Arnaud Ebalard | 70e1233 | 2013-12-19 23:27:28 +0100 | [diff] [blame] | 1 | /* |
| 2 | * rtc-isl12057 - Driver for Intersil ISL12057 I2C Real Time Clock |
| 3 | * |
| 4 | * Copyright (C) 2013, Arnaud EBALARD <arno@natisbad.org> |
| 5 | * |
| 6 | * This work is largely based on Intersil ISL1208 driver developed by |
| 7 | * Hebert Valerio Riedel <hvr@gnu.org>. |
| 8 | * |
| 9 | * Detailed datasheet on which this development is based is available here: |
| 10 | * |
| 11 | * http://natisbad.org/NAS2/refs/ISL12057.pdf |
| 12 | * |
| 13 | * This program is free software; you can redistribute it and/or modify |
| 14 | * it under the terms of the GNU General Public License as published by |
| 15 | * the Free Software Foundation; either version 2 of the License, or |
| 16 | * (at your option) any later version. |
| 17 | * |
| 18 | * This program is distributed in the hope that it will be useful, |
| 19 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 20 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 21 | * GNU General Public License for more details. |
| 22 | */ |
| 23 | |
| 24 | #include <linux/module.h> |
| 25 | #include <linux/mutex.h> |
| 26 | #include <linux/rtc.h> |
| 27 | #include <linux/i2c.h> |
| 28 | #include <linux/bcd.h> |
| 29 | #include <linux/rtc.h> |
| 30 | #include <linux/of.h> |
| 31 | #include <linux/of_device.h> |
| 32 | #include <linux/regmap.h> |
| 33 | |
| 34 | #define DRV_NAME "rtc-isl12057" |
| 35 | |
| 36 | /* RTC section */ |
| 37 | #define ISL12057_REG_RTC_SC 0x00 /* Seconds */ |
| 38 | #define ISL12057_REG_RTC_MN 0x01 /* Minutes */ |
| 39 | #define ISL12057_REG_RTC_HR 0x02 /* Hours */ |
| 40 | #define ISL12057_REG_RTC_HR_PM BIT(5) /* AM/PM bit in 12h format */ |
| 41 | #define ISL12057_REG_RTC_HR_MIL BIT(6) /* 24h/12h format */ |
| 42 | #define ISL12057_REG_RTC_DW 0x03 /* Day of the Week */ |
| 43 | #define ISL12057_REG_RTC_DT 0x04 /* Date */ |
| 44 | #define ISL12057_REG_RTC_MO 0x05 /* Month */ |
| 45 | #define ISL12057_REG_RTC_YR 0x06 /* Year */ |
| 46 | #define ISL12057_RTC_SEC_LEN 7 |
| 47 | |
| 48 | /* Alarm 1 section */ |
| 49 | #define ISL12057_REG_A1_SC 0x07 /* Alarm 1 Seconds */ |
| 50 | #define ISL12057_REG_A1_MN 0x08 /* Alarm 1 Minutes */ |
| 51 | #define ISL12057_REG_A1_HR 0x09 /* Alarm 1 Hours */ |
| 52 | #define ISL12057_REG_A1_HR_PM BIT(5) /* AM/PM bit in 12h format */ |
| 53 | #define ISL12057_REG_A1_HR_MIL BIT(6) /* 24h/12h format */ |
| 54 | #define ISL12057_REG_A1_DWDT 0x0A /* Alarm 1 Date / Day of the week */ |
| 55 | #define ISL12057_REG_A1_DWDT_B BIT(6) /* DW / DT selection bit */ |
| 56 | #define ISL12057_A1_SEC_LEN 4 |
| 57 | |
| 58 | /* Alarm 2 section */ |
| 59 | #define ISL12057_REG_A2_MN 0x0B /* Alarm 2 Minutes */ |
| 60 | #define ISL12057_REG_A2_HR 0x0C /* Alarm 2 Hours */ |
| 61 | #define ISL12057_REG_A2_DWDT 0x0D /* Alarm 2 Date / Day of the week */ |
| 62 | #define ISL12057_A2_SEC_LEN 3 |
| 63 | |
| 64 | /* Control/Status registers */ |
