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[PATCH V3 1/2] bcma: gpio: add own IRQ domain

To: linux-mips@linux-mips.org, Ralf Baechle <ralf@linux-mips.org>
Subject: [PATCH V3 1/2] bcma: gpio: add own IRQ domain
From: Rafał Miłecki <zajec5@gmail.com>
Date: Fri, 29 Nov 2013 18:48:10 +0100
Cc: Hauke Mehrtens <hauke@hauke-m.de>, Rafał Miłecki <zajec5@gmail.com>
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Input GPIO changes can generate interrupts, but we need kind of ACK for
them by changing IRQ polarity. This is required to stop hardware from
keep generating interrupts and generate another one on the next GPIO
state change.
This code allows using GPIOs with standard interrupts and add for
example GPIO buttons support.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
---
V3: Apply Hauke's comments.
1) Use IRQ domain for CONFIG_BCMA_HOST_SOC only
2) Optimize bcma_gpio_irq_handler
3) Register GPIO chip after doing everything else
4) Improve cleaning paths
---
 drivers/bcma/Kconfig                        |    1 +
 drivers/bcma/driver_gpio.c                  |  126 ++++++++++++++++++++++++++-
 include/linux/bcma/bcma_driver_chipcommon.h |    1 +
 3 files changed, 126 insertions(+), 2 deletions(-)

diff --git a/drivers/bcma/Kconfig b/drivers/bcma/Kconfig
index 7c081b3..0ee48be 100644
--- a/drivers/bcma/Kconfig
+++ b/drivers/bcma/Kconfig
@@ -75,6 +75,7 @@ config BCMA_DRIVER_GMAC_CMN
 config BCMA_DRIVER_GPIO
        bool "BCMA GPIO driver"
        depends on BCMA && GPIOLIB
+       select IRQ_DOMAIN if BCMA_HOST_SOC
        help
          Driver to provide access to the GPIO pins of the bcma bus.
 
diff --git a/drivers/bcma/driver_gpio.c b/drivers/bcma/driver_gpio.c
index 45f0996..fe9b1bc 100644
--- a/drivers/bcma/driver_gpio.c
+++ b/drivers/bcma/driver_gpio.c
@@ -9,6 +9,9 @@
  */
 
 #include <linux/gpio.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/irqdomain.h>
 #include <linux/export.h>
 #include <linux/bcma/bcma.h>
 
@@ -73,19 +76,117 @@ static void bcma_gpio_free(struct gpio_chip *chip, 
unsigned gpio)
        bcma_chipco_gpio_pullup(cc, 1 << gpio, 0);
 }
 
+#ifdef CONFIG_BCMA_HOST_SOC
 static int bcma_gpio_to_irq(struct gpio_chip *chip, unsigned gpio)
 {
        struct bcma_drv_cc *cc = bcma_gpio_get_cc(chip);
 
        if (cc->core->bus->hosttype == BCMA_HOSTTYPE_SOC)
-               return bcma_core_irq(cc->core);
+               return irq_find_mapping(cc->irq_domain, gpio);
        else
                return -EINVAL;
 }
 
