rtc: add rv3029c2 RTC support

Add support for the Micro Crystal RV3029-C2 RTC chips.

Signed-off-by: Heiko Schocher <hs@denx.de>
Signed-off-by: Gregory Hermant <gregory.hermant@calao-systems.com>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 464 insertions, 0 deletions

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 512b40ea32cd..4956e416b315 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -370,6 +370,15 @@ config RTC_DRV_EM3027
           This driver can also be built as a module. If so, the module
           will be called rtc-em3027.
 
+config RTC_DRV_RV3029C2
+        tristate "Micro Crystal RTC"
+        help
+          If you say yes here you get support for the Micro Crystal
+          RV3029-C2 RTC chips.
+
+          This driver can also be built as a module. If so, the module
+          will be called rtc-rv3029c2.
+
 endif # I2C
 
 comment "SPI RTC drivers"
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 4801a0af7bcd..692a79f6da35 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -83,6 +83,7 @@ obj-$(CONFIG_RTC_DRV_RP5C01)	+= rtc-rp5c01.o
 obj-$(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_RX8025)    += rtc-rx8025.o
 obj-$(CONFIG_RTC_DRV_RX8581)    += rtc-rx8581.o
 obj-$(CONFIG_RTC_DRV_S35390A)   += rtc-s35390a.o
diff --git a/drivers/rtc/rtc-rv3029c2.c b/drivers/rtc/rtc-rv3029c2.c
new file mode 100644
index 000000000000..ea09ff211dc6
--- /dev/null
+++ b/drivers/rtc/rtc-rv3029c2.c
@@ -0,0 +1,454 @@
+/*
+ * Micro Crystal RV-3029C2 rtc class driver
+ *
+ * Author: Gregory Hermant <gregory.hermant@calao-systems.com>
+ *
+ * based on previously existing rtc class drivers
+ *
+ * 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.
+ *
+ * NOTE: Currently this driver only supports the bare minimum for read
+ * and write the RTC and alarms. The extra features provided by this chip
+ * (trickle charger, eeprom, T° compensation) are unavailable.
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/bcd.h>
+#include <linux/rtc.h>
+
+/* Register map */
+/* control section */
+#define RV3029C2_ONOFF_CTRL             0x00
+#define RV3029C2_IRQ_CTRL               0x01
+#define RV3029C2_IRQ_CTRL_AIE           (1 << 0)
+#define RV3029C2_IRQ_FLAGS              0x02
+#define RV3029C2_IRQ_FLAGS_AF           (1 << 0)
+#define RV3029C2_STATUS                 0x03
+#define RV3029C2_STATUS_VLOW1           (1 << 2)
+#define RV3029C2_STATUS_VLOW2           (1 << 3)
+#define RV3029C2_STATUS_SR              (1 << 4)
+#define RV3029C2_STATUS_PON             (1 << 5)
+#define RV3029C2_STATUS_EEBUSY          (1 << 7)
+#define RV3029C2_RST_CTRL               0x04
+#define RV3029C2_CONTROL_SECTION_LEN    0x05
+
+/* watch section */
+#define RV3029C2_W_SEC                  0x08
+#define RV3029C2_W_MINUTES              0x09
+#define RV3029C2_W_HOURS                0x0A
+#define RV3029C2_REG_HR_12_24           (1<<6)  /* 24h/12h mode */
+#define RV3029C2_REG_HR_PM              (1<<5)  /* PM/AM bit in 12h mode */
+#define RV3029C2_W_DATE                 0x0B
+#define RV3029C2_W_DAYS                 0x0C
+#define RV3029C2_W_MONTHS               0x0D
+#define RV3029C2_W_YEARS                0x0E
+#define RV3029C2_WATCH_SECTION_LEN      0x07
+
+/* alarm section */
+#define RV3029C2_A_SC                   0x10
