Hi Atsushi,
like you, I started recently with Mark's m41t00.c driver to add support for
the new rtc-subsystem. Mark reviewed it and I added his changes.
There is still the question, if the code for the interrupt context
(workqueues) should stay or not. You bracketed all this with CONFIG_GEN_RTC.
I can't say, if this is a good idea. Maybe somebody else has some good
comments.
The driver supports now four different STM rtc chips: M41T00, M41T80, M41T81
and M41ST85. The chips M41ST84/85/87/94 should work similar as far the driver
supports them. Maybe even more.
That's why I named the driver rtc-m41txx.c and not m41t00.c as the original
one.
There is for sure still some work to do, so I appreciate any comments.
The enclosed patch was tested with linux-2.6.18-rc3 on an embedded Alchemy
MIPS-processor board (XXS1500).
Alexander
On Friday 04 August 2006 02:21, Mark A. Greer wrote:
> Atsushi,
>
> Alexander Bigga <[email protected]> has been working on moving this driver
> over to [its proper place in] drivers/rtc. Please sync up with him.
>
> I've included him on the cc list so he can see your email.
>
> Mark
--- linux-2.6.18-rc3/drivers/rtc/Makefile 2006-07-30 20:57:47.000000000 +0200
+++ linux-2.6.18-rc3-mips-dev/drivers/rtc/Makefile 2006-08-02
11:16:44.000000000 +0200
@@ -23,6 +23,7 @@
obj-$(CONFIG_RTC_DRV_S3C) += rtc-s3c.o
obj-$(CONFIG_RTC_DRV_RS5C348) += rtc-rs5c348.o
obj-$(CONFIG_RTC_DRV_M48T86) += rtc-m48t86.o
+obj-$(CONFIG_RTC_DRV_M41TXX) += rtc-m41txx.o
obj-$(CONFIG_RTC_DRV_DS1553) += rtc-ds1553.o
obj-$(CONFIG_RTC_DRV_EP93XX) += rtc-ep93xx.o
obj-$(CONFIG_RTC_DRV_SA1100) += rtc-sa1100.o
--- linux-2.6.18-rc3/drivers/rtc/Kconfig 2006-07-30 20:57:47.000000000 +0200
+++ linux-2.6.18-rc3-mips-dev/drivers/rtc/Kconfig 2006-08-04
14:26:12.000000000 +0200
@@ -218,6 +218,17 @@
This driver can also be built as a module. If so, the module
will be called rtc-m48t86.
+config RTC_DRV_M41TXX
+ tristate "ST M41Txx series RTC"
+ depends on RTC_CLASS
+ help
+ If you say Y here you will get support for the
+ ST M41T00 RTC chips series. Currently the following chips are
+ supported: M41T00, M41T80, M41T81 and M41ST85
+
+ This driver can also be built as a module. If so, the module
+ will be called rtc-m41txx.
+
config RTC_DRV_EP93XX
tristate "Cirrus Logic EP93XX"
depends on RTC_CLASS && ARCH_EP93XX
--- linux-2.6.18-rc3/drivers/rtc/rtc-m41txx.c 1970-01-01 01:00:00.000000000
+0100
+++ linux-2.6.18-rc3-mips-dev/drivers/rtc/rtc-m41txx.c 2006-08-04
14:23:08.000000000 +0200
@@ -0,0 +1,568 @@
+/*
+ * I2C client/driver for the ST M41T00 family of i2c rtc chips.
+ *
+ * Author: Mark A. Greer <[email protected]>
+ * Alexander Bigga <[email protected]>
+ *
+ * Based on m41t00.c by Mark A. Greer
+ *
+ * 2005, 2006 (c) MontaVista Software, Inc.
