diff options
Diffstat (limited to 'drivers/rtc/rtc-m41t80.c')
| -rw-r--r-- | drivers/rtc/rtc-m41t80.c | 1016 |
1 files changed, 1016 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-m41t80.c b/drivers/rtc/rtc-m41t80.c new file mode 100644 index 000000000..8a89bc52b --- /dev/null +++ b/drivers/rtc/rtc-m41t80.c @@ -0,0 +1,1016 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * I2C client/driver for the ST M41T80 family of i2c rtc chips. + * + * Author: Alexander Bigga <ab@mycable.de> + * + * Based on m41t00.c by Mark A. Greer <mgreer@mvista.com> + * + * 2006 (c) mycable GmbH + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/bcd.h> +#include <linux/clk-provider.h> +#include <linux/i2c.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of_device.h> +#include <linux/rtc.h> +#include <linux/slab.h> +#include <linux/mutex.h> +#include <linux/string.h> +#ifdef CONFIG_RTC_DRV_M41T80_WDT +#include <linux/fs.h> +#include <linux/ioctl.h> +#include <linux/miscdevice.h> +#include <linux/reboot.h> +#include <linux/watchdog.h> +#endif + +#define M41T80_REG_SSEC 0x00 +#define M41T80_REG_SEC 0x01 +#define M41T80_REG_MIN 0x02 +#define M41T80_REG_HOUR 0x03 +#define M41T80_REG_WDAY 0x04 +#define M41T80_REG_DAY 0x05 +#define M41T80_REG_MON 0x06 +#define M41T80_REG_YEAR 0x07 +#define M41T80_REG_ALARM_MON 0x0a +#define M41T80_REG_ALARM_DAY 0x0b +#define M41T80_REG_ALARM_HOUR 0x0c +#define M41T80_REG_ALARM_MIN 0x0d +#define M41T80_REG_ALARM_SEC 0x0e +#define M41T80_REG_FLAGS 0x0f +#define M41T80_REG_SQW 0x13 + +#define M41T80_DATETIME_REG_SIZE (M41T80_REG_YEAR + 1) +#define M41T80_ALARM_REG_SIZE \ + (M41T80_REG_ALARM_SEC + 1 - M41T80_REG_ALARM_MON) + +#define M41T80_SQW_MAX_FREQ 32768 + +#define M41T80_SEC_ST BIT(7) /* ST: Stop Bit */ +#define M41T80_ALMON_AFE BIT(7) /* AFE: AF Enable Bit */ +#define M41T80_ALMON_SQWE BIT(6) /* SQWE: SQW Enable Bit */ +#define M41T80_ALHOUR_HT BIT(6) /* HT: Halt Update Bit */ +#define M41T80_FLAGS_OF BIT(2) /* OF: Oscillator Failure Bit */ +#define M41T80_FLAGS_AF BIT(6) /* AF: Alarm Flag Bit */ +#define M41T80_FLAGS_BATT_LOW BIT(4) /* BL: Battery Low Bit */ +#define M41T80_WATCHDOG_RB2 BIT(7) /* RB: Watchdog resolution */ +#define M41T80_WATCHDOG_RB1 BIT(1) /* RB: Watchdog resolution */ +#define M41T80_WATCHDOG_RB0 BIT(0) /* RB: Watchdog resolution */ + +#define M41T80_FEATURE_HT BIT(0) /* Halt feature */ +#define M41T80_FEATURE_BL BIT(1) /* Battery low indicator */ +#define M41T80_FEATURE_SQ BIT(2) /* Squarewave feature */ +#define M41T80_FEATURE_WD BIT(3) /* Extra watchdog resolution */ +#define M41T80_FEATURE_SQ_ALT BIT(4) /* RSx bits are in reg 4 */ + +static const struct i2c_device_id m41t80_id[] = { + { "m41t62", M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT }, + { "m41t65", M41T80_FEATURE_HT | M41T80_FEATURE_WD }, + { "m41t80", M41T80_FEATURE_SQ }, + { "m41t81", M41T80_FEATURE_HT | M41T80_FEATURE_SQ}, + { "m41t81s", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, + { "m41t82", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, + { "m41t83", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, + { "m41st84", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, + { "m41st85", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, + { "m41st87", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, + { "rv4162", M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT }, + { } +}; +MODULE_DEVICE_TABLE(i2c, m41t80_id); + +static const struct of_device_id m41t80_of_match[] = { + { + .compatible = "st,m41t62", + .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT) + }, + { + .compatible = "st,m41t65", + .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_WD) + }, + { + .compatible = "st,m41t80", + .data = (void *)(M41T80_FEATURE_SQ) + }, + { + .compatible = "st,m41t81", + .