rtc: Add a driver for Micro Crystal RV8803
authorAlexandre Belloni <alexandre.belloni@free-electrons.com>
Mon, 2 Nov 2015 22:48:32 +0000 (23:48 +0100)
committerAlexandre Belloni <alexandre.belloni@free-electrons.com>
Sun, 8 Nov 2015 13:12:32 +0000 (14:12 +0100)
This driver supports the following functions:
 - reading and settings time
 - alarms when connected to an IRQ
 - reading and clearing the voltage low flags
 - nvram

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
drivers/rtc/Kconfig
drivers/rtc/Makefile
drivers/rtc/rtc-rv8803.c [new file with mode: 0644]

index 57c2dbc4f438a9c18b32df68bece3fa467c374e6..2a524244afec1d563f18cb8ccfb1b694c5ceb52e 100644 (file)
@@ -593,6 +593,15 @@ config RTC_DRV_RV3029C2
          This driver can also be built as a module. If so, the module
          will be called rtc-rv3029c2.
 
+config RTC_DRV_RV8803
+       tristate "Micro Crystal RV8803"
+       help
+         If you say yes here you get support for the Micro Crystal
+         RV8803 RTC chips.
+
+         This driver can also be built as a module. If so, the module
+         will be called rtc-rv8803.
+
 config RTC_DRV_S5M
        tristate "Samsung S2M/S5M series"
        depends on MFD_SEC_CORE
index e491eb524434220a09b766ba39cd369521b26244..231f7645161504c6022684e27d7235637a852884 100644 (file)
@@ -126,6 +126,7 @@ obj-$(CONFIG_RTC_DRV_RS5C313)       += rtc-rs5c313.o
 obj-$(CONFIG_RTC_DRV_RS5C348)  += rtc-rs5c348.o
 obj-$(CONFIG_RTC_DRV_RS5C372)  += rtc-rs5c372.o
 obj-$(CONFIG_RTC_DRV_RV3029C2) += rtc-rv3029c2.o
+obj-$(CONFIG_RTC_DRV_RV8803)   += rtc-rv8803.o
 obj-$(CONFIG_RTC_DRV_RX4581)   += rtc-rx4581.o
 obj-$(CONFIG_RTC_DRV_RX8025)   += rtc-rx8025.o
 obj-$(CONFIG_RTC_DRV_RX8581)   += rtc-rx8581.o
diff --git a/drivers/rtc/rtc-rv8803.c b/drivers/rtc/rtc-rv8803.c
new file mode 100644 (file)
index 0000000..e7329e2
--- /dev/null
@@ -0,0 +1,521 @@
+/*
+ * RTC driver for the Micro Crystal RV8803
+ *
+ * Copyright (C) 2015 Micro Crystal SA
+ *
+ * Alexandre Belloni <alexandre.belloni@free-electrons.com>
+ *
+ * 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 <linux/bcd.h>
+#include <linux/bitops.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/rtc.h>
+
+#define RV8803_SEC                     0x00
+#define RV8803_MIN                     0x01
+#define RV8803_HOUR                    0x02
+#define RV8803_WEEK                    0x03
+#define RV8803_DAY                     0x04
+#define RV8803_MONTH                   0x05
+#define RV8803_YEAR                    0x06
+#define RV8803_RAM                     0x07
+#define RV8803_ALARM_MIN               0x08
+#define RV8803_ALARM_HOUR              0x09
+#define RV8803_ALARM_WEEK_OR_DAY       0x0A
+#define RV8803_EXT                     0x0D
+#define RV8803_FLAG                    0x0E
+#define RV8803_CTRL                    0x0F
+
+#define RV8803_EXT_WADA                        BIT(6)
+
+#define RV8803_FLAG_V1F                        BIT(0)
+#define RV8803_FLAG_V2F                        BIT(1)
+#define RV8803_FLAG_AF                 BIT(3)
+#define RV8803_FLAG_TF                 BIT(4)
+#define RV8803_FLAG_UF                 BIT(5)
+
+#define RV8803_CTRL_RESET              BIT(0)
+
+#define RV8803_CTRL_EIE                        BIT(2)
+#define RV8803_CTRL_AIE                        BIT(3)
+#define RV8803_CTRL_TIE                        BIT(4)
+#define RV8803_CTRL_UIE                        BIT(5)
+
+struct rv8803_data {
+       struct i2c_client *client;
+       struct rtc_device *rtc;
+       spinlock_t flags_lock;
+       u8 ctrl;
+};
+
+static irqreturn_t rv8803_handle_irq(int irq, void *dev_id)
+{
+       struct i2c_client *client = dev_id;
+       struct rv8803_data *rv8803 = i2c_get_clientdata(client);
+       unsigned long events = 0;
+       u8 flags;
+
+       spin_lock(&rv8803->flags_lock);
+
+       flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
