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HID: cp2112: add IRQ chip handling
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The GPIO part doesn't provide interrupts when GPIO are toggled.
So use a polling mechanism if someone requests a GPIO as an IRQ.

Signed-off-by: Benjamin Tissoires <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>
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@bentiss
bentiss authored and Jiri Kosina committed Nov 28, 2016
1 parent e2b6535 commit 13de9cc
Showing 1 changed file with 202 additions and 3 deletions.
205 changes: 202 additions & 3 deletions drivers/hid/hid-cp2112.c
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Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,7 @@
* http://www.silabs.com/Support%20Documents/TechnicalDocs/AN495.pdf
*/

#include <linux/gpio.h>
#include <linux/gpio/driver.h>
#include <linux/hid.h>
#include <linux/i2c.h>
Expand Down Expand Up @@ -168,6 +169,12 @@ struct cp2112_device {
struct gpio_chip gc;
u8 *in_out_buffer;
spinlock_t lock;

struct gpio_desc *desc[8];
bool gpio_poll;
struct delayed_work gpio_poll_worker;
unsigned long irq_mask;
u8 gpio_prev_state;
};

static int gpio_push_pull = 0xFF;
Expand Down Expand Up @@ -233,7 +240,7 @@ static void cp2112_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
spin_unlock_irqrestore(&dev->lock, flags);
}

static int cp2112_gpio_get(struct gpio_chip *chip, unsigned offset)
static int cp2112_gpio_get_all(struct gpio_chip *chip)
{
struct cp2112_device *dev = gpiochip_get_data(chip);
struct hid_device *hdev = dev->hdev;
Expand All @@ -252,14 +259,25 @@ static int cp2112_gpio_get(struct gpio_chip *chip, unsigned offset)
goto exit;
}

ret = (buf[1] >> offset) & 1;
ret = buf[1];

exit:
spin_unlock_irqrestore(&dev->lock, flags);

return ret;
}

static int cp2112_gpio_get(struct gpio_chip *chip, unsigned int offset)
{
int ret;

ret = cp2112_gpio_get_all(chip);
if (ret < 0)
return ret;

return (ret >> offset) & 1;
}

static int cp2112_gpio_direction_output(struct gpio_chip *chip,
unsigned offset, int value)
{
Expand Down Expand Up @@ -1041,6 +1059,166 @@ static void chmod_sysfs_attrs(struct hid_device *hdev)
}
}

static void cp2112_gpio_irq_ack(struct irq_data *d)
{
}

static void cp2112_gpio_irq_mask(struct irq_data *d)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
struct cp2112_device *dev = gpiochip_get_data(gc);

__clear_bit(d->hwirq, &dev->irq_mask);
}

static void cp2112_gpio_irq_unmask(struct irq_data *d)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
struct cp2112_device *dev = gpiochip_get_data(gc);

__set_bit(d->hwirq, &dev->irq_mask);
}

static void cp2112_gpio_poll_callback(struct work_struct *work)
{
struct cp2112_device *dev = container_of(work, struct cp2112_device,
gpio_poll_worker.work);
struct irq_data *d;
u8 gpio_mask;
u8 virqs = (u8)dev->irq_mask;
u32 irq_type;
int irq, virq, ret;

ret = cp2112_gpio_get_all(&dev->gc);
if (ret == -ENODEV) /* the hardware has been disconnected */
return;
if (ret < 0)
goto exit;

gpio_mask = ret;

while (virqs) {
virq = ffs(virqs) - 1;
virqs &= ~BIT(virq);

if (!dev->gc.to_irq)
break;

irq = dev->gc.to_irq(&dev->gc, virq);

d = irq_get_irq_data(irq);
if (!d)
continue;

irq_type = irqd_get_trigger_type(d);

if (gpio_mask & BIT(virq)) {
/* Level High */

if (irq_type & IRQ_TYPE_LEVEL_HIGH)
handle_nested_irq(irq);

if ((irq_type & IRQ_TYPE_EDGE_RISING) &&
!(dev->gpio_prev_state & BIT(virq)))
handle_nested_irq(irq);
} else {
/* Level Low */

if (irq_type & IRQ_TYPE_LEVEL_LOW)
handle_nested_irq(irq);

if ((irq_type & IRQ_TYPE_EDGE_FALLING) &&
(dev->gpio_prev_state & BIT(virq)))
handle_nested_irq(irq);
}
}

dev->gpio_prev_state = gpio_mask;

exit:
if (dev->gpio_poll)
schedule_delayed_work(&dev->gpio_poll_worker, 10);
}


static unsigned int cp2112_gpio_irq_startup(struct irq_data *d)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
struct cp2112_device *dev = gpiochip_get_data(gc);

