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

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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: 6f108dd70d ("i2c: Clear client->irq in i2c_device_remove")
Signed-off-by: Jim Broadus <jbroadus@gmail.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Reviewed-by: Charles 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: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Jim Broadus 2019-02-19 11:30:27 -08:00 committed by Wolfram Sang
parent 088a8a7fb4
commit 93b6604c5a
2 changed files with 6 additions and 4 deletions
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9
drivers/i2c/i2c-core-base.c
View File

@ -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));

1
include/linux/i2c.h
View File

@ -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)