rtc: Add support for Intersil ISL12057 I2C RTC chip (70e12337) · Commits · 戴 / test

Documentation/devicetree/bindings/i2c/trivial-devices.txt

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		@@ -39,6 +39,7 @@ fsl,sgtl5000 SGTL5000: Ultra Low-Power Audio Codec
		gmt,g751 G751: Digital Temperature Sensor and Thermal Watchdog with Two-Wire Interface
		infineon,slb9635tt Infineon SLB9635 (Soft-) I2C TPM (old protocol, max 100khz)
		infineon,slb9645tt Infineon SLB9645 I2C TPM (new protocol, max 400khz)
		isl,isl12057 Intersil ISL12057 I2C RTC Chip
		maxim,ds1050 5 Bit Programmable, Pulse-Width Modulator
		maxim,max1237 Low-Power, 4-/12-Channel, 2-Wire Serial, 12-Bit ADCs
		maxim,max6625 9-Bit/12-Bit Temperature Sensors with I²C-Compatible Serial Interface

Documentation/devicetree/bindings/vendor-prefixes.txt

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		@@ -38,6 +38,7 @@ ibm International Business Machines (IBM)
		idt Integrated Device Technologies, Inc.
		img Imagination Technologies Ltd.
		intercontrol Inter Control Group
		isl Intersil
		linux Linux-specific binding
		lsi LSI Corp. (LSI Logic)
		marvell Marvell Technology Group Ltd.

drivers/rtc/Kconfig

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		@@ -304,6 +304,17 @@ config RTC_DRV_ISL12022
		This driver can also be built as a module. If so, the module
		will be called rtc-isl12022.

		config RTC_DRV_ISL12057
		depends on I2C
		select REGMAP_I2C
		tristate "Intersil ISL12057"
		help
		If you say yes here you get support for the Intersil ISL12057
		I2C RTC chip.

		This driver can also be built as a module. If so, the module
		will be called rtc-isl12057.

		config RTC_DRV_X1205
		tristate "Xicor/Intersil X1205"
		help

drivers/rtc/Makefile

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		@@ -58,6 +58,7 @@ obj-$(CONFIG_RTC_DRV_HID_SENSOR_TIME) += rtc-hid-sensor-time.o
		obj-$(CONFIG_RTC_DRV_IMXDI) += rtc-imxdi.o
		obj-$(CONFIG_RTC_DRV_ISL1208) += rtc-isl1208.o
		obj-$(CONFIG_RTC_DRV_ISL12022) += rtc-isl12022.o
		obj-$(CONFIG_RTC_DRV_ISL12057) += rtc-isl12057.o
		obj-$(CONFIG_RTC_DRV_JZ4740) += rtc-jz4740.o
		obj-$(CONFIG_RTC_DRV_LP8788) += rtc-lp8788.o
		obj-$(CONFIG_RTC_DRV_LPC32XX) += rtc-lpc32xx.o

drivers/rtc/rtc-isl12057.c

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		/*
		* rtc-isl12057 - Driver for Intersil ISL12057 I2C Real Time Clock
		*
		* Copyright (C) 2013, Arnaud EBALARD <arno@natisbad.org>
		*
		* This work is largely based on Intersil ISL1208 driver developed by
		* Hebert Valerio Riedel <hvr@gnu.org>.
		*
		* Detailed datasheet on which this development is based is available here:
		*
		* http://natisbad.org/NAS2/refs/ISL12057.pdf
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License as published by
		* the Free Software Foundation; either version 2 of the License, or
		* (at your option) any later version.
		*
		* This program is distributed in the hope that it will be useful,
		* but WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		* GNU General Public License for more details.
		*/

		#include <linux/module.h>
		#include <linux/mutex.h>
		#include <linux/rtc.h>
		#include <linux/i2c.h>
		#include <linux/bcd.h>
		#include <linux/rtc.h>
		#include <linux/of.h>
		#include <linux/of_device.h>
		#include <linux/regmap.h>

