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Subject[PATCH] i2c: new driver for ds1337 RTC
Date
From
ChangeSet 1.2331, 2005/03/31 14:08:02-08:00, jchapman@katalix.com

[PATCH] i2c: new driver for ds1337 RTC

Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>


drivers/i2c/chips/Kconfig | 11 +
drivers/i2c/chips/Makefile | 1
drivers/i2c/chips/ds1337.c | 402 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 414 insertions(+)


diff -Nru a/drivers/i2c/chips/Kconfig b/drivers/i2c/chips/Kconfig
--- a/drivers/i2c/chips/Kconfig 2005-03-31 15:18:15 -08:00
+++ b/drivers/i2c/chips/Kconfig 2005-03-31 15:18:15 -08:00
@@ -362,6 +362,17 @@
menu "Other I2C Chip support"
depends on I2C

+config SENSORS_DS1337
+ tristate "Dallas Semiconductor DS1337 Real Time Clock"
+ depends on I2C && EXPERIMENTAL
+ select I2C_SENSOR
+ help
+ If you say yes here you get support for Dallas Semiconductor
+ DS1337 real-time clock chips.
+
+ This driver can also be built as a module. If so, the module
+ will be called ds1337.
+
config SENSORS_EEPROM
tristate "EEPROM reader"
depends on I2C && EXPERIMENTAL
diff -Nru a/drivers/i2c/chips/Makefile b/drivers/i2c/chips/Makefile
--- a/drivers/i2c/chips/Makefile 2005-03-31 15:18:15 -08:00
+++ b/drivers/i2c/chips/Makefile 2005-03-31 15:18:15 -08:00
@@ -11,6 +11,7 @@
obj-$(CONFIG_SENSORS_ADM1025) += adm1025.o
obj-$(CONFIG_SENSORS_ADM1026) += adm1026.o
obj-$(CONFIG_SENSORS_ADM1031) += adm1031.o
+obj-$(CONFIG_SENSORS_DS1337) += ds1337.o
obj-$(CONFIG_SENSORS_DS1621) += ds1621.o
obj-$(CONFIG_SENSORS_EEPROM) += eeprom.o
obj-$(CONFIG_SENSORS_FSCHER) += fscher.o
diff -Nru a/drivers/i2c/chips/ds1337.c b/drivers/i2c/chips/ds1337.c
--- /dev/null Wed Dec 31 16:00:00 196900
+++ b/drivers/i2c/chips/ds1337.c 2005-03-31 15:18:15 -08:00
@@ -0,0 +1,402 @@
+/*
+ * linux/drivers/i2c/chips/ds1337.c
+ *
+ * Copyright (C) 2005 James Chapman <jchapman@katalix.com>
+ *
+ * based on linux/drivers/acron/char/pcf8583.c
+ * Copyright (C) 2000 Russell King
+ *
+ * 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.
