DW],
163 buf[ISL12022_REG_SR],
164 buf[ISL12022_REG_INT]);
165
166 tm->tm_sec = bcd2bin(buf[ISL12022_REG_SC] & 0x7F);
167 tm->tm_min = bcd2bin(buf[ISL12022_REG_MN] & 0x7F);
168 tm->tm_hour = bcd2bin(buf[ISL12022_REG_HR] & 0x3F);
169 tm->tm_mday = bcd2bin(buf[ISL12022_REG_DT] & 0x3F);
170 tm->tm_wday = buf[ISL12022_REG_DW] & 0x07;
171 tm->tm_mon = bcd2bin(buf[ISL12022_REG_MO] & 0x1F) - 1;
172 tm->tm_year = bcd2bin(buf[ISL12022_REG_YR]) + 100;
173
174 dev_dbg(dev, "%s: %ptR\n", __func__, tm);
175
176 return 0;
177}
178
179static int isl12022_rtc_set_time(struct device *dev, struct rtc_time *tm)
180{
181 struct regmap *regmap = dev_get_drvdata(dev);
182 int ret;
183 uint8_t buf[ISL12022_REG_DW + 1];
184
185 dev_dbg(dev, "%s: %ptR\n", __func__, tm);
186
187 /* Ensure the write enable bit is set. */
188 ret = regmap_update_bits(map: regmap, ISL12022_REG_INT,
189 ISL12022_INT_WRTC, ISL12022_INT_WRTC);
190 if (ret)
191 return ret;
192
193 /* hours, minutes and seconds */
194 buf[ISL12022_REG_SC] = bin2bcd(tm->tm_sec);
195 buf[ISL12022_REG_MN] = bin2bcd(tm->tm_min);
196 buf[ISL12022_REG_HR] = bin2bcd(tm->tm_hour) | ISL12022_HR_MIL;
197
198 buf[ISL12022_REG_DT] = bin2bcd(tm->tm_mday);
199
200 /* month, 1 - 12 */
201 buf[ISL12022_REG_MO] = bin2bcd(tm->tm_mon + 1);
202
203 /* year and century */
204 buf[ISL12022_REG_YR] = bin2bcd(tm->tm_year % 100);
205
206 buf[ISL12022_REG_DW] = tm->tm_wday & 0x07;
207
208 return regmap_bulk_write(map: regmap, ISL12022_REG_SC, val: buf, val_count: sizeof(buf));
209}
210
211static int isl12022_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
212{
213 struct regmap *regmap = dev_get_drvdata(dev);
214 u32 user, val;
215 int ret;
216
217 switch (cmd) {
218 case RTC_VL_READ:
219 ret = regmap_read(map: regmap, ISL12022_REG_SR, val: &val);
220 if (ret)
221 return ret;
222
223 user = 0;
224 if (val & ISL12022_SR_LBAT85)
225 user |= RTC_VL_BACKUP_LOW;
226
227 if (val & ISL12022_SR_LBAT75)
228 user |= RTC_VL_BACKUP_EMPTY;
229
230 return put_user(user, (u32 __user *)arg);
231
232 default:
233 return -ENOIOCTLCMD;
234 }
235}
236
237static const struct rtc_class_ops isl12022_rtc_ops = {
238 .ioctl = isl12022_rtc_ioctl,
239 .read_time = isl12022_rtc_read_time,
240 .set_time = isl12022_rtc_set_time,
241};
242
243static const struct regmap_config regmap_config = {
244 .reg_bits = 8,
245 .val_bits = 8,
246 .use_single_write = true,
247};
248
249static int isl12022_register_clock(struct device *dev)
250{
251 struct regmap *regmap = dev_get_drvdata(dev);
252 struct clk_hw *hw;
253 int ret;
254
255 if (!device_property_present(dev, propname: "#clock-cells")) {
256 /*
257 * Disabling the F_OUT pin reduces the power
258 * consumption in battery mode by ~25%.
259 */
260 regmap_update_bits(map: regmap, ISL12022_REG_INT, ISL12022_INT_FO_MASK,
261 ISL12022_INT_FO_OFF);
262
263 return 0;
264 }
265
266 if (!IS_ENABLED(CONFIG_COMMON_CLK))
267 return 0;
268
269 /*
270 * For now, only support a fixed clock of 32768Hz (the reset default).
