311 lines
8.9 KiB
C
311 lines
8.9 KiB
C
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/*
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* rtc-isl12057 - Driver for Intersil ISL12057 I2C Real Time Clock
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*
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* Copyright (C) 2013, Arnaud EBALARD <arno@natisbad.org>
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*
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* This work is largely based on Intersil ISL1208 driver developed by
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* Hebert Valerio Riedel <hvr@gnu.org>.
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*
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* Detailed datasheet on which this development is based is available here:
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*
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* http://natisbad.org/NAS2/refs/ISL12057.pdf
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/rtc.h>
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#include <linux/i2c.h>
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#include <linux/bcd.h>
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#include <linux/rtc.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/regmap.h>
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#define DRV_NAME "rtc-isl12057"
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/* RTC section */
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#define ISL12057_REG_RTC_SC 0x00 /* Seconds */
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#define ISL12057_REG_RTC_MN 0x01 /* Minutes */
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#define ISL12057_REG_RTC_HR 0x02 /* Hours */
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#define ISL12057_REG_RTC_HR_PM BIT(5) /* AM/PM bit in 12h format */
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#define ISL12057_REG_RTC_HR_MIL BIT(6) /* 24h/12h format */
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#define ISL12057_REG_RTC_DW 0x03 /* Day of the Week */
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#define ISL12057_REG_RTC_DT 0x04 /* Date */
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#define ISL12057_REG_RTC_MO 0x05 /* Month */
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#define ISL12057_REG_RTC_YR 0x06 /* Year */
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#define ISL12057_RTC_SEC_LEN 7
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/* Alarm 1 section */
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#define ISL12057_REG_A1_SC 0x07 /* Alarm 1 Seconds */
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#define ISL12057_REG_A1_MN 0x08 /* Alarm 1 Minutes */
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#define ISL12057_REG_A1_HR 0x09 /* Alarm 1 Hours */
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#define ISL12057_REG_A1_HR_PM BIT(5) /* AM/PM bit in 12h format */
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#define ISL12057_REG_A1_HR_MIL BIT(6) /* 24h/12h format */
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#define ISL12057_REG_A1_DWDT 0x0A /* Alarm 1 Date / Day of the week */
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#define ISL12057_REG_A1_DWDT_B BIT(6) /* DW / DT selection bit */
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#define ISL12057_A1_SEC_LEN 4
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/* Alarm 2 section */
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#define ISL12057_REG_A2_MN 0x0B /* Alarm 2 Minutes */
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#define ISL12057_REG_A2_HR 0x0C /* Alarm 2 Hours */
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#define ISL12057_REG_A2_DWDT 0x0D /* Alarm 2 Date / Day of the week */
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#define ISL12057_A2_SEC_LEN 3
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/* Control/Status registers */
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#define ISL12057_REG_INT 0x0E
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#define ISL12057_REG_INT_A1IE BIT(0) /* Alarm 1 interrupt enable bit */
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#define ISL12057_REG_INT_A2IE BIT(1) /* Alarm 2 interrupt enable bit */
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#define ISL12057_REG_INT_INTCN BIT(2) /* Interrupt control enable bit */
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#define ISL12057_REG_INT_RS1 BIT(3) /* Freq out control bit 1 */
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#define ISL12057_REG_INT_RS2 BIT(4) /* Freq out control bit 2 */
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#define ISL12057_REG_INT_EOSC BIT(7) /* Oscillator enable bit */
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#define ISL12057_REG_SR 0x0F
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#define ISL12057_REG_SR_A1F BIT(0) /* Alarm 1 interrupt bit */
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#define ISL12057_REG_SR_A2F BIT(1) /* Alarm 2 interrupt bit */
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#define ISL12057_REG_SR_OSF BIT(7) /* Oscillator failure bit */
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/* Register memory map length */
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#define ISL12057_MEM_MAP_LEN 0x10
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struct isl12057_rtc_data {
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struct regmap *regmap;
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struct mutex lock;
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};
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static void isl12057_rtc_regs_to_tm(struct rtc_time *tm, u8 *regs)
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{
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tm->tm_sec = bcd2bin(regs[ISL12057_REG_RTC_SC]);
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tm->tm_min = bcd2bin(regs[ISL12057_REG_RTC_MN]);
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if (regs[ISL12057_REG_RTC_HR] & ISL12057_REG_RTC_HR_MIL) { /* AM/PM */
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tm->tm_hour = bcd2bin(regs[ISL12057_REG_RTC_HR] & 0x0f);
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if (regs[ISL12057_REG_RTC_HR] & ISL12057_REG_RTC_HR_PM)
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tm->tm_hour += 12;
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} else { /* 24 hour mode */
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tm->tm_hour = bcd2bin(regs[ISL12057_REG_RTC_HR] & 0x3f);
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}
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tm->tm_mday = bcd2bin(regs[ISL12057_REG_RTC_DT]);
