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rtc-ds1307 exports NVRAM

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Export the NVRAM on DS1307 and DS1338 chips, like several of the
other drivers do for such combination RTC-and-NVRAM chips.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
David Brownell 2007-11-14 16:58:32 -08:00 committed by Linus Torvalds
parent a4b1d50e61
commit 682d73f685
2 changed files with 95 additions and 2 deletions
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4
drivers/rtc/Kconfig
View file

@ -135,8 +135,8 @@ config RTC_DRV_DS1307
The first seven registers on these chips hold an RTC, and other
registers may add features such as NVRAM, a trickle charger for
the RTC/NVRAM backup power, and alarms. This driver may not
expose all those available chip features.
the RTC/NVRAM backup power, and alarms. NVRAM is visible in
sysfs, but other chip features may not be available.
This driver can also be built as a module. If so, the module
will be called rtc-ds1307.

93
drivers/rtc/rtc-ds1307.c
View file

@ -89,6 +89,7 @@ enum ds_type {
struct ds1307 {
u8 reg_addr;
bool has_nvram;
u8 regs[8];
enum ds_type type;
struct i2c_msg msg[2];
@ -242,6 +243,87 @@ static const struct rtc_class_ops ds13xx_rtc_ops = {
.set_time = ds1307_set_time,
};
/*----------------------------------------------------------------------*/
#define NVRAM_SIZE 56
static ssize_t
ds1307_nvram_read(struct kobject *kobj, struct bin_attribute *attr,
char *buf, loff_t off, size_t count)
{
struct i2c_client *client;
struct ds1307 *ds1307;
struct i2c_msg msg[2];
int result;
client = to_i2c_client(container_of(kobj, struct device, kobj));
ds1307 = i2c_get_clientdata(client);
if (unlikely(off >= NVRAM_SIZE))
return 0;
if ((off + count) > NVRAM_SIZE)
count = NVRAM_SIZE - off;
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);
return -EIO;
}
return count;
}
static ssize_t
ds1307_nvram_write(struct kobject *kobj, struct bin_attribute *attr,
char *buf, loff_t off, size_t count)
{
struct i2c_client *client;
u8 buffer[NVRAM_SIZE + 1];
int ret;
client = to_i2c_client(container_of(kobj, struct device, kobj));
if (unlikely(off >= NVRAM_SIZE))
return -EFBIG;
if ((off + count) > NVRAM_SIZE)
count = NVRAM_SIZE - off;
if (unlikely(!count))
return count;
buffer[0] = 8 + off;
memcpy(buffer + 1, buf, count);
ret = i2c_master_send(client, buffer, count + 1);
return (ret < 0) ? ret : (ret - 1);
}
static struct bin_attribute nvram = {
.attr = {
.name = "nvram",
.mode = S_IRUGO | S_IWUSR,
.owner = THIS_MODULE,
},
.read = ds1307_nvram_read,
.write = ds1307_nvram_write,
.size = NVRAM_SIZE,
};
/*----------------------------------------------------------------------*/
static struct i2c_driver ds1307_driver;
static int __devinit ds1307_probe(struct i2c_client *client)
@ -413,6 +495,14 @@ read_rtc:
goto exit_free;
}
if (chip->nvram56) {
err = sysfs_create_bin_file(&client->dev.kobj, &nvram);
if (err == 0) {
ds1307->has_nvram = true;
dev_info(&client->dev, "56 bytes nvram\n");
}
}
return 0;
exit_bad:
@ -432,6 +522,9 @@ static int __devexit ds1307_remove(struct i2c_client *client)
{
struct ds1307 *ds1307 = i2c_get_clientdata(client);
if (ds1307->has_nvram)
sysfs_remove_bin_file(&client->dev.kobj, &nvram);
rtc_device_unregister(ds1307->rtc);
kfree(ds1307);
return 0;