+#define RV3029C2_A_MN                   0x11
+#define RV3029C2_A_HR                   0x12
+#define RV3029C2_A_DT                   0x13
+#define RV3029C2_A_DW                   0x14
+#define RV3029C2_A_MO                   0x15
+#define RV3029C2_A_YR                   0x16
+#define RV3029C2_ALARM_SECTION_LEN      0x07
+
+/* timer section */
+#define RV3029C2_TIMER_LOW              0x18
+#define RV3029C2_TIMER_HIGH             0x19
+
+/* temperature section */
+#define RV3029C2_TEMP_PAGE              0x20
+
+/* eeprom data section */
+#define RV3029C2_E2P_EEDATA1            0x28
+#define RV3029C2_E2P_EEDATA2            0x29
+
+/* eeprom control section */
+#define RV3029C2_CONTROL_E2P_EECTRL     0x30
+#define RV3029C2_TRICKLE_1K             (1<<0)  /*  1K resistance */
+#define RV3029C2_TRICKLE_5K             (1<<1)  /*  5K resistance */
+#define RV3029C2_TRICKLE_20K            (1<<2)  /* 20K resistance */
+#define RV3029C2_TRICKLE_80K            (1<<3)  /* 80K resistance */
+#define RV3029C2_CONTROL_E2P_XTALOFFSET 0x31
+#define RV3029C2_CONTROL_E2P_QCOEF      0x32
+#define RV3029C2_CONTROL_E2P_TURNOVER   0x33
+
+/* user ram section */
+#define RV3029C2_USR1_RAM_PAGE          0x38
+#define RV3029C2_USR1_SECTION_LEN       0x04
+#define RV3029C2_USR2_RAM_PAGE          0x3C
+#define RV3029C2_USR2_SECTION_LEN       0x04
+
+static int
+rv3029c2_i2c_read_regs(struct i2c_client *client, u8 reg, u8 *buf,
+        unsigned len)
+{
+        int ret;
+
+        if ((reg > RV3029C2_USR1_RAM_PAGE + 7) ||
+                (reg + len > RV3029C2_USR1_RAM_PAGE + 8))
+                return -EINVAL;
+
+        ret = i2c_smbus_read_i2c_block_data(client, reg, len, buf);
+        if (ret < 0)
+                return ret;
+        if (ret < len)
+                return -EIO;
+        return 0;
+}
+
+static int
+rv3029c2_i2c_write_regs(struct i2c_client *client, u8 reg, u8 const buf[],
+                        unsigned len)
+{
+        if ((reg > RV3029C2_USR1_RAM_PAGE + 7) ||
+                (reg + len > RV3029C2_USR1_RAM_PAGE + 8))
+                return -EINVAL;
+
+        return i2c_smbus_write_i2c_block_data(client, reg, len, buf);
+}
+
+static int
+rv3029c2_i2c_get_sr(struct i2c_client *client, u8 *buf)
+{
+        int ret = rv3029c2_i2c_read_regs(client, RV3029C2_STATUS, buf, 1);
+
+        if (ret < 0)
+                return -EIO;
+        dev_dbg(&client->dev, "status = 0x%.2x (%d)\n", buf[0], buf[0]);
+        return 0;
+}
+
+static int
+rv3029c2_i2c_set_sr(struct i2c_client *client, u8 val)
+{
+        u8 buf[1];
+        int sr;
+
+        buf[0] = val;
+        sr = rv3029c2_i2c_write_regs(client, RV3029C2_STATUS, buf, 1);
+        dev_dbg(&client->dev, "status = 0x%.2x (%d)\n", buf[0], buf[0]);
+        if (sr < 0)
+                return -EIO;
+        return 0;
+}
+
+static int
+rv3029c2_i2c_read_time(struct i2c_client *client, struct rtc_time *tm)
+{
+        u8 buf[1];
+        int ret;
+        u8 regs[RV3029C2_WATCH_SECTION_LEN] = { 0, };
+
+        ret = rv3029c2_i2c_get_sr(client, buf);
+        if (ret < 0) {
+                dev_err(&client->dev, "%s: reading SR failed\n", __func__);
+                return -EIO;
+        }
+
+        ret = rv3029c2_i2c_read_regs(client, RV3029C2_W_SEC , regs,
+                                        RV3029C2_WATCH_SECTION_LEN);
