[V3] [TWL4030 MADC] Fix ADC[3:6] readings

[Adam Lee]

Hello Jonathan, thanks for your comment.

Just submitted V4 with corrections:

1. regulator configuration is now done before iio_device_register
2. devm_regulator_put has been removed as it is not necessary

Let me know!

Adam

On Sun, Aug 2, 2015 at 9:55 AM, Jonathan Cameron <jic23 at kernel.org> wrote:
> On 21/07/15 01:49, Adam YH Lee wrote:
>> MADC[3:6] reads incorrect values without these two following changes:
>>
>> - enable the 3v1 bias regulator for ADC[3:6]
>> - configure ADC[3:6] lines as input, not as USB
>>
>> Signed-off-by: Adam YH Lee <adam.yh.lee at gmail.com>
>> ---
>>  drivers/iio/adc/twl4030-madc.c | 36 ++++++++++++++++++++++++++++++++++++
>>  1 file changed, 36 insertions(+)
>>
>> diff --git a/drivers/iio/adc/twl4030-madc.c b/drivers/iio/adc/twl4030-madc.c
>> index 94c5f05..ae33eba 100644
>> --- a/drivers/iio/adc/twl4030-madc.c
>> +++ b/drivers/iio/adc/twl4030-madc.c
>> @@ -45,13 +45,18 @@
>>  #include <linux/types.h>
>>  #include <linux/gfp.h>
>>  #include <linux/err.h>
>> +#include <linux/regulator/consumer.h>
>>
>>  #include <linux/iio/iio.h>
>>
>> +#define TWL4030_USB_SEL_MADC_MCPC    (1<<3)
>> +#define TWL4030_USB_CARKIT_ANA_CTRL  0xBB
>> +
>>  /**
>>   * struct twl4030_madc_data - a container for madc info
>>   * @dev:             Pointer to device structure for madc
>>   * @lock:            Mutex protecting this data structure
>> + * @regulator:               Pointer to bias regulator for madc
>>   * @requests:                Array of request struct corresponding to SW1, SW2 and RT
>>   * @use_second_irq:  IRQ selection (main or co-processor)
>>   * @imr:             Interrupt mask register of MADC
>> @@ -60,6 +65,7 @@
>>  struct twl4030_madc_data {
>>       struct device *dev;
>>       struct mutex lock;      /* mutex protecting this data structure */
>> +     struct regulator *usb3v1;
>>       struct twl4030_madc_request requests[TWL4030_MADC_NUM_METHODS];
>>       bool use_second_irq;
>>       u8 imr;
>> @@ -848,6 +854,33 @@ static int twl4030_madc_probe(struct platform_device *pdev)
>>               goto err_i2c;
>>       }
>>
> At this point in the driver the userspace (an in kernel) interfaces to read
> from the device are exposed. Thus if you need this stuff set up right, it
> wants to be done before the iio_device_register call.
>> +     /* Configure MADC[3:6] */
>> +     ret = twl_i2c_read_u8(TWL_MODULE_USB, &regval,
>> +                     TWL4030_USB_CARKIT_ANA_CTRL);
>> +     if (ret) {
>> +             dev_err(&pdev->dev, "unable to read reg CARKIT_ANA_CTRL  0x%X\n",
>> +                             TWL4030_USB_CARKIT_ANA_CTRL);
>> +             goto err_i2c;
>> +     }
>> +     regval |= TWL4030_USB_SEL_MADC_MCPC;
>> +     ret = twl_i2c_write_u8(TWL_MODULE_USB, regval,
>> +                              TWL4030_USB_CARKIT_ANA_CTRL);
>> +     if (ret) {
>> +             dev_err(&pdev->dev, "unable to write reg CARKIT_ANA_CTRL 0x%X\n",
>> +                             TWL4030_USB_CARKIT_ANA_CTRL);
>> +             goto err_i2c;
>> +     }
>> +
>> +
>> +     /* Enable 3v1 bias regulator for MADC[3:6] */
>> +     madc->usb3v1 = devm_regulator_get(madc->dev, "vusb3v1");
>> +     if (IS_ERR(madc->usb3v1))
>> +             return -ENODEV;
>> +
>> +     ret = regulator_enable(madc->usb3v1);
>> +     if (ret)
>> +             dev_err(madc->dev, "could not enable 3v1 bias regulator\n");
>> +
>>       return 0;
>>
>>  err_i2c:
>> @@ -867,6 +900,9 @@ static int twl4030_madc_remove(struct platform_device *pdev)
>>       twl4030_madc_set_current_generator(madc, 0, 0);
>>       twl4030_madc_set_power(madc, 0);
>>
>> +     regulator_disable(madc->usb3v1);
>> +     devm_regulator_put(madc->usb3v1);
> The whole point of devm_ allocators (or in this case _gets) is that when
> the driver is removed they are cleaned up automatically.  Hence you don't
> need them in your remove call.  Obviously it also clears up the error
> handling in probe as well.
>> +
>>       return 0;
>>  }
>>
>>
>