linux-kernel - Re: [regression 4.20-rc1, bisected] cpufreq fails to register on db820c

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Date:   Tue, 6 Nov 2018 16:26:04 +0100
From:   Niklas Cassel <niklas.cassel@...aro.org>
To:     Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Cc:     bgolaszewski@...libre.com, viresh.kumar@...aro.org,
        linux-kernel@...r.kernel.org
Subject: Re: [regression 4.20-rc1, bisected] cpufreq fails to register on
 db820c

On Tue, Nov 06, 2018 at 02:37:57PM +0000, Srinivas Kandagatla wrote:
> Hi Niklas,
> 
> thanks for reporting this..
> 
> I found the issue, DT support seems to be totally broken in NVMEM.
> Will send this fix once you can confirm it works for you!
> 
> Can you try this patch!
> ---------------------->cut<--------------------------
> 
> Author: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
> Date:   Tue Nov 6 14:32:30 2018 +0000
> 
>     nvmem: core: fix of_nvmem_cell_get()
> 
>     NVMEM DT support seems to be totally broken after
>     e888d445ac33 ("nvmem: resolve cells from DT at registration time")
>     Fix this!
> 
>     Fixes: e888d445ac33 ("nvmem: resolve cells from DT at registration
> time")
>     Reported-by: Niklas Cassel <niklas.cassel@...aro.org>
>     Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
> 
> diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
> index 9b18ce90f907..7ae8072f56ae 100644
> --- 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;
>  };
> @@ -530,6 +531,7 @@ static int nvmem_add_cells_from_of(struct nvmem_device
> *nvmem)
>                         return -ENOMEM;
> 
>                 cell->nvmem = nvmem;
> +               cell->np = child;
>                 cell->offset = be32_to_cpup(addr++);
>                 cell->bytes = be32_to_cpup(addr);
>                 cell->name = kasprintf(GFP_KERNEL, "%pOFn", child);
> @@ -960,14 +962,13 @@ nvmem_cell_get_from_lookup(struct device *dev, const
> char *con_id)
> 
>  #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);
> @@ -1001,7 +1002,6 @@ struct nvmem_cell *of_nvmem_cell_get(struct
> device_node *np, const char *id)
>         cell_np = of_parse_phandle(np, "nvmem-cells", index);
>         if (!cell_np)
>                 return ERR_PTR(-EINVAL);
> -
>         nvmem_np = of_get_next_parent(cell_np);
>         if (!nvmem_np)
>                 return ERR_PTR(-EINVAL);
> @@ -1011,7 +1011,7 @@ 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);
> 

Tested-by: Niklas Cassel <niklas.cassel@...aro.org>