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tm->tm_wday = bcd2bin(regs[ISL12057_REG_RTC_DW]) - 1; /* starts at 1 */
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tm->tm_mon = bcd2bin(regs[ISL12057_REG_RTC_MO]) - 1; /* starts at 1 */
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tm->tm_year = bcd2bin(regs[ISL12057_REG_RTC_YR]) + 100;
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}
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static int isl12057_rtc_tm_to_regs(u8 *regs, struct rtc_time *tm)
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{
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/*
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* The clock has an 8 bit wide bcd-coded register for the year.
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* tm_year is an offset from 1900 and we are interested in the
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* 2000-2099 range, so any value less than 100 is invalid.
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*/
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if (tm->tm_year < 100)
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return -EINVAL;
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regs[ISL12057_REG_RTC_SC] = bin2bcd(tm->tm_sec);
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regs[ISL12057_REG_RTC_MN] = bin2bcd(tm->tm_min);
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regs[ISL12057_REG_RTC_HR] = bin2bcd(tm->tm_hour); /* 24-hour format */
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regs[ISL12057_REG_RTC_DT] = bin2bcd(tm->tm_mday);
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regs[ISL12057_REG_RTC_MO] = bin2bcd(tm->tm_mon + 1);
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regs[ISL12057_REG_RTC_YR] = bin2bcd(tm->tm_year - 100);
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regs[ISL12057_REG_RTC_DW] = bin2bcd(tm->tm_wday + 1);
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return 0;
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}
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/*
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* Try and match register bits w/ fixed null values to see whether we
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* are dealing with an ISL12057. Note: this function is called early
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* during init and hence does need mutex protection.
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*/
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static int isl12057_i2c_validate_chip(struct regmap *regmap)
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{
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u8 regs[ISL12057_MEM_MAP_LEN];
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static const u8 mask[ISL12057_MEM_MAP_LEN] = { 0x80, 0x80, 0x80, 0xf8,
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0xc0, 0x60, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x60, 0x7c };
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int ret, i;
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ret = regmap_bulk_read(regmap, 0, regs, ISL12057_MEM_MAP_LEN);
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if (ret)
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return ret;
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for (i = 0; i < ISL12057_MEM_MAP_LEN; ++i) {
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if (regs[i] & mask[i]) /* check if bits are cleared */
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return -ENODEV;
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}
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return 0;
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}
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static int isl12057_rtc_read_time(struct device *dev, struct rtc_time *tm)
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{
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struct isl12057_rtc_data *data = dev_get_drvdata(dev);
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u8 regs[ISL12057_RTC_SEC_LEN];
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int ret;
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mutex_lock(&data->lock);
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ret = regmap_bulk_read(data->regmap, ISL12057_REG_RTC_SC, regs,
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ISL12057_RTC_SEC_LEN);
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mutex_unlock(&data->lock);
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if (ret) {
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dev_err(dev, "%s: RTC read failed\n", __func__);
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return ret;
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}
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isl12057_rtc_regs_to_tm(tm, regs);
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return rtc_valid_tm(tm);
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}
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static int isl12057_rtc_set_time(struct device *dev, struct rtc_time *tm)
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{
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struct isl12057_rtc_data *data = dev_get_drvdata(dev);
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u8 regs[ISL12057_RTC_SEC_LEN];
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int ret;
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ret = isl12057_rtc_tm_to_regs(regs, tm);
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if (ret)
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return ret;
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mutex_lock(&data->lock);
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ret = regmap_bulk_write(data->regmap, ISL12057_REG_RTC_SC, regs,
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ISL12057_RTC_SEC_LEN);
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mutex_unlock(&data->lock);
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if (ret)
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dev_err(dev, "%s: RTC write failed\n", __func__);
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return ret;
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}
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/*
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* Check current RTC status and enable/disable what needs to be. Return 0 if
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* everything went ok and a negative value upon error. Note: this function
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* is called early during init and hence does need mutex protection.