+       if (flags <= 0) {
+               spin_unlock(&rv8803->flags_lock);
+               return IRQ_NONE;
+       }
+
+       if (flags & RV8803_FLAG_V1F)
+               dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
+
+       if (flags & RV8803_FLAG_V2F)
+               dev_warn(&client->dev, "Voltage low, data loss detected.\n");
+
+       if (flags & RV8803_FLAG_TF) {
+               flags &= ~RV8803_FLAG_TF;
+               rv8803->ctrl &= ~RV8803_CTRL_TIE;
+               events |= RTC_PF;
+       }
+
+       if (flags & RV8803_FLAG_AF) {
+               flags &= ~RV8803_FLAG_AF;
+               rv8803->ctrl &= ~RV8803_CTRL_AIE;
+               events |= RTC_AF;
+       }
+
+       if (flags & RV8803_FLAG_UF) {
+               flags &= ~RV8803_FLAG_UF;
+               rv8803->ctrl &= ~RV8803_CTRL_UIE;
+               events |= RTC_UF;
+       }
+
+       if (events) {
+               rtc_update_irq(rv8803->rtc, 1, events);
+               i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
+               i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL,
+                                         rv8803->ctrl);
+       }
+
+       spin_unlock(&rv8803->flags_lock);
+
+       return IRQ_HANDLED;
+}
+
+static int rv8803_get_time(struct device *dev, struct rtc_time *tm)
+{
+       struct rv8803_data *rv8803 = dev_get_drvdata(dev);
+       u8 date1[7];
+       u8 date2[7];
+       u8 *date = date1;
+       int ret, flags;
+
+       flags = i2c_smbus_read_byte_data(rv8803->client, RV8803_FLAG);
+       if (flags < 0)
+               return flags;
+
+       if (flags & RV8803_FLAG_V2F) {
+               dev_warn(dev, "Voltage low, data is invalid.\n");
+               return -EINVAL;
+       }
+
+       ret = i2c_smbus_read_i2c_block_data(rv8803->client, RV8803_SEC,
+                                           7, date);
+       if (ret != 7)
+               return ret < 0 ? ret : -EIO;
+
+       if ((date1[RV8803_SEC] & 0x7f) == bin2bcd(59)) {
+               ret = i2c_smbus_read_i2c_block_data(rv8803->client, RV8803_SEC,
+                                                   7, date2);
+               if (ret != 7)
+                       return ret < 0 ? ret : -EIO;
+
+               if ((date2[RV8803_SEC] & 0x7f) != bin2bcd(59))
+                       date = date2;
+       }
+
+       tm->tm_sec  = bcd2bin(date[RV8803_SEC] & 0x7f);
+       tm->tm_min  = bcd2bin(date[RV8803_MIN] & 0x7f);
+       tm->tm_hour = bcd2bin(date[RV8803_HOUR] & 0x3f);
+       tm->tm_wday = ffs(date[RV8803_WEEK] & 0x7f);
+       tm->tm_mday = bcd2bin(date[RV8803_DAY] & 0x3f);
+       tm->tm_mon  = bcd2bin(date[RV8803_MONTH] & 0x1f) - 1;
+       tm->tm_year = bcd2bin(date[RV8803_YEAR]) + 100;
+
+       return rtc_valid_tm(tm);
+}
+
+static int rv8803_set_time(struct device *dev, struct rtc_time *tm)
+{
+       struct rv8803_data *rv8803 = dev_get_drvdata(dev);
+       u8 date[7];
+       int flags, ret;
+       unsigned long irqflags;
+
+       if ((tm->tm_year < 100) || (tm->tm_year > 199))
+               return -EINVAL;
+
+       date[RV8803_SEC]   = bin2bcd(tm->tm_sec);
+       date[RV8803_MIN]   = bin2bcd(tm->tm_min);
+       date[RV8803_HOUR]  = bin2bcd(tm->tm_hour);
+       date[RV8803_WEEK]  = 1 << (tm->tm_wday);
+       date[RV8803_DAY]   = bin2bcd(tm->tm_mday);
+       date[RV8803_MONTH] = bin2bcd(tm->tm_mon + 1);
+       date[RV8803_YEAR]  = bin2bcd(tm->tm_year - 100);
+
+       ret = i2c_smbus_write_i2c_block_data(rv8803->client, RV8803_SEC,
+                                            7, date);
+       if (ret < 0)
+               return ret;
+
+       spin_lock_irqsave(&rv8803->flags_lock, irqflags);
+
+       flags = i2c_smbus_read_byte_data(rv8803->client, RV8803_FLAG);
+       if (flags < 0) {
+               spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+               return flags;
