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Subject[PATCH 2.6.26.5] rtc-ds1307 : SMBus compatibility
This patch change all i2c access functions to SMBus access functions in order to use the ds1307 on SMBus.
I expect that using SMBus access functions is correct for all boards with i2C or SMBus adapter. Is it correct ?

I have tested it on my Geode LX board with a ds1307 device.

Please CC me your comments.
Thanks.

--- a/drivers/rtc/rtc-ds1307.c 2008-09-08 17:40:20.000000000 +0000
+++ b/drivers/rtc/rtc-ds1307.c 2008-10-07 13:21:57.000000000 +0000
@@ -92,7 +92,6 @@ struct ds1307 {
bool has_nvram;
u8 regs[8];
enum ds_type type;
- struct i2c_msg msg[2];
struct i2c_client *client;
struct i2c_client dev;
struct rtc_device *rtc;
@@ -138,12 +137,10 @@ static int ds1307_get_time(struct device
int tmp;

/* read the RTC date and time registers all at once */
- ds1307->msg[1].flags = I2C_M_RD;
- ds1307->msg[1].len = 7;
-
- tmp = i2c_transfer(to_i2c_adapter(ds1307->client->dev.parent),
- ds1307->msg, 2);
- if (tmp != 2) {
+ u8 *buf = ds1307->regs;
+ tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
+ DS1307_REG_SECS, 7, buf);
+ if (tmp != 7) {
dev_err(dev, "%s error %d\n", "read", tmp);
return -EIO;
}
@@ -180,7 +177,6 @@ static int ds1307_get_time(struct device
static int ds1307_set_time(struct device *dev, struct rtc_time *t)
{
struct ds1307 *ds1307 = dev_get_drvdata(dev);
- int result;
int tmp;
u8 *buf = ds1307->regs;

@@ -190,7 +186,6 @@ static int ds1307_set_time(struct device
t->tm_hour, t->tm_mday,
t->tm_mon, t->tm_year, t->tm_wday);

- *buf++ = 0; /* first register addr */
buf[DS1307_REG_SECS] = BIN2BCD(t->tm_sec);
buf[DS1307_REG_MIN] = BIN2BCD(t->tm_min);
buf[DS1307_REG_HOUR] = BIN2BCD(t->tm_hour);
@@ -215,16 +210,12 @@ static int ds1307_set_time(struct device
break;
}

- ds1307->msg[1].flags = 0;
- ds1307->msg[1].len = 8;
-
dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
"write", buf[0], buf[1], buf[2], buf[3],
buf[4], buf[5], buf[6]);

- result = i2c_transfer(to_i2c_adapter(ds1307->client->dev.parent),
- &ds1307->msg[1], 1);
- if (result != 1) {
+ tmp = i2c_smbus_write_i2c_block_data(ds1307->client, 0, 7, buf);
+ if (tmp < 0) {
dev_err(dev, "%s error %d\n", "write", tmp);
return -EIO;
}
@@ -246,8 +237,7 @@ ds1307_nvram_read(struct kobject *kobj,
{
struct i2c_client *client;
struct ds1307 *ds1307;
- struct i2c_msg msg[2];
- int result;
+ int tmp;

client = kobj_to_i2c_client(kobj);
ds1307 = i2c_get_clientdata(client);
@@ -259,24 +249,13 @@ ds1307_nvram_read(struct kobject *kobj,
if (unlikely(!count))
return count;

- msg[0].addr = client->addr;
- msg[0].flags = 0;
- msg[0].len = 1;
- msg[0].buf = buf;
-
- buf[0] = 8 + off;
-
- msg[1].addr = client->addr;
- msg[1].flags = I2C_M_RD;
- msg[1].len = count;
- msg[1].buf = buf;
-
- result = i2c_transfer(to_i2c_adapter(client->dev.parent), msg, 2);
- if (result != 2) {
- dev_err(&client->dev, "%s error %d\n", "nvram read", result);
+ tmp = i2c_smbus_read_i2c_block_data(client, 8 + off, count, buf);
+ if (tmp < 0) {
+ dev_err(&client->dev, "%s error %d\n", "read", tmp);
return -EIO;
}
- return count;
+
+ return tmp;
}

static ssize_t
@@ -284,8 +263,8 @@ ds1307_nvram_write(struct kobject *kobj,
char *buf, loff_t off, size_t count)
{
struct i2c_client *client;
- u8 buffer[NVRAM_SIZE + 1];
- int ret;
+ u8 buffer[NVRAM_SIZE];
+ int tmp;

client = kobj_to_i2c_client(kobj);

