Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input

Pull input updates from Dmitry Torokhov:

 - three new touchscreen drivers: Hycon HY46XX, ILITEK Lego Series,
   and MStar MSG2638

 - a new driver for Azoteq IQS626A proximity and touch controller

 - addition of Amazon Game Controller to the list of devices handled
   by the xpad driver

 - Elan touchscreen driver will avoid binding to devices described as
   I2CHID compatible in ACPI tables

 - various driver fixes

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input: (56 commits)
  Input: xpad - add support for Amazon Game Controller
  Input: ili210x - add missing negation for touch indication on ili210x
  MAINTAINERS: repair reference in HYCON HY46XX TOUCHSCREEN SUPPORT
  Input: add driver for the Hycon HY46XX touchpanel series
  dt-bindings: touchscreen: Add HY46XX bindings
  dt-bindings: Add Hycon Technology vendor prefix
  Input: cyttsp - flag the device properly
  Input: cyttsp - set abs params for ABS_MT_TOUCH_MAJOR
  Input: cyttsp - drop the phys path
  Input: cyttsp - reduce reset pulse timings
  Input: cyttsp - error message on boot mode exit error
  Input: apbps2 - remove useless variable
  Input: mms114 - support MMS136
  Input: mms114 - convert bindings to YAML and extend
  Input: Add support for ILITEK Lego Series
  dt-bindings: input: touchscreen: ilitek_ts_i2c: Add bindings
  Input: add MStar MSG2638 touchscreen driver
  dt-bindings: input/touchscreen: add bindings for msg2638
  Input: silead - add workaround for x86 BIOS-es which bring the chip up in a stuck state
  Input: elants_i2c - do not bind to i2c-hid compatible ACPI instantiated devices
  ...

1 files changed, 41 insertions, 5 deletions

diff --git a/drivers/input/touchscreen/silead.c b/drivers/input/touchscreen/silead.c
index 8fa2f3b7cfd8..1ee760bac0cf 100644
--- a/drivers/input/touchscreen/silead.c
+++ b/drivers/input/touchscreen/silead.c
@@ -20,6 +20,7 @@
 #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>
 
@@ -335,10 +336,8 @@ 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);
@@ -351,12 +350,49 @@ 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)
@@ -486,7 +522,7 @@ static int silead_ts_probe(struct i2c_client *client,
 
 	silead_ts_read_props(client);
 
-	/* We must have the IRQ provided by DT or ACPI subsytem */
+	/* We must have the IRQ provided by DT or ACPI subsystem */
 	if (client->irq <= 0)
 		return -ENODEV;