2018-08-14 23:46:02

by Justin Chen

Subject: [PATCH] gpio: brcmstb: allow 0 width GPIO banks

From: Justin Chen <[email protected]>

Sometimes we have empty banks within the GPIO block. This commit allows
proper handling of 0 width GPIO banks. We handle 0 width GPIO banks by
incrementing the bank and number of GPIOs, but not initializing them.
This will mean a call into the non-existent GPIOs will return an error.

Also remove banks and GPIO information from the dev_info print. This
information is misleading since the incremented banks and gpio_base do
not reflect the actual GPIOs that got initialized. We leave this
information out since it is already printed with dev_dbg.

Signed-off-by: Justin Chen <[email protected]>
---
drivers/gpio/gpio-brcmstb.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/gpio-brcmstb.c b/drivers/gpio/gpio-brcmstb.c
index 16c7f9f..8658910 100644
--- a/drivers/gpio/gpio-brcmstb.c
+++ b/drivers/gpio/gpio-brcmstb.c
@@ -664,6 +664,18 @@ static int brcmstb_gpio_probe(struct platform_device *pdev)
struct brcmstb_gpio_bank *bank;
struct gpio_chip *gc;

+ /*
+ * If bank_width is 0, then there is an empty bank in the
+ * register block. Special handling for this case.
+ */
+ if (bank_width == 0) {
+ dev_dbg(dev, "Width 0 found: Empty bank @ %d\n",
+ num_banks);
+ num_banks++;
+ gpio_base += MAX_GPIO_PER_BANK;
+ continue;
+ }
+
bank = devm_kzalloc(dev, sizeof(*bank), GFP_KERNEL);
if (!bank) {
err = -ENOMEM;
@@ -740,8 +752,7 @@ static int brcmstb_gpio_probe(struct platform_device *pdev)
goto fail;
}

- dev_info(dev, "Registered %d banks (GPIO(s): %d-%d)\n",
- num_banks, priv->gpio_base, gpio_base - 1);
+ dev_info(dev, "Brcmstb GPIO registered\n");

if (priv->parent_wake_irq && need_wakeup_event)
pm_wakeup_event(dev, 0);
--
2.7.4

2018-08-16 03:35:15

by Florian Fainelli

Subject: Re: [PATCH] gpio: brcmstb: allow 0 width GPIO banks

On 08/14/2018 04:31 PM, [email protected] wrote:
> From: Justin Chen <[email protected]>
>
> Sometimes we have empty banks within the GPIO block. This commit allows
> proper handling of 0 width GPIO banks. We handle 0 width GPIO banks by
> incrementing the bank and number of GPIOs, but not initializing them.
> This will mean a call into the non-existent GPIOs will return an error.
>
> Also remove banks and GPIO information from the dev_info print. This
> information is misleading since the incremented banks and gpio_base do
> not reflect the actual GPIOs that got initialized. We leave this
> information out since it is already printed with dev_dbg.
>
> Signed-off-by: Justin Chen <[email protected]>
> ---
> drivers/gpio/gpio-brcmstb.c | 15 +++++++++++++--
> 1 file changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpio/gpio-brcmstb.c b/drivers/gpio/gpio-brcmstb.c
> index 16c7f9f..8658910 100644
> --- a/drivers/gpio/gpio-brcmstb.c
> +++ b/drivers/gpio/gpio-brcmstb.c
> @@ -664,6 +664,18 @@ static int brcmstb_gpio_probe(struct platform_device *pdev)
> struct brcmstb_gpio_bank *bank;
> struct gpio_chip *gc;
>
> + /*
> + * If bank_width is 0, then there is an empty bank in the
> + * register block. Special handling for this case.
> + */
> + if (bank_width == 0) {
> + dev_dbg(dev, "Width 0 found: Empty bank @ %d\n",
> + num_banks);

Stylistic nit: you would want the second line to be aligned at the start
of the opening parenthesis

> + num_banks++;
> + gpio_base += MAX_GPIO_PER_BANK;
> + continue;
> + }
> +
> bank = devm_kzalloc(dev, sizeof(*bank), GFP_KERNEL);
> if (!bank) {
> err = -ENOMEM;
> @@ -740,8 +752,7 @@ static int brcmstb_gpio_probe(struct platform_device *pdev)
> goto fail;
> }
>
> - dev_info(dev, "Registered %d banks (GPIO(s): %d-%d)\n",
> - num_banks, priv->gpio_base, gpio_base - 1);
> + dev_info(dev, "Brcmstb GPIO registered\n");

Not sure if there much value in preserving that message anymore, if the
controller is not there, nothing will show up in /sys/class/gpio, so you
would pretty quickly find out that something went wrong?

>
> if (priv->parent_wake_irq && need_wakeup_event)
> pm_wakeup_event(dev, 0);
>


--
Florian