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rtc: ds1307: generalise ram size and offset

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Generalise NVRAM to support RAM with other size and offset, such as the
64 bytes of SRAM on the mcp7941x.

[rdunlap@xenotime.net: fix printk format warning]
Signed-off-by: Austin Boyle <Austin.Boyle@aviatnet.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Cc: David Anders <danders.dev@gmail.com>
Cc: Alessandro Zummo <alessandro.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:
Austin Boyle 2012-03-23 15:02:38 -07:00 committed by Linus Torvalds
parent 40ce972d59
commit 9eab0a788d
1 changed files with 47 additions and 31 deletions
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78
drivers/rtc/rtc-ds1307.c
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@ -105,6 +105,8 @@ enum ds_type {
struct ds1307 {
u8 offset; /* register's offset */
u8 regs[11];
u16 nvram_offset;
struct bin_attribute *nvram;
enum ds_type type;
unsigned long flags;
#define HAS_NVRAM 0 /* bit 0 == sysfs file active */
@ -119,19 +121,22 @@ struct ds1307 {
};
struct chip_desc {
unsigned nvram56:1;
unsigned alarm:1;
u16 nvram_offset;
u16 nvram_size;
};
static const struct chip_desc chips[last_ds_type] = {
[ds_1307] = {
.nvram56 = 1,
.nvram_offset = 8,
.nvram_size = 56,
},
[ds_1337] = {
.alarm = 1,
},
[ds_1338] = {
.nvram56 = 1,
.nvram_offset = 8,
.nvram_size = 56,
},
[ds_1339] = {
.alarm = 1,
@ -139,6 +144,11 @@ static const struct chip_desc chips[last_ds_type] = {
[ds_3231] = {
.alarm = 1,
},
[mcp7941x] = {
/* this is battery backed SRAM */
.nvram_offset = 0x20,
.nvram_size = 0x40,
},
};
static const struct i2c_device_id ds1307_id[] = {
@ -543,8 +553,6 @@ static const struct rtc_class_ops ds13xx_rtc_ops = {
/*----------------------------------------------------------------------*/
#define NVRAM_SIZE 56
static ssize_t
ds1307_nvram_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *attr,
@ -557,14 +565,15 @@ ds1307_nvram_read(struct file *filp, struct kobject *kobj,
client = kobj_to_i2c_client(kobj);
ds1307 = i2c_get_clientdata(client);
if (unlikely(off >= NVRAM_SIZE))
if (unlikely(off >= ds1307->nvram->size))
return 0;
if ((off + count) > NVRAM_SIZE)
count = NVRAM_SIZE - off;
if ((off + count) > ds1307->nvram->size)
count = ds1307->nvram->size - off;
if (unlikely(!count))
return count;
result = ds1307->read_block_data(client, 8 + off, count, buf);
result = ds1307->read_block_data(client, ds1307->nvram_offset + off,
count, buf);
if (result < 0)
dev_err(&client->dev, "%s error %d\n", "nvram read", result);
return result;
@ -582,14 +591,15 @@ ds1307_nvram_write(struct file *filp, struct kobject *kobj,
client = kobj_to_i2c_client(kobj);
ds1307 = i2c_get_clientdata(client);
if (unlikely(off >= NVRAM_SIZE))
if (unlikely(off >= ds1307->nvram->size))
return -EFBIG;
if ((off + count) > NVRAM_SIZE)
count = NVRAM_SIZE - off;
if ((off + count) > ds1307->nvram->size)
count = ds1307->nvram->size - off;
if (unlikely(!count))
return count;
result = ds1307->write_block_data(client, 8 + off, count, buf);
result = ds1307->write_block_data(client, ds1307->nvram_offset + off,
count, buf);
if (result < 0) {
dev_err(&client->dev, "%s error %d\n", "nvram write", result);
return result;
@ -597,17 +607,6 @@ ds1307_nvram_write(struct file *filp, struct kobject *kobj,
return count;
}
static struct bin_attribute nvram = {
.attr = {
.name = "nvram",
.mode = S_IRUGO | S_IWUSR,
},
.read = ds1307_nvram_read,
.write = ds1307_nvram_write,
.size = NVRAM_SIZE,
};
/*----------------------------------------------------------------------*/
static int __devinit ds1307_probe(struct i2c_client *client,
@ -894,16 +893,31 @@ static int __devinit ds1307_probe(struct i2c_client *client,
dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
}
if (chip->nvram56) {
err = sysfs_create_bin_file(&client->dev.kobj, &nvram);
if (err == 0) {
set_bit(HAS_NVRAM, &ds1307->flags);
dev_info(&client->dev, "56 bytes nvram\n");
if (chip->nvram_size) {
ds1307->nvram = kzalloc(sizeof(struct bin_attribute),
GFP_KERNEL);
if (!ds1307->nvram) {
err = -ENOMEM;
goto exit_nvram;
}
ds1307->nvram->attr.name = "nvram";
ds1307->nvram->attr.mode = S_IRUGO | S_IWUSR;
ds1307->nvram->read = ds1307_nvram_read,
ds1307->nvram->write = ds1307_nvram_write,
ds1307->nvram->size = chip->nvram_size;
ds1307->nvram_offset = chip->nvram_offset;
err = sysfs_create_bin_file(&client->dev.kobj, ds1307->nvram);
if (err) {
kfree(ds1307->nvram);
goto exit_nvram;
}
set_bit(HAS_NVRAM, &ds1307->flags);
dev_info(&client->dev, "%zu bytes nvram\n", ds1307->nvram->size);
}
return 0;
exit_nvram:
exit_irq:
rtc_device_unregister(ds1307->rtc);
exit_free:
@ -920,8 +934,10 @@ static int __devexit ds1307_remove(struct i2c_client *client)
cancel_work_sync(&ds1307->work);
}
if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags))
sysfs_remove_bin_file(&client->dev.kobj, &nvram);
if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags)) {
sysfs_remove_bin_file(&client->dev.kobj, ds1307->nvram);
kfree(ds1307->nvram);
}
rtc_device_unregister(ds1307->rtc);
kfree(ds1307);