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_SQ) + }, + { + .compatible = "st,m41t81s", + .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ) + }, + { + .compatible = "st,m41t82", + .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ) + }, + { + .compatible = "st,m41t83", + .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ) + }, + { + .compatible = "st,m41t84", + .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ) + }, + { + .compatible = "st,m41t85", + .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ) + }, + { + .compatible = "st,m41t87", + .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ) + }, + { + .compatible = "microcrystal,rv4162", + .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT) + }, + /* DT compatibility only, do not use compatibles below: */ + { + .compatible = "st,rv4162", + .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT) + }, + { + .compatible = "rv4162", + .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT) + }, + { } +}; +MODULE_DEVICE_TABLE(of, m41t80_of_match); + +struct m41t80_data { + unsigned long features; + struct i2c_client *client; + struct rtc_device *rtc; +#ifdef CONFIG_COMMON_CLK + struct clk_hw sqw; + unsigned long freq; + unsigned int sqwe; +#endif +}; + +static irqreturn_t m41t80_handle_irq(int irq, void *dev_id) +{ + struct i2c_client *client = dev_id; + struct m41t80_data *m41t80 = i2c_get_clientdata(client); + struct mutex *lock = &m41t80->rtc->ops_lock; + unsigned long events = 0; + int flags, flags_afe; + + mutex_lock(lock); + + flags_afe = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); + if (flags_afe < 0) { + mutex_unlock(lock); + return IRQ_NONE; + } + + flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); + if (flags <= 0) { + mutex_unlock(lock); + return IRQ_NONE; + } + + if (flags & M41T80_FLAGS_AF) { + flags &= ~M41T80_FLAGS_AF; + flags_afe &= ~M41T80_ALMON_AFE; + events |= RTC_AF; + } + + if (events) { + rtc_update_irq(m41t80->rtc, 1, events); + i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS, flags); + i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, + flags_afe); + } + + mutex_unlock(lock); + + return IRQ_HANDLED; +} + +static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + struct i2c_client *client = to_i2c_client(dev); + unsigned char buf[8]; + int err, flags; + + flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); + if (flags < 0) + return flags; + + if (flags & M41T80_FLAGS_OF) { + dev_err(&client->dev, "Oscillator failure, data is invalid.\n"); + return -EINVAL; + } + + err = i2c_smbus_read_i2c_block_data(client, M41T80_REG_SSEC, + sizeof(buf), buf); + if (err < 0) { + dev_err(&client->dev, "Unable to read date\n"); + return err; + } + + tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f); + tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f); + tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f); + tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f); + tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07; + tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1; + + /* assume 20YY not 19YY, and ignore the Century Bit */ + tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100; + return 0; +} + +static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + struct i2c_client *client = to_i2c_client(dev); + struct m41t80_data *clientdata = i2c_get_clientdata(client); + unsigned char buf[8]; + int err, flags; + + buf[M41T80_REG_SSEC] = 0; + buf[M41T80_REG_SEC] = bin2bcd(tm->tm_sec); + buf[M41T80_REG_MIN] = bin2bcd(tm->tm_min); + buf[M41T80_REG_HOUR] = bin2bcd(tm->tm_hour); + buf[M41T80_REG_DAY] = bin2bcd(tm->tm_mday); + buf[M41T80_REG_MON] = bin2bcd(tm->tm_mon + 1); + buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year - 