eeprom: ee1004: Add nvmem support

Currently the driver does not register a nvmem provider, which means
that userspace programs cannot access the ee1004 EEPROM through the
standard nvmem sysfs API.
Fix this by replacing the custom sysfs attribute with a standard nvmem
interface, which also takes care of backwards compatibility.

Tested on a Dell Inspiron 3505.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Link: https://lore.kernel.org/r/20240625063459.429953-2-W_Armin@gmx.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/misc/eeprom/Kconfig b/drivers/misc/eeprom/Kconfig
index 4e61ac18cc96c6ad7efef3814f25d5f1e46aba9c..9df12399bda37c6d1ace0eef69c2f62446015aae 100644 (file)
--- a/drivers/misc/eeprom/Kconfig
+++ b/drivers/misc/eeprom/Kconfig
@@ -109,6 +109,8 @@ config EEPROM_IDT_89HPESX
 config EEPROM_EE1004
        tristate "SPD EEPROMs on DDR4 memory modules"
        depends on I2C && SYSFS
+       select NVMEM
+       select NVMEM_SYSFS
        help
          Enable this driver to get read support to SPD EEPROMs following
          the JEDEC EE1004 standard. These are typically found on DDR4

diff --git a/drivers/misc/eeprom/ee1004.c b/drivers/misc/eeprom/ee1004.c
index b1f760cc3be0c56a47281f09e734c2cf9836a97f..2e69024380b6983288c8a01d071983706cc551c6 100644 (file)
--- a/drivers/misc/eeprom/ee1004.c
+++ b/drivers/misc/eeprom/ee1004.c
@@ -16,6 +16,7 @@
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/nvmem-provider.h>
 
 /*
  * DDR4 memory modules use special EEPROMs following the Jedec EE1004
@@ -145,13 +146,17 @@ static ssize_t ee1004_eeprom_read(struct i2c_client *client, char *buf,
        return i2c_smbus_read_i2c_block_data_or_emulated(client, offset, count, buf);
 }
 
-static ssize_t eeprom_read(struct file *filp, struct kobject *kobj,
-                          struct bin_attribute *bin_attr,
-                          char *buf, loff_t off, size_t count)
+static int ee1004_read(void *priv, unsigned int off, void *val, size_t count)
 {
-       struct i2c_client *client = kobj_to_i2c_client(kobj);
-       size_t requested = count;
-       int ret = 0;
+       struct i2c_client *client = priv;
+       char *buf = val;
+       int ret;
+
+       if (unlikely(!count))
+               return count;
+
+       if (off + count > EE1004_EEPROM_SIZE)
+               return -EINVAL;
 
        /*
         * Read data from chip, protecting against concurrent access to
@@ -161,28 +166,21 @@ static ssize_t eeprom_read(struct file *filp, struct kobject *kobj,
 
        while (count) {
                ret = ee1004_eeprom_read(client, buf, off, count);
-               if (ret < 0)
-                       goto out;
+               if (ret < 0) {
+                       mutex_unlock(&ee1004_bus_lock);
+                       return ret;
+               }
 
                buf += ret;
                off += ret;
                count -= ret;
        }
-out:
+
        mutex_unlock(&ee1004_bus_lock);
 
-       return ret < 0 ? ret : requested;
+       return 0;
 }
 
-static BIN_ATTR_RO(eeprom, EE1004_EEPROM_SIZE);
-
-static struct bin_attribute *ee1004_attrs[] = {
-       &bin_attr_eeprom,
-       NULL
-};
-
-BIN_ATTRIBUTE_GROUPS(ee1004);
-
 static void ee1004_probe_temp_sensor(struct i2c_client *client)
 {
        struct i2c_board_info info = { .type = "jc42" };
@@ -220,7 +218,24 @@ static void ee1004_cleanup_bus_data(void *data)
 
 static int ee1004_probe(struct i2c_client *client)
 {
+       struct nvmem_config config = {
+               .dev = &client->dev,
+               .name = dev_name(&client->dev),
+               .id = NVMEM_DEVID_NONE,
+               .owner = THIS_MODULE,
+               .type = NVMEM_TYPE_EEPROM,
+               .read_only = true,
+               .root_only = false,
+               .reg_read = ee1004_read,
+               .size = EE1004_EEPROM_SIZE,
+               .word_size = 1,
+               .stride = 1,
+               .priv = client,
+               .compat = true,
+               .base_dev = &client->dev,
+       };
        struct ee1004_bus_data *bd;
+       struct nvmem_device *ndev;
        int err, cnr = 0;
 
        /* Make sure we can operate on this adapter */
@@ -272,6 +287,10 @@ static int ee1004_probe(struct i2c_client *client)
 
        mutex_unlock(&ee1004_bus_lock);
 
+       ndev = devm_nvmem_register(&client->dev, &config);
+       if (IS_ERR(ndev))
+               return PTR_ERR(ndev);
+
        dev_info(&client->dev,
                 "%u byte EE1004-compliant SPD EEPROM, read-only\n",
                 EE1004_EEPROM_SIZE);
@@ -284,7 +303,6 @@ static int ee1004_probe(struct i2c_client *client)
 static struct i2c_driver ee1004_driver = {
        .driver = {
                .name = "ee1004",
-               .dev_groups = ee1004_groups,
        },
        .probe = ee1004_probe,
        .id_table = ee1004_ids,