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Re: [PATCH] MIPS: BCM47XX: Prepare support for GPIO buttons

To: Rafał Miłecki <zajec5@gmail.com>, linux-mips@linux-mips.org, Ralf Baechle <ralf@linux-mips.org>
Subject: Re: [PATCH] MIPS: BCM47XX: Prepare support for GPIO buttons
From: Hauke Mehrtens <hauke@hauke-m.de>
Date: Thu, 28 Nov 2013 13:21:15 +0100
In-reply-to: <1385634758-22723-1-git-send-email-zajec5@gmail.com>
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On 11/28/2013 11:32 AM, Rafał Miłecki wrote:
> So far this adds support for one Netgear model only, but it's designed
> and ready to add many more device. We could hopefully import database
> from OpenWrt.
> 
> Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
> ---
> This should apply cleanly on top of (still not pushed):
> MIPS: BCM47XX: Prepare support for LEDs
> ---

It would be nice if include/linux/gpio_keys.h is used for that, but I
know the generic gpio system does not provide enough functionality to do
so with this gpio controller.

Have you tried to extend the gpio system to make this possible?

As far as I read your comment your are getting an interrupt till you
change the polarity?

Hauke

>  arch/mips/bcm47xx/Kconfig           |    2 +
>  arch/mips/bcm47xx/Makefile          |    2 +-
>  arch/mips/bcm47xx/bcm47xx_private.h |    3 +
>  arch/mips/bcm47xx/buttons.c         |  225 
> +++++++++++++++++++++++++++++++++++
>  arch/mips/bcm47xx/setup.c           |    1 +
>  5 files changed, 232 insertions(+), 1 deletion(-)
>  create mode 100644 arch/mips/bcm47xx/buttons.c
> 
> diff --git a/arch/mips/bcm47xx/Kconfig b/arch/mips/bcm47xx/Kconfig
> index 09fc922..f3e9684 100644
> --- a/arch/mips/bcm47xx/Kconfig
> +++ b/arch/mips/bcm47xx/Kconfig
> @@ -11,6 +11,7 @@ config BCM47XX_SSB
>       select SSB_PCICORE_HOSTMODE if PCI
>       select SSB_DRIVER_GPIO
>       select GPIOLIB
> +     select INPUT
>       select LEDS_GPIO_REGISTER
>       default y
>       help
> @@ -28,6 +29,7 @@ config BCM47XX_BCMA
>       select BCMA_DRIVER_PCI_HOSTMODE if PCI
>       select BCMA_DRIVER_GPIO
>       select GPIOLIB
> +     select INPUT
>       select LEDS_GPIO_REGISTER
>       default y
>       help
> diff --git a/arch/mips/bcm47xx/Makefile b/arch/mips/bcm47xx/Makefile
> index 84e9aed..006a05e 100644
> --- a/arch/mips/bcm47xx/Makefile
> +++ b/arch/mips/bcm47xx/Makefile
> @@ -4,5 +4,5 @@
>  #
>  
>  obj-y                                += irq.o nvram.o prom.o serial.o 
> setup.o time.o sprom.o
> -obj-y                                += board.o leds.o
> +obj-y                                += board.o buttons.o leds.o
>  obj-$(CONFIG_BCM47XX_SSB)    += wgt634u.o
> diff --git a/arch/mips/bcm47xx/bcm47xx_private.h 
> b/arch/mips/bcm47xx/bcm47xx_private.h
> index 1a1e600..5c94ace 100644
> --- a/arch/mips/bcm47xx/bcm47xx_private.h
> +++ b/arch/mips/bcm47xx/bcm47xx_private.h
> @@ -3,6 +3,9 @@
>  
>  #include <linux/kernel.h>
>  
> +/* buttons.c */
> +int __init bcm47xx_buttons_register(void);
> +
>  /* leds.c */
>  void __init bcm47xx_leds_register(void);
>  
> diff --git a/arch/mips/bcm47xx/buttons.c b/arch/mips/bcm47xx/buttons.c
> new file mode 100644
> index 0000000..058cb64
> --- /dev/null
> +++ b/arch/mips/bcm47xx/buttons.c
> @@ -0,0 +1,225 @@
> +#include "bcm47xx_private.h"
> +
> +#include <linux/interrupt.h>
> +#include <linux/input.h>
> +#include <linux/ssb/ssb_embedded.h>
> +#include <bcm47xx_board.h>
> +#include <bcm47xx.h>
> +
> +struct input_dev *input;
> +
> +/**************************************************
