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Subject[PATCH 10/11] rtc: ds1307: use generic nvmem
Date
Instead of adding a binary sysfs attribute from the driver (which suffers
from a race condition as the attribute appears after the device), use the
core to register an nvmem device.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
---
drivers/rtc/rtc-ds1307.c | 88 ++++++++++++------------------------------------
1 file changed, 22 insertions(+), 66 deletions(-)

diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index bac920a50ece..6f91c11a5f03 100644
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -117,7 +117,7 @@ struct ds1307 {
u8 offset; /* register's offset */
u8 regs[11];
u16 nvram_offset;
- struct bin_attribute *nvram;
+ struct nvmem_config nvmem_cfg;
enum ds_type type;
unsigned long flags;
#define HAS_NVRAM 0 /* bit 0 == sysfs file active */
@@ -885,43 +885,24 @@ static const struct rtc_class_ops mcp794xx_rtc_ops = {

/*----------------------------------------------------------------------*/

-static ssize_t
-ds1307_nvram_read(struct file *filp, struct kobject *kobj,
- struct bin_attribute *attr,
- char *buf, loff_t off, size_t count)
+static int ds1307_nvram_read(void *priv, unsigned int offset, void *val,
+ size_t bytes)
{
- struct ds1307 *ds1307;
- int result;
-
- ds1307 = dev_get_drvdata(kobj_to_dev(kobj));
+ struct ds1307 *ds1307 = priv;

- result = regmap_bulk_read(ds1307->regmap, ds1307->nvram_offset + off,
- buf, count);
- if (result)
- dev_err(ds1307->dev, "%s error %d\n", "nvram read", result);
- return result;
+ return regmap_bulk_read(ds1307->regmap, ds1307->nvram_offset + offset,
+ val, bytes);
}

-static ssize_t
-ds1307_nvram_write(struct file *filp, struct kobject *kobj,
- struct bin_attribute *attr,
- char *buf, loff_t off, size_t count)
+static int ds1307_nvram_write(void *priv, unsigned int offset, void *val,
+ size_t bytes)
{
- struct ds1307 *ds1307;
- int result;
+ struct ds1307 *ds1307 = priv;

- ds1307 = dev_get_drvdata(kobj_to_dev(kobj));
-
- result = regmap_bulk_write(ds1307->regmap, ds1307->nvram_offset + off,
- buf, count);
- if (result) {
- dev_err(ds1307->dev, "%s error %d\n", "nvram write", result);
- return result;
- }
- return count;
+ return regmap_bulk_write(ds1307->regmap, ds1307->nvram_offset + offset,
+ val, bytes);
}

-
/*----------------------------------------------------------------------*/

static u8 do_trickle_setup_ds1339(struct ds1307 *ds1307,
@@ -1693,37 +1674,17 @@ static int ds1307_probe(struct i2c_client *client,
}

if (chip->nvram_size) {
-
- ds1307->nvram = devm_kzalloc(ds1307->dev,
- sizeof(struct bin_attribute),
- GFP_KERNEL);
- if (!ds1307->nvram) {
- dev_err(ds1307->dev,
- "cannot allocate memory for nvram sysfs\n");
- } else {
-
- ds1307->nvram->attr.name = "nvram";
- ds1307->nvram->attr.mode = S_IRUGO | S_IWUSR;
-
- sysfs_bin_attr_init(ds1307->nvram);
-
- 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(&ds1307->dev->kobj,
- ds1307->nvram);
- if (err) {
- dev_err(ds1307->dev,
- "unable to create sysfs file: %s\n",
- ds1307->nvram->attr.name);
- } else {
- set_bit(HAS_NVRAM, &ds1307->flags);
- dev_info(ds1307->dev, "%zu bytes nvram\n",
- ds1307->nvram->size);
- }
- }
+ ds1307->nvmem_cfg.name = "ds1307_nvram";
+ ds1307->nvmem_cfg.word_size = 1;
+ ds1307->nvmem_cfg.stride = 1;
+ ds1307->nvmem_cfg.size = chip->nvram_size;
+ ds1307->nvmem_cfg.reg_read = ds1307_nvram_read;
+ ds1307->nvmem_cfg.reg_write = ds1307_nvram_write;
+ ds1307->nvmem_cfg.priv = ds1307;
+ ds1307->nvram_offset = chip->nvram_offset;
+
+ ds1307->rtc->nvmem_config = &ds1307->nvmem_cfg;
+ ds1307->rtc->nvram_old_abi = true;
}

ds1307->rtc->ops = rtc_ops;
@@ -1742,11 +1703,6 @@ static int ds1307_probe(struct i2c_client *client,

static int ds1307_remove(struct i2c_client *client)
{
- struct ds1307 *ds1307 = i2c_get_clientdata(client);
-
- if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags))
- sysfs_remove_bin_file(&ds1307->dev->kobj, ds1307->nvram);
-
return 0;
}

--
2.11.0
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