rtc: ds1742: use generic nvmem

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>

diff --git a/drivers/rtc/rtc-ds1742.c b/drivers/rtc/rtc-ds1742.c
index 84e19fe..52baf92 100644 (file)
--- 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),