Commit 93b6604c authored by Jim Broadus's avatar Jim Broadus Committed by Wolfram Sang
Browse files

i2c: Allow recovery of the initial IRQ by an I2C client device. 



A previous change allowed I2C client devices to discover new IRQs upon
reprobe by clearing the IRQ in i2c_device_remove. However, if an IRQ was
assigned in i2c_new_device, that information is lost.

For example, the touchscreen and trackpad devices on a Dell Inspiron laptop
are I2C devices whose IRQs are defined by ACPI extended IRQ types. The
client device structures are initialized during an ACPI walk. After
removing the i2c_hid device, modprobe fails.

This change caches the initial IRQ value in i2c_new_device and then resets
the client device IRQ to the initial value in i2c_device_remove.

Fixes: 6f108dd7 ("i2c: Clear client->irq in i2c_device_remove")
Signed-off-by: default avatarJim Broadus <jbroadus@gmail.com>
Reviewed-by: default avatarBenjamin Tissoires <benjamin.tissoires@redhat.com>
Reviewed-by: default avatarCharles Keepax <ckeepax@opensource.cirrus.com>
[wsa: this is an easy to backport fix for the regression. We will
refactor the code to handle irq assignments better in general.]
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 088a8a7f

drivers/i2c/i2c-core-base.c

+5 −4
Original line number Diff line number Diff line
@@ -430,7 +430,7 @@ static int i2c_device_remove(struct device *dev) 
	dev_pm_clear_wake_irq(&client->dev);

	device_init_wakeup(&client->dev, false);



	client->irq = 0;

	client->irq = client->init_irq;



	return status;

}
@@ -741,10 +741,11 @@ 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;

	if (!client->irq)

		client->irq = i2c_dev_irq_from_resources(info->resources,

	client->init_irq = info->irq;

	if (!client->init_irq)

		client->init_irq = i2c_dev_irq_from_resources(info->resources,

							 info->num_resources);

	client->irq = client->init_irq;



	strlcpy(client->name, info->type, sizeof(client->name));

include/linux/i2c.h

+1 −0
Original line number Diff line number Diff line
@@ -333,6 +333,7 @@ struct i2c_client { 
	char name[I2C_NAME_SIZE];

	struct i2c_adapter *adapter;	/* the adapter we sit on	*/

	struct device dev;		/* the device structure		*/

	int init_irq;			/* irq set at initialization	*/

	int irq;			/* irq issued by device		*/

	struct list_head detected;

#if IS_ENABLED(CONFIG_I2C_SLAVE)

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