| 65 | #define ISL12057_REG_INT 0x0E |
| 66 | #define ISL12057_REG_INT_A1IE BIT(0) /* Alarm 1 interrupt enable bit */ |
| 67 | #define ISL12057_REG_INT_A2IE BIT(1) /* Alarm 2 interrupt enable bit */ |
| 68 | #define ISL12057_REG_INT_INTCN BIT(2) /* Interrupt control enable bit */ |
| 69 | #define ISL12057_REG_INT_RS1 BIT(3) /* Freq out control bit 1 */ |
| 70 | #define ISL12057_REG_INT_RS2 BIT(4) /* Freq out control bit 2 */ |
| 71 | #define ISL12057_REG_INT_EOSC BIT(7) /* Oscillator enable bit */ |
| 72 | |
| 73 | #define ISL12057_REG_SR 0x0F |
| 74 | #define ISL12057_REG_SR_A1F BIT(0) /* Alarm 1 interrupt bit */ |
| 75 | #define ISL12057_REG_SR_A2F BIT(1) /* Alarm 2 interrupt bit */ |
| 76 | #define ISL12057_REG_SR_OSF BIT(7) /* Oscillator failure bit */ |
| 77 | |
| 78 | /* Register memory map length */ |
| 79 | #define ISL12057_MEM_MAP_LEN 0x10 |
| 80 | |
| 81 | struct isl12057_rtc_data { |
| 82 | struct regmap *regmap; |
| 83 | struct mutex lock; |
| 84 | }; |
| 85 | |
| 86 | static void isl12057_rtc_regs_to_tm(struct rtc_time *tm, u8 *regs) |
| 87 | { |
| 88 | tm->tm_sec = bcd2bin(regs[ISL12057_REG_RTC_SC]); |
| 89 | tm->tm_min = bcd2bin(regs[ISL12057_REG_RTC_MN]); |
| 90 | |
| 91 | if (regs[ISL12057_REG_RTC_HR] & ISL12057_REG_RTC_HR_MIL) { /* AM/PM */ |
| 92 | tm->tm_hour = bcd2bin(regs[ISL12057_REG_RTC_HR] & 0x0f); |
| 93 | if (regs[ISL12057_REG_RTC_HR] & ISL12057_REG_RTC_HR_PM) |
| 94 | tm->tm_hour += 12; |
| 95 | } else { /* 24 hour mode */ |
| 96 | tm->tm_hour = bcd2bin(regs[ISL12057_REG_RTC_HR] & 0x3f); |
| 97 | } |
| 98 | |
| 99 | tm->tm_mday = bcd2bin(regs[ISL12057_REG_RTC_DT]); |
| 100 | tm->tm_wday = bcd2bin(regs[ISL12057_REG_RTC_DW]) - 1; /* starts at 1 */ |
| 101 | tm->tm_mon = bcd2bin(regs[ISL12057_REG_RTC_MO]) - 1; /* starts at 1 */ |
| 102 | tm->tm_year = bcd2bin(regs[ISL12057_REG_RTC_YR]) + 100; |
| 103 | } |
| 104 | |
| 105 | static int isl12057_rtc_tm_to_regs(u8 *regs, struct rtc_time *tm) |
| 106 | { |
| 107 | /* |
| 108 | * The clock has an 8 bit wide bcd-coded register for the year. |
| 109 | * tm_year is an offset from 1900 and we are interested in the |
| 110 | * 2000-2099 range, so any value less than 100 is invalid. |
| 111 | */ |
| 112 | if (tm->tm_year < 100) |
| 113 | return -EINVAL; |
| 114 | |
| 115 | regs[ISL12057_REG_RTC_SC] = bin2bcd(tm->tm_sec); |
| 116 | regs[ISL12057_REG_RTC_MN] = bin2bcd(tm->tm_min); |
| 117 | regs[ISL12057_REG_RTC_HR] = bin2bcd(tm->tm_hour); /* 24-hour format */ |
| 118 | regs[ISL12057_REG_RTC_DT] = bin2bcd(tm->tm_mday); |
| 119 | regs[ISL12057_REG_RTC_MO] = bin2bcd(tm->tm_mon + 1); |
| 120 | regs[ISL12057_REG_RTC_YR] = bin2bcd(tm->tm_year - 100); |
| 121 | regs[ISL12057_REG_RTC_DW] = bin2bcd(tm->tm_wday + 1); |
| 122 | |
| 123 | return 0; |
| 124 | } |
| 125 | |
| 126 | /* |
| 127 | * Try and match register bits w/ fixed null values to see whether we |
| 128 | * are dealing with an ISL12057. Note: this function is called early |