+ *
+ * Driver for Dallas Semiconductor DS1337 real time clock chip
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/i2c-sensor.h>
+#include <linux/string.h>
+#include <linux/rtc.h> /* get the user-level API */
+#include <linux/bcd.h>
+#include <linux/list.h>
+
+/* Device registers */
+#define DS1337_REG_HOUR 2
+#define DS1337_REG_DAY 3
+#define DS1337_REG_DATE 4
+#define DS1337_REG_MONTH 5
+#define DS1337_REG_CONTROL 14
+#define DS1337_REG_STATUS 15
+
+/* FIXME - how do we export these interface constants? */
+#define DS1337_GET_DATE 0
+#define DS1337_SET_DATE 1
+
+/*
+ * Functions declaration
+ */
+static unsigned short normal_i2c[] = { 0x68, I2C_CLIENT_END };
+static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END };
+
+SENSORS_INSMOD_1(ds1337);
+
+static int ds1337_attach_adapter(struct i2c_adapter *adapter);
+static int ds1337_detect(struct i2c_adapter *adapter, int address, int kind);
+static void ds1337_init_client(struct i2c_client *client);
+static int ds1337_detach_client(struct i2c_client *client);
+static int ds1337_command(struct i2c_client *client, unsigned int cmd,
+ void *arg);
+
+/*
+ * Driver data (common to all clients)
+ */
+static struct i2c_driver ds1337_driver = {
+ .owner = THIS_MODULE,
+ .name = "ds1337",
+ .flags = I2C_DF_NOTIFY,
+ .attach_adapter = ds1337_attach_adapter,
+ .detach_client = ds1337_detach_client,
+ .command = ds1337_command,
+};
+
+/*
+ * Client data (each client gets its own)
+ */
+struct ds1337_data {
+ struct i2c_client client;
+ struct list_head list;
+ int id;
+};
+
+/*
+ * Internal variables
+ */
+static int ds1337_id;
+static LIST_HEAD(ds1337_clients);
+
+static inline int ds1337_read(struct i2c_client *client, u8 reg, u8 *value)
+{
+ s32 tmp = i2c_smbus_read_byte_data(client, reg);
+
+ if (tmp < 0)
+ return -EIO;
+
+ *value = tmp;
+
+ return 0;
+}
+
+/*
+ * Chip access functions
+ */
+static int ds1337_get_datetime(struct i2c_client *client, struct rtc_time *dt)
+{
+ struct ds1337_data *data = i2c_get_clientdata(client);
+ int result;
+ u8 buf[7];
+ u8 val;
+ struct i2c_msg msg[2];
+ u8 offs = 0;
+
+ if (!dt) {
+ dev_dbg(&client->adapter->dev, "%s: EINVAL: dt=NULL\n",
+ __FUNCTION__);
+
+ return -EINVAL;
+ }
+
+ msg[0].addr = client->addr;
+ msg[0].flags = 0;
+ msg[0].len = 1;
+ msg[0].buf = &offs;
+
+ msg[1].addr = client->addr;
+ msg[1].flags = I2C_M_RD;
+ msg[1].len = sizeof(buf);
+ msg[1].buf = &buf[0];
+
+ result = client->adapter->algo->master_xfer(client->adapter,
+ &msg[0], 2);
+
+ dev_dbg(&client->adapter->dev,
+ "%s: [%d] %02x %02x %02x %02x %02x %02x %02x\n",
+ __FUNCTION__, result, buf[0], buf[1], buf[2], buf[3],
+ buf[4], buf[5], buf[6]);
+
+ if (result >= 0) {
+ dt->tm_sec = BCD_TO_BIN(buf[0]);
+ dt->tm_min = BCD_TO_BIN(buf[1]);
+ val = buf[2] & 0x3f;
+ dt->tm_hour = BCD_TO_BIN(val);
+ dt->tm_wday = BCD_TO_BIN(buf[3]) - 1;
+ dt->tm_mday = BCD_TO_BIN(buf[4]);
+ val = buf[5] & 0x7f;
+ dt->tm_mon = BCD_TO_BIN(val);
+ dt->tm_year = 1900 + BCD_TO_BIN(buf[6]);
+ if (buf[5] & 0x80)
+ dt->tm_year += 100;
+
+ dev_dbg(&client->adapter->dev, "%s: secs=%d, mins=%d, "
+ "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