100); + buf[M41T80_REG_WDAY] = tm->tm_wday; + + /* If the square wave output is controlled in the weekday register */ + if (clientdata->features & M41T80_FEATURE_SQ_ALT) { + int val; + + val = i2c_smbus_read_byte_data(client, M41T80_REG_WDAY); + if (val < 0) + return val; + + buf[M41T80_REG_WDAY] |= (val & 0xf0); + } + + err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_SSEC, + sizeof(buf), buf); + if (err < 0) { + dev_err(&client->dev, "Unable to write to date registers\n"); + return err; + } + + /* Clear the OF bit of Flags Register */ + flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); + if (flags < 0) + return flags; + + err = i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS, + flags & ~M41T80_FLAGS_OF); + if (err < 0) { + dev_err(&client->dev, "Unable to write flags register\n"); + return err; + } + + return err; +} + +static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq) +{ + struct i2c_client *client = to_i2c_client(dev); + struct m41t80_data *clientdata = i2c_get_clientdata(client); + int reg; + + if (clientdata->features & M41T80_FEATURE_BL) { + reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); + if (reg < 0) + return reg; + seq_printf(seq, "battery\t\t: %s\n", + (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok"); + } + return 0; +} + +static int m41t80_alarm_irq_enable(struct device *dev, unsigned int enabled) +{ + struct i2c_client *client = to_i2c_client(dev); + int flags, retval; + + flags = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); + if (flags < 0) + return flags; + + if (enabled) + flags |= M41T80_ALMON_AFE; + else + flags &= ~M41T80_ALMON_AFE; + + retval = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, flags); + if (retval < 0) { + dev_err(dev, "Unable to enable alarm IRQ %d\n", retval); + return retval; + } + return 0; +} + +static int m41t80_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) +{ + struct i2c_client *client = to_i2c_client(dev); + u8 alarmvals[5]; + int ret, err; + + alarmvals[0] = bin2bcd(alrm->time.tm_mon + 1); + alarmvals[1] = bin2bcd(alrm->time.tm_mday); + alarmvals[2] = bin2bcd(alrm->time.tm_hour); + alarmvals[3] = bin2bcd(alrm->time.tm_min); + alarmvals[4] = bin2bcd(alrm->time.tm_sec); + + /* Clear AF and AFE flags */ + ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); + if (ret < 0) + return ret; + err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, + ret & ~(M41T80_ALMON_AFE)); + if (err < 0) { + dev_err(dev, "Unable to clear AFE bit\n"); + return err; + } + + /* Keep SQWE bit value */ + alarmvals[0] |= (ret & M41T80_ALMON_SQWE); + + ret = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); + if (ret < 0) + return ret; + + err = i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS, + ret & ~(M41T80_FLAGS_AF)); + if (err < 0) { + dev_err(dev, "Unable to clear AF bit\n"); + return err; + } + + /* Write the alarm */ + err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_ALARM_MON, + 5, alarmvals); + if (err) + return err; + + /* Enable the alarm interrupt */ + if (alrm->enabled) { + alarmvals[0] |= M41T80_ALMON_AFE; + err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, + alarmvals[0]); + if (err) + return err; + } + + return 0; +} + +static int m41t80_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) +{ + struct i2c_client *client = to_i2c_client(dev); + u8 alarmvals[5]; + int flags, ret; + + ret = i2c_smbus_read_i2c_block_data(client, M41T80_REG_ALARM_MON, + 5, alarmvals); + if (ret != 5) + return ret < 0 ? ret : -EIO; + + flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); + if (flags < 0) + return flags; + + alrm->time.tm_sec = bcd2bin(alarmvals[4] & 0x7f); + alrm->time.tm_min = bcd2bin(alarmvals[3] & 0x7f); + alrm->time.tm_hour = bcd2bin(alarmvals[2] & 0x3f); + alrm->time.tm_mday = bcd2bin(alarmvals[1] & 0x3f); + alrm->time.tm_mon = bcd2bin(alarmvals[0] & 0x3f) - 1; + + alrm->enabled = !!