[PATCH] iio : Add cm3218 smbus ara and acpi support

[Marc CAPDEVILLE]

On asus T100, Capella cm3218 chip is implemented as ambiant light
sensor. This chip expose an smbus ARA protocol device on standard
address 0x0c. The chip is not functional before all alerts are
acknowledged.
On asus T100, this device is enumerated on ACPI bus and the description
give tow I2C connection. The first is the connection to the ARA device
and the second gives the real address of the device.

So, on device probe, if an interrupt resource is given, we declare an
smbus_alert device, and if the i2c address is the ARA address, we lookup
for the second in the ACPI resource list and change it in the client
structur.

Signed-off-by: Marc CAPDEVILLE <m.capdeville@xxxxxxxxxx>
---
 drivers/iio/light/Kconfig   |  19 +++++++
 drivers/iio/light/cm32181.c | 119 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 138 insertions(+)

diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index 2356ed9..6b1dacc 100644
--- a/drivers/iio/light/Kconfig
+++ b/drivers/iio/light/Kconfig
@@ -94,6 +94,25 @@ config CM32181
 	 To compile this driver as a module, choose M here:
 	 the module will be called cm32181.
 
+if CM32181
+config CM3218
+	depends on CM32181
+	depends on I2C_SMBUS
+	bool "Support for smbus ara protocol on cm3218 chip"
+	help
+	 Say Y here if you want to support Capella cm3218
+	 ambiant light sensor with smbus ARA protocol.
+
+config CM3218_ACPI
+	depends on CM3218
+	depends on ACPI
+	bool "Support for second address on acpi enumerated cm3218"
+	help
+	 Say Y here if you want to support Capella cm3218
+	 ambiant light sensor enumerated on ACPI.
+
+endif #CM32181
+
 config CM3232
 	depends on I2C
 	tristate "CM3232 ambient light sensor"
diff --git a/drivers/iio/light/cm32181.c b/drivers/iio/light/cm32181.c
index d6fd0da..9b69177 100644
--- a/drivers/iio/light/cm32181.c
+++ b/drivers/iio/light/cm32181.c
@@ -18,6 +18,12 @@
 #include <linux/iio/sysfs.h>
 #include <linux/iio/events.h>
 #include <linux/init.h>
+#if defined(CONFIG_I2C_SMBUS) && defined(CONFIG_CM3218)
+#include <linux/i2c-smbus.h>
+#if  defined(CONFIG_ACPI) && defined(CONFIG_CM3218_ACPI)
+#include <linux/acpi.h>
+#endif
+#endif
 
 /* Registers Address */
 #define CM32181_REG_ADDR_CMD		0x00
@@ -47,6 +53,10 @@
 #define CM32181_CALIBSCALE_RESOLUTION	1000
 #define MLUX_PER_LUX			1000
 
+#if defined(CONFIG_I2C_SMBUS) && defined(CONFIG_CM3218)
+#define CM3218_ARA_ADDR			0x0c
+#endif
+
 static const u8 cm32181_reg[CM32181_CONF_REG_NUM] = {
 	CM32181_REG_ADDR_CMD,
 };
@@ -57,6 +67,9 @@ static const int als_it_value[] = {25000, 50000, 100000, 200000, 400000,
 
 struct cm32181_chip {
 	struct i2c_client *client;
+#if  defined(CONFIG_I2C_SMBUS) && defined(CONFIG_CM3218)
+	struct i2c_client *ara;
+#endif
 	struct mutex lock;
 	u16 conf_regs[CM32181_CONF_REG_NUM];
 	int calibscale;
@@ -81,7 +94,11 @@ static int cm32181_reg_init(struct cm32181_chip *cm32181)
 		return ret;
 
 	/* check device ID */
+#ifdef CONFIG_CM3218
+	if ((ret & 0xFF) != 0x81 && (ret & 0xFF) != 0x18)
+#else
 	if ((ret & 0xFF) != 0x81)
+#endif
 		return -ENODEV;
 
 	/* Default Values */
@@ -298,12 +315,59 @@ static const struct iio_info cm32181_info = {
 	.attrs			= &cm32181_attribute_group,
 };
 