+ __FUNCTION__, dt->tm_sec, dt->tm_min,
+ dt->tm_hour, dt->tm_mday,
+ dt->tm_mon, dt->tm_year, dt->tm_wday);
+ } else {
+ dev_err(&client->adapter->dev, "ds1337[%d]: error reading "
+ "data! %d\n", data->id, result);
+ result = -EIO;
+ }
+
+ return result;
+}
+
+static int ds1337_set_datetime(struct i2c_client *client, struct rtc_time *dt)
+{
+ struct ds1337_data *data = i2c_get_clientdata(client);
+ int result;
+ u8 buf[8];
+ u8 val;
+ struct i2c_msg msg[1];
+
+ if (!dt) {
+ dev_dbg(&client->adapter->dev, "%s: EINVAL: dt=NULL\n",
+ __FUNCTION__);
+
+ return -EINVAL;
+ }
+
+ dev_dbg(&client->adapter->dev, "%s: secs=%d, mins=%d, hours=%d, "
+ "mday=%d, mon=%d, year=%d, wday=%d\n", __FUNCTION__,
+ dt->tm_sec, dt->tm_min, dt->tm_hour,
+ dt->tm_mday, dt->tm_mon, dt->tm_year, dt->tm_wday);
+
+ buf[0] = 0; /* reg offset */
+ buf[1] = BIN_TO_BCD(dt->tm_sec);
+ buf[2] = BIN_TO_BCD(dt->tm_min);
+ buf[3] = BIN_TO_BCD(dt->tm_hour) | (1 << 6);
+ buf[4] = BIN_TO_BCD(dt->tm_wday) + 1;
+ buf[5] = BIN_TO_BCD(dt->tm_mday);
+ buf[6] = BIN_TO_BCD(dt->tm_mon);
+ if (dt->tm_year >= 2000) {
+ val = dt->tm_year - 2000;
+ buf[6] |= (1 << 7);
+ } else {
+ val = dt->tm_year - 1900;
+ }
+ buf[7] = BIN_TO_BCD(val);
+
+ msg[0].addr = client->addr;
+ msg[0].flags = 0;
+ msg[0].len = sizeof(buf);
+ msg[0].buf = &buf[0];
+
+ result = client->adapter->algo->master_xfer(client->adapter,
+ &msg[0], 1);
+ if (result < 0) {
+ dev_err(&client->adapter->dev, "ds1337[%d]: error "
+ "writing data! %d\n", data->id, result);
+ result = -EIO;
+ } else {
+ result = 0;
+ }
+
+ return result;
+}
+
+static int ds1337_command(struct i2c_client *client, unsigned int cmd,
+ void *arg)
+{
+ dev_dbg(&client->adapter->dev, "%s: cmd=%d\n", __FUNCTION__, cmd);
+
+ switch (cmd) {
+ case DS1337_GET_DATE:
+ return ds1337_get_datetime(client, arg);
+
+ case DS1337_SET_DATE:
+ return ds1337_set_datetime(client, arg);
+
+ default:
+ return -EINVAL;
+ }
+}
+
+/*
+ * Public API for access to specific device. Useful for low-level
+ * RTC access from kernel code.
+ */
+int ds1337_do_command(int id, int cmd, void *arg)
+{
+ struct list_head *walk;
+ struct list_head *tmp;
+ struct ds1337_data *data;
+
+ list_for_each_safe(walk, tmp, &ds1337_clients) {
+ data = list_entry(walk, struct ds1337_data, list);
+ if (data->id == id)
+ return ds1337_command(&data->client, cmd, arg);
+ }
+
+ return -ENODEV;
+}
+
+static int ds1337_attach_adapter(struct i2c_adapter *adapter)
+{
+ return i2c_detect(adapter, &addr_data, ds1337_detect);
+}
+
+/*
+ * The following function does more than just detection. If detection
+ * succeeds, it also registers the new chip.
+ */
+static int ds1337_detect(struct i2c_adapter *adapter, int address, int kind)
+{
+ struct i2c_client *new_client;
+ struct ds1337_data *data;
+ int err = 0;
+ const char *name = "";
+
+ if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
+ I2C_FUNC_I2C))
+ goto exit;
+
+ if (!(data = kmalloc(sizeof(struct ds1337_data), GFP_KERNEL))) {
+ err = -ENOMEM;
+ goto exit;
+ }
+ memset(data, 0, sizeof(struct ds1337_data));
+ INIT_LIST_HEAD(&data->list);
+
+ /* The common I2C client data is placed right before the
+ * DS1337-specific data.