INIT_DELAYED_WORK(&dev->gpio_poll_worker, cp2112_gpio_poll_callback);

cp2112_gpio_direction_input(gc, d->hwirq);

if (!dev->gpio_poll) {
dev->gpio_poll = true;
schedule_delayed_work(&dev->gpio_poll_worker, 0);
}

cp2112_gpio_irq_unmask(d);
return 0;
}

static void cp2112_gpio_irq_shutdown(struct irq_data *d)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
struct cp2112_device *dev = gpiochip_get_data(gc);

cancel_delayed_work_sync(&dev->gpio_poll_worker);
}

static int cp2112_gpio_irq_type(struct irq_data *d, unsigned int type)
{
return 0;
}

static struct irq_chip cp2112_gpio_irqchip = {
.name = "cp2112-gpio",
.irq_startup = cp2112_gpio_irq_startup,
.irq_shutdown = cp2112_gpio_irq_shutdown,
.irq_ack = cp2112_gpio_irq_ack,
.irq_mask = cp2112_gpio_irq_mask,
.irq_unmask = cp2112_gpio_irq_unmask,
.irq_set_type = cp2112_gpio_irq_type,
};

static int __maybe_unused cp2112_allocate_irq(struct cp2112_device *dev,
int pin)
{
int ret;

if (dev->desc[pin])
return -EINVAL;

dev->desc[pin] = gpiochip_request_own_desc(&dev->gc, pin,
"HID/I2C:Event");
if (IS_ERR(dev->desc[pin])) {
dev_err(dev->gc.parent, "Failed to request GPIO\n");
return PTR_ERR(dev->desc[pin]);
}

ret = gpiochip_lock_as_irq(&dev->gc, pin);
if (ret) {
dev_err(dev->gc.parent, "Failed to lock GPIO as interrupt\n");
goto err_desc;
}

ret = gpiod_to_irq(dev->desc[pin]);
if (ret < 0) {
dev_err(dev->gc.parent, "Failed to translate GPIO to IRQ\n");
goto err_lock;
}

return ret;

err_lock:
gpiochip_unlock_as_irq(&dev->gc, pin);
err_desc:
gpiochip_free_own_desc(dev->desc[pin]);
dev->desc[pin] = NULL;
return ret;
}

static int cp2112_probe(struct hid_device *hdev, const struct hid_device_id *id)
{
struct cp2112_device *dev;
Expand Down Expand Up @@ -1163,8 +1341,17 @@ static int cp2112_probe(struct hid_device *hdev, const struct hid_device_id *id)
chmod_sysfs_attrs(hdev);
hid_hw_power(hdev, PM_HINT_NORMAL);

ret = gpiochip_irqchip_add(&dev->gc, &cp2112_gpio_irqchip, 0,
handle_simple_irq, IRQ_TYPE_NONE);
if (ret) {
dev_err(dev->gc.parent, "failed to add IRQ chip\n");
goto err_sysfs_remove;
}

return ret;

err_sysfs_remove:
sysfs_remove_group(&hdev->dev.kobj, &cp2112_attr_group);
err_gpiochip_remove:
gpiochip_remove(&dev->gc);
err_free_i2c:
Expand All @@ -1181,10 +1368,22 @@ static int cp2112_probe(struct hid_device *hdev, const struct hid_device_id *id)
static void cp2112_remove(struct hid_device *hdev)
{
struct cp2112_device *dev = hid_get_drvdata(hdev);
int i;

sysfs_remove_group(&hdev->dev.kobj, &cp2112_attr_group);
gpiochip_remove(&dev->gc);
i2c_del_adapter(&dev->adap);

if (dev->gpio_poll) {
dev->gpio_poll = false;
cancel_delayed_work_sync(&dev->gpio_poll_worker);
}

for (i = 0; i < ARRAY_SIZE(dev->desc); i++) {
gpiochip_unlock_as_irq(&dev->gc, i);
gpiochip_free_own_desc(dev->desc[i]);
}

gpiochip_remove(&dev->gc);
/* i2c_del_adapter has finished removing all i2c devices from our
* adapter. Well behaved devices should no longer call our cp2112_xfer
* and should have waited for any pending calls to finish. It has also
Expand Down

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