i2c-for-6.11-rc3

SMBusAlert handling in the I2C core gets two fixes. One to avoid an
 endless loop when scanning for handlers and one to make sure handlers
 are always called even if HW has broken behaviour. The I2C header gets a
 compilation fix is ACPI is enabled but I2C isn't. The testunit gets a
 rename in the code to match the documentation.
 
 Two fixes on the Qualcomm GENI I2C controller are cleaning up the
 error exit patch in the runtime_resume() function. The first is
 disabling the clock, the second disables the icc on the way out.
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Merge tag 'i2c-for-6.11-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux

Pull i2c fixes from Wolfram Sang:

 - Two fixes for SMBusAlert handling in the I2C core: one to avoid an
   endless loop when scanning for handlers and one to make sure handlers
   are always called even if HW has broken behaviour

 - I2C header build fix for when ACPI is enabled but I2C isn't

 - The testunit gets a rename in the code to match the documentation

 - Two fixes for the Qualcomm GENI I2C controller are cleaning up the
   error exit patch in the runtime_resume() function. The first is
   disabling the clock, the second disables the icc on the way out

* tag 'i2c-for-6.11-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: testunit: match HostNotify test name with docs
  i2c: qcom-geni: Add missing geni_icc_disable in geni_i2c_runtime_resume
  i2c: qcom-geni: Add missing clk_disable_unprepare in geni_i2c_runtime_resume
  i2c: Fix conditional for substituting empty ACPI functions
  i2c: smbus: Send alert notifications to all devices if source not found
  i2c: smbus: Improve handling of stuck alerts

drivers/i2c/busses/i2c-qcom-geni.c

@@ -990,8 +990,11 @@ static int __maybe_unused geni_i2c_runtime_resume(struct device *dev)
 		return ret;
 
 	ret = geni_se_resources_on(&gi2c->se);
-	if (ret)
+	if (ret) {
+		clk_disable_unprepare(gi2c->core_clk);
+		geni_icc_disable(&gi2c->se);
 		return ret;
+	}
 
 	enable_irq(gi2c->irq);
 	gi2c->suspended = 0;

drivers/i2c/i2c-slave-testunit.c

@@ -18,7 +18,7 @@
 
 enum testunit_cmds {
 	TU_CMD_READ_BYTES = 1,	/* save 0 for ABORT, RESET or similar */
-	TU_CMD_HOST_NOTIFY,
+	TU_CMD_SMBUS_HOST_NOTIFY,
 	TU_CMD_SMBUS_BLOCK_PROC_CALL,
 	TU_NUM_CMDS
 };
@@ -60,7 +60,7 @@ static void i2c_slave_testunit_work(struct work_struct *work)
 		msg.len = tu->regs[TU_REG_DATAH];
 		break;
 
-	case TU_CMD_HOST_NOTIFY:
+	case TU_CMD_SMBUS_HOST_NOTIFY:
 		msg.addr = 0x08;
 		msg.flags = 0;
 		msg.len = 3;

drivers/i2c/i2c-smbus.c

@@ -34,6 +34,7 @@ static int smbus_do_alert(struct device *dev, void *addrp)
 	struct i2c_client *client = i2c_verify_client(dev);
 	struct alert_data *data = addrp;
 	struct i2c_driver *driver;
+	int ret;
 
 	if (!client || client->addr != data->addr)
 		return 0;
@@ -47,16 +48,47 @@ static int smbus_do_alert(struct device *dev, void *addrp)
 	device_lock(dev);
 	if (client->dev.driver) {
 		driver = to_i2c_driver(client->dev.driver);
-		if (driver->alert)
+		if (driver->alert) {
+			/* Stop iterating after we find the device */
 			driver->alert(client, data->type, data->data);
-		else
+			ret = -EBUSY;
+		} else {
 			dev_warn(&client->dev, "no driver alert()!\n");
-	} else
+			ret = -EOPNOTSUPP;
+		}
+	} else {
 		dev_dbg(&client->dev, "alert with no driver\n");
+		ret = -ENODEV;
+	}
 	device_unlock(dev);
 
-	/* Stop iterating after we find the device */
-	return -EBUSY;
+	return ret;
+}
+
+/* Same as above, but call back all drivers with alert handler */
+
+static int smbus_do_alert_force(struct device *dev, void *addrp)
+{
+	struct i2c_client *client = i2c_verify_client(dev);
+	struct alert_data *data = addrp;
+	struct i2c_driver *driver;
+
+	if (!client || (client->flags & I2C_CLIENT_TEN))
+		return 0;
+
+	/*
+	 * Drivers should either disable alerts, or provide at least
+	 * a minimal handler. Lock so the driver won't change.
+	 */
+	device_lock(dev);
+	if (client->dev.driver) {
+		driver = to_i2c_driver(client->dev.driver);
+		if (driver->alert)
+			driver->alert(client, data->type, data->data);
+	}
+	device_unlock(dev);
+
+	return 0;
 }
 
 /*
@@ -67,6 +99,7 @@ static irqreturn_t smbus_alert(int irq, void *d)
 {
 	struct i2c_smbus_alert *alert = d;
 	struct i2c_client *ara;
+	unsigned short prev_addr = I2C_CLIENT_END; /* Not a valid address */
 
 	ara = alert->ara;
 
@@ -94,8 +127,25 @@ static irqreturn_t smbus_alert(int irq, void *d)
 			data.addr, data.data);
 
 		/* Notify driver for the device which issued the alert */
-		device_for_each_child(&ara->adapter->dev, &data,
-				      smbus_do_alert);
+		status = device_for_each_child(&ara->adapter->dev, &data,
+					       smbus_do_alert);
+		/*
+		 * If we read the same address more than once, and the alert
+		 * was not handled by a driver, it won't do any good to repeat
+		 * the loop because it will never terminate. Try again, this
+		 * time calling the alert handlers of all devices connected to
+		 * the bus, and abort the loop afterwards. If this helps, we
+		 * are all set. If it doesn't, there is nothing else we can do,
+		 * so we might as well abort the loop.
+		 * Note: This assumes that a driver with alert handler handles
+		 * the alert properly and clears it if necessary.
+		 */
+		if (data.addr == prev_addr && status != -EBUSY) {
+			device_for_each_child(&ara->adapter->dev, &data,
+					      smbus_do_alert_force);
+			break;
+		}
+		prev_addr = data.addr;
 	}
 
 	return IRQ_HANDLED;

include/linux/i2c.h

@@ -1066,7 +1066,7 @@ static inline int of_i2c_get_board_info(struct device *dev,
 struct acpi_resource;
 struct acpi_resource_i2c_serialbus;
 
-#if IS_ENABLED(CONFIG_ACPI)
+#if IS_ENABLED(CONFIG_ACPI) && IS_ENABLED(CONFIG_I2C)
 bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
 			       struct acpi_resource_i2c_serialbus **i2c);
 int i2c_acpi_client_count(struct acpi_device *adev);