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*/
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static int isl12057_check_rtc_status(struct device *dev, struct regmap *regmap)
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{
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int ret;
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/* Enable oscillator if not already running */
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ret = regmap_update_bits(regmap, ISL12057_REG_INT,
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ISL12057_REG_INT_EOSC, 0);
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if (ret < 0) {
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dev_err(dev, "Unable to enable oscillator\n");
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return ret;
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}
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/* Clear oscillator failure bit if needed */
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ret = regmap_update_bits(regmap, ISL12057_REG_SR,
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ISL12057_REG_SR_OSF, 0);
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if (ret < 0) {
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dev_err(dev, "Unable to clear oscillator failure bit\n");
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return ret;
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}
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/* Clear alarm bit if needed */
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ret = regmap_update_bits(regmap, ISL12057_REG_SR,
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ISL12057_REG_SR_A1F, 0);
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if (ret < 0) {
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dev_err(dev, "Unable to clear alarm bit\n");
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return ret;
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}
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return 0;
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}
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static const struct rtc_class_ops rtc_ops = {
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.read_time = isl12057_rtc_read_time,
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.set_time = isl12057_rtc_set_time,
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};
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static struct regmap_config isl12057_rtc_regmap_config = {
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.reg_bits = 8,
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.val_bits = 8,
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};
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static int isl12057_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct device *dev = &client->dev;
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struct isl12057_rtc_data *data;
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struct rtc_device *rtc;
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struct regmap *regmap;
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int ret;
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
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I2C_FUNC_SMBUS_BYTE_DATA |
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I2C_FUNC_SMBUS_I2C_BLOCK))
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return -ENODEV;
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regmap = devm_regmap_init_i2c(client, &isl12057_rtc_regmap_config);
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if (IS_ERR(regmap)) {
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ret = PTR_ERR(regmap);
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dev_err(dev, "regmap allocation failed: %d\n", ret);
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return ret;
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}
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ret = isl12057_i2c_validate_chip(regmap);
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if (ret)
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return ret;
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ret = isl12057_check_rtc_status(dev, regmap);
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if (ret)
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return ret;
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data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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mutex_init(&data->lock);
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data->regmap = regmap;
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dev_set_drvdata(dev, data);
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rtc = devm_rtc_device_register(dev, DRV_NAME, &rtc_ops, THIS_MODULE);
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if (IS_ERR(rtc))
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return PTR_ERR(rtc);
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return 0;
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}
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#ifdef CONFIG_OF
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static struct of_device_id isl12057_dt_match[] = {
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{ .compatible = "isl,isl12057" },
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{ },
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};
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#endif
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static const struct i2c_device_id isl12057_id[] = {
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{ "isl12057", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, isl12057_id);
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static struct i2c_driver isl12057_driver = {
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.driver = {
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.name = DRV_NAME,
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.owner = THIS_MODULE,
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.of_match_table = of_match_ptr(isl12057_dt_match),
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},
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.probe = isl12057_probe,
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.id_table = isl12057_id,
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};
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module_i2c_driver(isl12057_driver);
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MODULE_AUTHOR("Arnaud EBALARD <arno@natisbad.org>");
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MODULE_DESCRIPTION("Intersil ISL12057 RTC driver");
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MODULE_LICENSE("GPL");
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