		#define DRV_NAME "rtc-isl12057"

		/* RTC section */
		#define ISL12057_REG_RTC_SC 0x00 /* Seconds */
		#define ISL12057_REG_RTC_MN 0x01 /* Minutes */
		#define ISL12057_REG_RTC_HR 0x02 /* Hours */
		#define ISL12057_REG_RTC_HR_PM BIT(5) /* AM/PM bit in 12h format */
		#define ISL12057_REG_RTC_HR_MIL BIT(6) /* 24h/12h format */
		#define ISL12057_REG_RTC_DW 0x03 /* Day of the Week */
		#define ISL12057_REG_RTC_DT 0x04 /* Date */
		#define ISL12057_REG_RTC_MO 0x05 /* Month */
		#define ISL12057_REG_RTC_YR 0x06 /* Year */
		#define ISL12057_RTC_SEC_LEN 7

		/* Alarm 1 section */
		#define ISL12057_REG_A1_SC 0x07 /* Alarm 1 Seconds */
		#define ISL12057_REG_A1_MN 0x08 /* Alarm 1 Minutes */
		#define ISL12057_REG_A1_HR 0x09 /* Alarm 1 Hours */
		#define ISL12057_REG_A1_HR_PM BIT(5) /* AM/PM bit in 12h format */
		#define ISL12057_REG_A1_HR_MIL BIT(6) /* 24h/12h format */
		#define ISL12057_REG_A1_DWDT 0x0A /* Alarm 1 Date / Day of the week */
		#define ISL12057_REG_A1_DWDT_B BIT(6) /* DW / DT selection bit */
		#define ISL12057_A1_SEC_LEN 4

		/* Alarm 2 section */
		#define ISL12057_REG_A2_MN 0x0B /* Alarm 2 Minutes */
		#define ISL12057_REG_A2_HR 0x0C /* Alarm 2 Hours */
		#define ISL12057_REG_A2_DWDT 0x0D /* Alarm 2 Date / Day of the week */
		#define ISL12057_A2_SEC_LEN 3

		/* Control/Status registers */
		#define ISL12057_REG_INT 0x0E
		#define ISL12057_REG_INT_A1IE BIT(0) /* Alarm 1 interrupt enable bit */
		#define ISL12057_REG_INT_A2IE BIT(1) /* Alarm 2 interrupt enable bit */
		#define ISL12057_REG_INT_INTCN BIT(2) /* Interrupt control enable bit */
		#define ISL12057_REG_INT_RS1 BIT(3) /* Freq out control bit 1 */
		#define ISL12057_REG_INT_RS2 BIT(4) /* Freq out control bit 2 */
		#define ISL12057_REG_INT_EOSC BIT(7) /* Oscillator enable bit */

		#define ISL12057_REG_SR 0x0F
		#define ISL12057_REG_SR_A1F BIT(0) /* Alarm 1 interrupt bit */
		#define ISL12057_REG_SR_A2F BIT(1) /* Alarm 2 interrupt bit */
		#define ISL12057_REG_SR_OSF BIT(7) /* Oscillator failure bit */

		/* Register memory map length */
		#define ISL12057_MEM_MAP_LEN 0x10

		struct isl12057_rtc_data {
		struct regmap *regmap;
		struct mutex lock;
		};

		static void isl12057_rtc_regs_to_tm(struct rtc_time tm, u8 regs)
		{
		tm->tm_sec = bcd2bin(regs[ISL12057_REG_RTC_SC]);
		tm->tm_min = bcd2bin(regs[ISL12057_REG_RTC_MN]);

