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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 | // SPDX-License-Identifier: GPL-2.0-or-later /* * The Netronix embedded controller is a microcontroller found in some * e-book readers designed by the original design manufacturer Netronix, Inc. * It contains RTC, battery monitoring, system power management, and PWM * functionality. * * This driver implements access to the RTC time and date. * * Copyright 2020 Jonathan Neuschäfer <j.neuschaefer@gmx.net> */ #include <linux/mfd/ntxec.h> #include <linux/module.h> #include <linux/platform_device.h> #include <linux/regmap.h> #include <linux/rtc.h> #include <linux/types.h> struct ntxec_rtc { struct device *dev; struct ntxec *ec; }; #define NTXEC_REG_WRITE_YEAR 0x10 #define NTXEC_REG_WRITE_MONTH 0x11 #define NTXEC_REG_WRITE_DAY 0x12 #define NTXEC_REG_WRITE_HOUR 0x13 #define NTXEC_REG_WRITE_MINUTE 0x14 #define NTXEC_REG_WRITE_SECOND 0x15 #define NTXEC_REG_READ_YEAR_MONTH 0x20 #define NTXEC_REG_READ_MDAY_HOUR 0x21 #define NTXEC_REG_READ_MINUTE_SECOND 0x23 static int ntxec_read_time(struct device *dev, struct rtc_time *tm) { struct ntxec_rtc *rtc = dev_get_drvdata(dev); unsigned int value; int res; retry: res = regmap_read(rtc->ec->regmap, NTXEC_REG_READ_MINUTE_SECOND, &value); if (res < 0) return res; tm->tm_min = value >> 8; tm->tm_sec = value & 0xff; res = regmap_read(rtc->ec->regmap, NTXEC_REG_READ_MDAY_HOUR, &value); if (res < 0) return res; tm->tm_mday = value >> 8; tm->tm_hour = value & 0xff; res = regmap_read(rtc->ec->regmap, NTXEC_REG_READ_YEAR_MONTH, &value); if (res < 0) return res; tm->tm_year = (value >> 8) + 100; tm->tm_mon = (value & 0xff) - 1; /* * Read the minutes/seconds field again. If it changed since the first * read, we can't assume that the values read so far are consistent, * and should start from the beginning. */ res = regmap_read(rtc->ec->regmap, NTXEC_REG_READ_MINUTE_SECOND, &value); if (res < 0) return res; if (tm->tm_min != value >> 8 || tm->tm_sec != (value & 0xff)) goto retry; return 0; } static int ntxec_set_time(struct device *dev, struct rtc_time *tm) { struct ntxec_rtc *rtc = dev_get_drvdata(dev); /* * To avoid time overflows while we're writing the full date/time, * set the seconds field to zero before doing anything else. For the * next 59 seconds (plus however long it takes until the RTC's next * update of the second field), the seconds field will not overflow * into the other fields. */ struct reg_sequence regs[] = { { NTXEC_REG_WRITE_SECOND, ntxec_reg8(0) }, { NTXEC_REG_WRITE_YEAR, ntxec_reg8(tm->tm_year - 100) }, { NTXEC_REG_WRITE_MONTH, ntxec_reg8(tm->tm_mon + 1) }, { NTXEC_REG_WRITE_DAY, ntxec_reg8(tm->tm_mday) }, { NTXEC_REG_WRITE_HOUR, ntxec_reg8(tm->tm_hour) }, { NTXEC_REG_WRITE_MINUTE, ntxec_reg8(tm->tm_min) }, { NTXEC_REG_WRITE_SECOND, ntxec_reg8(tm->tm_sec) }, }; return regmap_multi_reg_write(rtc->ec->regmap, regs, ARRAY_SIZE(regs)); } static const struct rtc_class_ops ntxec_rtc_ops = { .read_time = ntxec_read_time, .set_time = ntxec_set_time, }; static int ntxec_rtc_probe(struct platform_device *pdev) { struct rtc_device *dev; struct ntxec_rtc *rtc; pdev->dev.of_node = pdev->dev.parent->of_node; rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL); if (!rtc) return -ENOMEM; rtc->dev = &pdev->dev; rtc->ec = dev_get_drvdata(pdev->dev.parent); platform_set_drvdata(pdev, rtc); dev = devm_rtc_allocate_device(&pdev->dev); if (IS_ERR(dev)) return PTR_ERR(dev); dev->ops = &ntxec_rtc_ops; dev->range_min = RTC_TIMESTAMP_BEGIN_2000; dev->range_max = 9025257599LL; /* 2255-12-31 23:59:59 */ return devm_rtc_register_device(dev); } static struct platform_driver ntxec_rtc_driver = { .driver = { .name = "ntxec-rtc", }, .probe = ntxec_rtc_probe, }; module_platform_driver(ntxec_rtc_driver); MODULE_AUTHOR("Jonathan Neuschäfer <j.neuschaefer@gmx.net>"); MODULE_DESCRIPTION("RTC driver for Netronix EC"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:ntxec-rtc"); |