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Date: Wed, 17 Jul 2013 20:04:37 +0200
From: Lars-Peter Clausen <lars@...afoo.de>
To: Oleksandr Kozaruk <oleksandr.kozaruk@...com>
CC: tony@...mide.com, benoit.cousson@...aro.org, rnayak@...com,
peter.ujfalusi@...com, kishon@...com, jic23@....ac.uk,
grant.likely@...aro.org, rob.herring@...xeda.com,
sameo@...ux.intel.com, ch.naveen@...sung.com, poeschel@...onage.de,
milo.kim@...com, balajitk@...com, gg@...mlogic.co.uk,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
linux-iio@...r.kernel.org, devicetree-discuss@...ts.ozlabs.org,
linux-omap@...r.kernel.org
Subject: Re: [PATCH v5 2/2] iio: twl6030-gpadc: TWL6030, TWL6032 GPADC driver
On 07/17/2013 01:12 PM, Oleksandr Kozaruk wrote:
> The GPADC is general purpose ADC found on TWL6030, and TWL6032 PMIC,
> known also as Phoenix and PhoenixLite.
>
> The TWL6030 and TWL6032 have GPADC with 17 and 19 channels
> respectively. Some channels have current source and are used for
> measuring voltage drop on resistive load for detecting battery ID
> resistance, or measuring voltage drop on NTC resistors for external
> temperature measurements. Some channels measure voltage, (i.e. battery
> voltage), and have voltage dividers, thus, capable to scale voltage.
> Some channels are dedicated for measuring die temperature.
>
> Some channels are calibrated in 2 points, having offsets from ideal
> values kept in trim registers. This is used to correct measurements.
>
> The differences between GPADC in TWL6030 and TWL6032:
> - 10 bit vs 12 bit ADC;
> - 17 vs 19 channels;
> - channels have different purpose(i.e. battery voltage
> channel 8 vs channel 18);
> - trim values are interpreted differently.
>
> Based on the driver patched from Balaji TK, Graeme Gregory, Ambresh K,
> Girish S Ghongdemath.
>
> Signed-off-by: Balaji T K <balajitk@...com>
> Signed-off-by: Graeme Gregory <gg@...mlogic.co.uk>
> Signed-off-by: Oleksandr Kozaruk <oleksandr.kozaruk@...com>
Almost there (I hope). But please run scripts/checkpatch, make C=2 and make
coccicheck on your driver and fix all errors those tools give you before
submitting the driver upstream.
[...]
> +static int twl6030_gpadc_get_raw(struct twl6030_gpadc_data *gpadc,
> + int channel, int *res)
> +{
> + u8 reg = gpadc->pdata->channel_to_reg(channel);
> + __le16 val;
> + int raw_code;
> + int ret;
> +
> + ret = twl6030_gpadc_read(reg, (u8 *)&val);
> + if (ret) {
> + dev_dbg(gpadc->dev, "unable to read register 0x%X\n", reg);
> + return ret;
> + }
> +
> + raw_code = le16_to_cpup(&val);
raw_code = le16_to_cpu(val)
> + dev_dbg(gpadc->dev, "GPADC raw code: %d", raw_code);
> +
> + if (twl6030_channel_calibrated(gpadc->pdata, channel))
> + *res = twl6030_gpadc_make_correction(gpadc, channel, raw_code);
> + else
> + *res = raw_code;
> +
> + return ret;
> +}
> +
[...]
> +static int twl6030_gpadc_read_raw(struct iio_dev *indio_dev,
> + const struct iio_chan_spec *chan,
> + int *val, int *val2, long mask)
> +{
> + struct twl6030_gpadc_data *gpadc = iio_priv(indio_dev);
> + int ret = -EINVAL;
> + long timeout;
> +
> + mutex_lock(&gpadc->lock);
> +
> + ret = gpadc->pdata->start_conversion(chan->channel);
> + if (ret) {
> + dev_err(gpadc->dev, "failed to start conversion\n");
> + goto err;
> + }
> + /* wait for conversion to complete */
> + timeout = wait_for_completion_interruptible_timeout(
> + &gpadc->irq_complete, msecs_to_jiffies(5000));
> + if (!timeout)
> + return -ETIMEDOUT;
> + else if (timeout < 0)
> + return EINTR;
You still hold the mutex, try this instead:
ret = wait_for_....
if (ret == 0)
ret = -ETIMEDOUT;
if (ret < 0)
goto err;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_RAW:
> + ret = twl6030_gpadc_get_raw(gpadc, chan->channel, val);
> + ret = ret ? -EIO : IIO_VAL_INT;
> + break;
> +
> + case IIO_CHAN_INFO_PROCESSED:
> + ret = twl6030_gpadc_get_processed(gpadc, chan->channel, val);
> + ret = ret ? -EIO : IIO_VAL_INT;
> + break;
> +
> + default:
> + break;
> + }
> +err:
> + mutex_unlock(&gpadc->lock);
> +
> + return ret;
> +}
[...]
> +
> +static int twl6032_calibration(struct twl6030_gpadc_data *gpadc)
> +{
> + int chn, d1 = 0, d2 = 0, temp;
> + u8 trim_regs[17];
> + int ret;
> +
> + ret = twl_i2c_read(TWL6030_MODULE_ID2, trim_regs + 1,
> + TWL6030_GPADC_TRIM1, 16);
> + if (ret < 0) {
> + dev_err(gpadc->dev, "calibration failed\n");
> + return ret;
> + }
> +
> + /*
> + * Loop to calculate the value needed for returning voltages from
> + * GPADC not values.
> + *
> + * gain is calculated to 3 decimal places fixed point.
