2018-09-10 9:32 GMT+02:00 Srinivas Kandagatla [off-list ref]:

On 07/09/18 11:07, Bartosz Golaszewski wrote:

quoted

From: Bartosz Golaszewski <redacted>

Add a way for machine code users to associate devices with nvmem cells.

Signed-off-by: Bartosz Golaszewski <redacted>
---
  drivers/nvmem/core.c          | 143 +++++++++++++++++++++++++++-------
  include/linux/nvmem-machine.h |  16 ++++
  2 files changed, 132 insertions(+), 27 deletions(-)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index da7a9d5beb33..9e2f9c993a07 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c

@@ -62,6 +62,9 @@ static DEFINE_IDA(nvmem_ida);
  static DEFINE_MUTEX(nvmem_cell_mutex);
  static LIST_HEAD(nvmem_cell_tables);
  +static DEFINE_MUTEX(nvmem_lookup_mutex);
+static LIST_HEAD(nvmem_lookup_list);
+
  static BLOCKING_NOTIFIER_HEAD(nvmem_notifier);
    #ifdef CONFIG_DEBUG_LOCK_ALLOC

@@ -285,6 +288,18 @@ static struct nvmem_device *of_nvmem_find(struct

device_node *nvmem_np)
        return to_nvmem_device(d);
  }
  +static struct nvmem_device *nvmem_find(const char *name)
+{
+       struct device *d;
+
+       d = bus_find_device_by_name(&nvmem_bus_type, NULL, name);
+
+       if (!d)
+               return NULL;
+
+       return to_nvmem_device(d);
+}
+

This is removed and added back in same patch, you should consider
positioning the caller if possible to avoid any un-necessary changes.

quoted

  static void nvmem_cell_drop(struct nvmem_cell *cell)
  {
        mutex_lock(&nvmem_mutex);

@@ -421,6 +436,21 @@ nvmem_find_cell_by_index(struct nvmem_device *nvmem,

int index)
        return cell;
  }
  +static struct nvmem_cell *
+nvmem_cell_get_from_lookup(struct device *dev, const char *con_id)
+{
+       struct nvmem_cell *cell = ERR_PTR(-ENOENT);
+       struct nvmem_cell_lookup *lookup;
+       struct nvmem_device *nvmem;
+       const char *dev_id;
+
+       if (!dev)
+               return ERR_PTR(-EINVAL);
+
+       dev_id = dev_name(dev);
+
+       mutex_lock(&nvmem_lookup_mutex);
+
+       list_for_each_entry(lookup, &nvmem_lookup_list, node) {
+               if ((strcmp(lookup->dev_id, dev_id) == 0) &&
+                   (strcmp(lookup->con_id, con_id) == 0)) {
+                       /* This is the right entry. */
+                       nvmem = __nvmem_device_get(NULL,
lookup->nvmem_name);
+                       if (!nvmem) {
+                               /* Provider may not be registered yet. */
+                               cell = ERR_PTR(-EPROBE_DEFER);
+                               goto out;
+                       }
+
+                       cell = nvmem_find_cell_by_name(nvmem,
+                                                      lookup->cell_name);
+                       if (!cell)
+                               goto out;

Here nvmem refcount has already increased, you should probably fix this!

Indeed.

quoted

+               }
+       }
+
+out:
+       mutex_unlock(&nvmem_lookup_mutex);
+       return cell;
+}

...

quoted

diff --git a/include/linux/nvmem-machine.h b/include/linux/nvmem-machine.h

Should be part of nvmem-consumer.h.

If anything, this should probably go to nvmem-provider.h. But I like
the gpiolib way of putting machine-specific code into a separate
header. Most systems are not interested in these definitions anyway.
IMO this is a valid use case where creating a new header makes sense.

Bart

quoted

index 1e199dfaacab..7859c08934d5 100644

--- a/include/linux/nvmem-machine.h
+++ b/include/linux/nvmem-machine.h

@@ -26,16 +26,32 @@ struct nvmem_cell_table {
        struct list_head        node;
  };
  +struct nvmem_cell_lookup {
+       const char              *nvmem_name;
+       const char              *cell_name;
+       const char              *dev_id;
+       const char              *con_id;
+       struct list_head        node;
+};

Consider adding kerneldoc to this structure.

quoted

+
  #if IS_ENABLED(CONFIG_NVMEM)
    void nvmem_add_cell_table(struct nvmem_cell_table *table);
  void nvmem_del_cell_table(struct nvmem_cell_table *table);
  +void nvmem_add_cell_lookups(struct nvmem_cell_lookup *entries, size_t
nentries);
+void nvmem_del_cell_lookups(struct nvmem_cell_lookup *entries, size_t
nentries);
+
  #else /* CONFIG_NVMEM */
    static inline void nvmem_add_cell_table(struct nvmem_cell_table
*table) {}
  static inline void nvmem_del_cell_table(struct nvmem_cell_table *table)
{}
  +static inline void
+nvmem_add_cell_lookups(struct nvmem_cell_lookup *entries, size_t
nentries) {}
+static inline void
+nvmem_del_cell_lookups(struct nvmem_cell_lookup *entries, size_t
nentries) {}
+
  #endif /* CONFIG_NVMEM */
    #endif  /* ifndef _LINUX_NVMEM_MACHINE_H */