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Commit 682d73f6 authored by David Brownell's avatar David Brownell Committed by Linus Torvalds
Browse files

rtc-ds1307 exports NVRAM 



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: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Acked-by: default avatarAlessandro Zummo <a.zummo@towertech.it>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a4b1d50e

drivers/rtc/Kconfig

+2 −2
Original line number Diff line number Diff line
@@ -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.

drivers/rtc/rtc-ds1307.c

+93 −0
Original line number Diff line number Diff line
@@ -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 @@ static int __devinit ds1307_probe(struct i2c_client *client) 
		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;