[PATCH AUTOSEL 4.14 05/12] Input: elants_i2c - do not bind to i2c-hid compatible ACPI instantiated devices

[PATCH AUTOSEL 4.14 05/12] Input: elants_i2c - do not bind to i2c-hid compatible ACPI instantiated devices

[Sasha Levin]

From: Hans de Goede <hdegoede@redhat.com>

[ Upstream commit 65299e8bfb24774e6340e93ae49f6626598917c8 ]

Several users have been reporting that elants_i2c gives several errors
during probe and that their touchscreen does not work on their Lenovo AMD
based laptops with a touchscreen with a ELAN0001 ACPI hardware-id:

[    0.550596] elants_i2c i2c-ELAN0001:00: i2c-ELAN0001:00 supply vcc33 not found, using dummy regulator
[    0.551836] elants_i2c i2c-ELAN0001:00: i2c-ELAN0001:00 supply vccio not found, using dummy regulator
[    0.560932] elants_i2c i2c-ELAN0001:00: elants_i2c_send failed (77 77 77 77): -121
[    0.562427] elants_i2c i2c-ELAN0001:00: software reset failed: -121
[    0.595925] elants_i2c i2c-ELAN0001:00: elants_i2c_send failed (77 77 77 77): -121
[    0.597974] elants_i2c i2c-ELAN0001:00: software reset failed: -121
[    0.621893] elants_i2c i2c-ELAN0001:00: elants_i2c_send failed (77 77 77 77): -121
[    0.622504] elants_i2c i2c-ELAN0001:00: software reset failed: -121
[    0.632650] elants_i2c i2c-ELAN0001:00: elants_i2c_send failed (4d 61 69 6e): -121
[    0.634256] elants_i2c i2c-ELAN0001:00: boot failed: -121
[    0.699212] elants_i2c i2c-ELAN0001:00: invalid 'hello' packet: 00 00 ff ff
[    1.630506] elants_i2c i2c-ELAN0001:00: Failed to read fw id: -121
[    1.645508] elants_i2c i2c-ELAN0001:00: unknown packet 00 00 ff ff

Despite these errors, the elants_i2c driver stays bound to the device
(it returns 0 from its probe method despite the errors), blocking the
i2c-hid driver from binding.

Manually unbinding the elants_i2c driver and binding the i2c-hid driver
makes the touchscreen work.

Check if the ACPI-fwnode for the touchscreen contains one of the i2c-hid
compatiblity-id strings and if it has the I2C-HID spec's DSM to get the
HID descriptor address, If it has both then make elants_i2c not bind,
so that the i2c-hid driver can bind.

This assumes that non of the (older) elan touchscreens which actually
need the elants_i2c driver falsely advertise an i2c-hid compatiblity-id
+ DSM in their ACPI-fwnodes. If some of them actually do have this
false advertising, then this change may lead to regressions.

While at it also drop the unnecessary DEVICE_NAME prefixing of the
"I2C check functionality error", dev_err already outputs the driver-name.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=207759
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210405202756.16830-1-hdegoede@redhat.com

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/input/touchscreen/elants_i2c.c | 44 ++++++++++++++++++++++++--
 1 file changed, 42 insertions(+), 2 deletions(-)

diff --git a/drivers/input/touchscreen/elants_i2c.c b/drivers/input/touchscreen/elants_i2c.c
index 0f4cda7282a2..fd48fb6ef210 100644
--- a/drivers/input/touchscreen/elants_i2c.c
+++ b/drivers/input/touchscreen/elants_i2c.c
@@ -40,6 +40,7 @@
 #include <linux/of.h>
 #include <linux/gpio/consumer.h>
 #include <linux/regulator/consumer.h>
+#include <linux/uuid.h>
 #include <asm/unaligned.h>
 
 /* Device, Driver information */
@@ -1138,6 +1139,40 @@ static void elants_i2c_power_off(void *_data)
 	}
 }
 
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id i2c_hid_ids[] = {
+	{"ACPI0C50", 0 },
+	{"PNP0C50", 0 },
+	{ },
+};
+
+static const guid_t i2c_hid_guid =
+	GUID_INIT(0x3CDFF6F7, 0x4267, 0x4555,
+		  0xAD, 0x05, 0xB3, 0x0A, 0x3D, 0x89, 0x38, 0xDE);
+
+static bool elants_acpi_is_hid_device(struct device *dev)
+{
+	acpi_handle handle = ACPI_HANDLE(dev);
+	union acpi_object *obj;
+
+	if (acpi_match_device_ids(ACPI_COMPANION(dev), i2c_hid_ids))
+		return false;
+
+	obj = acpi_evaluate_dsm_typed(handle, &i2c_hid_guid, 1, 1, NULL, ACPI_TYPE_INTEGER);
+	if (obj) {
+		ACPI_FREE(obj);
+		return true;
+	}
+
+	return false;
+}
+#else
+static bool elants_acpi_is_hid_device(struct device *dev)
+{
+	return false;
+}
+#endif
+
 static int elants_i2c_probe(struct i2c_client *client,
 			    const struct i2c_device_id *id)
 {
@@ -1146,9 +1181,14 @@ static int elants_i2c_probe(struct i2c_client *client,
 	unsigned long irqflags;
 	int error;
 
+	/* Don't bind to i2c-hid compatible devices, these are handled by the i2c-hid drv. */
+	if (elants_acpi_is_hid_device(&client->dev)) {
+		dev_warn(&client->dev, "This device appears to be an I2C-HID device, not binding\n");
+		return -ENODEV;
+	}
+
 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
-		dev_err(&client->dev,
-			"%s: i2c check functionality error\n", DEVICE_NAME);
+		dev_err(&client->dev, "I2C check functionality error\n");
 		return -ENXIO;
 	}
 
-- 
2.30.2

[PATCH AUTOSEL 4.14 06/12] Input: silead - add workaround for x86 BIOS-es which bring the chip up in a stuck state

[Sasha Levin]

From: Hans de Goede <hdegoede@redhat.com>

[ Upstream commit e479187748a8f151a85116a7091c599b121fdea5 ]

Some buggy BIOS-es bring up the touchscreen-controller in a stuck
state where it blocks the I2C bus. Specifically this happens on
the Jumper EZpad 7 tablet model.