(alarmvals[0] & M41T80_ALMON_AFE); + alrm->pending = (flags & M41T80_FLAGS_AF) && alrm->enabled; + + return 0; +} + +static struct rtc_class_ops m41t80_rtc_ops = { + .read_time = m41t80_rtc_read_time, + .set_time = m41t80_rtc_set_time, + .proc = m41t80_rtc_proc, +}; + +#ifdef CONFIG_PM_SLEEP +static int m41t80_suspend(struct device *dev) +{ + struct i2c_client *client = to_i2c_client(dev); + + if (client->irq >= 0 && device_may_wakeup(dev)) + enable_irq_wake(client->irq); + + return 0; +} + +static int m41t80_resume(struct device *dev) +{ + struct i2c_client *client = to_i2c_client(dev); + + if (client->irq >= 0 && device_may_wakeup(dev)) + disable_irq_wake(client->irq); + + return 0; +} +#endif + +static SIMPLE_DEV_PM_OPS(m41t80_pm, m41t80_suspend, m41t80_resume); + +#ifdef CONFIG_COMMON_CLK +#define sqw_to_m41t80_data(_hw) container_of(_hw, struct m41t80_data, sqw) + +static unsigned long m41t80_decode_freq(int setting) +{ + return (setting == 0) ? 0 : (setting == 1) ? M41T80_SQW_MAX_FREQ : + M41T80_SQW_MAX_FREQ >> setting; +} + +static unsigned long m41t80_get_freq(struct m41t80_data *m41t80) +{ + struct i2c_client *client = m41t80->client; + int reg_sqw = (m41t80->features & M41T80_FEATURE_SQ_ALT) ? + M41T80_REG_WDAY : M41T80_REG_SQW; + int ret = i2c_smbus_read_byte_data(client, reg_sqw); + + if (ret < 0) + return 0; + return m41t80_decode_freq(ret >> 4); +} + +static unsigned long m41t80_sqw_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + return sqw_to_m41t80_data(hw)->freq; +} + +static long m41t80_sqw_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *prate) +{ + if (rate >= M41T80_SQW_MAX_FREQ) + return M41T80_SQW_MAX_FREQ; + if (rate >= M41T80_SQW_MAX_FREQ / 4) + return M41T80_SQW_MAX_FREQ / 4; + if (!rate) + return 0; + return 1 << ilog2(rate); +} + +static int m41t80_sqw_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct m41t80_data *m41t80 = sqw_to_m41t80_data(hw); + struct i2c_client *client = m41t80->client; + int reg_sqw = (m41t80->features & M41T80_FEATURE_SQ_ALT) ? + M41T80_REG_WDAY : M41T80_REG_SQW; + int reg, ret, val = 0; + + if (rate >= M41T80_SQW_MAX_FREQ) + val = 1; + else if (rate >= M41T80_SQW_MAX_FREQ / 4) + val = 2; + else if (rate) + val = 15 - ilog2(rate); + + reg = i2c_smbus_read_byte_data(client, reg_sqw); + if (reg < 0) + return reg; + + reg = (reg & 0x0f) | (val << 4); + + ret = i2c_smbus_write_byte_data(client, reg_sqw, reg); + if (!ret) + m41t80->freq = m41t80_decode_freq(val); + return ret; +} + +static int m41t80_sqw_control(struct clk_hw *hw, bool enable) +{ + struct m41t80_data *m41t80 = sqw_to_m41t80_data(hw); + struct i2c_client *client = m41t80->client; + int ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); + + if (ret < 0) + return ret; + + if (enable) + ret |= M41T80_ALMON_SQWE; + else + ret &= ~M41T80_ALMON_SQWE; + + ret = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, ret); + if (!ret) + m41t80->sqwe = enable; + return ret; +} + +static int m41t80_sqw_prepare(struct clk_hw *hw) +{ + return m41t80_sqw_control(hw, 1); +} + +static void m41t80_sqw_unprepare(struct clk_hw *hw) +{ + m41t80_sqw_control(hw, 0); +} + +static int m41t80_sqw_is_prepared(struct clk_hw *hw) +{ + return sqw_to_m41t80_data(hw)->sqwe; +} + +static const struct clk_ops m41t80_sqw_ops = { + .prepare = m41t80_sqw_prepare, + .unprepare = m41t80_sqw_unprepare, + .is_prepared = m41t80_sqw_is_prepared, + .recalc_rate = m41t80_sqw_recalc_rate, + .round_rate = m41t80_sqw_round_rate, + .set_rate = m41t80_sqw_set_rate, +}; + +static struct clk *m41t80_sqw_register_clk(struct m41t80_data *m41t80) +{ + struct i2c_client *client = m41t80->client; + struct device_node *node = client->dev.of_node; + struct clk *clk; + struct clk_init_data init; + int ret; + + /* First disable the clock */ + ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); + if (ret < 0) + return ERR_PTR(ret); + ret = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, + ret & ~(M41T80_ALMON_SQWE)); + if (ret < 0) + return ERR_PTR(ret); + + init.name = "m41t80-sqw"; + init.ops = &m41t80_sqw_ops; + init.flags = 0; + init.parent_names = NULL; + init.num_parents = 0; + m41t80->sqw.init = &init; + m41t80->freq = m41t80_get_freq(m41t80); + + /* optional override of the clockname */ + of_property_read_string(node, "clock-output-names", &init.name); + + /* register the clock */ + clk = clk_register(&client->dev, &m41t80->sqw); + if (!IS_ERR(clk)) + of_clk_add_provider(node, of_clk_src_simple_get, clk); + + return clk; +} +#endif + +#ifdef CONFIG_RTC_DRV_M41T80_WDT +/* + ***************************************************************************** + * + * Watchdog Driver + * + ***************************************************************************** + */ +static DEFINE_MUTEX(m41t80_rtc_mutex); +static struct i2c_client *save_client; + +/* Default margin */ +#define WD_TIMO 60 /* 1..31 seconds */ + +static int wdt_margin = WD_TIMO; +module_param(wdt_margin, int, 0); +MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)"); + +static unsigned long wdt_is_open; +static int boot_flag; + +/** + * wdt_ping: + * + * Reload counter one with the watchdog timeout. We don't bother reloading + * the cascade counter. + */ +static void wdt_ping(void) +{ + unsigned char i2c_data[2]; + struct i2c_msg msgs1[1] = { + { + .addr = save_client->addr, + .flags = 0, + .len = 2, + .buf = i2c_data, + }, + }; + struct m41t80_data *clientdata = i2c_get_clientdata(save_client); + + i2c_data[0] = 0x09; /* watchdog register */ + + if (wdt_margin > 31) + i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */ + else + /* + * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02) + */ + i2c_data[1] = wdt_margin << 2 | 0x82; + + /* + * M41T65 has three bits for watchdog resolution. Don't set bit 7, as + * that would be an invalid resolution. + */ + if (clientdata->features & M41T80_FEATURE_WD) + i2c_data[1] &= ~M41T80_WATCHDOG_RB2; + + i2c_transfer(save_client->adapter, msgs1, 1); +} + +/** + * wdt_disable: + * + * disables watchdog. + */ +static void wdt_disable(void) +{ + unsigned char i2c_data[2], i2c_buf[0x10]; + struct i2c_msg msgs0[2] = { + { + .addr = save_client->addr, + .flags = 0, + .len = 1, + .buf = i2c_data, + }, + { + .addr = save_client->addr, + .flags = I2C_M_RD, + .len = 1, + .buf = i2c_buf, + }, + }; + struct i2c_msg msgs1[1] = { + { + .addr = save_client->addr, + .flags = 0, + .len = 2, + .buf = i2c_data, + }, + }; + + i2c_data[0] = 0x09; + i2c_transfer(save_client->adapter, msgs0, 2); + + i2c_data[0] = 0x09; + i2c_data[1] = 0x00; + i2c_transfer(save_client->adapter, msgs1, 1); +} + +/** + * wdt_write: + * @file: file handle to the watchdog + * @buf: buffer to write (unused as data does not matter here + * @count: count of bytes + * @ppos: pointer to the position to write. No seeks allowed + * + * A write to a watchdog device is defined as a keepalive signal. Any + * write of data will do, as we we don't define content meaning. + */ +static ssize_t wdt_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + if (count) { + wdt_ping(); + return 1; + } + return 0; +} + +static ssize_t wdt_read(struct file *file, char __user *buf, + size_t count, loff_t *ppos) +{ + return 0; +} + +/** + * wdt_ioctl: + * @file: file handle to the device + * @cmd: watchdog command + * @arg: argument pointer + * + * The watchdog API defines a common set of functions for all watchdogs + * according to their available features. We only actually usefully support + * querying capabilities and current status. + */ +static int wdt_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + int new_margin, rv; + static struct watchdog_info ident = { + .