On 04/06/11 13:31, Alan Cox wrote: > Actually this is generic 'I have no GPIO' support for the AK8975, instead > we have to go bus polling. > > Huang Liang produced an initial patch which worked by removing the support > for GPIO pins. This patch instead makes GPIO support optional and Huang then > fixed some bugs in it. cc'd linux-iio > Signed-off-by: Alan Cox <alan@xxxxxxxxxxxxxxx> > --- > > drivers/staging/iio/magnetometer/ak8975.c | 120 ++++++++++++++++++++--------- > 1 files changed, 83 insertions(+), 37 deletions(-) > > diff --git a/drivers/staging/iio/magnetometer/ak8975.c b/drivers/staging/iio/magnetometer/ak8975.c > index 420f206..d71904a 100644 > --- a/drivers/staging/iio/magnetometer/ak8975.c > +++ b/drivers/staging/iio/magnetometer/ak8975.c > @@ -206,7 +206,7 @@ static int ak8975_setup(struct i2c_client *client) > } > > /* Precalculate scale factor for each axis and > - store in the device data. */ > + store in the device data. */ > data->raw_to_gauss[0] = ((data->asa[0] + 128) * 30) >> 8; > data->raw_to_gauss[1] = ((data->asa[1] + 128) * 30) >> 8; > data->raw_to_gauss[2] = ((data->asa[2] + 128) * 30) >> 8; > @@ -316,6 +316,59 @@ static ssize_t show_scale(struct device *dev, struct device_attribute *devattr, > return sprintf(buf, "%ld\n", data->raw_to_gauss[this_attr->address]); > } > > +static int wait_conversion_complete_gpio(struct ak8975_data *data) > +{ > + struct i2c_client *client = data->client; > + u8 read_status; > + u32 timeout_ms = AK8975_MAX_CONVERSION_TIMEOUT; > + int ret; > + > + /* Wait for the conversion to complete. */ > + while (timeout_ms) { > + msleep(AK8975_CONVERSION_DONE_POLL_TIME); > + if (gpio_get_value(data->eoc_gpio)) > + break; > + timeout_ms -= AK8975_CONVERSION_DONE_POLL_TIME; > + } > + if (!timeout_ms) { > + dev_err(&client->dev, "Conversion timeout happened\n"); > + return -EINVAL; > + } > + > + ret = ak8975_read_data(client, AK8975_REG_ST1, 1, &read_status); > + if (ret < 0) { > + dev_err(&client->dev, "Error in reading ST1\n"); > + return ret; > + } > + return read_status; > +} > + > +static int wait_conversion_complete_polled(struct ak8975_data *data) > +{ > + struct i2c_client *client = data->client; > + u8 read_status; > + u32 timeout_ms = AK8975_MAX_CONVERSION_TIMEOUT; > + int ret; > + > + /* Wait for the conversion to complete. */ > + while (timeout_ms) { > + msleep(AK8975_CONVERSION_DONE_POLL_TIME); > + ret = ak8975_read_data(client, AK8975_REG_ST1, 1, &read_status); > + if (ret < 0) { > + dev_err(&client->dev, "Error in reading ST1\n"); > + return ret; > + } > + if (read_status) > + break; > + timeout_ms -= AK8975_CONVERSION_DONE_POLL_TIME; > + } > + if (!timeout_ms) { > + dev_err(&client->dev, "Conversion timeout happened\n"); > + return -EINVAL; > + } > + return read_status; > +} > + > /* > * Emits the raw flux value for the x, y, or z axis. > */ > @@ -326,7 +379,6 @@ static ssize_t show_raw(struct device *dev, struct device_attribute *devattr, > struct ak8975_data *data = indio_dev->dev_data; > struct i2c_client *client = data->client; > struct iio_dev_attr *this_attr = to_iio_dev_attr(devattr); > - u32 timeout_ms = AK8975_MAX_CONVERSION_TIMEOUT; > u16 meas_reg; > s16 raw; > u8 read_status; > @@ -352,23 +404,14 @@ static ssize_t show_raw(struct device *dev, struct device_attribute *devattr, > } > > /* Wait for the conversion to complete. */ > - while (timeout_ms) { > - msleep(AK8975_CONVERSION_DONE_POLL_TIME); > - if (gpio_get_value(data->eoc_gpio)) > - break; > - timeout_ms -= AK8975_CONVERSION_DONE_POLL_TIME; > - } > - if (!timeout_ms) { > - dev_err(&client->dev, "Conversion timeout happened\n"); > - ret = -EINVAL; > + if (data->eoc_gpio) > + ret = wait_conversion_complete_gpio(data); > + else > + ret = wait_conversion_complete_polled(data); > + if (ret < 0) > goto exit; > - } > > - ret = ak8975_read_data(client, AK8975_REG_ST1, 1, &read_status); > - if (ret < 0) { > - dev_err(&client->dev, "Error in reading ST1\n"); > - goto exit; > - } > + read_status = ret; > > if (read_status & AK8975_REG_ST1_DRDY_MASK) { > ret = ak8975_read_data(client, AK8975_REG_ST2, 1, &read_status); > @@ -454,25 +497,26 @@ static int ak8975_probe(struct i2c_client *client, > data->eoc_irq = client->irq; > data->eoc_gpio = irq_to_gpio(client->irq); > > - if (!data->eoc_gpio) { > - dev_err(&client->dev, "failed, no valid GPIO\n"); > - err = -EINVAL; > - goto exit_free; > - } > - > - err = gpio_request(data->eoc_gpio, "ak_8975"); > - if (err < 0) { > - dev_err(&client->dev, "failed to request GPIO %d, error %d\n", > - data->eoc_gpio, err); > - goto exit_free; > - } > + /* We may not have a GPIO based IRQ to scan, that is fine, we will > + poll if so */ > + if (data->eoc_gpio > 0) { > + err = gpio_request(data->eoc_gpio, "ak_8975"); > + if (err < 0) { > + dev_err(&client->dev, > + "failed to request GPIO %d, error %d\n", > + data->eoc_gpio, err); > + goto exit_free; > + } > > - err = gpio_direction_input(data->eoc_gpio); > - if (err < 0) { > - dev_err(&client->dev, "Failed to configure input direction for" > - " GPIO %d, error %d\n", data->eoc_gpio, err); > - goto exit_gpio; > - } > + err = gpio_direction_input(data->eoc_gpio); > + if (err < 0) { > + dev_err(&client->dev, > + "Failed to configure input direction for GPIO %d, error %d\n", > + data->eoc_gpio, err); > + goto exit_gpio; > + } > + } else > + data->eoc_gpio = 0; /* No GPIO available */ > > /* Perform some basic start-of-day setup of the device. */ > err = ak8975_setup(client); > @@ -503,7 +547,8 @@ static int ak8975_probe(struct i2c_client *client, > exit_free_iio: > iio_free_device(data->indio_dev); > exit_gpio: > - gpio_free(data->eoc_gpio); > + if (data->eoc_gpio) > + gpio_free(data->eoc_gpio); > exit_free: > kfree(data); > exit: > @@ -517,7 +562,8 @@ static int ak8975_remove(struct i2c_client *client) > iio_device_unregister(data->indio_dev); > iio_free_device(data->indio_dev); > > - gpio_free(data->eoc_gpio); > + if (data->eoc_gpio) > + gpio_free(data->eoc_gpio); > > kfree(data); > > -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html