+ */
+ new_client = &data->client;
+ i2c_set_clientdata(new_client, data);
+ new_client->addr = address;
+ new_client->adapter = adapter;
+ new_client->driver = &ds1337_driver;
+ new_client->flags = 0;
+
+ /*
+ * Now we do the remaining detection. A negative kind means that
+ * the driver was loaded with no force parameter (default), so we
+ * must both detect and identify the chip. A zero kind means that
+ * the driver was loaded with the force parameter, the detection
+ * step shall be skipped. A positive kind means that the driver
+ * was loaded with the force parameter and a given kind of chip is
+ * requested, so both the detection and the identification steps
+ * are skipped.
+ *
+ * For detection, we read registers that are most likely to cause
+ * detection failure, i.e. those that have more bits with fixed
+ * or reserved values.
+ */
+
+ /* Default to an DS1337 if forced */
+ if (kind == 0)
+ kind = ds1337;
+
+ if (kind < 0) { /* detection and identification */
+ u8 data;
+
+ /* Check that status register bits 6-2 are zero */
+ if ((ds1337_read(new_client, DS1337_REG_STATUS, &data) < 0) ||
+ (data & 0x7c))
+ goto exit_free;
+
+ /* Check for a valid day register value */
+ if ((ds1337_read(new_client, DS1337_REG_DAY, &data) < 0) ||
+ (data == 0) || (data & 0xf8))
+ goto exit_free;
+
+ /* Check for a valid date register value */
+ if ((ds1337_read(new_client, DS1337_REG_DATE, &data) < 0) ||
+ (data == 0) || (data & 0xc0) || ((data & 0x0f) > 9) ||
+ (data >= 0x32))
+ goto exit_free;
+
+ /* Check for a valid month register value */
+ if ((ds1337_read(new_client, DS1337_REG_MONTH, &data) < 0) ||
+ (data == 0) || (data & 0x60) || ((data & 0x0f) > 9) ||
+ ((data >= 0x13) && (data <= 0x19)))
+ goto exit_free;
+
+ /* Check that control register bits 6-5 are zero */
+ if ((ds1337_read(new_client, DS1337_REG_CONTROL, &data) < 0) ||
+ (data & 0x60))
+ goto exit_free;
+
+ kind = ds1337;
+ }
+
+ if (kind == ds1337)
+ name = "ds1337";
+
+ /* We can fill in the remaining client fields */
+ strlcpy(new_client->name, name, I2C_NAME_SIZE);
+
+ /* Tell the I2C layer a new client has arrived */
+ if ((err = i2c_attach_client(new_client)))
+ goto exit_free;
+
+ /* Initialize the DS1337 chip */
+ ds1337_init_client(new_client);
+
+ /* Add client to local list */
+ data->id = ds1337_id++;
+ list_add(&data->list, &ds1337_clients);
+
+ return 0;
+
+exit_free:
+ kfree(data);
+exit:
+ return err;
+}
+
+static void ds1337_init_client(struct i2c_client *client)
+{
+ s32 val;
+
+ /* Ensure that device is set in 24-hour mode */
+ val = i2c_smbus_read_byte_data(client, DS1337_REG_HOUR);
+ if ((val >= 0) && (val & (1 << 6)) == 0)
+ i2c_smbus_write_byte_data(client, DS1337_REG_HOUR,
+ val | (1 << 6));
+}
+
+static int ds1337_detach_client(struct i2c_client *client)
+{
+ int err;
+ struct ds1337_data *data = i2c_get_clientdata(client);
+
+ if ((err = i2c_detach_client(client))) {
+ dev_err(&client->dev, "Client deregistration failed, "
+ "client not detached.\n");
+ return err;
+ }
+
+ list_del(&data->list);
+ kfree(data);
+ return 0;
+}
+
+static int __init ds1337_init(void)
+{
+ return i2c_add_driver(&ds1337_driver);
+}
+
+static void __exit ds1337_exit(void)
+{
+ i2c_del_driver(&ds1337_driver);
+}
+
+MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
+MODULE_DESCRIPTION("DS1337 RTC driver");
+MODULE_LICENSE("GPL");
+
+module_init(ds1337_init);
+module_exit(ds1337_exit);
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