> + * Database
> + **************************************************/
> +
> +struct bcm47xx_button {
> +     unsigned int code;
> +     int gpio;
> +     bool active_low;
> +     bool last_value;
> +     struct work_struct work;
> +};
> +
> +static struct bcm47xx_button
> +bcm47xx_buttons_netgear_wndr4500_v1[] = {
> +     {
> +             .code           = KEY_WPS_BUTTON,
> +             .gpio           = 4,
> +             .active_low     = 1,
> +     },
> +     {
> +             .code           = KEY_RFKILL,
> +             .gpio           = 5,
> +             .active_low     = 1,
> +     },
> +     {
> +             .code           = KEY_RESTART,
> +             .gpio           = 6,
> +             .active_low     = 1,
> +     },
> +};
> +
> +/**************************************************
> + * Handlers
> + **************************************************/
> +
> +static void bcm47xx_buttons_work(struct work_struct *work)
> +{
> +     struct bcm47xx_button *button =
> +             container_of(work, struct bcm47xx_button, work);
> +
> +     input_event(input, EV_KEY, button->code, button->last_value ^ 1);
> +     input_sync(input);
> +}
> +
> +static void bcm47xx_buttons_gpio_polarity(u32 mask, u32 value)
> +{
> +     switch (bcm47xx_bus_type) {
> +#ifdef CONFIG_BCM47XX_SSB
> +     case BCM47XX_BUS_TYPE_SSB:
> +             ssb_gpio_polarity(&bcm47xx_bus.ssb, mask, value);
> +             return;
> +#endif
> +#ifdef CONFIG_BCM47XX_BCMA
> +     case BCM47XX_BUS_TYPE_BCMA:
> +             bcma_chipco_gpio_polarity(&bcm47xx_bus.bcma.bus.drv_cc, mask,
> +                                       value);
> +             return;
> +#endif
> +     }
> +     WARN_ON(1);
> +}
> +
> +static irqreturn_t bcm47xx_buttons_irq(int irq, void *dev_id)
> +{
> +     struct bcm47xx_button *button = dev_id;
> +     int gpio = button->gpio;
> +     u32 val = __gpio_get_value(gpio);
> +
> +     if (val != button->last_value) {
> +             button->last_value = val;
> +
> +             /*
> +              * As soon as button state changes, adjust interrupt polarity.
> +              * This prevents hardware from keep generating interrupts for
> +              * the current state.
> +              */
> +             bcm47xx_buttons_gpio_polarity(BIT(gpio), val ? BIT(gpio) : 0);
> +
> +             schedule_work(&button->work);
> +
> +             return IRQ_HANDLED;
> +     }
> +
> +     return IRQ_NONE;
> +}
> +
> +/**************************************************
> + * Init
> + **************************************************/
> +
> +struct {
> +     struct bcm47xx_button   *buttons;
> +     int                     num_buttons;
> +} bcm47xx_buttons_bdata;
> +
> +#define bcm47xx_set_bdata(dev_buttons) do {                          \
> +     bcm47xx_buttons_bdata.buttons = dev_buttons;                    \
> +     bcm47xx_buttons_bdata.num_buttons = ARRAY_SIZE(dev_buttons);    \
> +} while (0)
> +
> +static int __init bcm47xx_button_setup(struct bcm47xx_button *button)
> +{
> +     int gpio = button->gpio;
> +     int val, err;
> +
> +     err = gpio_request_one(gpio, GPIOF_IN, "button");
> +     if (err) {
> +             pr_err("Failed to request GPIO %d, error %d\n", gpio, err);
> +             return err;
> +     }
> +
> +     gpio_direction_input(gpio);
> +     val = __gpio_get_value(gpio);
> +     bcm47xx_buttons_gpio_polarity(BIT(gpio), val ? BIT(gpio) : 0);
> +     button->last_value = val;
> +
> +     val = gpio_to_irq(button->gpio);