+       }
+
+       ret = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG,
+                                       flags & ~RV8803_FLAG_V2F);
+
+       spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+
+       return ret;
+}
+
+static int rv8803_get_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+       struct rv8803_data *rv8803 = dev_get_drvdata(dev);
+       struct i2c_client *client = rv8803->client;
+       u8 alarmvals[3];
+       int flags, ret;
+
+       ret = i2c_smbus_read_i2c_block_data(client, RV8803_ALARM_MIN,
+                                           3, alarmvals);
+       if (ret != 3)
+               return ret < 0 ? ret : -EIO;
+
+       flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
+       if (flags < 0)
+               return flags;
+
+       alrm->time.tm_sec  = 0;
+       alrm->time.tm_min  = bcd2bin(alarmvals[0] & 0x7f);
+       alrm->time.tm_hour = bcd2bin(alarmvals[1] & 0x3f);
+       alrm->time.tm_wday = -1;
+       alrm->time.tm_mday = bcd2bin(alarmvals[2] & 0x3f);
+       alrm->time.tm_mon  = -1;
+       alrm->time.tm_year = -1;
+
+       alrm->enabled = !!(rv8803->ctrl & RV8803_CTRL_AIE);
+       alrm->pending = (flags & RV8803_FLAG_AF) && alrm->enabled;
+
+       return 0;
+}
+
+static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+       struct i2c_client *client = to_i2c_client(dev);
+       struct rv8803_data *rv8803 = dev_get_drvdata(dev);
+       u8 alarmvals[3];
+       u8 ctrl[2];
+       int ret, err;
+       unsigned long irqflags;
+
+       /* The alarm has no seconds, round up to nearest minute */
+       if (alrm->time.tm_sec) {
+               time64_t alarm_time = rtc_tm_to_time64(&alrm->time);
+
+               alarm_time += 60 - alrm->time.tm_sec;
+               rtc_time64_to_tm(alarm_time, &alrm->time);
+       }
+
+       spin_lock_irqsave(&rv8803->flags_lock, irqflags);
+
+       ret = i2c_smbus_read_i2c_block_data(client, RV8803_FLAG, 2, ctrl);
+       if (ret != 2) {
+               spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+               return ret < 0 ? ret : -EIO;
+       }
+
+       alarmvals[0] = bin2bcd(alrm->time.tm_min);
+       alarmvals[1] = bin2bcd(alrm->time.tm_hour);
+       alarmvals[2] = bin2bcd(alrm->time.tm_mday);
+
+       if (rv8803->ctrl & (RV8803_CTRL_AIE | RV8803_CTRL_UIE)) {
+               rv8803->ctrl &= ~(RV8803_CTRL_AIE | RV8803_CTRL_UIE);
+               err = i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL,
+                                               rv8803->ctrl);
+               if (err) {
+                       spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+                       return err;
+               }
+       }
+
+       ctrl[1] &= ~RV8803_FLAG_AF;
+       err = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG, ctrl[1]);
+       spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+       if (err)
+               return err;
+
+       err = i2c_smbus_write_i2c_block_data(rv8803->client, RV8803_ALARM_MIN,
+                                            3, alarmvals);
+       if (err)
+               return err;
+
+       if (alrm->enabled) {
+               if (rv8803->rtc->uie_rtctimer.enabled)
+                       rv8803->ctrl |= RV8803_CTRL_UIE;
+               if (rv8803->rtc->aie_timer.enabled)
+                       rv8803->ctrl |= RV8803_CTRL_AIE;
+
+               err = i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL,
+                                               rv8803->ctrl);
+               if (err)
+                       return err;
+       }
+
+       return 0;
+}
+
+static int rv8803_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+       struct i2c_client *client = to_i2c_client(dev);
+       struct rv8803_data *rv8803 = dev_get_drvdata(dev);