		if (regs[ISL12057_REG_RTC_HR] & ISL12057_REG_RTC_HR_MIL) { /* AM/PM */
		tm->tm_hour = bcd2bin(regs[ISL12057_REG_RTC_HR] & 0x0f);
		if (regs[ISL12057_REG_RTC_HR] & ISL12057_REG_RTC_HR_PM)
		tm->tm_hour += 12;
		} else { /* 24 hour mode */
		tm->tm_hour = bcd2bin(regs[ISL12057_REG_RTC_HR] & 0x3f);
		}

		tm->tm_mday = bcd2bin(regs[ISL12057_REG_RTC_DT]);
		tm->tm_wday = bcd2bin(regs[ISL12057_REG_RTC_DW]) - 1; /* starts at 1 */
		tm->tm_mon = bcd2bin(regs[ISL12057_REG_RTC_MO]) - 1; /* starts at 1 */
		tm->tm_year = bcd2bin(regs[ISL12057_REG_RTC_YR]) + 100;
		}

		static int isl12057_rtc_tm_to_regs(u8 regs, struct rtc_time tm)
		{
		/*
		* The clock has an 8 bit wide bcd-coded register for the year.
		* tm_year is an offset from 1900 and we are interested in the
		* 2000-2099 range, so any value less than 100 is invalid.
		*/
		if (tm->tm_year < 100)
		return -EINVAL;

		regs[ISL12057_REG_RTC_SC] = bin2bcd(tm->tm_sec);
		regs[ISL12057_REG_RTC_MN] = bin2bcd(tm->tm_min);
		regs[ISL12057_REG_RTC_HR] = bin2bcd(tm->tm_hour); /* 24-hour format */
		regs[ISL12057_REG_RTC_DT] = bin2bcd(tm->tm_mday);
		regs[ISL12057_REG_RTC_MO] = bin2bcd(tm->tm_mon + 1);
		regs[ISL12057_REG_RTC_YR] = bin2bcd(tm->tm_year - 100);
		regs[ISL12057_REG_RTC_DW] = bin2bcd(tm->tm_wday + 1);

		return 0;
		}

		/*
		* Try and match register bits w/ fixed null values to see whether we
		* are dealing with an ISL12057. Note: this function is called early
		* during init and hence does need mutex protection.
		*/
		static int isl12057_i2c_validate_chip(struct regmap *regmap)
		{
		u8 regs[ISL12057_MEM_MAP_LEN];
		static const u8 mask[ISL12057_MEM_MAP_LEN] = { 0x80, 0x80, 0x80, 0xf8,
		0xc0, 0x60, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x60, 0x7c };
		int ret, i;

		ret = regmap_bulk_read(regmap, 0, regs, ISL12057_MEM_MAP_LEN);
		if (ret)
		return ret;

		for (i = 0; i < ISL12057_MEM_MAP_LEN; ++i) {
		if (regs[i] & mask[i]) /* check if bits are cleared */
		return -ENODEV;
		}

		return 0;
		}

		static int isl12057_rtc_read_time(struct device dev, struct rtc_time tm)
		{
		struct isl12057_rtc_data *data = dev_get_drvdata(dev);
		u8 regs[ISL12057_RTC_SEC_LEN];
		int ret;

		mutex_lock(&data->lock);
		ret = regmap_bulk_read(data->regmap, ISL12057_REG_RTC_SC, regs,
		ISL12057_RTC_SEC_LEN);
		mutex_unlock(&data->lock);

		if (ret) {
		dev_err(dev, "%s: RTC read failed\n", __func__);
		return ret;
		}

		isl12057_rtc_regs_to_tm(tm, regs);

		return rtc_valid_tm(tm);
		}

		static int isl12057_rtc_set_time(struct device dev, struct rtc_time tm)
		{
		struct isl12057_rtc_data *data = dev_get_drvdata(dev);
		u8 regs[ISL12057_RTC_SEC_LEN];
		int ret;

		ret = isl12057_rtc_tm_to_regs(regs, tm);
		if (ret)
		return ret;

		mutex_lock(&data->lock);
		ret = regmap_bulk_write(data->regmap, ISL12057_REG_RTC_SC, regs,
		ISL12057_RTC_SEC_LEN);
		mutex_unlock(&data->lock);

		if (ret)
		dev_err(dev, "%s: RTC write failed\n", __func__);

		return ret;
		}

		/*
		* Check current RTC status and enable/disable what needs to be. Return 0 if
		* everything went ok and a negative value upon error. Note: this function
		* is called early during init and hence does need mutex protection.
		*/
		static int isl12057_check_rtc_status(struct device dev, struct regmap regmap)
		{
		int ret;

