> How about:
> ---
> From daa7571bbf337704332c0cfeec9b8fd5aeae596f Mon Sep 17 00:00:00 2001
> From: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
> Date: Wed, 4 Jan 2017 18:26:54 +0100
> Subject: [PATCH] I2C: add the source of the IRQ in struct i2c_client
>
> With commit 4d5538f5882a ("i2c: use an IRQ to report Host Notify events,
> not alert"), the IRQ provided in struct i2c_client might be assigned while
> it has not been explicitly declared by either the platform information
> or OF or ACPI.
> Some drivers (lis3lv02d) rely on the fact that the IRQ gets assigned or
> not to trigger a different behavior (exposing /dev/freefall in this case).
>
> Provide a way for others to know who set the IRQ and so they can behave
> accordingly.
>
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
> ---
> drivers/i2c/i2c-core.c | 7 +++++++
> include/linux/i2c.h | 11 +++++++++++
> 2 files changed, 18 insertions(+)
>
> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> index cf9e396..226c75d 100644
> --- a/drivers/i2c/i2c-core.c
> +++ b/drivers/i2c/i2c-core.c
> @@ -935,8 +935,12 @@ static int i2c_device_probe(struct device *dev)
> irq = of_irq_get_byname(dev->of_node, "irq");
> if (irq == -EINVAL || irq == -ENODATA)
> irq = of_irq_get(dev->of_node, 0);
> + if (irq > 0)
> + client->irq_source = I2C_IRQ_SOURCE_OF;
> } else if (ACPI_COMPANION(dev)) {
> irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
> + if (irq > 0)
> + client->irq_source = I2C_IRQ_SOURCE_ACPI;
> }
> if (irq == -EPROBE_DEFER)
> return irq;
> @@ -947,6 +951,8 @@ static int i2c_device_probe(struct device *dev)
> if (irq < 0) {
> dev_dbg(dev, "Using Host Notify IRQ\n");
> irq = i2c_smbus_host_notify_to_irq(client);
> + if (irq > 0)
> + client->irq_source = I2C_IRQ_SOURCE_HOST_NOTIFY;
> }
> if (irq < 0)
> irq = 0;
> @@ -1317,6 +1323,7 @@ i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
> client->flags = info->flags;
> client->addr = info->addr;
> client->irq = info->irq;
> + client->irq_source = I2C_IRQ_SOURCE_PLATFORM;
>
> strlcpy(client->name, info->type, sizeof(client->name));
>
> diff --git a/include/linux/i2c.h b/include/linux/i2c.h
> index b2109c5..7d0368d 100644
> --- a/include/linux/i2c.h
> +++ b/include/linux/i2c.h
> @@ -213,6 +213,13 @@ struct i2c_driver {
> };
> #define to_i2c_driver(d) container_of(d, struct i2c_driver, driver)
>
> +enum i2c_irq_source {
> + I2C_IRQ_SOURCE_PLATFORM,
> + I2C_IRQ_SOURCE_OF,
> + I2C_IRQ_SOURCE_ACPI,
> + I2C_IRQ_SOURCE_HOST_NOTIFY,
> +};
> +
> /**
> * struct i2c_client - represent an I2C slave device
> * @flags: I2C_CLIENT_TEN indicates the device uses a ten bit chip address;
> @@ -227,6 +234,9 @@ struct i2c_driver {
> * userspace_devices list
> * @slave_cb: Callback when I2C slave mode of an adapter is used. The adapter
> * calls it to pass on slave events to the slave driver.
> + * @irq_source: Enum which provides the source of the IRQ. Useful to know
> + * if the IRQ was issued from Host Notify or if it was provided by an other
> + * component.
I'd think some documentation somewhere makes sense why we need to
distinguish this in some cases?
> *
> * An i2c_client identifies a single device (i.e. chip) connected to an
> * i2c bus. The behaviour exposed to Linux is defined by the driver
> @@ -245,6 +255,7 @@ struct i2c_client {
> #if IS_ENABLED(CONFIG_I2C_SLAVE)
> i2c_slave_cb_t slave_cb; /* callback for slave mode */
> #endif
> + enum i2c_irq_source irq_source; /* which component assigned the irq */
> };
> #define to_i2c_client(d) container_of(d, struct i2c_client, dev)
>
> Dmitry, Wolfram, Jean, would this be acceptable for you?
Adding something to i2c_driver is not exactly cheap, but from what I
glimpsed from this thread, this is one of the cleanest solution to this
problem?
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