+ * 2006 (c) mycable GmbH
+ *
+ * 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/module.h>
+#include <linux/interrupt.h>
+#include <linux/i2c.h>
+#include <linux/rtc.h>
+#include <linux/bcd.h>
+#include <linux/workqueue.h>
+#include <linux/platform_device.h>
+#include <linux/m41t00.h>
+#include <asm/time.h>
+#include <asm/rtc.h>
+
+#define M41TXX_SEC_ST (1 << 7) /* ST: Stop Bit */
+#define M41TXX_HOUR_CB (1 << 6) /* CB: Century Bit */
+#define M41TXX_HOUR_CEB (1 << 7) /* CEB: Century Enable Bit */
+#define M41TXX_ALHOUR_HT (1 << 6) /* HT: Halt Update Bit */
+#define M41TXX_FLAGS_BATT_LOW (1 << 4) /* BL: Battery Low Bit */
+
+#define M41TXX_FEATURE_HT (1 << 0)
+#define M41TXX_FEATURE_BL (1 << 1)
+
+#define DRV_VERSION "0.03"
+
+
+static struct i2c_driver m41txx_driver;
+static struct i2c_client *save_client;
+
+static unsigned short normal_i2c[] = { M41T00_I2C_ADDR, I2C_CLIENT_END };
+
+/* Insmod parameters */
+I2C_CLIENT_INSMOD;
+
+/* Prototypes */
+static int m41txx_attach(struct i2c_adapter *adapter);
+static int m41txx_detach(struct i2c_client *client);
+static int m41txx_probe(struct i2c_adapter *adapter, int address,
+ int kind);
+
+/* exports the i2c_client structure; used by a m41t85 watchdog-driver. */
+struct i2c_client *m41txx_get_i2c_client(void)
+{
+ return save_client;
+}
+EXPORT_SYMBOL(m41txx_get_i2c_client);
+
+static struct i2c_driver m41txx_driver = {
+ .driver = {
+ .name = M41T00_DRV_NAME,
+ },
+ .id = I2C_DRIVERID_STM41T00,
+ .attach_adapter = &m41txx_attach,
+ .detach_client = &m41txx_detach,
+};
+
+struct m41txx_chip_info {
+ u8 type;
+ char *name;
+ u8 read_limit;
+ u8 sec; /* Offsets for chip regs */
+ u8 min;
+ u8 hour;
+ u8 wday;
+ u8 day;
+ u8 mon;
+ u8 year;
+ u8 alarm_mon;
+ u8 alarm_hour;
+ u8 flags;
+ u8 sqw;
+ u8 sqw_freq;
+ u8 features;
+};
+
+static struct m41txx_chip_info m41txx_chip_info_tbl[] = {
+ { /* M41T00/11 */
+ .type = M41T00_TYPE_M41T00,
+ .name = "m41t00",
+ .read_limit = 5,
+ .sec = 0,
+ .min = 1,
+ .hour = 2,
+ .wday = 3,
+ .day = 4,
+ .mon = 5,
+ .year = 6,
+ .features = 0,
+ },
+ { /* M41T80 */
+ .type = M41T00_TYPE_M41T80,
+ .name = "m41t80",
+ .read_limit = 1,
+ .sec = 1,
+ .min = 2,
+ .hour = 3,
+ .wday = 4,
+ .day = 5,
+ .mon = 6,
+ .year = 7,
+ .alarm_mon = 0xa,
+ .alarm_hour = 0xc,
+ .flags = 0xf,
+ .sqw = 0x13,
+ .features = 0,
+ },
+ { /* M41T81 */
+ .type = M41T00_TYPE_M41T81,
+ .name = "m41t81",
+ .read_limit = 1,
+ .sec = 1,
+ .min = 2,
+ .hour = 3,
+ .wday = 4,
+ .day = 5,
+ .mon = 6,
+ .year = 7,
+ .alarm_mon = 0xa,
+ .alarm_hour = 0xc,
+ .flags = 0xf,
+ .sqw = 0x13,
+ .features = M41TXX_FEATURE_HT,
+ },
+ { /* M41ST84/85/87/94 */
+ .type = M41T00_TYPE_M41T85,
+ .name = "m41t85",