+        if (ret < 0) {
+                dev_err(&client->dev, "%s: reading RTC section failed\n",
+                        __func__);
+                return ret;
+        }
+
+        tm->tm_sec = bcd2bin(regs[RV3029C2_W_SEC-RV3029C2_W_SEC]);
+        tm->tm_min = bcd2bin(regs[RV3029C2_W_MINUTES-RV3029C2_W_SEC]);
+
+        /* HR field has a more complex interpretation */
+        {
+                const u8 _hr = regs[RV3029C2_W_HOURS-RV3029C2_W_SEC];
+                if (_hr & RV3029C2_REG_HR_12_24) {
+                        /* 12h format */
+                        tm->tm_hour = bcd2bin(_hr & 0x1f);
+                        if (_hr & RV3029C2_REG_HR_PM)   /* PM flag set */
+                                tm->tm_hour += 12;
+                } else /* 24h format */
+                        tm->tm_hour = bcd2bin(_hr & 0x3f);
+        }
+
+        tm->tm_mday = bcd2bin(regs[RV3029C2_W_DATE-RV3029C2_W_SEC]);
+        tm->tm_mon = bcd2bin(regs[RV3029C2_W_MONTHS-RV3029C2_W_SEC]) - 1;
+        tm->tm_year = bcd2bin(regs[RV3029C2_W_YEARS-RV3029C2_W_SEC]) + 100;
+        tm->tm_wday = bcd2bin(regs[RV3029C2_W_DAYS-RV3029C2_W_SEC]) - 1;
+
+        return 0;
+}
+
+static int rv3029c2_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+        return rv3029c2_i2c_read_time(to_i2c_client(dev), tm);
+}
+
+static int
+rv3029c2_i2c_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alarm)
+{
+        struct rtc_time *const tm = &alarm->time;
+        int ret;
+        u8 regs[8];
+
+        ret = rv3029c2_i2c_get_sr(client, regs);
+        if (ret < 0) {
+                dev_err(&client->dev, "%s: reading SR failed\n", __func__);
+                return -EIO;
+        }
+
+        ret = rv3029c2_i2c_read_regs(client, RV3029C2_A_SC, regs,
+                                        RV3029C2_ALARM_SECTION_LEN);
+
+        if (ret < 0) {
+                dev_err(&client->dev, "%s: reading alarm section failed\n",
+                        __func__);
+                return ret;
+        }
+
+        tm->tm_sec = bcd2bin(regs[RV3029C2_A_SC-RV3029C2_A_SC] & 0x7f);
+        tm->tm_min = bcd2bin(regs[RV3029C2_A_MN-RV3029C2_A_SC] & 0x7f);
+        tm->tm_hour = bcd2bin(regs[RV3029C2_A_HR-RV3029C2_A_SC] & 0x3f);
+        tm->tm_mday = bcd2bin(regs[RV3029C2_A_DT-RV3029C2_A_SC] & 0x3f);
+        tm->tm_mon = bcd2bin(regs[RV3029C2_A_MO-RV3029C2_A_SC] & 0x1f) - 1;
+        tm->tm_year = bcd2bin(regs[RV3029C2_A_YR-RV3029C2_A_SC] & 0x7f) + 100;
+        tm->tm_wday = bcd2bin(regs[RV3029C2_A_DW-RV3029C2_A_SC] & 0x07) - 1;
+
+        return 0;
+}
+
+static int
+rv3029c2_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+        return rv3029c2_i2c_read_alarm(to_i2c_client(dev), alarm);
+}
+
+static int rv3029c2_rtc_i2c_alarm_set_irq(struct i2c_client *client,
+                                        int enable)
+{
+        int ret;
+        u8 buf[1];
+
+        /* enable AIE irq */
+        ret = rv3029c2_i2c_read_regs(client, RV3029C2_IRQ_CTRL, buf, 1);
+        if (ret < 0) {
+                dev_err(&client->dev, "can't read INT reg\n");
+                return ret;
+        }
+        if (enable)
+                buf[0] |= RV3029C2_IRQ_CTRL_AIE;
+        else
+                buf[0] &= ~RV3029C2_IRQ_CTRL_AIE;
+
