2018-06-26 13:06 GMT+02:00 Srinivas Kandagatla [off-list ref]:

Thanks for the patch,

On 26/06/18 11:22, Bartosz Golaszewski wrote:

quoted

From: Bartosz Golaszewski <redacted>

We can currently only register nvmem cells from device tree or by
manually calling nvmem_add_cells(). The latter options however forces
users to make sure that the nvmem provider with which the cells are
associated is registered before the call.

This patch proposes a new solution inspired by other frameworks that
offer resource lookups (GPIO, PWM etc.). It adds a function that allows
machine code to register nvmem lookup which are later lazily used to
add corresponding nvmem cells.

Overall the idea look fine to me.

This needs to be documented in ./Documentation/nvmem/nvmem.txt

quoted

Signed-off-by: Bartosz Golaszewski <redacted>
---
  drivers/nvmem/core.c           | 57 +++++++++++++++++++++++++++++++++-
  include/linux/nvmem-consumer.h |  6 ++++
  include/linux/nvmem-provider.h |  6 ++++
  3 files changed, 68 insertions(+), 1 deletion(-)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index b5b0cdc21d01..a2e87b464319 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c

@@ -62,6 +62,9 @@ static DEFINE_IDA(nvmem_ida);
  static LIST_HEAD(nvmem_cells);
  static DEFINE_MUTEX(nvmem_cells_mutex);
  +static LIST_HEAD(nvmem_cell_lookups);
+static DEFINE_MUTEX(nvmem_lookup_mutex);
+
  #ifdef CONFIG_DEBUG_LOCK_ALLOC
  static struct lock_class_key eeprom_lock_key;
  #endif

@@ -247,6 +250,23 @@ static const struct attribute_group

*nvmem_ro_root_dev_groups[] = {
        NULL,
  };
  +/**
+ * nvmem_register_lookup() - register a number of nvmem cell lookup
entries
+ *

Can we rename this to nvmem_add_lookup_table()?
register sound bit heavy here.

We should also have something like nvmem_remove_lookup_table() for
consistency, and it should ensure that it clears the cells entry too.

What do you mean by clearing the cells entry exactly?

Bart

quoted

+ * @lookup: array of nvmem cell lookup entries
+ * @nentries: number of lookup entries in the array
+ */
+void nvmem_register_lookup(struct nvmem_cell_lookup *lookup, size_t
nentries)
+{
+       int i;
+ > +   mutex_lock(&nvmem_lookup_mutex);
+       for (i = 0; i < nentries; i++)
+               list_add_tail(&lookup[i].list, &nvmem_cell_lookups);
+       mutex_unlock(&nvmem_lookup_mutex);
+}
+EXPORT_SYMBOL_GPL(nvmem_register_lookup);
+
  static void nvmem_release(struct device *dev)
  {
        struct nvmem_device *nvmem = to_nvmem_device(dev);

@@ -916,6 +936,37 @@ struct nvmem_cell *of_nvmem_cell_get(struct

device_node *np,
  EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
  #endif