[PATCH v2 07/15] nvmem: core: allow single and dynamic device ids

[Sascha Hauer]

On Mon, Aug 18, 2025 at 07:44:41PM +0200, Marco Felsch wrote:
> At the moment only DEVICE_ID_DYNAMIC is supported. Add support for
> NVMEM_DEVID_NONE to allow static device names via of-aliases and to
> align our core with Linux.
> 
> While on it fix the nvmem_register_cdev() by using the dev_name() which
> honors the DEVICE_ID_* cases else we end up with different names for the
> devfs and the device itself.
> 
> The dev_dbg() message can be dropped as well since the register_device()
> can print this message too.
> 
> Signed-off-by: Marco Felsch <m.felsch at pengutronix.de>
> ---
>  drivers/nvmem/core.c           | 16 +++++++++++-----
>  include/linux/nvmem-provider.h |  4 ++++
>  2 files changed, 15 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
> index 4dbeb1e116ae398f1f2748238d97468c1096262a..7e1dcceb00b924548b4582504b8ccaa4f29c4bdc 100644
> --- a/drivers/nvmem/core.c
> +++ b/drivers/nvmem/core.c
> @@ -442,17 +442,23 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
>  	if (config->read_only || !config->reg_write || of_property_read_bool(np, "read-only"))
>  		nvmem->read_only = true;
>  
> -	dev_set_name(&nvmem->dev, "%s", config->name);
> -	nvmem->dev.id = DEVICE_ID_DYNAMIC;
> -
> -	dev_dbg(nvmem->dev.parent, "Registering nvmem device %s\n", config->name);
> +	dev_set_name(&nvmem->dev, "%s", config->name ? : "nvmem");
> +	switch (config->id) {
> +	case NVMEM_DEVID_NONE:
> +		nvmem->dev.id = DEVICE_ID_SINGLE;
> +		break;
> +	case NVMEM_DEVID_AUTO:
> +	default:
> +		nvmem->dev.id = DEVICE_ID_DYNAMIC;
> +		break;
> +	}
>  
>  	rval = register_device(&nvmem->dev);
>  	if (rval)
>  		goto err_remove_cells;
>  
>  	if (!config->cdev) {
> -		rval = nvmem_register_cdev(nvmem, config->name);
> +		rval = nvmem_register_cdev(nvmem, dev_name(&nvmem->dev));

This change breaks the "nvmem" command and with it the nvmem test.
"nvmem -c 1k" used to create a /dev/rmem0 cdev. With this change it
now creates a "/dev/rmem00" cdev.

I Fixed this with the following.

---------------------------------8<-----------------------------------
>From 171ed3f457ff8ba336f0300939c3ec39a4cda5eb Mon Sep 17 00:00:00 2001
From: Sascha Hauer <s.hauer at pengutronix.de>
Date: Wed, 20 Aug 2025 09:28:19 +0200
Subject: [PATCH] fixup! nvmem: core: allow single and dynamic device ids

Rename "rmem" driver to "nvmem-rmem". Without it both the rmem container
device and the nvmem device are named "rmem" with different ids.

---
 commands/nvmem.c     | 2 +-
 drivers/nvmem/rmem.c | 5 +++--
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/commands/nvmem.c b/commands/nvmem.c
index 3bfa1ff19a..25f80db6fd 100644
--- a/commands/nvmem.c
+++ b/commands/nvmem.c
@@ -35,7 +35,7 @@ static int nvmem_create_dynamic_rmem(unsigned long create_size,
 	int ret = 0;
 
 	buffer = xzalloc(create_size);
-	dev = add_generic_device("rmem", dynamic_rmem_idx, NULL,
+	dev = add_generic_device("nvmem-rmem", dynamic_rmem_idx, NULL,
 				 (resource_size_t)(uintptr_t)buffer,
 				 (resource_size_t)create_size,
 				 IORESOURCE_MEM, NULL);
diff --git a/drivers/nvmem/rmem.c b/drivers/nvmem/rmem.c
index 378a93110d..de9b7af6e4 100644
--- a/drivers/nvmem/rmem.c
+++ b/drivers/nvmem/rmem.c
@@ -118,7 +118,8 @@ static int rmem_probe(struct device *dev)
 
 	config.dev = priv->dev = dev;
 	config.priv = priv;
-	config.name = dev_name(dev);
+	config.name = "rmem";
+	config.id = NVMEM_DEVID_AUTO;
 	config.size = resource_size(mem);
 	priv->size = config.size;
 
@@ -138,7 +139,7 @@ static const struct of_device_id rmem_match[] = {
 MODULE_DEVICE_TABLE(of, rmem_match);
 
 static struct driver rmem_driver = {
-	.name = "rmem",
+	.name = "nvmem-rmem",
 	.of_compatible = rmem_match,
 	.probe = rmem_probe,
 };
-- 
2.39.5



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