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING | + WDIOF_SETTIMEOUT, + .firmware_version = 1, + .identity = "M41T80 WTD" + }; + + switch (cmd) { + case WDIOC_GETSUPPORT: + return copy_to_user((struct watchdog_info __user *)arg, &ident, + sizeof(ident)) ? -EFAULT : 0; + + case WDIOC_GETSTATUS: + case WDIOC_GETBOOTSTATUS: + return put_user(boot_flag, (int __user *)arg); + case WDIOC_KEEPALIVE: + wdt_ping(); + return 0; + case WDIOC_SETTIMEOUT: + if (get_user(new_margin, (int __user *)arg)) + return -EFAULT; + /* Arbitrary, can't find the card's limits */ + if (new_margin < 1 || new_margin > 124) + return -EINVAL; + wdt_margin = new_margin; + wdt_ping(); + fallthrough; + case WDIOC_GETTIMEOUT: + return put_user(wdt_margin, (int __user *)arg); + + case WDIOC_SETOPTIONS: + if (copy_from_user(&rv, (int __user *)arg, sizeof(int))) + return -EFAULT; + + if (rv & WDIOS_DISABLECARD) { + pr_info("disable watchdog\n"); + wdt_disable(); + } + + if (rv & WDIOS_ENABLECARD) { + pr_info("enable watchdog\n"); + wdt_ping(); + } + + return -EINVAL; + } + return -ENOTTY; +} + +static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + int ret; + + mutex_lock(&m41t80_rtc_mutex); + ret = wdt_ioctl(file, cmd, arg); + mutex_unlock(&m41t80_rtc_mutex); + + return ret; +} + +/** + * wdt_open: + * @inode: inode of device + * @file: file handle to device + * + */ +static int wdt_open(struct inode *inode, struct file *file) +{ + if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) { + mutex_lock(&m41t80_rtc_mutex); + if (test_and_set_bit(0, &wdt_is_open)) { + mutex_unlock(&m41t80_rtc_mutex); + return -EBUSY; + } + /* + * Activate + */ + wdt_is_open = 1; + mutex_unlock(&m41t80_rtc_mutex); + return stream_open(inode, file); + } + return -ENODEV; +} + +/** + * wdt_close: + * @inode: inode to board + * @file: file handle to board + * + */ +static int wdt_release(struct inode *inode, struct file *file) +{ + if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) + clear_bit(0, &wdt_is_open); + return 0; +} + +/** + * notify_sys: + * @this: our notifier block + * @code: the event being reported + * @unused: unused + * + * Our notifier is called on system shutdowns. We want to turn the card + * off at reboot otherwise the machine will reboot again during memory + * test or worse yet during the following fsck. This would suck, in fact + * trust me - if it happens it does suck. + */ +static int wdt_notify_sys(struct notifier_block *this, unsigned long code, + void *unused) +{ + if (code == SYS_DOWN || code == SYS_HALT) + /* Disable Watchdog */ + wdt_disable(); + return NOTIFY_DONE; +} + +static const struct file_operations wdt_fops = { + .owner = THIS_MODULE, + .read = wdt_read, + .unlocked_ioctl = wdt_unlocked_ioctl, + .compat_ioctl = compat_ptr_ioctl, + .write = wdt_write, + .open = wdt_open, + .release = wdt_release, + .llseek = no_llseek, +}; + +static struct miscdevice wdt_dev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &wdt_fops, +}; + +/* + * The WDT card needs to learn about soft shutdowns in order to + * turn the timebomb registers off. + */ +static struct notifier_block wdt_notifier = { + .notifier_call = wdt_notify_sys, +}; +#endif /* CONFIG_RTC_DRV_M41T80_WDT */ + +/* + ***************************************************************************** + * + * Driver Interface + * + ***************************************************************************** + */ + +static int m41t80_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct i2c_adapter *adapter = client->adapter; + int rc = 0; + struct rtc_time tm; + struct