Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=aa5bd7e929325dbb48be43c3dccf7d1da433e38e
Commit:     aa5bd7e929325dbb48be43c3dccf7d1da433e38e
Parent:     e9f2bd8191a416fbd17e8bfc002dba5411937997
Author:     Dale Farnsworth <[EMAIL PROTECTED]>
AuthorDate: Tue May 8 00:26:39 2007 -0700
Committer:  Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Tue May 8 11:15:03 2007 -0700

    rtc: add RTC class driver for the Maxim MAX6900
    
    Signed-off-by: Dale Farnsworth.org <[EMAIL PROTECTED]>
    Cc: Alessandro Zummo <[EMAIL PROTECTED]>
    Cc: David Brownell <[EMAIL PROTECTED]>
    Cc: Jean Delvare <[EMAIL PROTECTED]>
    Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
    Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
 drivers/rtc/Kconfig       |   10 ++
 drivers/rtc/Makefile      |    1 +
 drivers/rtc/rtc-max6900.c |  311 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 322 insertions(+), 0 deletions(-)

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 372d749..1b853c4 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -334,6 +334,16 @@ config RTC_DRV_TEST
          This driver can also be built as a module. If so, the module
          will be called rtc-test.
 
+config RTC_DRV_MAX6900
+       tristate "Maxim 6900"
+       depends on RTC_CLASS && I2C
+       help
+         If you say yes here you will get support for the
+         Maxim MAX6900 I2C RTC chip.
+
+         This driver can also be built as a module. If so, the module
+         will be called rtc-max6900.
+
 config RTC_DRV_MAX6902
        tristate "Maxim 6902"
        depends on RTC_CLASS && SPI
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index cad027d..f9a3e01 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -35,6 +35,7 @@ obj-$(CONFIG_RTC_DRV_EP93XX)  += rtc-ep93xx.o
 obj-$(CONFIG_RTC_DRV_SA1100)   += rtc-sa1100.o
 obj-$(CONFIG_RTC_DRV_VR41XX)   += rtc-vr41xx.o
 obj-$(CONFIG_RTC_DRV_PL031)    += rtc-pl031.o
+obj-$(CONFIG_RTC_DRV_MAX6900)  += rtc-max6900.o
 obj-$(CONFIG_RTC_DRV_MAX6902)  += rtc-max6902.o
 obj-$(CONFIG_RTC_DRV_V3020)    += rtc-v3020.o
 obj-$(CONFIG_RTC_DRV_AT91RM9200)+= rtc-at91rm9200.o
diff --git a/drivers/rtc/rtc-max6900.c b/drivers/rtc/rtc-max6900.c
new file mode 100644
index 0000000..eee4ee5
--- /dev/null
+++ b/drivers/rtc/rtc-max6900.c
@@ -0,0 +1,311 @@
+/*
+ * rtc class driver for the Maxim MAX6900 chip
+ *
+ * Author: Dale Farnsworth <[EMAIL PROTECTED]>
+ *
+ * based on previously existing rtc class drivers
+ *
+ * 2007 (c) MontaVista, Software, Inc.  This file is licensed under
+ * the terms of the GNU General Public License version 2.  This program
+ * is licensed "as is" without any warranty of any kind, whether express
+ * or implied.
