From 4d61ff6b9960cb00cf2c12abd5769aa2dd475415 Mon Sep 17 00:00:00 2001 From: Philippe De Muyter Date: Tue, 5 May 2015 16:23:44 -0700 Subject: rtc: add rtc-abx80x, a driver for the Abracon AB x80x i2c rtc This is a basic driver for the ultra-low-power Abracon AB x80x series of RTC chips. It supports in particular, the supersets AB0805 and AB1805. It allows reading and writing the time, and enables the supercapacitor/ battery charger. [arnd@arndb.de: abx805 depends on i2c] [alexandre.belloni@free-electrons.com: renam buffer from date to buf in abx80x_rtc_read_time()] Signed-off-by: Philippe De Muyter Cc: Alessandro Zummo Signed-off-by: Alexandre Belloni Signed-off-by: Arnd Bergmann Cc: Paul Bolle Cc: Arnd Bergmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/rtc/Kconfig | 10 ++ drivers/rtc/Makefile | 1 + drivers/rtc/rtc-abx80x.c | 307 +++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 318 insertions(+) create mode 100644 drivers/rtc/rtc-abx80x.c (limited to 'drivers/rtc') diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig index 6149ae01e11f..0fe4ad8826b2 100644 --- a/drivers/rtc/Kconfig +++ b/drivers/rtc/Kconfig @@ -164,6 +164,16 @@ config RTC_DRV_ABB5ZES3 This driver can also be built as a module. If so, the module will be called rtc-ab-b5ze-s3. +config RTC_DRV_ABX80X + tristate "Abracon ABx80x" + help + If you say yes here you get support for Abracon AB080X and AB180X + families of ultra-low-power battery- and capacitor-backed real-time + clock chips. + + This driver can also be built as a module. If so, the module + will be called rtc-abx80x. + config RTC_DRV_AS3722 tristate "ams AS3722 RTC driver" depends on MFD_AS3722 diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile index c31731c29762..2b82e2b0311b 100644 --- a/drivers/rtc/Makefile +++ b/drivers/rtc/Makefile @@ -25,6 +25,7 @@ obj-$(CONFIG_RTC_DRV_88PM80X) += rtc-88pm80x.o obj-$(CONFIG_RTC_DRV_AB3100) += rtc-ab3100.o obj-$(CONFIG_RTC_DRV_AB8500) += rtc-ab8500.o obj-$(CONFIG_RTC_DRV_ABB5ZES3) += rtc-ab-b5ze-s3.o +obj-$(CONFIG_RTC_DRV_ABX80X) += rtc-abx80x.o obj-$(CONFIG_RTC_DRV_ARMADA38X) += rtc-armada38x.o obj-$(CONFIG_RTC_DRV_AS3722) += rtc-as3722.o obj-$(CONFIG_RTC_DRV_AT32AP700X)+= rtc-at32ap700x.o diff --git a/drivers/rtc/rtc-abx80x.c b/drivers/rtc/rtc-abx80x.c new file mode 100644 index 000000000000..4337c3bc6ace --- /dev/null +++ b/drivers/rtc/rtc-abx80x.c @@ -0,0 +1,307 @@ +/* + * A driver for the I2C members of the Abracon AB x8xx RTC family, + * and compatible: AB 1805 and AB 0805 + * + * Copyright 2014-2015 Macq S.A. + * + * Author: Philippe De Muyter + * Author: Alexandre Belloni + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + */ + +#include +#include +#include +#include + +#define ABX8XX_REG_HTH 0x00 +#define ABX8XX_REG_SC 0x01 +#define ABX8XX_REG_MN 0x02 +#define ABX8XX_REG_HR 0x03 +#define ABX8XX_REG_DA 0x04 +#define ABX8XX_REG_MO 0x05 +#define ABX8XX_REG_YR 0x06 +#define ABX8XX_REG_WD 0x07 + +#define ABX8XX_REG_CTRL1 0x10 +#define ABX8XX_CTRL_WRITE BIT(1) +#define ABX8XX_CTRL_12_24 BIT(6) + +#define ABX8XX_REG_CFG_KEY 0x1f +#define ABX8XX_CFG_KEY_MISC 0x9d + +#define ABX8XX_REG_ID0 0x28 + +#define ABX8XX_REG_TRICKLE 0x20 +#define ABX8XX_TRICKLE_CHARGE_ENABLE 0xa0 +#define ABX8XX_TRICKLE_STANDARD_DIODE 0x8 +#define ABX8XX_TRICKLE_SCHOTTKY_DIODE 0x4 + +static u8 trickle_resistors[] = {0, 3, 6, 11}; + +enum abx80x_chip {AB0801, AB0803, AB0804, AB0805, + AB1801, AB1803, AB1804, AB1805, ABX80X}; + +struct abx80x_cap { + u16 pn; + bool