diff options
| -rw-r--r-- | drivers/rtc/Kconfig | 4 | ||||
| -rw-r--r-- | drivers/rtc/rtc-ds1307.c | 93 |
2 files changed, 95 insertions, 2 deletions
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig index 7958635f12cc..e5cdc0294aaa 100644 --- a/drivers/rtc/Kconfig +++ b/drivers/rtc/Kconfig @@ -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. diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c index db6f3f0d8982..bc1c7fe94ad3 100644 --- a/drivers/rtc/rtc-ds1307.c +++ b/drivers/rtc/rtc-ds1307.c @@ -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; |