+        ret = rv3029c2_i2c_write_regs(client, RV3029C2_IRQ_CTRL, buf, 1);
+        if (ret < 0) {
+                dev_err(&client->dev, "can't set INT reg\n");
+                return ret;
+        }
+
+        return 0;
+}
+
+static int rv3029c2_rtc_i2c_set_alarm(struct i2c_client *client,
+                                        struct rtc_wkalrm *alarm)
+{
+        struct rtc_time *const tm = &alarm->time;
+        int ret;
+        u8 regs[8];
+
+        /*
+         * The clock has an 8 bit wide bcd-coded register (they never learn)
+         * 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;
+
+        ret = rv3029c2_i2c_get_sr(client, regs);
+        if (ret < 0) {
+                dev_err(&client->dev, "%s: reading SR failed\n", __func__);
+                return -EIO;
+        }
+        regs[RV3029C2_A_SC-RV3029C2_A_SC] = bin2bcd(tm->tm_sec & 0x7f);
+        regs[RV3029C2_A_MN-RV3029C2_A_SC] = bin2bcd(tm->tm_min & 0x7f);
+        regs[RV3029C2_A_HR-RV3029C2_A_SC] = bin2bcd(tm->tm_hour & 0x3f);
+        regs[RV3029C2_A_DT-RV3029C2_A_SC] = bin2bcd(tm->tm_mday & 0x3f);
+        regs[RV3029C2_A_MO-RV3029C2_A_SC] = bin2bcd((tm->tm_mon & 0x1f) - 1);
+        regs[RV3029C2_A_DW-RV3029C2_A_SC] = bin2bcd((tm->tm_wday & 7) - 1);
+        regs[RV3029C2_A_YR-RV3029C2_A_SC] = bin2bcd((tm->tm_year & 0x7f) - 100);
+
+        ret = rv3029c2_i2c_write_regs(client, RV3029C2_A_SC, regs,
+                                        RV3029C2_ALARM_SECTION_LEN);
+        if (ret < 0)
+                return ret;
+
+        if (alarm->enabled) {
+                u8 buf[1];
+
+                /* clear AF flag */
+                ret = rv3029c2_i2c_read_regs(client, RV3029C2_IRQ_FLAGS,
+                                                buf, 1);
+                if (ret < 0) {
+                        dev_err(&client->dev, "can't read alarm flag\n");
+                        return ret;
+                }
+                buf[0] &= ~RV3029C2_IRQ_FLAGS_AF;
+                ret = rv3029c2_i2c_write_regs(client, RV3029C2_IRQ_FLAGS,
+                                                buf, 1);
+                if (ret < 0) {
+                        dev_err(&client->dev, "can't set alarm flag\n");
+                        return ret;
+                }
+                /* enable AIE irq */
+                ret = rv3029c2_rtc_i2c_alarm_set_irq(client, 1);
+                if (ret)
+                        return ret;
+
+                dev_dbg(&client->dev, "alarm IRQ armed\n");
+        } else {
+                /* disable AIE irq */
+                ret = rv3029c2_rtc_i2c_alarm_set_irq(client, 1);
+                if (ret)
+                        return ret;
+
+                dev_dbg(&client->dev, "alarm IRQ disabled\n");
+        }
+
+        return 0;
+}
+
+static int rv3029c2_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+        return rv3029c2_rtc_i2c_set_alarm(to_i2c_client(dev), alarm);
+}
+
+static int
+rv3029c2_i2c_set_time(struct i2c_client *client, struct rtc_time const *tm)
+{
+        u8 regs[8];
+        int ret;
+
+        /*
+         * The clock has an 8 bit wide bcd-coded register (they never learn)
+         * 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[RV3029C2_W_SEC-RV3029C2_W_SEC] = bin2bcd(tm->tm_sec);