+       int ctrl, flags, err;
+       unsigned long irqflags;
+
+       ctrl = rv8803->ctrl;
+
+       if (enabled) {
+               if (rv8803->rtc->uie_rtctimer.enabled)
+                       ctrl |= RV8803_CTRL_UIE;
+               if (rv8803->rtc->aie_timer.enabled)
+                       ctrl |= RV8803_CTRL_AIE;
+       } else {
+               if (!rv8803->rtc->uie_rtctimer.enabled)
+                       ctrl &= ~RV8803_CTRL_UIE;
+               if (!rv8803->rtc->aie_timer.enabled)
+                       ctrl &= ~RV8803_CTRL_AIE;
+       }
+
+       spin_lock_irqsave(&rv8803->flags_lock, irqflags);
+       flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
+       if (flags < 0) {
+               spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+               return flags;
+       }
+       flags &= ~(RV8803_FLAG_AF | RV8803_FLAG_UF);
+       err = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
+       spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+       if (err)
+               return err;
+
+       if (ctrl != rv8803->ctrl) {
+               rv8803->ctrl = ctrl;
+               err = i2c_smbus_write_byte_data(client, RV8803_CTRL,
+                                               rv8803->ctrl);
+               if (err)
+                       return err;
+       }
+
+       return 0;
+}
+
+static int rv8803_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
+{
+       struct i2c_client *client = to_i2c_client(dev);
+       struct rv8803_data *rv8803 = dev_get_drvdata(dev);
+       int flags, ret = 0;
+       unsigned long irqflags;
+
+       switch (cmd) {
+       case RTC_VL_READ:
+               flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
+               if (flags < 0)
+                       return flags;
+
+               if (flags & RV8803_FLAG_V1F)
+                       dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
+
+               if (flags & RV8803_FLAG_V2F)
+                       dev_warn(&client->dev, "Voltage low, data loss detected.\n");
+
+               flags &= RV8803_FLAG_V1F | RV8803_FLAG_V2F;
+
+               if (copy_to_user((void __user *)arg, &flags, sizeof(int)))
+                       return -EFAULT;
+
+               return 0;
+
+       case RTC_VL_CLR:
+               spin_lock_irqsave(&rv8803->flags_lock, irqflags);
+               flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
+               if (flags < 0) {
+                       spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+                       return flags;
+               }
+
+               flags &= ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F);
+               ret = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
+               spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+               if (ret < 0)
+                       return ret;
+
+               return 0;
+
+       default:
+               return -ENOIOCTLCMD;
+       }
+}
+
+static ssize_t rv8803_nvram_write(struct file *filp, struct kobject *kobj,
+                                 struct bin_attribute *attr,
+                                 char *buf, loff_t off, size_t count)
+{
+       struct device *dev = kobj_to_dev(kobj);
+       struct i2c_client *client = to_i2c_client(dev);
+       int ret;
+
+       ret = i2c_smbus_write_byte_data(client, RV8803_RAM, buf[0]);
+       if (ret < 0)
+               return ret;
+
+       return 1;
+}
+
+static ssize_t rv8803_nvram_read(struct file *filp, struct kobject *kobj,
+                                struct bin_attribute *attr,
+                                char *buf, loff_t off, size_t count)
+{
+       struct device *dev = kobj_to_dev(kobj);
+       struct i2c_client *client = to_i2c_client(dev);
+       int ret;
+
+       ret = i2c_smbus_read_byte_data(client, RV8803_RAM);
