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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>
This commit is contained in:
Andreas Werner 2014-01-23 15:55:20 -08:00 committed by Linus Torvalds
parent 11ba5a1eeb
commit d643a49ae1
1 changed files with 68 additions and 13 deletions
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81
drivers/rtc/rtc-rx8581.c
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@ -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;
rx8581 = devm_kzalloc(&client->dev, sizeof(struct rx8581), GFP_KERNEL);
if (!rx8581)
return -ENOMEM;
i2c_set_clientdata(client, rx8581);
rx8581->client = client;
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;
}
dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
rtc = devm_rtc_device_register(&client->dev, rx8581_driver.driver.name,
&rx8581_rtc_ops, THIS_MODULE);
rx8581->rtc = devm_rtc_device_register(&client->dev,
rx8581_driver.driver.name, &rx8581_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc))
return PTR_ERR(rtc);
i2c_set_clientdata(client, rtc);
if (IS_ERR(rx8581->rtc)) {
dev_err(&client->dev,
"unable to register the class device\n");
return PTR_ERR(rx8581->rtc);
}
return 0;
}