@@ -296,11 +275,14 @@ ds1307_nvram_write(struct kobject *kobj,
if (unlikely(!count))
return count;

- buffer[0] = 8 + off;
- memcpy(buffer + 1, buf, count);
+ memcpy(buffer, buf, count);

- ret = i2c_master_send(client, buffer, count + 1);
- return (ret < 0) ? ret : (ret - 1);
+ tmp = i2c_smbus_write_i2c_block_data(client, 8 + off, count, buffer);
+ if (tmp < 0) {
+ dev_err(&client->dev, "%s error %d\n", "write", tmp);
+ return -EIO;
+ }
+ return count;
}

static struct bin_attribute nvram = {
@@ -325,11 +307,15 @@ static int __devinit ds1307_probe(struct
struct ds1307 *ds1307;
int err = -ENODEV;
int tmp;
+ u8 *buf;
+
const struct chip_desc *chip = &chips[id->driver_data];
struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);

if (!i2c_check_functionality(adapter,
- I2C_FUNC_I2C | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
+ I2C_FUNC_SMBUS_WRITE_BYTE_DATA
+ | I2C_FUNC_SMBUS_WRITE_I2C_BLOCK
+ | I2C_FUNC_SMBUS_READ_I2C_BLOCK))
return -EIO;

if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL)))
@@ -338,35 +324,21 @@ static int __devinit ds1307_probe(struct
ds1307->client = client;
i2c_set_clientdata(client, ds1307);

- ds1307->msg[0].addr = client->addr;
- ds1307->msg[0].flags = 0;
- ds1307->msg[0].len = 1;
- ds1307->msg[0].buf = &ds1307->reg_addr;
-
- ds1307->msg[1].addr = client->addr;
- ds1307->msg[1].flags = I2C_M_RD;
- ds1307->msg[1].len = sizeof(ds1307->regs);
- ds1307->msg[1].buf = ds1307->regs;
-
ds1307->type = id->driver_data;

switch (ds1307->type) {
case ds_1337:
case ds_1339:
- ds1307->reg_addr = DS1337_REG_CONTROL;
- ds1307->msg[1].len = 2;
-
+ buf = &ds1307->regs[DS1337_REG_CONTROL];
/* get registers that the "rtc" read below won't read... */
- tmp = i2c_transfer(adapter, ds1307->msg, 2);
+ tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
+ DS1337_REG_CONTROL, 2, buf);
if (tmp != 2) {
pr_debug("read error %d\n", tmp);
err = -EIO;
goto exit_free;
}

- ds1307->reg_addr = 0;
- ds1307->msg[1].len = sizeof(ds1307->regs);
-
/* oscillator off? turn it on, so clock can tick. */
if (ds1307->regs[0] & DS1337_BIT_nEOSC)
i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
@@ -385,9 +357,9 @@ static int __devinit ds1307_probe(struct

read_rtc:
/* read RTC registers */
-
- tmp = i2c_transfer(adapter, ds1307->msg, 2);
- if (tmp != 2) {
+ buf = ds1307->regs;
+ tmp = i2c_smbus_read_i2c_block_data(ds1307->client, 0, 8, buf);
+ if (tmp != 8) {
pr_debug("read error %d\n", tmp);
err = -EIO;
goto exit_free;
--
Sébastien Barré
Bureau d'étude - Développement
SDEL Contrôle Commande
D2A - Rue Nungesser et Coli
44860 Saint Aignan de Grand Lieu
FRANCE
Tél : +33(0)2 40 84 50 88
Fax : +33(0)2 40 84 51 10
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