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/bcd.h>
+#include <linux/rtc.h>
+#include <linux/delay.h>
+
+#define DRV_NAME "max6900"
+#define DRV_VERSION "0.1"
+
+/*
+ * register indices
+ */
+#define MAX6900_REG_SC                 0       /* seconds      00-59 */
+#define MAX6900_REG_MN                 1       /* minutes      00-59 */
+#define MAX6900_REG_HR                 2       /* hours        00-23 */
+#define MAX6900_REG_DT                 3       /* day of month 00-31 */
+#define MAX6900_REG_MO                 4       /* month        01-12 */
+#define MAX6900_REG_DW                 5       /* day of week   1-7  */
+#define MAX6900_REG_YR                 6       /* year         00-99 */
+#define MAX6900_REG_CT                 7       /* control */
+#define MAX6900_REG_LEN                        8
+
+#define MAX6900_REG_CT_WP              (1 << 7)        /* Write Protect */
+
+/*
+ * register read/write commands
+ */
+#define MAX6900_REG_CONTROL_WRITE      0x8e
+#define MAX6900_REG_BURST_READ         0xbf
+#define MAX6900_REG_BURST_WRITE                0xbe
+#define MAX6900_REG_RESERVED_READ      0x96
+
+#define MAX6900_IDLE_TIME_AFTER_WRITE  3       /* specification says 2.5 mS */
+
+#define MAX6900_I2C_ADDR               0xa0
+
+static unsigned short normal_i2c[] = {
+       MAX6900_I2C_ADDR >> 1,
+       I2C_CLIENT_END
+};
+
+I2C_CLIENT_INSMOD;                     /* defines addr_data */
+
+static int max6900_probe(struct i2c_adapter *adapter, int addr, int kind);
+
+static int max6900_i2c_read_regs(struct i2c_client *client, u8 *buf)
+{
+       u8 reg_addr[1] = { MAX6900_REG_BURST_READ };
+       struct i2c_msg msgs[2] = {
+               {
+                       .addr   = client->addr,
+                       .flags  = 0, /* write */
+                       .len    = sizeof(reg_addr),
+                       .buf    = reg_addr
+               },
+               {
+                       .addr   = client->addr,
+                       .flags  = I2C_M_RD,
+                       .len    = MAX6900_REG_LEN,
+                       .buf    = buf
+               }
+       };
+       int rc;
+
+       rc = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
+       if (rc != ARRAY_SIZE(msgs)) {
+               dev_err(&client->dev, "%s: register read failed\n",
+                       __FUNCTION__);
+               return -EIO;
+       }
+       return 0;
+}
+
+static int max6900_i2c_write_regs(struct i2c_client *client, u8 const *buf)
+{
+       u8 i2c_buf[MAX6900_REG_LEN + 1] = { MAX6900_REG_BURST_WRITE };
+       struct i2c_msg msgs[1] = {
+               {
+                       .addr   = client->addr,
+                       .flags  = 0, /* write */
+                       .len    = MAX6900_REG_LEN + 1,
+                       .buf    = i2c_buf
+               }
+       };
+       int rc;
+
+       memcpy(&i2c_buf[1], buf, MAX6900_REG_LEN);
+
+       rc = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
+       if (rc != ARRAY_SIZE(msgs)) {
+               dev_err(&client->dev, "%s: register write failed\n",
+                       __FUNCTION__);
+               return -EIO;
+       }
+       msleep(MAX6900_IDLE_TIME_AFTER_WRITE);
+       return 0;
+}
+
+static int max6900_i2c_validate_client(struct i2c_client *client)
+{
+       u8 regs[MAX6900_REG_LEN];
+       u8 zero_mask[MAX6900_REG_LEN] = {
+               0x80,   /* seconds */
+               0x80,   /* minutes */
+               0x40,   /* hours */
+               0xc0,   /* day of month */
+               0xe0,   /* month */
+               0xf8,   /* day of week */
+               0x00,   /* year */
+               0x7f,   /* control */
+       };
+       int i;
+       int rc;
+       int reserved;
+
+       reserved = i2c_smbus_read_byte_data(client, MAX6900_REG_RESERVED_READ);
+       if (reserved != 0x07)
+               return -ENODEV;
+
+       rc = max6900_i2c_read_regs(client, regs);
+       if (rc < 0)
+               return rc;
+
+       for (i = 0; i < MAX6900_REG_LEN; ++i) {
+               if (regs[i] & zero_mask[i])
+                       return -ENODEV;
+       }
+
+       return 0;
+}
+
+static int max6900_i2c_read_time(struct i2c_client *client, struct rtc_time 
*tm)
+{
+       int rc;
+       u8 regs[MAX6900_REG_LEN];
+
+       rc = max6900_i2c_read_regs(client, regs);
+       if (rc < 0)
+               return rc;
+
+       tm->tm_sec = BCD2BIN(regs[MAX6900_REG_SC]);
+       tm->tm_min = BCD2BIN(regs[MAX6900_REG_MN]);