+       if (ret < 0)
+               return ret;
+
+       buf[0] = ret;
+
+       return 1;
+}
+
+static struct bin_attribute rv8803_nvram_attr = {
+       .attr = {
+               .name = "nvram",
+               .mode = S_IRUGO | S_IWUSR,
+       },
+       .size = 1,
+       .read = rv8803_nvram_read,
+       .write = rv8803_nvram_write,
+};
+
+static struct rtc_class_ops rv8803_rtc_ops = {
+       .read_time = rv8803_get_time,
+       .set_time = rv8803_set_time,
+       .ioctl = rv8803_ioctl,
+};
+
+static int rv8803_probe(struct i2c_client *client,
+                       const struct i2c_device_id *id)
+{
+       struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
+       struct rv8803_data *rv8803;
+       int err, flags;
+
+       if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
+                                    I2C_FUNC_SMBUS_I2C_BLOCK)) {
+               dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n");
+               return -EIO;
+       }
+
+       rv8803 = devm_kzalloc(&client->dev, sizeof(struct rv8803_data),
+                             GFP_KERNEL);
+       if (!rv8803)
+               return -ENOMEM;
+
+       rv8803->client = client;
+       i2c_set_clientdata(client, rv8803);
+
+       flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
+       if (flags < 0)
+               return flags;
+
+       if (flags & RV8803_FLAG_V1F)
+               dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
+
+       if (flags & RV8803_FLAG_V2F)
+               dev_warn(&client->dev, "Voltage low, data loss detected.\n");
+
+       if (flags & RV8803_FLAG_AF)
+               dev_warn(&client->dev, "An alarm maybe have been missed.\n");
+
+       if (client->irq > 0) {
+               err = devm_request_threaded_irq(&client->dev, client->irq,
+                                               NULL, rv8803_handle_irq,
+                                               IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+                                               "rv8803", client);
+               if (err) {
+                       dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
+                       client->irq = 0;
+               } else {
+                       rv8803_rtc_ops.read_alarm = rv8803_get_alarm;
+                       rv8803_rtc_ops.set_alarm = rv8803_set_alarm;
+                       rv8803_rtc_ops.alarm_irq_enable = rv8803_alarm_irq_enable;
+               }
+       }
+
+       rv8803->rtc = devm_rtc_device_register(&client->dev, client->name,
+                                              &rv8803_rtc_ops, THIS_MODULE);
+       if (IS_ERR(rv8803->rtc)) {
+               dev_err(&client->dev, "unable to register the class device\n");
+               return PTR_ERR(rv8803->rtc);
+       }
+
+       err = i2c_smbus_write_byte_data(rv8803->client, RV8803_EXT,
+                                       RV8803_EXT_WADA);
+       if (err)
+               return err;
+
+       err = device_create_bin_file(&client->dev, &rv8803_nvram_attr);
+       if (err)
+               return err;
+
+       rv8803->rtc->max_user_freq = 1;
+
+       return 0;
+}
+
+static int rv8803_remove(struct i2c_client *client)
+{
+       device_remove_bin_file(&client->dev, &rv8803_nvram_attr);
+
+       return 0;
+}
+
+static const struct i2c_device_id rv8803_id[] = {
+       { "rv8803", 0 },
+       { }
+};
+MODULE_DEVICE_TABLE(i2c, rv8803_id);
+
+static struct i2c_driver rv8803_driver = {
+       .driver = {
+               .name = "rtc-rv8803",
+       },
+       .probe          = rv8803_probe,
+       .remove         = rv8803_remove,
+       .id_table       = rv8803_id,
+};
+module_i2c_driver(rv8803_driver);
+
+MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>");
+MODULE_DESCRIPTION("Micro Crystal RV8803 RTC driver");
+MODULE_LICENSE("GPL v2");