+static void bcma_gpio_irq_unmask(struct irq_data *d)
+{
+       struct bcma_drv_cc *cc = irq_data_get_irq_chip_data(d);
+       int gpio = irqd_to_hwirq(d);
+
+       bcma_chipco_gpio_intmask(cc, BIT(gpio), BIT(gpio));
+}
+
+static void bcma_gpio_irq_mask(struct irq_data *d)
+{
+       struct bcma_drv_cc *cc = irq_data_get_irq_chip_data(d);
+       int gpio = irqd_to_hwirq(d);
+
+       bcma_chipco_gpio_intmask(cc, BIT(gpio), 0);
+}
+
+static struct irq_chip bcma_gpio_irq_chip = {
+       .name           = "BCMA-GPIO",
+       .irq_mask       = bcma_gpio_irq_mask,
+       .irq_unmask     = bcma_gpio_irq_unmask,
+};
+
+static irqreturn_t bcma_gpio_irq_handler(int irq, void *dev_id)
+{
+       struct bcma_drv_cc *cc = dev_id;
+       u32 val = bcma_cc_read32(cc, BCMA_CC_GPIOIN);
+       u32 mask = bcma_cc_read32(cc, BCMA_CC_GPIOIRQ);
+       u32 pol = bcma_cc_read32(cc, BCMA_CC_GPIOPOL);
+       u32 irqs = (val ^ pol) & mask;
+       u32 pol_mask = 0, pol_val = 0;
+       int gpio;
+
+       for_each_set_bit(gpio, (unsigned long *)&irqs, cc->gpio.ngpio) {
+               generic_handle_irq(bcma_gpio_to_irq(&cc->gpio, gpio));
+               pol_mask |= BIT(gpio);
+               if (val & BIT(gpio))
+                       pol_val |= BIT(gpio);
+       }
+       bcma_chipco_gpio_polarity(cc, pol_mask, pol_val);
+
+       return irqs ? IRQ_HANDLED : IRQ_NONE;
+}
+
+static int bcma_gpio_irq_domain_init(struct bcma_drv_cc *cc)
+{
+       struct gpio_chip *chip = &cc->gpio;
+       int gpio, hwirq, err;
+
+       cc->irq_domain = irq_domain_add_linear(NULL, chip->ngpio,
+                                              &irq_domain_simple_ops, cc);
+       if (!cc->irq_domain) {
+               err = -ENODEV;
+               goto err_irq_domain;
+       }
+       for (gpio = 0; gpio < chip->ngpio; gpio++) {
+               int irq = irq_create_mapping(cc->irq_domain, gpio);
+
+               irq_set_chip_data(irq, cc);
+               irq_set_chip_and_handler(irq, &bcma_gpio_irq_chip,
+                                        handle_simple_irq);
+       }
+
+       hwirq = bcma_core_irq(cc->core);
+       err = request_irq(hwirq, bcma_gpio_irq_handler, IRQF_SHARED, "gpio",
+                         cc);
+       if (err)
+               goto err_req_irq;
+
+       return 0;
+
+err_req_irq:
+       for (gpio = 0; gpio < chip->ngpio; gpio++) {
+               int irq = irq_find_mapping(cc->irq_domain, gpio);
+
+               irq_dispose_mapping(irq);
+       }
+       irq_domain_remove(cc->irq_domain);
+err_irq_domain:
+       return err;
+}
+
+static void bcma_gpio_irq_domain_exit(struct bcma_drv_cc *cc)
+{
+       struct gpio_chip *chip = &cc->gpio;
+       int gpio;
+
+       free_irq(bcma_core_irq(cc->core), cc);
+       for (gpio = 0; gpio < chip->ngpio; gpio++) {
+               int irq = irq_find_mapping(cc->irq_domain, gpio);
+
+               irq_dispose_mapping(irq);
+       }
+       irq_domain_remove(cc->irq_domain);
+}
+#endif
+
 int bcma_gpio_init(struct bcma_drv_cc *cc)
 {
        struct gpio_chip *chip = &cc->gpio;
+       int err;
 
        chip->label             = "bcma_gpio";
        chip->owner             = THIS_MODULE;
@@ -95,7 +196,9 @@ int bcma_gpio_init(struct bcma_drv_cc *cc)
        chip->set               = bcma_gpio_set_value;
        chip->direction_input   = bcma_gpio_direction_input;
        chip->direction_output  = bcma_gpio_direction_output;
+#ifdef CONFIG_BCMA_HOST_SOC
        chip->to_irq            = bcma_gpio_to_irq;
+#endif
        chip->ngpio             = 16;
        /* There is just one SoC in one device and its GPIO addresses should be
         * deterministic to address them more easily. The other buses could get
@@ -105,10 +208,29 @@ int bcma_gpio_init(struct bcma_drv_cc *cc)
        else
                chip->base              = -1;
 
-       return gpiochip_add(chip);
+#ifdef CONFIG_BCMA_HOST_SOC
+       err = bcma_gpio_irq_domain_init(cc);
+       if (err)
+               return err;
+#endif
+
+       err = gpiochip_add(chip);
+       if (err) {
+#ifdef CONFIG_BCMA_HOST_SOC
+               bcma_gpio_irq_domain_exit(cc);
+#endif
+               return err;
+       }
+
+       bcma_cc_set32(cc, BCMA_CC_IRQMASK, BCMA_CC_IRQ_GPIO);
+
+       return 0;
 }
 
 int bcma_gpio_unregister(struct bcma_drv_cc *cc)
 {
+#ifdef CONFIG_BCMA_HOST_SOC
+       bcma_gpio_irq_domain_exit(cc);
+#endif
        return gpiochip_remove(&cc->gpio);
 }
diff --git a/include/linux/bcma/bcma_driver_chipcommon.h 
b/include/linux/bcma/bcma_driver_chipcommon.h
index c49e1a1..63d105c 100644
--- a/include/linux/bcma/bcma_driver_chipcommon.h
+++ b/include/linux/bcma/bcma_driver_chipcommon.h
@@ -640,6 +640,7 @@ struct bcma_drv_cc {
        spinlock_t gpio_lock;
 #ifdef CONFIG_BCMA_DRIVER_GPIO
        struct gpio_chip gpio;
+       struct irq_domain *irq_domain;
 #endif
 };
 
-- 
1.7.10.4


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