+        regs[RV3029C2_W_MINUTES-RV3029C2_W_SEC] = bin2bcd(tm->tm_min);
+        regs[RV3029C2_W_HOURS-RV3029C2_W_SEC] = bin2bcd(tm->tm_hour);
+        regs[RV3029C2_W_DATE-RV3029C2_W_SEC] = bin2bcd(tm->tm_mday);
+        regs[RV3029C2_W_MONTHS-RV3029C2_W_SEC] = bin2bcd(tm->tm_mon+1);
+        regs[RV3029C2_W_DAYS-RV3029C2_W_SEC] = bin2bcd((tm->tm_wday & 7)+1);
+        regs[RV3029C2_W_YEARS-RV3029C2_W_SEC] = bin2bcd(tm->tm_year - 100);
+
+        ret = rv3029c2_i2c_write_regs(client, RV3029C2_W_SEC, regs,
+                                        RV3029C2_WATCH_SECTION_LEN);
+        if (ret < 0)
+                return ret;
+
+        ret = rv3029c2_i2c_get_sr(client, regs);
+        if (ret < 0) {
+                dev_err(&client->dev, "%s: reading SR failed\n", __func__);
+                return ret;
+        }
+        /* clear PON bit */
+        ret = rv3029c2_i2c_set_sr(client, (regs[0] & ~RV3029C2_STATUS_PON));
+        if (ret < 0) {
+                dev_err(&client->dev, "%s: reading SR failed\n", __func__);
+                return ret;
+        }
+
+        return 0;
+}
+
+static int rv3029c2_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+        return rv3029c2_i2c_set_time(to_i2c_client(dev), tm);
+}
+
+static const struct rtc_class_ops rv3029c2_rtc_ops = {
+        .read_time      = rv3029c2_rtc_read_time,
+        .set_time       = rv3029c2_rtc_set_time,
+        .read_alarm     = rv3029c2_rtc_read_alarm,
+        .set_alarm      = rv3029c2_rtc_set_alarm,
+};
+
+static struct i2c_device_id rv3029c2_id[] = {
+        { "rv3029c2", 0 },
+        { }
+};
+MODULE_DEVICE_TABLE(i2c, rv3029c2_id);
+
+static int __devinit
+rv3029c2_probe(struct i2c_client *client, const struct i2c_device_id *id)
+{
+        struct rtc_device *rtc;
+        int rc = 0;
+        u8 buf[1];
+
+        if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_EMUL))
+                return -ENODEV;
+
+        rtc = rtc_device_register(client->name,
+                                &client->dev, &rv3029c2_rtc_ops,
+                                THIS_MODULE);
+
+        if (IS_ERR(rtc))
+                return PTR_ERR(rtc);
+
+        i2c_set_clientdata(client, rtc);
+
+        rc = rv3029c2_i2c_get_sr(client, buf);
+        if (rc < 0) {
+                dev_err(&client->dev, "reading status failed\n");
+                goto exit_unregister;
+        }
+
+        return 0;
+
+exit_unregister:
+        rtc_device_unregister(rtc);
+
+        return rc;
+}
+
+static int __devexit rv3029c2_remove(struct i2c_client *client)
+{
+        struct rtc_device *rtc = i2c_get_clientdata(client);
+
+        rtc_device_unregister(rtc);
+
+        return 0;
+}
+
+static struct i2c_driver rv3029c2_driver = {
+        .driver = {
+                .name = "rtc-rv3029c2",
+        },
+        .probe = rv3029c2_probe,
+        .remove = __devexit_p(rv3029c2_remove),
+        .id_table = rv3029c2_id,
+};
+
+static int __init rv3029c2_init(void)
+{
+        return i2c_add_driver(&rv3029c2_driver);
+}
+
+static void __exit rv3029c2_exit(void)
+{
+        i2c_del_driver(&rv3029c2_driver);
+}
+
+module_init(rv3029c2_init);
+module_exit(rv3029c2_exit);
+
+MODULE_AUTHOR("Gregory Hermant <gregory.hermant@calao-systems.com>");
+MODULE_DESCRIPTION("Micro Crystal RV3029C2 RTC driver");
+MODULE_LICENSE("GPL");