+#if defined(CONFIG_ACPI) && defined(CONFIG_CM3218_ACPI)
+static int cm3218_get_i2c_client(struct acpi_resource *ares, void *data)
+{
+	struct i2c_client *client = data;
+	struct acpi_resource_i2c_serialbus *sb;
+	acpi_status status;
+	acpi_handle adapter_handle;
+	acpi_handle client_adapter_handle;
+
+	if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
+		return 1;
+
+	sb = &ares->data.i2c_serial_bus;
+	if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C)
+		return 1;
+
+	status = acpi_get_handle(acpi_device_handle(ACPI_COMPANION(&client->dev)),
+				 sb->resource_source.string_ptr,
+				 &adapter_handle);
+	if (!ACPI_SUCCESS(status))
+		return 1;
+
+	client_adapter_handle = acpi_device_handle(ACPI_COMPANION(&client->adapter->dev));
+
+	if (adapter_handle != client_adapter_handle)
+		return 1;
+
+	if (sb->slave_address == client->addr)
+		return 1;
+
+	client->addr = sb->slave_address;
+	client->flags &= ~I2C_CLIENT_TEN;
+	if (sb->access_mode == ACPI_I2C_10BIT_MODE)
+		client->flags |= I2C_CLIENT_TEN;
+
+	return -1;
+}
+#endif
+
 static int cm32181_probe(struct i2c_client *client,
 			const struct i2c_device_id *id)
 {
 	struct cm32181_chip *cm32181;
 	struct iio_dev *indio_dev;
 	int ret;
+#if defined(CONFIG_I2C_SMBUS) && defined(CONFIG_CM3218)
+	struct i2c_smbus_alert_setup ara_setup;
+#if defined(CONFIG_ACPI) && defined(CONFIG_CM3218_ACPI)
+	struct acpi_device *adev;
+	LIST_HEAD(ares);
+#endif
+#endif
+
 
 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*cm32181));
 	if (!indio_dev) {
@@ -323,6 +387,30 @@ static int cm32181_probe(struct i2c_client *client,
 	indio_dev->name = id->name;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 
+#if defined(CONFIG_I2C_SMBUS) && defined(CONFIG_CM3218)
+	if (client->irq > 0) {
+		if (client->addr == CM3218_ARA_ADDR) {
+#if defined(CONFIG_ACPI) && defined(CONFIG_CM3218_ACPI)
+			adev = ACPI_COMPANION(&client->dev);
+			if (!adev)
+				return -ENODEV;
+			ret = acpi_dev_get_resources(adev,
+						     &ares,
+						     cm3218_get_i2c_client,
+						     client);
+			acpi_dev_free_resource_list(&ares);
+			if (ret < 0)
+				return -ENODEV;
+#else
+			return -ENODEV;
+#endif
+		}
+		ara_setup.irq = client->irq;
+		ara_setup.alert_edge_triggered = 0;
+		cm32181->ara = i2c_setup_smbus_alert(client->adapter,
+						     &ara_setup);
+	}
+#endif
 	ret = cm32181_reg_init(cm32181);
 	if (ret) {
 		dev_err(&client->dev,
@@ -342,8 +430,24 @@ static int cm32181_probe(struct i2c_client *client,
 	return 0;
 }
 
+#if defined(CONFIG_I2C_SMBUS) && defined(CONFIG_CM3218)
+static int cm32181_remove(struct i2c_client *client)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+	struct cm32181_chip *cm32181 = iio_priv(indio_dev);
+
+	if (cm32181->ara)
+		i2c_unregister_device(cm32181->ara);
+
+	return 0;
+};
+#endif
+
 static const struct i2c_device_id cm32181_id[] = {
 	{ "cm32181", 0 },
+#if defined(CONFIG_I2C_SMBUS) && defined(CONFIG_CM3218)
+	{ "CPLM3218", 1 },
+#endif
 	{ }
 };
 
@@ -355,13 +459,28 @@ static const struct of_device_id cm32181_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, cm32181_of_match);
 
+#if defined(CONFIG_ACPI) && defined(CONFIG_CM3218_ACPI)
+static const struct acpi_device_id cm32181_acpi_match[] = {
+	{ "CPLM3218", 0 },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(acpi, cm32181_acpi_match);
+#endif
+
 static struct i2c_driver cm32181_driver = {
 	.driver = {
 		.name	= "cm32181",
 		.of_match_table = of_match_ptr(cm32181_of_match),
+#if defined(CONFIG_ACPI) && defined(CONFIG_CM3218_ACPI)
+		.acpi_match_table = ACPI_PTR(cm32181_acpi_match),
+#endif
 	},
 	.id_table       = cm32181_id,
 	.probe		= cm32181_probe,
+#if defined(CONFIG_I2C_SMBUS) && defined(CONFIG_CM3218)
+	.remove		= cm32181_remove,
+#endif
 };
 
 module_i2c_driver(cm32181_driver);
-- 
2.1.4