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Merge branch 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 

Pull i2c fixes from Wolfram Sang:
 "An I2C core fix to prevent a use-after-free in a rare error path,
  and an I2C ACPI addition to work around broken HW/firmware related
  to touchscreens"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: core: fix use after free in of_i2c_notify
  i2c: acpi: Force bus speed to 400KHz if a Silead touchscreen is present
This commit is contained in:
Linus Torvalds 2019-11-17 08:15:41 -08:00
parent 1d4c79ed32 a4c2fec16f
commit 6b27354cca
2 changed files with 29 additions and 3 deletions
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28
drivers/i2c/i2c-core-acpi.c
View File

@ -39,6 +39,7 @@ struct i2c_acpi_lookup {
int index;
u32 speed;
u32 min_speed;
u32 force_speed;
};
/**
@ -285,6 +286,19 @@ i2c_acpi_match_device(const struct acpi_device_id *matches,
return acpi_match_device(matches, &client->dev);
}
static const struct acpi_device_id i2c_acpi_force_400khz_device_ids[] = {
/*
* These Silead touchscreen controllers only work at 400KHz, for
* some reason they do not work at 100KHz. On some devices the ACPI
* tables list another device at their bus as only being capable
* of 100KHz, testing has shown that these other devices work fine
* at 400KHz (as can be expected of any recent i2c hw) so we force
* the speed of the bus to 400 KHz if a Silead device is present.
*/
{ "MSSL1680", 0 },
{}
};
static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level,
void *data, void **return_value)
{
@ -303,6 +317,9 @@ static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level,
if (lookup->speed <= lookup->min_speed)
lookup->min_speed = lookup->speed;
if (acpi_match_device_ids(adev, i2c_acpi_force_400khz_device_ids) == 0)
lookup->force_speed = 400000;
return AE_OK;
}
@ -340,7 +357,16 @@ u32 i2c_acpi_find_bus_speed(struct device *dev)
return 0;
}
return lookup.min_speed != UINT_MAX ? lookup.min_speed : 0;
if (lookup.force_speed) {
if (lookup.force_speed != lookup.min_speed)
dev_warn(dev, FW_BUG "DSDT uses known not-working I2C bus speed %d, forcing it to %d\n",
lookup.min_speed, lookup.force_speed);
return lookup.force_speed;
} else if (lookup.min_speed != UINT_MAX) {
return lookup.min_speed;
} else {
return 0;
}
}
EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);

4
drivers/i2c/i2c-core-of.c
View File

@ -245,14 +245,14 @@ static int of_i2c_notify(struct notifier_block *nb, unsigned long action,
}
client = of_i2c_register_device(adap, rd->dn);
put_device(&adap->dev);
if (IS_ERR(client)) {
dev_err(&adap->dev, "failed to create client for '%pOF'\n",
rd->dn);
put_device(&adap->dev);
of_node_clear_flag(rd->dn, OF_POPULATED);
return notifier_from_errno(PTR_ERR(client));
}
put_device(&adap->dev);
break;
case OF_RECONFIG_CHANGE_REMOVE:
/* already depopulated? */