has_tc; +}; + +static struct abx80x_cap abx80x_caps[] = { + [AB0801] = {.pn = 0x0801}, + [AB0803] = {.pn = 0x0803}, + [AB0804] = {.pn = 0x0804, .has_tc = true}, + [AB0805] = {.pn = 0x0805, .has_tc = true}, + [AB1801] = {.pn = 0x1801}, + [AB1803] = {.pn = 0x1803}, + [AB1804] = {.pn = 0x1804, .has_tc = true}, + [AB1805] = {.pn = 0x1805, .has_tc = true}, + [ABX80X] = {.pn = 0} +}; + +static struct i2c_driver abx80x_driver; + +static int abx80x_enable_trickle_charger(struct i2c_client *client, + u8 trickle_cfg) +{ + int err; + + /* + * Write the configuration key register to enable access to the Trickle + * register + */ + err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CFG_KEY, + ABX8XX_CFG_KEY_MISC); + if (err < 0) { + dev_err(&client->dev, "Unable to write configuration key\n"); + return -EIO; + } + + err = i2c_smbus_write_byte_data(client, ABX8XX_REG_TRICKLE, + ABX8XX_TRICKLE_CHARGE_ENABLE | + trickle_cfg); + if (err < 0) { + dev_err(&client->dev, "Unable to write trickle register\n"); + return -EIO; + } + + return 0; +} + +static int abx80x_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + struct i2c_client *client = to_i2c_client(dev); + unsigned char buf[8]; + int err; + + err = i2c_smbus_read_i2c_block_data(client, ABX8XX_REG_HTH, + sizeof(buf), buf); + if (err < 0) { + dev_err(&client->dev, "Unable to read date\n"); + return -EIO; + } + + tm->tm_sec = bcd2bin(buf[ABX8XX_REG_SC] & 0x7F); + tm->tm_min = bcd2bin(buf[ABX8XX_REG_MN] & 0x7F); + tm->tm_hour = bcd2bin(buf[ABX8XX_REG_HR] & 0x3F); + tm->tm_wday = buf[ABX8XX_REG_WD] & 0x7; + tm->tm_mday = bcd2bin(buf[ABX8XX_REG_DA] & 0x3F); + tm->tm_mon = bcd2bin(buf[ABX8XX_REG_MO] & 0x1F) - 1; + tm->tm_year = bcd2bin(buf[ABX8XX_REG_YR]) + 100; + + err = rtc_valid_tm(tm); + if (err < 0) + dev_err(&client->dev, "retrieved date/time is not valid.\n"); + + return err; +} + +static int abx80x_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + struct i2c_client *client = to_i2c_client(dev); + unsigned char buf[8]; + int err; + + if (tm->tm_year < 100) + return -EINVAL; + + buf[ABX8XX_REG_HTH] = 0; + buf[ABX8XX_REG_SC] = bin2bcd(tm->tm_sec); + buf[ABX8XX_REG_MN] = bin2bcd(tm->tm_min); + buf[ABX8XX_REG_HR] = bin2bcd(tm->tm_hour); + buf[ABX8XX_REG_DA] = bin2bcd(tm->tm_mday); + buf[ABX8XX_REG_MO] = bin2bcd(tm->tm_mon + 1); + buf[ABX8XX_REG_YR] = bin2bcd(tm->tm_year - 100); + buf[ABX8XX_REG_WD] = tm->tm_wday; + + err = i2c_smbus_write_i2c_block_data(client, ABX8XX_REG_HTH, + sizeof(buf), buf); + if (err < 0) { + dev_err(&client->dev, "Unable to write to date registers\n"); + return -EIO; + } + + return 0; +} + +static const struct rtc_class_ops abx80x_rtc_ops = { + .read_time = abx80x_rtc_read_time, + .set_time = abx80x_rtc_set_time, +}; + +static int abx80x_dt_trickle_cfg(struct device_node *np) +{ + const char *diode; + int trickle_cfg = 0; + int i, ret; + u32 tmp; + + ret = of_property_read_string(np, "abracon,tc-diode", &diode); + if (ret) + return ret; + + if (!strcmp(diode, "standard")) + trickle_cfg |= ABX8XX_TRICKLE_STANDARD_DIODE; + else if (!strcmp(diode, "schottky")) + trickle_cfg |= ABX8XX_TRICKLE_SCHOTTKY_DIODE; + else + return -EINVAL; + + ret = of_property_read_u32(np, "abracon,tc-resistor", &tmp); + if (ret) + return ret; + + for (i = 0; i < sizeof(trickle_resistors); i++) + if (trickle_resistors[i] == tmp) + break; + + if (i == sizeof(trickle_resistors)) + return -EINVAL; + + return (trickle_cfg | i); +} + +static int abx80x_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct device_node *np = client->dev.of_node; + struct rtc_device *rtc; + int i, data, err, trickle_cfg = -EINVAL; + char buf[7]; + unsigned int part = id->driver_data; + unsigned int partnumber; + unsigned int majrev, minrev; + unsigned int lot; + unsigned int wafer; + unsigned int uid; + + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) + return -ENODEV; + + err = i2c_smbus_read_i2c_block_data(client, ABX8XX_REG_ID0, + sizeof(buf), buf); + if (err < 0) { + dev_err(&client->dev, "Unable to read partnumber\n"); + return -EIO; + } + + partnumber = (buf[0] << 8) | buf[1]; + majrev = buf[2] >> 3; + minrev = buf[2] & 0x7; + lot = ((buf[4] & 0x80) << 2) | ((buf[6] & 0x80) << 1) | buf[3]; + uid = ((buf[4] & 0x7f) << 8) | buf[5]; + wafer = (buf[6] & 0x7c) >> 2; + dev_info(&client->dev, "model %04x, revision %u.%u, lot %x, wafer %x, uid %x\n", + partnumber, majrev, minrev, lot, wafer, uid); + + data = i2c_smbus_read_byte_data(client, ABX8XX_REG_CTRL1); + if (data < 0) { + dev_err(&client->dev, "Unable to read control register\n"); + return -EIO; + } + + err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CTRL1, + ((data & ~ABX8XX_CTRL_12_24) | + ABX8XX_CTRL_WRITE)); + if (err < 0) { + dev_err(&client->dev, "Unable to write control register\n"); + return -EIO; + } + + /* part autodetection */ + if (part == ABX80X) { + for (i = 0; abx80x_caps[i].pn; i++) + if (partnumber == abx80x_caps[i].pn) + break; + if (abx80x_caps[i].pn == 0) { + dev_err(&client->dev, "Unknown part: %04x\n", + partnumber); + return -EINVAL; + } + part = i; + } + + if (partnumber != abx80x_caps[part].pn) { + dev_err(&client->dev, "partnumber mismatch %04x != %04x\n", + partnumber, abx80x_caps[part].pn); + return -EINVAL; + } + + if (np && abx80x_caps[part].has_tc) + trickle_cfg = abx80x_dt_trickle_cfg(np); + + if (trickle_cfg > 0) { + dev_info(&client->dev, "Enabling trickle charger: %02x\n", + trickle_cfg); + abx80x_enable_trickle_charger(client, trickle_cfg); + } + + rtc = devm_rtc_device_register(&client->dev, abx80x_driver.driver.name, + &abx80x_rtc_ops, THIS_MODULE); + + if (IS_ERR(rtc)) + return PTR_ERR(rtc); + + i2c_set_clientdata(client, rtc); + + return 0; +} + +static int abx80x_remove(struct i2c_client *client) +{ + return 0; +} + +static const struct i2c_device_id abx80x_id[] = { + { "abx80x", ABX80X }, + { "ab0801", AB0801 }, + { "ab0803", AB0803 }, + { "ab0804", AB0804 }, + { "ab0805", AB0805 }, + { "ab1801", AB1801 }, + { "ab1803", AB1803 }, + { "ab1804", AB1804 }, + { "ab1805", AB1805 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, abx80x_id); + +static struct i2c_driver abx80x_driver = { + .driver = { + .name = "rtc-abx80x", + }, + .probe = abx80x_probe, + .remove = abx80x_remove, + .id_table = abx80x_id, +}; + +module_i2c_driver(abx80x_driver); + +MODULE_AUTHOR("Philippe De Muyter "); +MODULE_AUTHOR("Alexandre Belloni "); +MODULE_DESCRIPTION("Abracon ABX80X RTC driver"); +MODULE_LICENSE("GPL v2"); -- cgit v1.2.3-55-g7522 From 489405fe5ed38e65f6f82f131a39c67f3bae6045 Mon Sep 17 00:00:00 2001 From: Gregory CLEMENT Date: Tue, 5 May 2015 16:24:05 -0700 Subject: rtc: armada38x: fix concurrency access in armada38x_rtc_set_time While setting the time, the RTC TIME register should not be accessed. However due to hardware constraints, setting the RTC time involves sleeping during 100ms. This sleep was done outside the critical section protected by the spinlock, so it was possible to read the RTC TIME register and get an incorrect value. This patch introduces a mutex for protecting the RTC TIME access, unlike the spinlock it is allowed to sleep in a critical section protected by a mutex. The RTC STATUS register can still be used from the interrupt handler but it has no effect on setting the time. Signed-off-by: Gregory CLEMENT Acked-by: Alexandre Belloni Acked-by: Andrew Lunn Cc: Alessandro Zummo Cc: [4.0] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/rtc/rtc-armada38x.