+ .read_limit = 1,
+ .sec = 1,
+ .min = 2,
+ .hour = 3,
+ .wday = 4,
+ .day = 5,
+ .mon = 6,
+ .year = 7,
+ .alarm_mon = 0xa,
+ .alarm_hour = 0xc,
+ .flags = 0xf,
+ .sqw = 0x13,
+ .features = M41TXX_FEATURE_HT | M41TXX_FEATURE_BL,
+ },
+};
+static struct m41txx_chip_info *m41txx_chip;
+
+static int m41txx_get_datetime(struct i2c_client *client,
+ struct rtc_time *tm)
+{
+
+ s32 sec, min, hour, day, mon, year;
+ s32 sec1, min1, hour1, day1, mon1, year1;
+ u8 reads = 0;
+ u8 buf[8], dt_addr[1] = { 0 }; /* offset into rtc's regs */
+
+ struct i2c_msg msgs[] = {
+ {
+ .addr = client->addr,
+ .flags = 0,
+ .len = 1,
+ .buf = dt_addr,
+ },
+ {
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = 8,
+ .buf = buf,
+ },
+ };
+
+ sec = min = hour = day = mon = year = 0;
+
+ do {
+ if (i2c_transfer(client->adapter, msgs, 2) < 0)
+ goto read_err;
+
+ sec1 = sec;
+ min1 = min;
+ hour1 = hour;
+ day1 = day;
+ mon1 = mon;
+ year1 = year;
+
+ sec = buf[m41txx_chip->sec] & 0x7f;
+ min = buf[m41txx_chip->min] & 0x7f;
+ hour = buf[m41txx_chip->hour] & 0x3f;
+ day = buf[m41txx_chip->day] & 0x3f;
+ mon = buf[m41txx_chip->mon] & 0x1f;
+ year = buf[m41txx_chip->year];
+
+ } while ((++reads < m41txx_chip->read_limit) && ((sec != sec1)
+ || (min != min1) || (hour != hour1) || (day != day1)
+ || (mon != mon1) || (year != year1)));
+
+ if ((m41txx_chip->read_limit > 1)
+ && ((sec != sec1) || (min != min1)
+ || (hour != hour1) || (day != day1) || (mon != mon1)
+ || (year != year1)))
+ goto read_err;
+
+ tm->tm_sec = BCD2BIN(sec);
+ tm->tm_min = BCD2BIN(min);
+ tm->tm_hour = BCD2BIN(hour);
+ tm->tm_mday = BCD2BIN(day);
+ tm->tm_wday = buf[m41txx_chip->wday] & 0x07;
+ tm->tm_mon = BCD2BIN(mon) - 1;
+
+ if (buf[m41txx_chip->hour] & M41TXX_HOUR_CB)
+ tm->tm_year = BCD2BIN(year) + 100;
+ else
+ tm->tm_year = BCD2BIN(year);
+
+ return 0;
+
+read_err:
+ dev_err(&client->dev, "m41txx_get_datetime: Read error\n");
+ return 0;
+}
+
+
+/* Sets the given date and time to the real time clock. */
+int m41txx_set_datetime(struct i2c_client *client, struct rtc_time *tm)
+{
+ unsigned char buf[8];
+ unsigned char wbuf[8];
+ unsigned char dt_addr[1] = { 0 }; /* offset into rtc's regs */
+
+ struct i2c_msg msgs_in[] = {
+ {
+ .addr = client->addr,
+ .flags = 0,
+ .len = 1,
+ .buf = dt_addr,
+ },
+ {
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = 8,
+ .buf = wbuf,
+ },
+ };
+ struct i2c_msg msgs[] = {
+ {
+ .addr = client->addr,
+ .flags = 0,
+ .len = 8,
+ .buf = buf,
+ },
+ };
+
+ /* Read current reg values into wbuf[0..8] */
+ if (i2c_transfer(client->adapter, msgs_in, 2) < 0)
+ goto read_err;
+
+ /* Merge time-data and register flags into buf[0..8] */
+ buf[0] = 0x01;