| 129 | * during init and hence does need mutex protection. |
| 130 | */ |
| 131 | static int isl12057_i2c_validate_chip(struct regmap *regmap) |
| 132 | { |
| 133 | u8 regs[ISL12057_MEM_MAP_LEN]; |
| 134 | static const u8 mask[ISL12057_MEM_MAP_LEN] = { 0x80, 0x80, 0x80, 0xf8, |
| 135 | 0xc0, 0x60, 0x00, 0x00, |
| 136 | 0x00, 0x00, 0x00, 0x00, |
| 137 | 0x00, 0x00, 0x60, 0x7c }; |
| 138 | int ret, i; |
| 139 | |
| 140 | ret = regmap_bulk_read(regmap, 0, regs, ISL12057_MEM_MAP_LEN); |
| 141 | if (ret) |
| 142 | return ret; |
| 143 | |
| 144 | for (i = 0; i < ISL12057_MEM_MAP_LEN; ++i) { |
| 145 | if (regs[i] & mask[i]) /* check if bits are cleared */ |
| 146 | return -ENODEV; |
| 147 | } |
| 148 | |
| 149 | return 0; |
| 150 | } |
| 151 | |
| 152 | static int isl12057_rtc_read_time(struct device *dev, struct rtc_time *tm) |
| 153 | { |
| 154 | struct isl12057_rtc_data *data = dev_get_drvdata(dev); |
| 155 | u8 regs[ISL12057_RTC_SEC_LEN]; |
| 156 | int ret; |
| 157 | |
| 158 | mutex_lock(&data->lock); |
| 159 | ret = regmap_bulk_read(data->regmap, ISL12057_REG_RTC_SC, regs, |
| 160 | ISL12057_RTC_SEC_LEN); |
| 161 | mutex_unlock(&data->lock); |
| 162 | |
| 163 | if (ret) { |
| 164 | dev_err(dev, "%s: RTC read failed\n", __func__); |
| 165 | return ret; |
| 166 | } |
| 167 | |
| 168 | isl12057_rtc_regs_to_tm(tm, regs); |
| 169 | |
| 170 | return rtc_valid_tm(tm); |
| 171 | } |
| 172 | |
| 173 | static int isl12057_rtc_set_time(struct device *dev, struct rtc_time *tm) |
| 174 | { |
| 175 | struct isl12057_rtc_data *data = dev_get_drvdata(dev); |
| 176 | u8 regs[ISL12057_RTC_SEC_LEN]; |
| 177 | int ret; |
| 178 | |
| 179 | ret = isl12057_rtc_tm_to_regs(regs, tm); |
| 180 | if (ret) |
| 181 | return ret; |
| 182 | |
| 183 | mutex_lock(&data->lock); |
| 184 | ret = regmap_bulk_write(data->regmap, ISL12057_REG_RTC_SC, regs, |
| 185 | ISL12057_RTC_SEC_LEN); |
| 186 | mutex_unlock(&data->lock); |
| 187 | |
| 188 | if (ret) |
| 189 | dev_err(dev, "%s: RTC write failed\n", __func__); |
| 190 | |
| 191 | return ret; |
| 192 | } |
| 193 | |
| 194 | /* |
| 195 | * Check current RTC status and enable/disable what needs to be. Return 0 if |
| 196 | * everything went ok and a negative value upon error. Note: this function |
| 197 | * is called early during init and hence does need mutex protection. |
| 198 | */ |
| 199 | static int isl12057_check_rtc_status(struct device *dev, struct regmap *regmap) |
| 200 | { |
| 201 | int ret; |
| 202 | |
| 203 | /* Enable oscillator if not already running */ |
| 204 | ret = regmap_update_bits(regmap, ISL12057_REG_INT, |
| 205 | ISL12057_REG_INT_EOSC, 0); |
| 206 | if (ret < 0) { |
| 207 | dev_err(dev, "Unable to enable oscillator\n"); |
| 208 | return ret; |
| 209 | } |
| 210 | |
| 211 | /* Clear oscillator failure bit if needed */ |
| 212 | ret = regmap_update_bits(regmap, ISL12057_REG_SR, |
| 213 | ISL12057_REG_SR_OSF, 0); |
| 214 | if (ret < 0) { |