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) (limited to 'drivers/rtc') diff --git a/drivers/rtc/rtc-armada38x.c b/drivers/rtc/rtc-armada38x.c index 43e04af39e09..cb70ced7e0db 100644 --- a/drivers/rtc/rtc-armada38x.c +++ b/drivers/rtc/rtc-armada38x.c @@ -40,6 +40,13 @@ struct armada38x_rtc { void __iomem *regs; void __iomem *regs_soc; spinlock_t lock; + /* + * While setting the time, the RTC TIME register should not be + * accessed. Setting the RTC time involves sleeping during + * 100ms, so a mutex instead of a spinlock is used to protect + * it + */ + struct mutex mutex_time; int irq; }; @@ -59,8 +66,7 @@ static int armada38x_rtc_read_time(struct device *dev, struct rtc_time *tm) struct armada38x_rtc *rtc = dev_get_drvdata(dev); unsigned long time, time_check, flags; - spin_lock_irqsave(&rtc->lock, flags); - + mutex_lock(&rtc->mutex_time); time = readl(rtc->regs + RTC_TIME); /* * WA for failing time set attempts. As stated in HW ERRATA if @@ -71,7 +77,7 @@ static int armada38x_rtc_read_time(struct device *dev, struct rtc_time *tm) if ((time_check - time) > 1) time_check = readl(rtc->regs + RTC_TIME); - spin_unlock_irqrestore(&rtc->lock, flags); + mutex_unlock(&rtc->mutex_time); rtc_time_to_tm(time_check, tm); @@ -94,19 +100,12 @@ static int armada38x_rtc_set_time(struct device *dev, struct rtc_time *tm) * then wait for 100ms before writing to the time register to be * sure that the data will be taken into account. */ - spin_lock_irqsave(&rtc->lock, flags); - + mutex_lock(&rtc->mutex_time); rtc_delayed_write(0, rtc, RTC_STATUS); - - spin_unlock_irqrestore(&rtc->lock, flags); - msleep(100); - - spin_lock_irqsave(&rtc->lock, flags); - rtc_delayed_write(time, rtc, RTC_TIME); + mutex_unlock(&rtc->mutex_time); - spin_unlock_irqrestore(&rtc->lock, flags); out: return ret; } @@ -230,6 +229,7 @@ static __init int armada38x_rtc_probe(struct platform_device *pdev) return -ENOMEM; spin_lock_init(&rtc->lock); + mutex_init(&rtc->mutex_time); res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rtc"); rtc->regs = devm_ioremap_resource(&pdev->dev, res); -- cgit v1.2.3-55-g7522 From f98b733e93e00365b4df78fbb33c2cad3080f6bb Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Thu, 14 May 2015 15:16:50 -0700 Subject: drivers/rtc/rtc-armada38x.c: remove unused local `flags' Reported-by: Fengguang Wu Cc: Gregory CLEMENT Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/rtc/rtc-armada38x.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/rtc') diff --git a/drivers/rtc/rtc-armada38x.c b/drivers/rtc/rtc-armada38x.c index cb70ced7e0db..4b62d1a875e4 100644 --- a/drivers/rtc/rtc-armada38x.c +++ b/drivers/rtc/rtc-armada38x.c @@ -64,7 +64,7 @@ static void rtc_delayed_write(u32 val, struct armada38x_rtc *rtc, int offset) static int armada38x_rtc_read_time(struct device *dev, struct rtc_time *tm) { struct armada38x_rtc *rtc = dev_get_drvdata(dev); - unsigned long time, time_check, flags; + unsigned long time, time_check; mutex_lock(&rtc->mutex_time); time = readl(rtc->regs + RTC_TIME); -- cgit v1.2.3-55-g7522