+ buf[m41txx_chip->sec] = BIN2BCD(tm->tm_sec)
+ | (wbuf[m41txx_chip->sec] & ~0x7f);
+ buf[m41txx_chip->min] = BIN2BCD(tm->tm_min)
+ | (wbuf[m41txx_chip->min] & ~0x7f);
+ if (tm->tm_year > 100) {
+ /* M41T85_REG_HOUR_CB enables the CENTURY Bit (CB) */
+ buf[m41txx_chip->hour] = BIN2BCD(tm->tm_hour)
+ | M41TXX_HOUR_CB | M41TXX_HOUR_CEB ;
+ buf[m41txx_chip->year] = BIN2BCD(tm->tm_year - 100);
+ } else {
+ buf[m41txx_chip->hour] = BIN2BCD(tm->tm_hour);
+ buf[m41txx_chip->year] = BIN2BCD(tm->tm_year);
+ }
+ buf[m41txx_chip->wday] = (tm->tm_wday & 0x07)
+ | (wbuf[m41txx_chip->wday] & ~0x07);
+ buf[m41txx_chip->day] = BIN2BCD(tm->tm_mday)
+ | (wbuf[m41txx_chip->day] & ~0x3f);
+ buf[m41txx_chip->mon] = BIN2BCD(tm->tm_mon + 1)
+ | (wbuf[m41txx_chip->mon] & ~0x1f);
+
+ if (i2c_transfer(client->adapter, msgs, 1) != 1) {
+ dev_err(&client->dev, "%s: write error\n", __FUNCTION__);
+ return -EIO;
+ }
+ return 0;
+read_err:
+ dev_err(&client->dev, "m41txx_set_datetime: Read error\n");
+ return 0;
+}
+
+ulong m41t00_get_rtc_time(void)
+{
+ struct rtc_time tm;
+
+ m41txx_get_datetime(save_client, &tm);
+
+ return mktime(tm.tm_year, tm.tm_mon,
+ tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);
+}
+EXPORT_SYMBOL_GPL(m41t00_get_rtc_time);
+
+static void m41txx_set(void *arg)
+{
+ struct rtc_time tm;
+ int nowtime = *(int *) arg;
+
+ to_tm(nowtime, &tm);
+ m41txx_set_datetime(save_client, &tm);
+
+}
+
+static ulong new_time;
+static struct workqueue_struct *m41txx_wq;
+static DECLARE_WORK(m41txx_work, m41txx_set, &new_time);
+
+int m41t00_set_rtc_time(ulong nowtime)
+{
+ new_time = nowtime;
+
+ if (in_interrupt())
+ queue_work(m41txx_wq, &m41txx_work);
+ else
+ m41txx_set(&new_time);
+
+ return 0;
+}
+
+EXPORT_SYMBOL_GPL(m41t00_set_rtc_time);
+
+/*
+
*****************************************************************************
+ *
+ * platform_data Driver Interface
+ *
+
*****************************************************************************
+ */
+static int __init m41txx_platform_probe(struct platform_device *pdev)
+{
+ struct m41t00_platform_data *pdata;
+ int i;
+
+ if (pdev && (pdata = pdev->dev.platform_data)) {
+ normal_i2c[0] = pdata->i2c_addr;
+
+ for (i = 0; i < ARRAY_SIZE(m41txx_chip_info_tbl); i++)
+ if (m41txx_chip_info_tbl[i].type == pdata->type) {
+ m41txx_chip = &m41txx_chip_info_tbl[i];
+ m41txx_chip->sqw_freq = pdata->sqw_freq;
+ return i2c_add_driver(&m41txx_driver);
+ }
+ }
+ return -ENODEV;
+}
+
+static int __exit m41txx_platform_remove(struct platform_device *pdev)
+{
+ return i2c_del_driver(&m41txx_driver);
+}
+
+static struct platform_driver m41txx_platform_driver = {
+ .probe = m41txx_platform_probe,
+ .remove = m41txx_platform_remove,