		/* Enable oscillator if not already running */
		ret = regmap_update_bits(regmap, ISL12057_REG_INT,
		ISL12057_REG_INT_EOSC, 0);
		if (ret < 0) {
		dev_err(dev, "Unable to enable oscillator\n");
		return ret;
		}

		/* Clear oscillator failure bit if needed */
		ret = regmap_update_bits(regmap, ISL12057_REG_SR,
		ISL12057_REG_SR_OSF, 0);
		if (ret < 0) {
		dev_err(dev, "Unable to clear oscillator failure bit\n");
		return ret;
		}

		/* Clear alarm bit if needed */
		ret = regmap_update_bits(regmap, ISL12057_REG_SR,
		ISL12057_REG_SR_A1F, 0);
		if (ret < 0) {
		dev_err(dev, "Unable to clear alarm bit\n");
		return ret;
		}

		return 0;
		}

		static const struct rtc_class_ops rtc_ops = {
		.read_time = isl12057_rtc_read_time,
		.set_time = isl12057_rtc_set_time,
		};

		static struct regmap_config isl12057_rtc_regmap_config = {
		.reg_bits = 8,
		.val_bits = 8,
		};

		static int isl12057_probe(struct i2c_client *client,
		const struct i2c_device_id *id)
		{
		struct device *dev = &client->dev;
		struct isl12057_rtc_data *data;
		struct rtc_device *rtc;
		struct regmap *regmap;
		int ret;

		if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C \|
		I2C_FUNC_SMBUS_BYTE_DATA \|
		I2C_FUNC_SMBUS_I2C_BLOCK))
		return -ENODEV;

		regmap = devm_regmap_init_i2c(client, &isl12057_rtc_regmap_config);
		if (IS_ERR(regmap)) {
		ret = PTR_ERR(regmap);
		dev_err(dev, "regmap allocation failed: %d\n", ret);
		return ret;
		}

		ret = isl12057_i2c_validate_chip(regmap);
		if (ret)
		return ret;

		ret = isl12057_check_rtc_status(dev, regmap);
		if (ret)
		return ret;

		data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
		if (!data)
		return -ENOMEM;

		mutex_init(&data->lock);
		data->regmap = regmap;
		dev_set_drvdata(dev, data);

		rtc = devm_rtc_device_register(dev, DRV_NAME, &rtc_ops, THIS_MODULE);
		if (IS_ERR(rtc))
		return PTR_ERR(rtc);

		return 0;
		}

		#ifdef CONFIG_OF
		static struct of_device_id isl12057_dt_match[] = {
		{ .compatible = "isl,isl12057" },
		{ },
		};
		#endif

		static const struct i2c_device_id isl12057_id[] = {
		{ "isl12057", 0 },
		{ }
		};
		MODULE_DEVICE_TABLE(i2c, isl12057_id);

		static struct i2c_driver isl12057_driver = {
		.driver = {
		.name = DRV_NAME,
		.owner = THIS_MODULE,
		.of_match_table = of_match_ptr(isl12057_dt_match),
		},
		.probe = isl12057_probe,
		.id_table = isl12057_id,
		};
		module_i2c_driver(isl12057_driver);

		MODULE_AUTHOR("Arnaud EBALARD <arno@natisbad.org>");
		MODULE_DESCRIPTION("Intersil ISL12057 RTC driver");
		MODULE_LICENSE("GPL");

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