On Wed, 23 Jul 2008 13:07:54 +0200 Marc Pignat <marc.pignat at hevs.ch> wrote:
> SPI driver for analog to digital converters national semiconductor ADC081S101,
> ADC124S501, ...
>
> Signed-off-by: Marc Pignat <marc.pignat at hevs.ch>
>
> Hi all!
>
> patch against 2.6.26, tested on a custom arm board and only compil-tested on
> x86.
>
> This driver add support for National Semiconductor ADC<bb><c>S<sss> chip family,
> where:
> * bb is the resolution in number of bits (8, 10, 12)
> * c is the number of channels (1, 2, 4)
> * sss is the maximum conversion speed (021 for 200 kSPS, 051 for 500
> kSPS and 101 for 1 MSPS)
>
> Some remarks:
> * The chip type (-> the number of inputs) are determined by the module alias,
> is it a good idea? it could be implemented using platform data.
>
> * The Makefile seems ordered alphabetically, what order should be used for
> the Konfig file?
>
That changelog is a bit of a mess. I cleaned up up as:
SPI driver for analog to digital converters national semiconductor
ADC081S101, ADC124S501, ...
This driver adds support for National Semiconductor ADC<bb><c>S<sss> chip
family, where:
* bb is the resolution in number of bits (8, 10, 12)
* c is the number of channels (1, 2, 4)
* sss is the maximum conversion speed (021 for 200 kSPS, 051 for 500
kSPS and 101 for 1 MSPS)
Some remarks:
* The chip type (-> the number of inputs) are determined by the module
alias, is it a good idea? it could be implemented using platform data.
Signed-off-by: Marc Pignat <marc.pignat at hevs.ch>
Cc: "Mark M. Hoffman" <mhoffman at lightlink.com>
Cc: Jean Delvare <khali at linux-fr.org>
Cc: David Brownell <david-b at pacbell.net>
but then didn't apply the patch.
>
> ...
>
> +/* sysfs hook function */
> +static ssize_t adcxx_read(struct device *dev,
> + struct device_attribute *devattr, char *buf)
> +{
> + struct spi_device *spi = to_spi_device(dev);
> + struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
> + struct adcxx *adc = dev_get_drvdata(&spi->dev);
> +
> + u8 tx_buf[2] = { attr->index << 3 }; /* other bits are don't care */
> + u8 rx_buf[2];
> + int status;
> + int value;
The driver has rather a lot of inexplicable blank lines in the middle
of the automatic variable definitions. The preferred style is no blank
lines within the definitions and a single blank line after them all,
thanks.
>
> ...
>
> +static int __devinit adcxx_probe(struct spi_device *spi, int channels)
> +{
> + struct adcxx *adc;
> + int status;
> + int i;
> +
> + adc = kzalloc(sizeof *adc, GFP_KERNEL);
> + if (!adc)
> + return -ENOMEM;
> +
> + /* set a default value for the reference */
> + adc->reference = 3300;
> +
> + adc->channels = channels;
> +
> + mutex_init(&adc->lock);
> +
> + dev_set_drvdata(&spi->dev, adc);
> +
> + for (i = 0; i < 3 + adc->channels; i++) {
> + status = device_create_file(&spi->dev, &ad_input[i].dev_attr);
> + if (status)
> + goto out_dev_create_file_failed;
> + }
> +
> + adc->hwmon_dev = hwmon_device_register(&spi->dev);
> + if (IS_ERR(adc->hwmon_dev)) {
> + dev_dbg(&spi->dev, "hwmon_device_register failed.\n");
> + status = PTR_ERR(adc->hwmon_dev);
> + goto out_dev_reg_failed;
> + }
> +
> + return 0;
> +
> +out_dev_create_file_failed:
> + hwmon_device_unregister(adc->hwmon_dev);
> + for (i = 0; i < 3 + adc->channels; i++)
> + device_remove_file(&spi->dev, &ad_input[i].dev_attr);
> +out_dev_reg_failed:
> + dev_set_drvdata(&spi->dev, NULL);
> + kfree(adc);
> + return status;
> +}
The error recovery here is messed up. The targets of the `goto's are
reversed. But even if that is fixed, we can end up doing
device_remove_file() of objects which weren't successfully created.
That might work, or it might generate runtime warnings or it might
crash. I don't know. It'd be best to just avoid doing it?