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = M41T00_DRV_NAME,
+ },
+};
+
+static int m41txx_rtc_proc(struct device *dev, struct seq_file *seq)
+{
+ unsigned char reg;
+
+ if (m41txx_chip->flags & M41TXX_FEATURE_BL ) {
+ reg = i2c_smbus_read_byte_data(to_i2c_client(dev),
+ m41txx_chip->flags);
+ seq_printf(seq, "battery\t\t: %s\n",
+ (reg & M41TXX_FLAGS_BATT_LOW) ? "exhausted" : "ok");
+ }
+ return 0;
+}
+
+static int m41txx_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ return m41txx_get_datetime(to_i2c_client(dev), tm);
+}
+
+static int m41txx_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ return m41txx_set_datetime(to_i2c_client(dev), tm);
+}
+
+
+static struct rtc_class_ops m41txx_rtc_ops = {
+ .read_time = m41txx_rtc_read_time,
+ .set_time = m41txx_rtc_set_time,
+ .proc = m41txx_rtc_proc,
+};
+
+/*
+
*****************************************************************************
+ *
+ * Driver Interface
+ *
+
*****************************************************************************
+ */
+static int m41txx_probe(struct i2c_adapter *adapter, int address, int kind)
+{
+ int rc = 0;
+
+ struct i2c_client *client;
+ struct rtc_device *rtc;
+ struct rtc_time tm;
+
+ dev_dbg(&adapter->dev, "%s\n", __FUNCTION__);
+
+ if (!i2c_check_functionality(adapter, I2C_FUNC_I2C
+ | I2C_FUNC_SMBUS_BYTE_DATA)) {
+ rc = -ENODEV;
+ goto exit;
+ }
+
+ if (!(client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL))) {
+ rc = -ENOMEM;
+ goto exit;
+ }
+
+ /* I2C client */
+ strlcpy(client->name, m41txx_chip->name, I2C_NAME_SIZE);
+ client->addr = address;
+ client->adapter = adapter;
+ client->driver = &m41txx_driver;
+
+ /* Inform the i2c layer */
+ if ((rc = i2c_attach_client(client)))
+ goto exit_kfree;
+
+ dev_info(&client->dev,
+ "chip found, driver version " DRV_VERSION "\n");
+
+ rtc = rtc_device_register(m41txx_chip->name, &client->dev,
+ &m41txx_rtc_ops, THIS_MODULE);
+
+ if (IS_ERR(rtc)) {
+ rc = PTR_ERR(rtc);
+ goto exit_detach;
+ }
+
+ i2c_set_clientdata(client, rtc);
+
+ if (m41txx_chip->type != M41T00_TYPE_M41T00) {
+ /* If asked, disable SQW, set SQW frequency & re-enable */
+ if (m41txx_chip->sqw_freq)
+ if (((rc = i2c_smbus_read_byte_data(client,
+ m41txx_chip->alarm_mon)) < 0)
+ || ((rc = i2c_smbus_write_byte_data(client,
+ m41txx_chip->alarm_mon,
+ rc & ~0x40)) < 0)
+ || ((rc = i2c_smbus_write_byte_data(client,
+ m41txx_chip->sqw,
+ m41txx_chip->sqw_freq)) < 0)
+ || ((rc = i2c_smbus_write_byte_data(client,
+ m41txx_chip->alarm_mon,
+ rc | 0x40)) < 0))
+ goto sqw_err;
+
+ /* Make sure HT (Halt Update) bit is cleared */
+ if ((rc = i2c_smbus_read_byte_data(client,
+ m41txx_chip->alarm_hour)) < 0)
+ goto ht_err;
