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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 | // SPDX-License-Identifier: GPL-2.0 /* * An rtc/i2c driver for the Dallas DS1672 * Copyright 2005-06 Tower Technologies * * Author: Alessandro Zummo <a.zummo@towertech.it> */ #include <linux/i2c.h> #include <linux/rtc.h> #include <linux/module.h> /* Registers */ #define DS1672_REG_CNT_BASE 0 #define DS1672_REG_CONTROL 4 #define DS1672_REG_TRICKLE 5 #define DS1672_REG_CONTROL_EOSC 0x80 /* * In the routines that deal directly with the ds1672 hardware, we use * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch * Time is set to UTC. */ static int ds1672_read_time(struct device *dev, struct rtc_time *tm) { struct i2c_client *client = to_i2c_client(dev); unsigned long time; unsigned char addr = DS1672_REG_CONTROL; unsigned char buf[4]; struct i2c_msg msgs[] = { {/* setup read ptr */ .addr = client->addr, .len = 1, .buf = &addr }, {/* read date */ .addr = client->addr, .flags = I2C_M_RD, .len = 1, .buf = buf }, }; /* read control register */ if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) { dev_warn(&client->dev, "Unable to read the control register\n"); return -EIO; } if (buf[0] & DS1672_REG_CONTROL_EOSC) { dev_warn(&client->dev, "Oscillator not enabled. Set time to enable.\n"); return -EINVAL; } addr = DS1672_REG_CNT_BASE; msgs[1].len = 4; /* read date registers */ if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) { dev_err(&client->dev, "%s: read error\n", __func__); return -EIO; } dev_dbg(&client->dev, "%s: raw read data - counters=%02x,%02x,%02x,%02x\n", __func__, buf[0], buf[1], buf[2], buf[3]); time = ((unsigned long)buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0]; rtc_time64_to_tm(time, tm); dev_dbg(&client->dev, "%s: tm is %ptR\n", __func__, tm); return 0; } static int ds1672_set_time(struct device *dev, struct rtc_time *tm) { struct i2c_client *client = to_i2c_client(dev); int xfer; unsigned char buf[6]; unsigned long secs = rtc_tm_to_time64(tm); buf[0] = DS1672_REG_CNT_BASE; buf[1] = secs & 0x000000FF; buf[2] = (secs & 0x0000FF00) >> 8; buf[3] = (secs & 0x00FF0000) >> 16; buf[4] = (secs & 0xFF000000) >> 24; buf[5] = 0; /* set control reg to enable counting */ xfer = i2c_master_send(client, buf, 6); if (xfer != 6) { dev_err(&client->dev, "%s: send: %d\n", __func__, xfer); return -EIO; } return 0; } static const struct rtc_class_ops ds1672_rtc_ops = { .read_time = ds1672_read_time, .set_time = ds1672_set_time, }; static int ds1672_probe(struct i2c_client *client) { int err = 0; struct rtc_device *rtc; dev_dbg(&client->dev, "%s\n", __func__); if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) return -ENODEV; rtc = devm_rtc_allocate_device(&client->dev); if (IS_ERR(rtc)) return PTR_ERR(rtc); rtc->ops = &ds1672_rtc_ops; rtc->range_max = U32_MAX; err = devm_rtc_register_device(rtc); if (err) return err; i2c_set_clientdata(client, rtc); return 0; } static const struct i2c_device_id ds1672_id[] = { { "ds1672", 0 }, { } }; MODULE_DEVICE_TABLE(i2c, ds1672_id); static const __maybe_unused struct of_device_id ds1672_of_match[] = { { .compatible = "dallas,ds1672" }, { } }; MODULE_DEVICE_TABLE(of, ds1672_of_match); static struct i2c_driver ds1672_driver = { .driver = { .name = "rtc-ds1672", .of_match_table = of_match_ptr(ds1672_of_match), }, .probe = ds1672_probe, .id_table = ds1672_id, }; module_i2c_driver(ds1672_driver); MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>"); MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver"); MODULE_LICENSE("GPL"); |