nvmem: core: fix regression in of_nvmem_cell_get()

NVMEM DT support seems to be totally broken after
commit e888d445ac33 ("nvmem: resolve cells from DT at registration time")
Fix this!

Index used in of_nvmem_cell_get() to find cell is specific to
consumer, It can not be used for searching the cell in provider.
Use device_node instead of this to find the matching cell in device
tree case.

Fixes: e888d445ac33 ("nvmem: resolve cells from DT at registration time")
Reported-by: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Tested-by: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 9b18ce9..27f67df 100644 (file)
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -44,6 +44,7 @@ struct nvmem_cell {
        int                     bytes;
        int                     bit_offset;
        int                     nbits;
+       struct device_node      *np;
        struct nvmem_device     *nvmem;
        struct list_head        node;
 };
@@ -298,6 +299,7 @@ static void nvmem_cell_drop(struct nvmem_cell *cell)
        mutex_lock(&nvmem_mutex);
        list_del(&cell->node);
        mutex_unlock(&nvmem_mutex);
+       of_node_put(cell->np);
        kfree(cell->name);
        kfree(cell);
 }
@@ -530,6 +532,7 @@ static int nvmem_add_cells_from_of(struct nvmem_device *nvmem)
                        return -ENOMEM;
 
                cell->nvmem = nvmem;
+               cell->np = of_node_get(child);
                cell->offset = be32_to_cpup(addr++);
                cell->bytes = be32_to_cpup(addr);
                cell->name = kasprintf(GFP_KERNEL, "%pOFn", child);
@@ -960,14 +963,13 @@ out:
 
 #if IS_ENABLED(CONFIG_OF)
 static struct nvmem_cell *
-nvmem_find_cell_by_index(struct nvmem_device *nvmem, int index)
+nvmem_find_cell_by_node(struct nvmem_device *nvmem, struct device_node *np)
 {
        struct nvmem_cell *cell = NULL;
-       int i = 0;
 
        mutex_lock(&nvmem_mutex);
        list_for_each_entry(cell, &nvmem->cells, node) {
-               if (index == i++)
+               if (np == cell->np)
                        break;
        }
        mutex_unlock(&nvmem_mutex);
@@ -1011,7 +1013,7 @@ struct nvmem_cell *of_nvmem_cell_get(struct device_node *np, const char *id)
        if (IS_ERR(nvmem))
                return ERR_CAST(nvmem);
 
-       cell = nvmem_find_cell_by_index(nvmem, index);
+       cell = nvmem_find_cell_by_node(nvmem, cell_np);
        if (!cell) {
                __nvmem_device_put(nvmem);
                return ERR_PTR(-ENOENT);