> +     err = request_irq(val, bcm47xx_buttons_irq, IRQF_SHARED, "gpio",
> +                       button);
> +     if (err) {
> +             pr_err("Failed to reqeust irq %d\n", val);
> +             gpio_free(gpio);
> +             return err;
> +     }
> +
> +     INIT_WORK(&button->work, bcm47xx_buttons_work);
> +
> +     return 0;
> +}
> +
> +int __init bcm47xx_buttons_register(void)
> +{
> +#ifdef CONFIG_BCM47XX_SSB
> +     struct ssb_bus *ssb;
> +#endif
> +#ifdef CONFIG_BCM47XX_BCMA
> +     struct bcma_drv_cc *bcma_cc;
> +#endif
> +     enum bcm47xx_board board = bcm47xx_board_get();
> +     u32 gpio_mask = 0;
> +     int i, err;
> +
> +     switch (board) {
> +     case BCM47XX_BOARD_NETGEAR_WNDR4500V1:
> +             bcm47xx_set_bdata(bcm47xx_buttons_netgear_wndr4500_v1);
> +             break;
> +     default:
> +             pr_debug("No buttons configuration found for this device\n");
> +             return -ENOTSUPP;
> +     }
> +
> +     input = input_allocate_device();
> +     if (!input) {
> +             err = -ENOMEM;
> +             goto err_input_alloc;
> +     }
> +
> +     input->name = "bcm47xx_buttons";
> +
> +     for (i = 0; i < bcm47xx_buttons_bdata.num_buttons; i++) {
> +             struct bcm47xx_button *button;
> +
> +             button = &bcm47xx_buttons_bdata.buttons[i];
> +             gpio_mask |= BIT(button->gpio);
> +             err = bcm47xx_button_setup(button);
> +             if (err)
> +                     goto err_buttons_setup;
> +             input_set_capability(input, EV_KEY, button->code);
> +     }
> +
> +     err = input_register_device(input);
> +     if (err) {
> +             pr_err("Unable to register input device, error: %d\n", err);
> +             goto err_input_reg;
> +     }
> +
> +     /*
> +      * Set a list of GPIOs that should generate interrupts and enable GPIO
> +      * interrupts in the ChipCommon core.
> +      */
> +     switch (bcm47xx_bus_type) {
> +#ifdef CONFIG_BCM47XX_SSB
> +     case BCM47XX_BUS_TYPE_SSB:
> +             ssb = &bcm47xx_bus.ssb;
> +             ssb_gpio_intmask(ssb, gpio_mask, gpio_mask);
> +             if (&ssb->chipco)
> +                     chipco_set32(&ssb->chipco, SSB_CHIPCO_IRQMASK,
> +                                  SSB_CHIPCO_IRQ_GPIO);
> +             break;
> +#endif
> +#ifdef CONFIG_BCM47XX_BCMA
> +     case BCM47XX_BUS_TYPE_BCMA:
> +             bcma_cc = &bcm47xx_bus.bcma.bus.drv_cc;
> +             bcma_chipco_gpio_intmask(bcma_cc, gpio_mask, gpio_mask);
> +             bcma_cc_set32(bcma_cc, BCMA_CC_IRQMASK, BCMA_CC_IRQ_GPIO);
> +             break;
> +#endif
> +     }
> +
> +     return 0;
> +
> +err_input_reg:
> +err_buttons_setup:
> +     for (i = i - 1; i >= 0; i--) {
> +             struct bcm47xx_button *button;
> +
> +             button = &bcm47xx_buttons_bdata.buttons[i];
> +             free_irq(gpio_to_irq(button->gpio), button);
> +             gpio_free(button->gpio);
> +     }
> +     input_free_device(input);
> +err_input_alloc:
> +     pr_err("Failed to register bcm47xx buttons, error: %d\n", err);
> +     return err;
> +}
> diff --git a/arch/mips/bcm47xx/setup.c b/arch/mips/bcm47xx/setup.c
> index 7e61c0b..a791124 100644
> --- a/arch/mips/bcm47xx/setup.c
> +++ b/arch/mips/bcm47xx/setup.c
> @@ -242,6 +242,7 @@ static int __init bcm47xx_register_bus_complete(void)
>  #endif
>       }
>  
> +     bcm47xx_buttons_register();
>       bcm47xx_leds_register();
>  
>       return 0;
> 


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