> + */
> + for (chn = 0; chn < TWL6032_GPADC_MAX_CHANNELS; chn++) {
> +
> + switch (chn) {
> + case 0:
> + case 1:
> + case 2:
> + case 3:
> + case 4:
> + case 5:
> + case 6:
> + case 11:
> + case 12:
> + case 13:
> + case 14:
> + /* D1 */
> + d1 = (trim_regs[3] & 0x1F) << 2;
> + d1 |= (trim_regs[1] & 0x06) >> 1;
> + if (trim_regs[1] & 0x01)
> + d1 = -d1;
> +
> + /* D2 */
> + d2 = (trim_regs[4] & 0x3F) << 2;
> + d2 |= (trim_regs[2] & 0x06) >> 1;
> + if (trim_regs[2] & 0x01)
> + d2 = -d2;
> + break;
> + case 8:
> + /* D1 */
> + temp = (trim_regs[3] & 0x1F) << 2;
> + temp |= (trim_regs[1] & 0x06) >> 1;
> + if (trim_regs[1] & 0x01)
> + temp = -temp;
> +
> + d1 = (trim_regs[8] & 0x18) << 1;
> + d1 |= (trim_regs[7] & 0x1E) >> 1;
> + if (trim_regs[7] & 0x01)
> + d1 = -d1;
> +
> + d1 += temp;
> +
> + /* D2 */
> + temp = (trim_regs[4] & 0x3F) << 2;
> + temp |= (trim_regs[2] & 0x06) >> 1;
> + if (trim_regs[2] & 0x01)
> + temp = -temp;
> +
> + d2 = (trim_regs[10] & 0x1F) << 2;
> + d2 |= (trim_regs[8] & 0x06) >> 1;
> + if (trim_regs[8] & 0x01)
> + d2 = -d2;
> +
> + d2 += temp;
> + break;
> + case 9:
> + /* D1 */
> + temp = (trim_regs[3] & 0x1F) << 2;
> + temp |= (trim_regs[1] & 0x06) >> 1;
> + if (trim_regs[1] & 0x01)
> + temp = -temp;
> +
> + d1 = (trim_regs[14] & 0x18) << 1;
> + d1 |= (trim_regs[12] & 0x1E) >> 1;
> + if (trim_regs[12] & 0x01)
> + d1 = -d1;
> +
> + d1 += temp;
> +
> + /* D2 */
> + temp = (trim_regs[4] & 0x3F) << 2;
> + temp |= (trim_regs[2] & 0x06) >> 1;
> + if (trim_regs[2] & 0x01)
> + temp = -temp;
> +
> + d2 = (trim_regs[16] & 0x1F) << 2;
> + d2 |= (trim_regs[14] & 0x06) >> 1;
> + if (trim_regs[14] & 0x01)
> + d2 = -d2;
> +
> + d2 += temp;
> + case 10:
> + /* D1 */
> + d1 = (trim_regs[11] & 0x0F) << 3;
> + d1 |= (trim_regs[9] & 0x0E) >> 1;
> + if (trim_regs[9] & 0x01)
> + d1 = -d1;
> +
> + /* D2 */
> + d2 = (trim_regs[15] & 0x0F) << 3;
> + d2 |= (trim_regs[13] & 0x0E) >> 1;
> + if (trim_regs[13] & 0x01)
> + d2 = -d2;
> + break;
> + case 7:
> + case 18:
> + /* D1 */
> + temp = (trim_regs[3] & 0x1F) << 2;
> + temp |= (trim_regs[1] & 0x06) >> 1;
> + if (trim_regs[1] & 0x01)
> + temp = -temp;
> +
> + d1 = (trim_regs[5] & 0x7E) >> 1;
> + if (trim_regs[5] & 0x01)
> + d1 = -d1;
> +.
> + d1 += temp;
> +
> + /* D2 */
> + temp = (trim_regs[4] & 0x3F) << 2;
> + temp |= (trim_regs[2] & 0x06) >> 1;
> + if (trim_regs[2] & 0x01)
> + temp = -temp;
> +
> + d2 = (trim_regs[6] & 0xFE) >> 1;
> + if (trim_regs[6] & 0x01)
> + d2 = -d2;
> +
> + d2 += temp;
> + break;
There is quite a bit of copy paste in here. Putting the bit swizziling into
a helper function should also improbe legibility.
> + default:
> + /* No data for other channels */
> + continue;
> + }
> +
> + twl6030_calibrate_channel(gpadc, chn, d1, d2);
> + }
> +
> + return 0;
> +}
> +[...]
> +static int twl6030_gpadc_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct twl6030_gpadc_data *gpadc;
> + const struct twl6030_gpadc_platform_data *pdata;
> + const struct of_device_id *match;
> + struct iio_dev *indio_dev;
> + int irq;
> + int ret;
> +
> + match = of_match_device(of_match_ptr(of_twl6030_match_tbl), dev);
> + pdata = match ? match->data : dev->platform_data;
The twl6030_gpadc_platform_data struct is not available outside of this
file, so it is rather unlikely that dev->platfrom_data will contain such a
struct.
[...]
> +
> +static int twl6030_gpadc_remove(struct platform_device *pdev)
> +{
> + struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> +
> + twl6030_gpadc_disable_irq(TWL6030_GPADC_RT_SW1_EOC_MASK);
> + free_irq(platform_get_irq(pdev, 0), indio_dev);
The last parameter needs to match that of the request_irq call
> + iio_device_unregister(indio_dev);
> + iio_device_free(indio_dev);
> +
> + return 0;
> +}
[...]
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