drivers/rtc/rtc-rx8581.c: add SMBus-only adapters support

Add support for SMBus-only adapters (e.g.  i2c-piix4).  The driver has
implemented only support for I2C adapters which implement the
I2C_FUNC_SMBUS_I2C_BLOCK functionality before.

With this patch it is possible to load and use the RTC driver with I2C and
SMBUS adapters like the rtc-ds1307 does.

Tested on AMD G Series Platform (i2c-piix4 adapter driver).

Signed-off-by: Andreas Werner <andreas.werner@men.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/rtc/rtc-rx8581.c b/drivers/rtc/rtc-rx8581.c
index 00b0eb7..de8d9c4 100644 (file)
--- a/drivers/rtc/rtc-rx8581.c
+++ b/drivers/rtc/rtc-rx8581.c
@@ -52,8 +52,45 @@
 #define RX8581_CTRL_STOP       0x02 /* STOP bit */
 #define RX8581_CTRL_RESET      0x01 /* RESET bit */
 
+struct rx8581 {
+       struct i2c_client       *client;
+       struct rtc_device       *rtc;
+       s32 (*read_block_data)(const struct i2c_client *client, u8 command,
+                               u8 length, u8 *values);
+       s32 (*write_block_data)(const struct i2c_client *client, u8 command,
+                               u8 length, const u8 *values);
+};
+
 static struct i2c_driver rx8581_driver;
 
+static int rx8581_read_block_data(const struct i2c_client *client, u8 command,
+                                       u8 length, u8 *values)
+{
+       s32 i, data;
+
+       for (i = 0; i < length; i++) {
+               data = i2c_smbus_read_byte_data(client, command + i);
+               if (data < 0)
+                       return data;
+               values[i] = data;
+       }
+       return i;
+}
+
+static int rx8581_write_block_data(const struct i2c_client *client, u8 command,
+                                       u8 length, const u8 *values)
+{
+       s32 i, ret;
+
+       for (i = 0; i < length; i++) {
+               ret = i2c_smbus_write_byte_data(client, command + i,
+                                               values[i]);
+               if (ret < 0)
+                       return ret;
+       }
+       return length;
+}
+
 /*
  * In the routines that deal directly with the rx8581 hardware, we use
  * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
@@ -62,6 +99,7 @@ static int rx8581_get_datetime(struct i2c_client *client, struct rtc_time *tm)
 {
        unsigned char date[7];
        int data, err;
+       struct rx8581 *rx8581 = i2c_get_clientdata(client);
 
        /* First we ensure that the "update flag" is not set, we read the
         * time and date then re-read the "update flag". If the update flag
@@ -80,14 +118,13 @@ static int rx8581_get_datetime(struct i2c_client *client, struct rtc_time *tm)
                        err = i2c_smbus_write_byte_data(client,
                                RX8581_REG_FLAG, (data & ~RX8581_FLAG_UF));
                        if (err != 0) {
-                               dev_err(&client->dev, "Unable to write device "
-                                       "flags\n");
+                               dev_err(&client->dev, "Unable to write device flags\n");
                                return -EIO;
                        }
                }
 
                /* Now read time and date */
-               err = i2c_smbus_read_i2c_block_data(client, RX8581_REG_SC,
+               err = rx8581->read_block_data(client, RX8581_REG_SC,
                        7, date);
                if (err < 0) {
                        dev_err(&client->dev, "Unable to read date\n");
@@ -140,6 +177,7 @@ static int rx8581_set_datetime(struct i2c_client *client, struct rtc_time *tm)
 {
        int data, err;
        unsigned char buf[7];
+       struct rx8581 *rx8581 = i2c_get_clientdata(client);
 
        dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
                "mday=%d, mon=%d, year=%d, wday=%d\n",
@@ -176,7 +214,7 @@ static int rx8581_set_datetime(struct i2c_client *client, struct rtc_time *tm)
        }
 
        /* write register's data */
-       err = i2c_smbus_write_i2c_block_data(client, RX8581_REG_SC, 7, buf);
+       err = rx8581->write_block_data(client, RX8581_REG_SC, 7, buf);
        if (err < 0) {
                dev_err(&client->dev, "Unable to write to date registers\n");
                return -EIO;
@@ -231,22 +269,39 @@ static const struct rtc_class_ops rx8581_rtc_ops = {
 static int rx8581_probe(struct i2c_client *client,
                        const struct i2c_device_id *id)
 {
-       struct rtc_device *rtc;
+       struct rx8581     *rx8581;
 
        dev_dbg(&client->dev, "%s\n", __func__);
 
-       if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
-               return -ENODEV;
+       if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA)
+               && !i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
+               return -EIO;
 
-       dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
+       rx8581 = devm_kzalloc(&client->dev, sizeof(struct rx8581), GFP_KERNEL);
+       if (!rx8581)
+               return -ENOMEM;
 
-       rtc = devm_rtc_device_register(&client->dev, rx8581_driver.driver.name,
-                                       &rx8581_rtc_ops, THIS_MODULE);
+       i2c_set_clientdata(client, rx8581);
+       rx8581->client = client;
 
-       if (IS_ERR(rtc))
-               return PTR_ERR(rtc);
+       if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
+               rx8581->read_block_data = i2c_smbus_read_i2c_block_data;
+               rx8581->write_block_data = i2c_smbus_write_i2c_block_data;
+       } else {
+               rx8581->read_block_data = rx8581_read_block_data;
+               rx8581->write_block_data = rx8581_write_block_data;
+       }
 
-       i2c_set_clientdata(client, rtc);
+       dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
+
+       rx8581->rtc = devm_rtc_device_register(&client->dev,
+               rx8581_driver.driver.name, &rx8581_rtc_ops, THIS_MODULE);
+
+       if (IS_ERR(rx8581->rtc)) {
+               dev_err(&client->dev,
+                       "unable to register the class device\n");
+               return PTR_ERR(rx8581->rtc);
+       }
 
        return 0;
 }