[PATH v3 4/4] i2c: i2c-diolan-u2c: sysfs bus frequency support

Octavian Purdila
2014-10-15T20:04:03Z

Add support for showing and changing the bus frequency via
sysfs.

Tested on a DLN2 adapter run in U2C-12 compatibility mode.

Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
---
drivers/i2c/busses/i2c-diolan-u2c.c | 49 +++++++++++++++++++++++++------------
1 file changed, 34 insertions(+), 15 deletions(-)

diff --git a/drivers/i2c/busses/i2c-diolan-u2c.c b/drivers/i2c/busses/i2c-diolan-u2c.c
index b19a310..ff4e120 100644
--- a/drivers/i2c/busses/i2c-diolan-u2c.c
+++ b/drivers/i2c/busses/i2c-diolan-u2c.c
@@ -71,6 +71,9 @@
#define U2C_I2C_FREQ_STD 100000
#define U2C_I2C_FREQ(s) (1000000 / (2 * (s - 1) + 10))

+#define U2C_I2C_MIN_FREQ U2C_I2C_FREQ(U2C_I2C_SPEED_2KHZ)
+#define U2C_I2C_MAX_FREQ U2C_I2C_FREQ_FAST
+
#define DIOLAN_USB_TIMEOUT 100 /* in ms */
#define DIOLAN_SYNC_TIMEOUT 20 /* in ms */

@@ -298,31 +301,24 @@ static void diolan_get_serial(struct i2c_diolan_u2c *dev)
}
}

-static int diolan_init(struct i2c_diolan_u2c *dev)
+static int diolan_set_freq(struct i2c_adapter *adapter, unsigned int *frequency)
{
+ struct i2c_diolan_u2c *dev = i2c_get_adapdata(adapter);
int speed, ret;

- if (frequency >= 200000) {
+ if (*frequency >= 200000) {
speed = U2C_I2C_SPEED_FAST;
- frequency = U2C_I2C_FREQ_FAST;
- } else if (frequency >= 100000 || frequency == 0) {
+ *frequency = U2C_I2C_FREQ_FAST;
+ } else if (*frequency >= 100000 || *frequency == 0) {
speed = U2C_I2C_SPEED_STD;
- frequency = U2C_I2C_FREQ_STD;
+ *frequency = U2C_I2C_FREQ_STD;
} else {
- speed = U2C_I2C_SPEED(frequency);
+ speed = U2C_I2C_SPEED(*frequency);
if (speed > U2C_I2C_SPEED_2KHZ)
speed = U2C_I2C_SPEED_2KHZ;
- frequency = U2C_I2C_FREQ(speed);
+ *frequency = U2C_I2C_FREQ(speed);
}

- dev_info(&dev->interface->dev,
- "Diolan U2C at USB bus %03d address %03d speed %d Hz\n",
- dev->usb_dev->bus->busnum, dev->usb_dev->devnum, frequency);
-
- diolan_flush_input(dev);
- diolan_fw_version(dev);
- diolan_get_serial(dev);
-
/* Set I2C speed */
ret = diolan_set_speed(dev, speed);
if (ret < 0)
@@ -336,6 +332,23 @@ static int diolan_init(struct i2c_diolan_u2c *dev)
if (speed != U2C_I2C_SPEED_FAST)
ret = diolan_set_clock_synch_timeout(dev, DIOLAN_SYNC_TIMEOUT);

+ return 0;
+}
+
+static int diolan_init(struct i2c_diolan_u2c *dev)
+{
+ int ret;
+
+ diolan_flush_input(dev);
+ diolan_fw_version(dev);
+ diolan_get_serial(dev);
+
+ ret = diolan_set_freq(&dev->adapter, &frequency);
+
+ dev_info(&dev->interface->dev,
+ "Diolan U2C at USB bus %03d address %03d speed %d Hz\n",
+ dev->usb_dev->bus->busnum, dev->usb_dev->devnum, frequency);
+
return ret;
}

@@ -471,6 +484,9 @@ static int diolan_u2c_probe(struct usb_interface *interface,
dev->adapter.owner = THIS_MODULE;
dev->adapter.class = I2C_CLASS_HWMON;
dev->adapter.algo = &diolan_usb_algorithm;
+ dev->adapter.min_freq = U2C_I2C_MIN_FREQ;
+ dev->adapter.max_freq = U2C_I2C_MAX_FREQ;
+ dev->adapter.set_freq = diolan_set_freq;
i2c_set_adapdata(&dev->adapter, dev);
snprintf(dev->adapter.name, sizeof(dev->adapter.name),
DRIVER_NAME " at bus %03d device %03d",
@@ -485,6 +501,9 @@ static int diolan_u2c_probe(struct usb_interface *interface,
goto error_free;
}

+ /* set the current bus frequency */
+ dev->adapter.freq = frequency;
+
/* and finally attach to i2c layer */
ret = i2c_add_adapter(&dev->adapter);
if (ret < 0) {
--
1.9.1