| 215 | dev_err(dev, "Unable to clear oscillator failure bit\n"); |
| 216 | return ret; |
| 217 | } |
| 218 | |
| 219 | /* Clear alarm bit if needed */ |
| 220 | ret = regmap_update_bits(regmap, ISL12057_REG_SR, |
| 221 | ISL12057_REG_SR_A1F, 0); |
| 222 | if (ret < 0) { |
| 223 | dev_err(dev, "Unable to clear alarm bit\n"); |
| 224 | return ret; |
| 225 | } |
| 226 | |
| 227 | return 0; |
| 228 | } |
| 229 | |
| 230 | static const struct rtc_class_ops rtc_ops = { |
| 231 | .read_time = isl12057_rtc_read_time, |
| 232 | .set_time = isl12057_rtc_set_time, |
| 233 | }; |
| 234 | |
| 235 | static struct regmap_config isl12057_rtc_regmap_config = { |
| 236 | .reg_bits = 8, |
| 237 | .val_bits = 8, |
| 238 | }; |
| 239 | |
| 240 | static int isl12057_probe(struct i2c_client *client, |
| 241 | const struct i2c_device_id *id) |
| 242 | { |
| 243 | struct device *dev = &client->dev; |
| 244 | struct isl12057_rtc_data *data; |
| 245 | struct rtc_device *rtc; |
| 246 | struct regmap *regmap; |
| 247 | int ret; |
| 248 | |
| 249 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C | |
| 250 | I2C_FUNC_SMBUS_BYTE_DATA | |
| 251 | I2C_FUNC_SMBUS_I2C_BLOCK)) |
| 252 | return -ENODEV; |
| 253 | |
| 254 | regmap = devm_regmap_init_i2c(client, &isl12057_rtc_regmap_config); |
| 255 | if (IS_ERR(regmap)) { |
| 256 | ret = PTR_ERR(regmap); |
| 257 | dev_err(dev, "regmap allocation failed: %d\n", ret); |
| 258 | return ret; |
| 259 | } |
| 260 | |
| 261 | ret = isl12057_i2c_validate_chip(regmap); |
| 262 | if (ret) |
| 263 | return ret; |
| 264 | |
| 265 | ret = isl12057_check_rtc_status(dev, regmap); |
| 266 | if (ret) |
| 267 | return ret; |
| 268 | |
| 269 | data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); |
| 270 | if (!data) |
| 271 | return -ENOMEM; |
| 272 | |
| 273 | mutex_init(&data->lock); |
| 274 | data->regmap = regmap; |
| 275 | dev_set_drvdata(dev, data); |
| 276 | |
| 277 | rtc = devm_rtc_device_register(dev, DRV_NAME, &rtc_ops, THIS_MODULE); |
| 278 | if (IS_ERR(rtc)) |
| 279 | return PTR_ERR(rtc); |
| 280 | |
| 281 | return 0; |
| 282 | } |
| 283 | |
| 284 | #ifdef CONFIG_OF |
| 285 | static struct of_device_id isl12057_dt_match[] = { |
| 286 | { .compatible = "isl,isl12057" }, |
| 287 | { }, |
| 288 | }; |
| 289 | #endif |
| 290 | |
| 291 | static const struct i2c_device_id isl12057_id[] = { |
| 292 | { "isl12057", 0 }, |
| 293 | { } |
| 294 | }; |
| 295 | MODULE_DEVICE_TABLE(i2c, isl12057_id); |
| 296 | |
| 297 | static struct i2c_driver isl12057_driver = { |
| 298 | .driver = { |
| 299 | .name = DRV_NAME, |
| 300 | .owner = THIS_MODULE, |
| 301 | .of_match_table = of_match_ptr(isl12057_dt_match), |
| 302 | }, |
| 303 | .probe = isl12057_probe, |
| 304 | .id_table = isl12057_id, |
| 305 | }; |
| 306 | module_i2c_driver(isl12057_driver); |
| 307 | |
| 308 | MODULE_AUTHOR("Arnaud EBALARD <arno@natisbad.org>"); |
| 309 | MODULE_DESCRIPTION("Intersil ISL12057 RTC driver"); |
| 310 | MODULE_LICENSE("GPL"); |