+
+ if (rc & M41TXX_ALHOUR_HT) {
+ if (m41txx_chip->features & M41TXX_FEATURE_HT) {
+ m41txx_get_datetime(client, &tm);
+ dev_info(&client->dev,
+ "%s HT bit was set!\n", __FUNCTION__);
+ dev_info(&client->dev,
+ "%s Power Down at %04i-%02i-%02i %02i:%02i:%02i\n",
+ __FUNCTION__, tm.tm_year + 1900,
+ tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
+ tm.tm_min, tm.tm_sec);
+ }
+ if ((rc = i2c_smbus_write_byte_data(client,
+ m41txx_chip->alarm_hour,
+ rc & ~M41TXX_ALHOUR_HT)) < 0)
+ goto ht_err;
+ }
+ }
+
+ /* Make sure ST (stop) bit is cleared */
+ if ((rc = i2c_smbus_read_byte_data(client, m41txx_chip->sec)) < 0)
+ goto st_err;
+
+ if (rc & M41TXX_SEC_ST)
+ if ((rc = i2c_smbus_write_byte_data(client, m41txx_chip->sec,
+ rc & ~M41TXX_SEC_ST)) < 0)
+ goto st_err;
+
+ m41txx_wq = create_singlethread_workqueue(m41txx_chip->name);
+ save_client = client;
+ return 0;
+
+st_err:
+ dev_err(&client->dev, "%s: Can't clear ST bit\n", __FUNCTION__);
+ goto exit_detach;
+ht_err:
+ dev_err(&client->dev, "%s: Can't clear HT bit\n", __FUNCTION__);
+ goto exit_detach;
+sqw_err:
+ dev_err(&client->dev, "%s: Can't set SQW Frequency\n",
+ __FUNCTION__);
+
+exit_detach:
+ i2c_detach_client(client);
+exit_kfree:
+ kfree(client);
+exit:
+ return rc;
+}
+
+static int m41txx_attach(struct i2c_adapter *adap)
+{
+ return i2c_probe(adap, &addr_data, m41txx_probe);
+}
+
+static int m41txx_detach(struct i2c_client *client)
+{
+ int rc;
+
+ struct rtc_device *rtc = i2c_get_clientdata(client);
+
+ if (rtc)
+ rtc_device_unregister(rtc);
+
+ if ((rc = i2c_detach_client(client)) == 0) {
+ if (m41txx_wq)
+ destroy_workqueue(m41txx_wq);
+ kfree(client);
+ }
+
+ return rc;
+}
+
+static int __init m41txx_rtc_init(void)
+{
+ return platform_driver_register(&m41txx_platform_driver);
+}
+
+
+static void __exit m41txx_rtc_exit(void)
+{
+ platform_driver_unregister(&m41txx_platform_driver);
+}
+
+MODULE_AUTHOR
+ ("Mark A. Greer <[email protected]>, Alexander Bigga <[email protected]>");
+MODULE_DESCRIPTION("ST Microelectronics M41T00 RTC I2C Client Driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
+
+module_init(m41txx_rtc_init);
+module_exit(m41txx_rtc_exit);
--- linux-2.6.18-rc3/include/linux/m41t00.h 2006-07-30 20:57:47.000000000
+0200
+++ linux-2.6.18-rc3-mips-dev/include/linux/m41t00.h 2006-08-04
11:50:19.000000000 +0200
@@ -16,6 +16,7 @@
#define M41T00_I2C_ADDR 0x68
#define M41T00_TYPE_M41T00 0
+#define M41T00_TYPE_M41T80 80
#define M41T00_TYPE_M41T81 81
#define M41T00_TYPE_M41T85 85
--
Alexander Bigga Tel: +49 4873 90 10 866
mycable GmbH Fax: +49 4873 901 976
Boeker Stieg 43
D-24613 Aukrug eMail: [email protected]
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