After much poking at this problem I have found that the following steps
are necessary to unstuck the chip / bus:

1. Turn off the Silead chip.
2. Try to do an I2C transfer with the chip, this will fail in response to
   which the I2C-bus-driver will call: i2c_recover_bus() which will unstuck
   the I2C-bus. Note the unstuck-ing of the I2C bus only works if we first
   drop the chip of the bus by turning it off.
3. Turn the chip back on.

On the x86/ACPI systems were this problem is seen, step 1. and 3. require
making ACPI calls and dealing with ACPI Power Resources. This commit adds
a workaround which runtime-suspends the chip to turn it off, leaving it up
to the ACPI subsystem to deal with all the ACPI specific details.

There is no good way to detect this bug, so the workaround gets activated
by a new "silead,stuck-controller-bug" boolean device-property. Since this
is only used on x86/ACPI, this will be set by model specific device-props
set by drivers/platform/x86/touchscreen_dmi.c. Therefor this new
device-property is not documented in the DT-bindings.

Dmesg will contain the following messages on systems where the workaround
is activated:

[   54.309029] silead_ts i2c-MSSL1680:00: [Firmware Bug]: Stuck I2C bus: please ignore the next 'controller timed out' error
[   55.373593] i2c_designware 808622C1:04: controller timed out
[   55.582186] silead_ts i2c-MSSL1680:00: Silead chip ID: 0x80360000

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210405202745.16777-1-hdegoede@redhat.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/input/touchscreen/silead.c | 44 +++++++++++++++++++++++++++---
 1 file changed, 40 insertions(+), 4 deletions(-)

diff --git a/drivers/input/touchscreen/silead.c b/drivers/input/touchscreen/silead.c
index 7c0eeef29b3c..18c866129845 100644
--- a/drivers/input/touchscreen/silead.c
+++ b/drivers/input/touchscreen/silead.c
@@ -28,6 +28,7 @@
 #include <linux/input/mt.h>
 #include <linux/input/touchscreen.h>
 #include <linux/pm.h>
+#include <linux/pm_runtime.h>
 #include <linux/irq.h>
 #include <linux/regulator/consumer.h>
 
@@ -319,10 +320,8 @@ static int silead_ts_get_id(struct i2c_client *client)
 
 	error = i2c_smbus_read_i2c_block_data(client, SILEAD_REG_ID,
 					      sizeof(chip_id), (u8 *)&chip_id);
-	if (error < 0) {
-		dev_err(&client->dev, "Chip ID read error %d\n", error);
+	if (error < 0)
 		return error;
-	}
 
 	data->chip_id = le32_to_cpu(chip_id);
 	dev_info(&client->dev, "Silead chip ID: 0x%8X", data->chip_id);
@@ -335,12 +334,49 @@ static int silead_ts_setup(struct i2c_client *client)
 	int error;
 	u32 status;
 
+	/*
+	 * Some buggy BIOS-es bring up the chip in a stuck state where it
+	 * blocks the I2C bus. The following steps are necessary to
+	 * unstuck the chip / bus:
+	 * 1. Turn off the Silead chip.
+	 * 2. Try to do an I2C transfer with the chip, this will fail in
+	 *    response to which the I2C-bus-driver will call:
+	 *    i2c_recover_bus() which will unstuck the I2C-bus. Note the
+	 *    unstuck-ing of the I2C bus only works if we first drop the
+	 *    chip off the bus by turning it off.
+	 * 3. Turn the chip back on.
+	 *
+	 * On the x86/ACPI systems were this problem is seen, step 1. and
+	 * 3. require making ACPI calls and dealing with ACPI Power
+	 * Resources. The workaround below runtime-suspends the chip to
+	 * turn it off, leaving it up to the ACPI subsystem to deal with
+	 * this.
+	 */
+
+	if (device_property_read_bool(&client->dev,
+				      "silead,stuck-controller-bug")) {
+		pm_runtime_set_active(&client->dev);
+		pm_runtime_enable(&client->dev);
+		pm_runtime_allow(&client->dev);
+
+		pm_runtime_suspend(&client->dev);
+
+		dev_warn(&client->dev, FW_BUG "Stuck I2C bus: please ignore the next 'controller timed out' error\n");
+		silead_ts_get_id(client);
+
+		/* The forbid will also resume the device */
+		pm_runtime_forbid(&client->dev);
+		pm_runtime_disable(&client->dev);
+	}
+
 	silead_ts_set_power(client, SILEAD_POWER_OFF);
 	silead_ts_set_power(client, SILEAD_POWER_ON);
 
 	error = silead_ts_get_id(client);
-	if (error)
+	if (error) {
+		dev_err(&client->dev, "Chip ID read error %d\n", error);
 		return error;
+	}
 
 	error = silead_ts_init(client);
 	if (error)
-- 
2.30.2