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 two 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 the i2c address is the ARA address and the
device is enumerated via acpi, we change address of the device for
the one in the second acpi serial bus connection.
This free the ara address so we can register with the smbus_alert
driver.
If an interrupt resource is given, and a smbus_alert device was
found on the adapter, we request a treaded interrupt to
call i2c_smbus_alert_event to handle the alert.
In somme case, the treaded interrupt is not schedule before the driver
try to initialize chip registers. So if first registers access fail, we
call i2c_smbus_alert_event() to acknowledge initial alert, then retry
register access.
Signed-off-by: Marc CAPDEVILLE <m.capdeville@xxxxxxxxxx>
---
drivers/iio/light/cm32181.c | 120 ++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 115 insertions(+), 5 deletions(-)
diff --git a/drivers/iio/light/cm32181.c b/drivers/iio/light/cm32181.c
index aebf7dd071af..96c08755e6e3 100644
--- a/drivers/iio/light/cm32181.c
+++ b/drivers/iio/light/cm32181.c
@@ -18,6 +18,9 @@
#include <linux/iio/sysfs.h>
#include <linux/iio/events.h>
#include <linux/init.h>
+#include <linux/i2c-smbus.h>
+#include <linux/acpi.h>
+#include <linux/of_device.h>
/* Registers Address */
#define CM32181_REG_ADDR_CMD 0x00
@@ -47,6 +50,11 @@
#define CM32181_CALIBSCALE_RESOLUTION 1000
#define MLUX_PER_LUX 1000
+#define CM32181_ID 0x81
+#define CM3218_ID 0x18
+
+#define SMBUS_ARA_ADDR 0x0c
+
static const u8 cm32181_reg[CM32181_CONF_REG_NUM] = {
CM32181_REG_ADDR_CMD,
};
@@ -57,6 +65,7 @@ static const int als_it_value[] = {25000, 50000, 100000, 200000, 400000,
struct cm32181_chip {
struct i2c_client *client;
+ int chip_id;
struct mutex lock;
u16 conf_regs[CM32181_CONF_REG_NUM];
int calibscale;
@@ -77,11 +86,22 @@ static int cm32181_reg_init(struct cm32181_chip *cm32181)
s32 ret;
ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ID);
- if (ret < 0)
- return ret;
+ if (ret < 0) {
+ if (cm32181->chip_id == CM3218_ID) {
+ /*
+ * On cm3218, smbus alert trigger after probing,
+ * so poll for first alert here, then retry.
+ */
+ i2c_smbus_alert_event(client);
+ ret = i2c_smbus_read_word_data(client,
+ CM32181_REG_ADDR_ID);
+ } else {
+ return ret;
+ }
+ }
/* check device ID */
- if ((ret & 0xFF) != 0x81)
+ if ((ret & 0xFF) != cm32181->chip_id)
return -ENODEV;
/* Default Values */
@@ -297,12 +317,36 @@ static const struct iio_info cm32181_info = {
.attrs = &cm32181_attribute_group,
};
+static void cm3218_alert(struct i2c_client *client,
+ enum i2c_alert_protocol type,
+ unsigned int data)
+{
+ /*
+ * nothing to do for now.
+ * This is just here to acknownledge the cm3218 alert.
+ */
+}
+
+static irqreturn_t cm32181_irq(int irq, void *d)
+{
+ struct cm32181_chip *cm32181 = d;
+
+ if (cm32181->chip_id == CM3218_ID) {
+ /* This is cm3218 chip irq, so handle the smbus alert */
+ i2c_smbus_alert_event(cm32181->client);
+ }
+
+ return IRQ_HANDLED;
+}
+
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;
+ const struct of_device_id *of_id;
+ const struct acpi_device_id *acpi_id;
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*cm32181));
if (!indio_dev) {
@@ -322,6 +366,61 @@ static int cm32181_probe(struct i2c_client *client,
indio_dev->name = id->name;
indio_dev->modes = INDIO_DIRECT_MODE;
+ /* Lookup for chip ID from platform, acpi or of device table */
+ if (id) {
+ cm32181->chip_id = id->driver_data;
+ } else if (ACPI_COMPANION(&client->dev)) {
+ acpi_id = acpi_match_device(client->dev.driver->acpi_match_table,
+ &client->dev);
+ if (!acpi_id)
+ return -ENODEV;
+
+ cm32181->chip_id = (kernel_ulong_t)acpi_id->driver_data;
+ } else if (client->dev.of_node) {
+ of_id = of_match_device(client->dev.driver->of_match_table,
+ &client->dev);
+ if (!of_id)
+ return -ENODEV;
+
+ cm32181->chip_id = (kernel_ulong_t)of_id->data;
+ } else {
+ return -ENODEV;
+ }
+
+ if (cm32181->chip_id == CM3218_ID) {
+ if (ACPI_COMPANION(&client->dev) &&
+ client->addr == SMBUS_ARA_ADDR) {
+ /*
+ * In case this device as been enumerated by acpi
+ * with the reserved smbus ARA address (first acpi
+ * connection), request change of address to the second
+ * connection.
+ */
+ ret = i2c_acpi_set_connection(client, 1);
+ if (ret)
+ return ret;
+ }
+
+ /* cm3218 chip require an ara device on his adapter */
+ ret = i2c_require_smbus_alert(client);
+ if (ret < 0)
+ return ret;
+
+ /*
+ * If irq is given, request a threaded irq handler to manage
+ * smbus alert.
+ */
+ if (client->irq > 0) {
+ ret = devm_request_threaded_irq(&client->dev,
+ client->irq,
+ NULL, cm32181_irq,
+ IRQF_ONESHOT,
+ "cm32181", cm32181);
+ if (ret)
+ return ret;
+ }
+ }
+
ret = cm32181_reg_init(cm32181);
if (ret) {
dev_err(&client->dev,
@@ -342,25 +441,36 @@ static int cm32181_probe(struct i2c_client *client,
}
static const struct i2c_device_id cm32181_id[] = {
- { "cm32181", 0 },
+ { "cm32181", CM32181_ID },
+ { "cm3218", CM3218_ID },
{ }
};
MODULE_DEVICE_TABLE(i2c, cm32181_id);
static const struct of_device_id cm32181_of_match[] = {
- { .compatible = "capella,cm32181" },
+ { .compatible = "capella,cm32181", (void *)CM32181_ID },
+ { .compatible = "capella,cm3218", (void *)CM3218_ID },
{ }
};
MODULE_DEVICE_TABLE(of, cm32181_of_match);
+static const struct acpi_device_id cm32181_acpi_match[] = {
+ { "CPLM3218", CM3218_ID },
+ { }
+};
+
+MODULE_DEVICE_TABLE(acpi, cm32181_acpi_match);
+
static struct i2c_driver cm32181_driver = {
.driver = {
.name = "cm32181",
.of_match_table = of_match_ptr(cm32181_of_match),
+ .acpi_match_table = ACPI_PTR(cm32181_acpi_match),
},
.id_table = cm32181_id,
.probe = cm32181_probe,
+ .alert = cm3218_alert,
};
module_i2c_driver(cm32181_driver);
--
2.11.0