m41t80_data *m41t80_data = NULL; + bool wakeup_source = false; + + if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK | + I2C_FUNC_SMBUS_BYTE_DATA)) { + dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n"); + return -ENODEV; + } + + m41t80_data = devm_kzalloc(&client->dev, sizeof(*m41t80_data), + GFP_KERNEL); + if (!m41t80_data) + return -ENOMEM; + + m41t80_data->client = client; + if (client->dev.of_node) + m41t80_data->features = (unsigned long) + of_device_get_match_data(&client->dev); + else + m41t80_data->features = id->driver_data; + i2c_set_clientdata(client, m41t80_data); + + m41t80_data->rtc = devm_rtc_allocate_device(&client->dev); + if (IS_ERR(m41t80_data->rtc)) + return PTR_ERR(m41t80_data->rtc); + +#ifdef CONFIG_OF + wakeup_source = of_property_read_bool(client->dev.of_node, + "wakeup-source"); +#endif + if (client->irq > 0) { + rc = devm_request_threaded_irq(&client->dev, client->irq, + NULL, m41t80_handle_irq, + IRQF_TRIGGER_LOW | IRQF_ONESHOT, + "m41t80", client); + if (rc) { + dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n"); + client->irq = 0; + wakeup_source = false; + } + } + if (client->irq > 0 || wakeup_source) { + m41t80_rtc_ops.read_alarm = m41t80_read_alarm; + m41t80_rtc_ops.set_alarm = m41t80_set_alarm; + m41t80_rtc_ops.alarm_irq_enable = m41t80_alarm_irq_enable; + /* Enable the wakealarm */ + device_init_wakeup(&client->dev, true); + } + + m41t80_data->rtc->ops = &m41t80_rtc_ops; + m41t80_data->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000; + m41t80_data->rtc->range_max = RTC_TIMESTAMP_END_2099; + + if (client->irq <= 0) { + /* We cannot support UIE mode if we do not have an IRQ line */ + m41t80_data->rtc->uie_unsupported = 1; + } + + /* Make sure HT (Halt Update) bit is cleared */ + rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR); + + if (rc >= 0 && rc & M41T80_ALHOUR_HT) { + if (m41t80_data->features & M41T80_FEATURE_HT) { + m41t80_rtc_read_time(&client->dev, &tm); + dev_info(&client->dev, "HT bit was set!\n"); + dev_info(&client->dev, "Power Down at %ptR\n", &tm); + } + rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_HOUR, + rc & ~M41T80_ALHOUR_HT); + } + + if (rc < 0) { + dev_err(&client->dev, "Can't clear HT bit\n"); + return rc; + } + + /* Make sure ST (stop) bit is cleared */ + rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC); + + if (rc >= 0 && rc & M41T80_SEC_ST) + rc = i2c_smbus_write_byte_data(client, M41T80_REG_SEC, + rc & ~M41T80_SEC_ST); + if (rc < 0) { + dev_err(&client->dev, "Can't clear ST bit\n"); + return rc; + } + +#ifdef CONFIG_RTC_DRV_M41T80_WDT + if (m41t80_data->features & M41T80_FEATURE_HT) { + save_client = client; + rc = misc_register(&wdt_dev); + if (rc) + return rc; + rc = register_reboot_notifier(&wdt_notifier); + if (rc) { + misc_deregister(&wdt_dev); + return rc; + } + } +#endif +#ifdef CONFIG_COMMON_CLK + if (m41t80_data->features & M41T80_FEATURE_SQ) + m41t80_sqw_register_clk(m41t80_data); +#endif + + rc = rtc_register_device(m41t80_data->rtc); + if (rc) + return rc; + + return 0; +} + +static int m41t80_remove(struct i2c_client *client) +{ +#ifdef CONFIG_RTC_DRV_M41T80_WDT + struct m41t80_data *clientdata = i2c_get_clientdata(client); + + if (clientdata->features & M41T80_FEATURE_HT) { + misc_deregister(&wdt_dev); + unregister_reboot_notifier(&wdt_notifier); + } +#endif + + return 0; +} + +static struct i2c_driver m41t80_driver = { + .driver = { + .name = "rtc-m41t80", + .of_match_table = of_match_ptr(m41t80_of_match), + .pm = &m41t80_pm, + }, + .probe = m41t80_probe, + .remove = m41t80_remove, + .id_table = m41t80_id, +}; + +module_i2c_driver(m41t80_driver); + +MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>"); +MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver"); +MODULE_LICENSE("GPL"); |