[PATCH 1/2] nvmem: core: add support to auto devid

[PATCH 1/2] nvmem: core: add support to auto devid

[Srinivas Kandagatla]

For nvmem providers which have multiple instances, it is required
to suffix the provider name with proper id, so that they do not
confict for the same name. Currently the core does not handle
this case properly eventhough core already has logic to generate the id.

This patch add new devid type NVMEM_DEVID_AUTO for providers to be
able to allow core to assign id and append it to provier name.

Reported-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
---
 drivers/nvmem/core.c           | 10 ++++++++--
 include/linux/nvmem-provider.h |  3 +++
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 927eb5f6003f..aa87bd6415ab 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -629,12 +629,18 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
 	if (!config->no_of_node)
 		nvmem->dev.of_node = config->dev->of_node;
 
-	if (config->id == -1 && config->name) {
+	switch (config->id) {
+	case NVMEM_DEVID_NONE:
 		dev_set_name(&nvmem->dev, "%s", config->name);
-	} else {
+		break;
+	case NVMEM_DEVID_AUTO:
+		dev_set_name(&nvmem->dev, "%s%d", config->name, nvmem->id);
+		break;
+	default:
 		dev_set_name(&nvmem->dev, "%s%d",
 			     config->name ? : "nvmem",
 			     config->name ? config->id : nvmem->id);
+		break;
 	}
 
 	nvmem->read_only = device_property_present(config->dev, "read-only") ||
diff --git a/include/linux/nvmem-provider.h b/include/linux/nvmem-provider.h
index 6d6f8e5d24c9..06409a6c40bc 100644
--- a/include/linux/nvmem-provider.h
+++ b/include/linux/nvmem-provider.h
@@ -27,6 +27,9 @@ enum nvmem_type {
 	NVMEM_TYPE_BATTERY_BACKED,
 };
 
+#define NVMEM_DEVID_NONE	(-1)
+#define NVMEM_DEVID_AUTO	(-2)
+
 /**
  * struct nvmem_config - NVMEM device configuration
  *
-- 
2.21.0

[PATCH 2/2] nvmem: qfprom: use NVMEM_DEVID_AUTO for multiple instances

[Srinivas Kandagatla]

There could be multiple qfprom devices on some SoCs.  For example, on
MSM8939, qfprom@58000 holds efuse bits for Core Power Reduction (CPR),
and qfprom@5c000 holds bits for TSENS.  Registering multiple nvmem
devices with the same id results in the following failure on the second
device.

[    1.682731] sysfs: cannot create duplicate filename '/bus/nvmem/devices/qfprom0'
[    1.685889] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.19.107-00567-g11c887ce2838-dirty #334
[    1.693191] Hardware name: Square, Inc. T2 Devkit (DT)
[    1.701610] Call trace:
[    1.706673]  dump_backtrace+0x0/0x158
[    1.708987]  show_stack+0x14/0x20
[    1.712810]  dump_stack+0x98/0xbc
[    1.716114]  sysfs_warn_dup+0x60/0x78
[    1.719401]  sysfs_do_create_link_sd.isra.0+0xdc/0xe8
[    1.723047]  sysfs_create_link+0x20/0x40
[    1.728088]  bus_add_device+0x68/0x130
[    1.732083]  device_add+0x3f8/0x628
[    1.735639]  nvmem_register.part.4+0x150/0x348
[    1.739018]  devm_nvmem_register+0x4c/0xa8
[    1.743532]  qfprom_probe+0x94/0xb8
[    1.747615]  platform_drv_probe+0x50/0xa0
[    1.750998]  really_probe+0x1b8/0x298
[    1.755164]  driver_probe_device+0x58/0x100
[    1.758810]  __driver_attach+0xe0/0xe8
[    1.762802]  bus_for_each_dev+0x74/0xc8
[    1.766622]  driver_attach+0x20/0x28
[    1.770354]  bus_add_driver+0x1ac/0x218
[    1.774175]  driver_register+0x60/0x110
[    1.777734]  __platform_driver_register+0x40/0x48
[    1.781570]  qfprom_driver_init+0x18/0x20
[    1.786416]  do_one_initcall+0x5c/0x178
[    1.790418]  kernel_init_freeable+0x198/0x244
[    1.794062]  kernel_init+0x10/0x108
[    1.798567]  ret_from_fork+0x10/0x18
[    1.802084] qcom,qfprom: probe of 5c000.qfprom failed with error -17

Fix this issue by using NVMEM_DEVID_AUTO.

Reported-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
---
 drivers/nvmem/qfprom.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/nvmem/qfprom.c b/drivers/nvmem/qfprom.c
index 8a91717600be..8b425f8d847d 100644
--- a/drivers/nvmem/qfprom.c
+++ b/drivers/nvmem/qfprom.c
@@ -31,6 +31,7 @@ static struct nvmem_config econfig = {
 	.name = "qfprom",
 	.stride = 1,
 	.word_size = 1,
+	.id = NVMEM_DEVID_AUTO,
 	.reg_read = qfprom_reg_read,
 };
 
-- 
2.21.0