linux-kernel - Re: [PATCH v2 2/9] mfd: cs5535-mfd: Remove mfd

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Message-ID: <20191021111137.ey6cbrrb2af3wj5i@holly.lan>
Date:   Mon, 21 Oct 2019 12:11:37 +0100
From:   Daniel Thompson <daniel.thompson@...aro.org>
To:     Lee Jones <lee.jones@...aro.org>
Cc:     arnd@...db.de, broonie@...nel.org, linus.walleij@...aro.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        baohua@...nel.org, stephan@...hold.net
Subject: Re: [PATCH v2 2/9] mfd: cs5535-mfd: Remove mfd_cell->id hack

On Mon, Oct 21, 2019 at 11:58:15AM +0100, Lee Jones wrote:
> The current implementation abuses the platform 'id' mfd_cell member
> to index into the correct resources entry.  If we place all cells
> into their numbered slots, we can cycle through all the cell entries
> and only process the populated ones which avoids this behaviour.
> 
> Signed-off-by: Lee Jones <lee.jones@...aro.org>
> ---
>  drivers/mfd/cs5535-mfd.c | 31 +++++++++++++------------------
>  1 file changed, 13 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/mfd/cs5535-mfd.c b/drivers/mfd/cs5535-mfd.c
> index 2c47afc22d24..9ce6bbcdbda1 100644
> --- a/drivers/mfd/cs5535-mfd.c
> +++ b/drivers/mfd/cs5535-mfd.c
> @@ -62,26 +62,22 @@ static int cs5535_mfd_res_disable(struct platform_device *pdev)
>  static struct resource cs5535_mfd_resources[NR_BARS];
>  
>  static struct mfd_cell cs5535_mfd_cells[] = {

This array is sized from the initializer...

> -	{
> -		.id = SMB_BAR,
> +	[SMB_BAR] = {
>  		.name = "cs5535-smb",
>  		.num_resources = 1,
>  		.resources = &cs5535_mfd_resources[SMB_BAR],
>  	},
> -	{
> -		.id = GPIO_BAR,
> +	[GPIO_BAR] = {
>  		.name = "cs5535-gpio",
>  		.num_resources = 1,
>  		.resources = &cs5535_mfd_resources[GPIO_BAR],
>  	},
> -	{
> -		.id = MFGPT_BAR,
> +	[MFGPT_BAR] = {
>  		.name = "cs5535-mfgpt",
>  		.num_resources = 1,
>  		.resources = &cs5535_mfd_resources[MFGPT_BAR],
>  	},
> -	{
> -		.id = PMS_BAR,
> +	[PMS_BAR] = {
>  		.name = "cs5535-pms",
>  		.num_resources = 1,
>  		.resources = &cs5535_mfd_resources[PMS_BAR],
> @@ -89,8 +85,7 @@ static struct mfd_cell cs5535_mfd_cells[] = {
>  		.enable = cs5535_mfd_res_enable,
>  		.disable = cs5535_mfd_res_disable,
>  	},
> -	{
> -		.id = ACPI_BAR,
> +	[ACPI_BAR] = {
>  		.name = "cs5535-acpi",
>  		.num_resources = 1,
>  		.resources = &cs5535_mfd_resources[ACPI_BAR],
> @@ -115,16 +110,16 @@ static int cs5535_mfd_probe(struct pci_dev *pdev,
>  		return err;
>  
>  	/* fill in IO range for each cell; subdrivers handle the region */
> -	for (i = 0; i < ARRAY_SIZE(cs5535_mfd_cells); i++) {
> -		int bar = cs5535_mfd_cells[i].id;
> -		struct resource *r = &cs5535_mfd_resources[bar];
> +	for (i = 0; i < NR_BARS; i++) {

... which means this translation from ARRAY_SIZE() to NR_BARS
is rather odd.

I don't care whether the array is sized using NR_BARS or the loop
uses ARRAY_SIZE() but IMHO the loop boundary condition must match
the array declaration.

With that fixed free to throw the following onto the next rev:
Reviewed-by: Daniel Thompson <daniel.thompson@...aro.org>


Daniel.