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Subject[PATCH] rtc: Add SMBus-only adapters support to rtc-rx8581
This patch adds support for SMBus-only adapters (e.g. i2c-piix4).
The driver has implementet only support for I2C adapter
which implements 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>
---
drivers/rtc/rtc-rx8581.c | 81 ++++++++++++++++++++++++++++++++++++++++--------
1 file changed, 68 insertions(+), 13 deletions(-)

diff --git a/drivers/rtc/rtc-rx8581.c b/drivers/rtc/rtc-rx8581.c
index 00b0eb7..de8d9c4 100644
--- 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;
}
--
1.8.3.2


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