+       tm->tm_hour = BCD2BIN(regs[MAX6900_REG_HR] & 0x3f);
+       tm->tm_mday = BCD2BIN(regs[MAX6900_REG_DT]);
+       tm->tm_mon = BCD2BIN(regs[MAX6900_REG_MO]) - 1;
+       tm->tm_year = BCD2BIN(regs[MAX6900_REG_YR]) + 100;
+       tm->tm_wday = BCD2BIN(regs[MAX6900_REG_DW]);
+
+       return 0;
+}
+
+static int max6900_i2c_clear_write_protect(struct i2c_client *client)
+{
+       int rc;
+       rc = i2c_smbus_write_byte_data (client, MAX6900_REG_CONTROL_WRITE, 0);
+       if (rc < 0) {
+               dev_err(&client->dev, "%s: control register write failed\n",
+                       __FUNCTION__);
+               return -EIO;
+       }
+       return 0;
+}
+
+static int max6900_i2c_set_time(struct i2c_client *client,
+                               struct rtc_time const *tm)
+{
+       u8 regs[MAX6900_REG_LEN];
+       int rc;
+
+       rc = max6900_i2c_clear_write_protect(client);
+       if (rc < 0)
+               return rc;
+
+       regs[MAX6900_REG_SC] = BIN2BCD(tm->tm_sec);
+       regs[MAX6900_REG_MN] = BIN2BCD(tm->tm_min);
+       regs[MAX6900_REG_HR] = BIN2BCD(tm->tm_hour);
+       regs[MAX6900_REG_DT] = BIN2BCD(tm->tm_mday);
+       regs[MAX6900_REG_MO] = BIN2BCD(tm->tm_mon + 1);
+       regs[MAX6900_REG_YR] = BIN2BCD(tm->tm_year - 100);
+       regs[MAX6900_REG_DW] = BIN2BCD(tm->tm_wday);
+       regs[MAX6900_REG_CT] = MAX6900_REG_CT_WP;       /* set write protect */
+
+       rc = max6900_i2c_write_regs(client, regs);
+       if (rc < 0)
+               return rc;
+
+       return 0;
+}
+
+static int max6900_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+       return max6900_i2c_read_time(to_i2c_client(dev), tm);
+}
+
+static int max6900_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+       return max6900_i2c_set_time(to_i2c_client(dev), tm);
+}
+
+static int max6900_attach_adapter(struct i2c_adapter *adapter)
+{
+       return i2c_probe(adapter, &addr_data, max6900_probe);
+}
+
+static int max6900_detach_client(struct i2c_client *client)
+{
+       struct rtc_device *const rtc = i2c_get_clientdata(client);
+
+       if (rtc)
+               rtc_device_unregister(rtc);
+
+       return i2c_detach_client(client);
+}
+
+static struct i2c_driver max6900_driver = {
+       .driver         = {
+               .name   = DRV_NAME,
+       },
+       .id             = I2C_DRIVERID_MAX6900,
+       .attach_adapter = max6900_attach_adapter,
+       .detach_client  = max6900_detach_client,
+};
+
+static const struct rtc_class_ops max6900_rtc_ops = {
+       .read_time      = max6900_rtc_read_time,
+       .set_time       = max6900_rtc_set_time,
+};
+
+static int max6900_probe(struct i2c_adapter *adapter, int addr, int kind)
+{
+       int rc = 0;
+       struct i2c_client *client = NULL;
+       struct rtc_device *rtc = NULL;
+
+       if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {
+               rc = -ENODEV;
+               goto failout;
+       }
+
+       client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
+       if (client == NULL) {
+               rc = -ENOMEM;
+               goto failout;
+       }
+
+       client->addr = addr;
+       client->adapter = adapter;
+       client->driver = &max6900_driver;
+       strlcpy(client->name, DRV_NAME, I2C_NAME_SIZE);
+
+       if (kind < 0) {
+               rc = max6900_i2c_validate_client(client);
+               if (rc < 0)
+                       goto failout;
+       }
+
+       rc = i2c_attach_client(client);
+       if (rc < 0)
+               goto failout;
+
+       dev_info(&client->dev,
+                "chip found, driver version " DRV_VERSION "\n");
+
+       rtc = rtc_device_register(max6900_driver.driver.name,
+                                 &client->dev,
+                                 &max6900_rtc_ops, THIS_MODULE);
+       if (IS_ERR(rtc)) {
+               rc = PTR_ERR(rtc);
+               goto failout_detach;
+       }
+
+       i2c_set_clientdata(client, rtc);
+
+       return 0;
+
+failout_detach:
+       i2c_detach_client(client);
+failout:
+       kfree(client);
+       return rc;
+}
+
+static int __init max6900_init(void)
+{
+       return i2c_add_driver(&max6900_driver);
+}
+
+static void __exit max6900_exit(void)
+{
+       i2c_del_driver(&max6900_driver);
+}
+
+MODULE_DESCRIPTION("Maxim MAX6900 RTC driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
+
+module_init(max6900_init);
+module_exit(max6900_exit);
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