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Subject[PATCH 34/45] rtc: ds1742: 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@bootlin.com>
---
drivers/rtc/rtc-ds1742.c | 67 +++++++++++++++++++-----------------------------
1 file changed, 26 insertions(+), 41 deletions(-)

diff --git a/drivers/rtc/rtc-ds1742.c b/drivers/rtc/rtc-ds1742.c
index 84e19fe2ca3b..52baf925a690 100644
--- a/drivers/rtc/rtc-ds1742.c
+++ b/drivers/rtc/rtc-ds1742.c
@@ -53,9 +53,7 @@
struct rtc_plat_data {
void __iomem *ioaddr_nvram;
void __iomem *ioaddr_rtc;
- size_t size_nvram;
unsigned long last_jiffies;
- struct bin_attribute nvram_attr;
};

static int ds1742_rtc_set_time(struct device *dev, struct rtc_time *tm)
@@ -122,34 +120,28 @@ static const struct rtc_class_ops ds1742_rtc_ops = {
.set_time = ds1742_rtc_set_time,
};

-static ssize_t ds1742_nvram_read(struct file *filp, struct kobject *kobj,
- struct bin_attribute *bin_attr,
- char *buf, loff_t pos, size_t size)
+static int ds1742_nvram_read(void *priv, unsigned int pos, void *val,
+ size_t bytes)
{
- struct device *dev = container_of(kobj, struct device, kobj);
- struct platform_device *pdev = to_platform_device(dev);
- struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+ struct rtc_plat_data *pdata = priv;
void __iomem *ioaddr = pdata->ioaddr_nvram;
- ssize_t count;
+ u8 *buf = val;

- for (count = 0; count < size; count++)
+ for (; bytes; bytes--)
*buf++ = readb(ioaddr + pos++);
- return count;
+ return 0;
}

-static ssize_t ds1742_nvram_write(struct file *filp, struct kobject *kobj,
- struct bin_attribute *bin_attr,
- char *buf, loff_t pos, size_t size)
+static int ds1742_nvram_write(void *priv, unsigned int pos, void *val,
+ size_t bytes)
{
- struct device *dev = container_of(kobj, struct device, kobj);
- struct platform_device *pdev = to_platform_device(dev);
- struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+ struct rtc_plat_data *pdata = priv;
void __iomem *ioaddr = pdata->ioaddr_nvram;
- ssize_t count;
+ u8 *buf = val;

- for (count = 0; count < size; count++)
+ for (; bytes; bytes--)
writeb(*buf++, ioaddr + pos++);
- return count;
+ return 0;
}

static int ds1742_rtc_probe(struct platform_device *pdev)
@@ -160,6 +152,14 @@ static int ds1742_rtc_probe(struct platform_device *pdev)
struct rtc_plat_data *pdata;
void __iomem *ioaddr;
int ret = 0;
+ struct nvmem_config nvmem_cfg = {
+ .name = "ds1742_nvram",
+ .word_size = 1,
+ .stride = 1,
+ .reg_read = ds1742_nvram_read,
+ .reg_write = ds1742_nvram_write,
+ };
+

pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
if (!pdata)
@@ -171,15 +171,10 @@ static int ds1742_rtc_probe(struct platform_device *pdev)
return PTR_ERR(ioaddr);

pdata->ioaddr_nvram = ioaddr;
- pdata->size_nvram = resource_size(res) - RTC_SIZE;
- pdata->ioaddr_rtc = ioaddr + pdata->size_nvram;
+ pdata->ioaddr_rtc = ioaddr + resource_size(res) - RTC_SIZE;

- sysfs_bin_attr_init(&pdata->nvram_attr);
- pdata->nvram_attr.attr.name = "nvram";
- pdata->nvram_attr.attr.mode = S_IRUGO | S_IWUSR;
- pdata->nvram_attr.read = ds1742_nvram_read;
- pdata->nvram_attr.write = ds1742_nvram_write;
- pdata->nvram_attr.size = pdata->size_nvram;
+ nvmem_cfg.size = resource_size(res) - RTC_SIZE;
+ nvmem_cfg.priv = pdata;

/* turn RTC on if it was not on */
ioaddr = pdata->ioaddr_rtc;
@@ -202,24 +197,15 @@ static int ds1742_rtc_probe(struct platform_device *pdev)
return PTR_ERR(rtc);

rtc->ops = &ds1742_rtc_ops;
+ rtc->nvram_old_abi = true;

ret = rtc_register_device(rtc);
if (ret)
return ret;

- ret = sysfs_create_bin_file(&pdev->dev.kobj, &pdata->nvram_attr);
- if (ret)
- dev_err(&pdev->dev, "Unable to create sysfs entry: %s\n",
- pdata->nvram_attr.attr.name);
-
- return 0;
-}
-
-static int ds1742_rtc_remove(struct platform_device *pdev)
-{
- struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+ if (rtc_nvmem_register(rtc, &nvmem_cfg))
+ dev_err(&pdev->dev, "Unable to register nvmem\n");

- sysfs_remove_bin_file(&pdev->dev.kobj, &pdata->nvram_attr);
return 0;
}

@@ -231,7 +217,6 @@ MODULE_DEVICE_TABLE(of, ds1742_rtc_of_match);

static struct platform_driver ds1742_rtc_driver = {
.probe = ds1742_rtc_probe,
- .remove = ds1742_rtc_remove,
.driver = {
.name = "rtc-ds1742",
.of_match_table = of_match_ptr(ds1742_rtc_of_match),
--
2.16.1
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