nvmem: ensure sysfs writes handle write-protect pin

Commit 2a127da461a9 ("nvmem: add support for the write-protect pin")
added support for handling write-protect pins to the nvmem core, and
Commit 1c89074bf850 ("eeprom: at24: remove the write-protect pin support")
retrofitted the at24 driver to use this support.

These changes broke write() on the nvmem sysfs attribute for eeproms
which utilize a write-protect pin, as the write callback invokes the
nvmem device's reg_write callback directly which no longer handles
changing the state of the write-protect pin.

Change the read and write callbacks for the sysfs attribute to invoke
nvmme_reg_read/nvmem_reg_write helpers which handle this, rather than
calling reg_read/reg_write directly.

Fixes: 2a127da461a9 ("nvmem: add support for the write-protect pin")
Signed-off-by: Michael Auchter <michael.auchter@ni.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200511145042.31223-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index ad6e55a75bdbd30aa23daeefaee4fd945740db7a..927eb5f6003f054834502656d006d6b4257f0068 100644 (file)
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -66,6 +66,30 @@ static LIST_HEAD(nvmem_lookup_list);
 
 static BLOCKING_NOTIFIER_HEAD(nvmem_notifier);
 
+static int nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
+                         void *val, size_t bytes)
+{
+       if (nvmem->reg_read)
+               return nvmem->reg_read(nvmem->priv, offset, val, bytes);
+
+       return -EINVAL;
+}
+
+static int nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
+                          void *val, size_t bytes)
+{
+       int ret;
+
+       if (nvmem->reg_write) {
+               gpiod_set_value_cansleep(nvmem->wp_gpio, 0);
+               ret = nvmem->reg_write(nvmem->priv, offset, val, bytes);
+               gpiod_set_value_cansleep(nvmem->wp_gpio, 1);
+               return ret;
+       }
+
+       return -EINVAL;
+}
+
 #ifdef CONFIG_NVMEM_SYSFS
 static const char * const nvmem_type_str[] = {
        [NVMEM_TYPE_UNKNOWN] = "Unknown",
@@ -122,7 +146,7 @@ static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj,
        if (!nvmem->reg_read)
                return -EPERM;
 
-       rc = nvmem->reg_read(nvmem->priv, pos, buf, count);
+       rc = nvmem_reg_read(nvmem, pos, buf, count);
 
        if (rc)
                return rc;
@@ -159,7 +183,7 @@ static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj,
        if (!nvmem->reg_write)
                return -EPERM;
 
-       rc = nvmem->reg_write(nvmem->priv, pos, buf, count);
+       rc = nvmem_reg_write(nvmem, pos, buf, count);
 
        if (rc)
                return rc;
@@ -287,30 +311,6 @@ static void nvmem_sysfs_remove_compat(struct nvmem_device *nvmem,
 
 #endif /* CONFIG_NVMEM_SYSFS */
 
-static int nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
-                         void *val, size_t bytes)
-{
-       if (nvmem->reg_read)
-               return nvmem->reg_read(nvmem->priv, offset, val, bytes);
-
-       return -EINVAL;
-}
-
-static int nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
-                          void *val, size_t bytes)
-{
-       int ret;
-
-       if (nvmem->reg_write) {
-               gpiod_set_value_cansleep(nvmem->wp_gpio, 0);
-               ret = nvmem->reg_write(nvmem->priv, offset, val, bytes);
-               gpiod_set_value_cansleep(nvmem->wp_gpio, 1);
-               return ret;
-       }
-
-       return -EINVAL;
-}
-
 static void nvmem_release(struct device *dev)
 {
        struct nvmem_device *nvmem = to_nvmem_device(dev);