271 */
272 ret = regmap_update_bits(map: regmap, ISL12022_REG_INT,
273 ISL12022_INT_FO_MASK, ISL12022_INT_FO_32K);
274 if (ret)
275 return ret;
276
277 hw = devm_clk_hw_register_fixed_rate(dev, "isl12022", NULL, 0, 32768);
278 if (IS_ERR(ptr: hw))
279 return PTR_ERR(ptr: hw);
280
281 return devm_of_clk_add_hw_provider(dev, get: of_clk_hw_simple_get, data: hw);
282}
283
284static const u32 trip_levels[2][7] = {
285 { 2125000, 2295000, 2550000, 2805000, 3060000, 4250000, 4675000 },
286 { 1875000, 2025000, 2250000, 2475000, 2700000, 3750000, 4125000 },
287};
288
289static void isl12022_set_trip_levels(struct device *dev)
290{
291 struct regmap *regmap = dev_get_drvdata(dev);
292 u32 levels[2] = {0, 0};
293 int ret, i, j, x[2];
294 u8 val, mask;
295
296 device_property_read_u32_array(dev, propname: "isil,battery-trip-levels-microvolt",
297 val: levels, nval: 2);
298
299 for (i = 0; i < 2; i++) {
300 for (j = 0; j < ARRAY_SIZE(trip_levels[i]) - 1; j++) {
301 if (levels[i] <= trip_levels[i][j])
302 break;
303 }
304 x[i] = j;
305 }
306
307 val = FIELD_PREP(ISL12022_REG_VB85_MASK, x[0]) |
308 FIELD_PREP(ISL12022_REG_VB75_MASK, x[1]);
309 mask = ISL12022_REG_VB85_MASK | ISL12022_REG_VB75_MASK;
310
311 ret = regmap_update_bits(map: regmap, ISL12022_REG_PWR_VBAT, mask, val);
312 if (ret)
313 dev_warn(dev, "unable to set battery alarm levels: %d\n", ret);
314
315 /*
316 * Force a write of the TSE bit in the BETA register, in order
317 * to trigger an update of the LBAT75 and LBAT85 bits in the
318 * status register. In battery backup mode, those bits have
319 * another meaning, so without this, they may contain stale
320 * values for up to a minute after power-on.
321 */
322 regmap_write_bits(map: regmap, ISL12022_REG_BETA,
323 ISL12022_BETA_TSE, ISL12022_BETA_TSE);
324}
325
326static int isl12022_probe(struct i2c_client *client)
327{
328 struct rtc_device *rtc;
329 struct regmap *regmap;
330 int ret;
331
332 if (!i2c_check_functionality(adap: client->adapter, I2C_FUNC_I2C))
333 return -ENODEV;
334
335 regmap = devm_regmap_init_i2c(client, &regmap_config);
336 if (IS_ERR(ptr: regmap)) {
337 dev_err(&client->dev, "regmap allocation failed\n");
338 return PTR_ERR(ptr: regmap);
339 }
340
341 dev_set_drvdata(dev: &client->dev, data: regmap);
342
343 ret = isl12022_register_clock(dev: &client->dev);
344 if (ret)
345 return ret;
346
347 isl12022_set_trip_levels(dev: &client->dev);
348 isl12022_hwmon_register(dev: &client->dev);
349
350 rtc = devm_rtc_allocate_device(dev: &client->dev);
351 if (IS_ERR(ptr: rtc))
352 return PTR_ERR(ptr: rtc);
353
354 rtc->ops = &isl12022_rtc_ops;
355 rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
356 rtc->range_max = RTC_TIMESTAMP_END_2099;
357
358 return devm_rtc_register_device(rtc);
359}
360
361static const struct of_device_id isl12022_dt_match[] = {
362 { .compatible = "isl,isl12022" }, /* for backward compat., don't use */
363 { .compatible = "isil,isl12022" },
364 { },
365};
366MODULE_DEVICE_TABLE(of, isl12022_dt_match);
367
368static const struct i2c_device_id isl12022_id[] = {
369 { "isl12022", 0 },
370 { }
371};
372MODULE_DEVICE_TABLE(i2c, isl12022_id);
373
374static struct i2c_driver isl12022_driver = {
375 .driver = {
376 .name = "rtc-isl12022",
377 .of_match_table = isl12022_dt_match,
378 },
379 .probe = isl12022_probe,
380 .id_table = isl12022_id,
381};
382
383module_i2c_driver(isl12022_driver);
384
385MODULE_AUTHOR("roman.fietze@telemotive.de");
386MODULE_DESCRIPTION("ISL 12022 RTC driver");
387MODULE_LICENSE("GPL");
388

source code of linux/drivers/rtc/rtc-isl12022.c