On 09/13/2012 12:40 PM, Patil, Rachna wrote:

This patch adds support for TI's ADC driver.
This is a multifunctional device.
Analog input lines are provided on which
voltage measurements can be carried out.
You can have upto 8 input lines.

Hi,

couple of minor issues inline.

Signed-off-by: Patil, Rachna <redacted>
---
Changes in v2:
	Addressed review comments from Matthias Kaehlcke

Changes in v3:
	Addressed review comments from Jonathan Cameron.
	Added comments, new line appropriately.

 drivers/iio/adc/Kconfig              |    7 +
 drivers/iio/adc/Makefile             |    1 +
 drivers/iio/adc/ti_adc.c             |  223 ++++++++++++++++++++++++++++++++++
 drivers/mfd/ti_tscadc.c              |   18 +++-
 include/linux/mfd/ti_tscadc.h        |    9 ++-
 include/linux/platform_data/ti_adc.h |   14 ++
 6 files changed, 270 insertions(+), 2 deletions(-)
 create mode 100644 drivers/iio/adc/ti_adc.c
 create mode 100644 include/linux/platform_data/ti_adc.h

[...]

+
+struct adc_device {

Not really an issue, but I'd use a consistent function/struct prefix.
Currently you use both "adc" and "tiadc"

+	struct ti_tscadc_dev *mfd_tscadc;
+	struct iio_dev *idev;

idev is used only once in the remove callback. But you can get a pointer to
it easily using platform_get_drvdata. So I'd remove it from the adc_device
struct.

+	int channels;
+};
+
+static unsigned int adc_readl(struct adc_device *adc, unsigned int reg)
+{
+	return readl(adc->mfd_tscadc->tscadc_base + reg);
+}
+
+static void adc_writel(struct adc_device *adc, unsigned int reg,
+					unsigned int val)
+{
+	writel(val, adc->mfd_tscadc->tscadc_base + reg);
+}
+
+static void adc_step_config(struct adc_device *adc_dev)
+{
+	unsigned int    stepconfig;

extra whitespace

+	int i, channels = 0, steps;
+
+	/*
+	 * There are 16 configurable steps and 8 analog input
+	 * lines available which are shared between Touchscreen and ADC.
+	 *
+	 * Steps backwards i.e. from 16 towards 0 are used by ADC
+	 * depending on number of input lines needed.
+	 * Channel would represent which analog input
+	 * needs to be given to ADC to digitalize data.
+	 */
+
+	steps = TOTAL_STEPS - adc_dev->channels;
+	channels = TOTAL_CHANNELS - adc_dev->channels;
+
+	stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1;
+
+	for (i = (steps + 1); i <= TOTAL_STEPS; i++) {
+		adc_writel(adc_dev, REG_STEPCONFIG(i),
+				stepconfig | STEPCONFIG_INP(channels));
+		adc_writel(adc_dev, REG_STEPDELAY(i),
+				STEPCONFIG_OPENDLY);
+		channels++;
+	}
+	adc_writel(adc_dev, REG_SE, STPENB_STEPENB);
+}
+
[...]
+
+static const struct iio_info tiadc_info = {
+	.read_raw = &tiadc_read_raw,

    .driver_module = THIS_MODULE,

+};
+
+static int __devinit tiadc_probe(struct platform_device *pdev)
+{
+	struct iio_dev		*idev;

For consistency with other drivers please rename idev to indio_dev
throughout the driver.

+	int			err;
+	struct adc_device	*adc_dev;
+	struct ti_tscadc_dev	*tscadc_dev = pdev->dev.platform_data;
+	struct mfd_tscadc_board	*pdata;
+
+	pdata = (struct mfd_tscadc_board *)tscadc_dev->dev->platform_data;

The cast should not be necessary.

+	if (!pdata || !pdata->adc_init) {
+		dev_err(tscadc_dev->dev, "Could not find platform data\n");

I'd still use pdev->dev for the device parameter here. Seeing a message
printed by this driver for another device might be confusing.

+		return -EINVAL;
+	}
+
+	idev = iio_device_alloc(sizeof(struct adc_device));
+	if (idev == NULL) {
+		dev_err(&pdev->dev, "failed to allocate iio device.\n");
+		err = -ENOMEM;
+		goto err_ret;
+	}
+	adc_dev = iio_priv(idev);
+
+	tscadc_dev->adc = adc_dev;

This there any reason why you need to store a pointer to the adc struct in
the mfd struct? Is it going to be used outside of the adc driver? Currently
it is, as far as I can see, only used in the remove callback and
suspend/resume handlers. But there you can use iio_priv just as easily to
get the pointer to the adc device struct and it certainly will be also be
cleaner to do it that way.

+	adc_dev->mfd_tscadc = tscadc_dev;
+	adc_dev->idev = idev;
+	adc_dev->channels = pdata->adc_init->adc_channels;
+
+	idev->dev.parent = &pdev->dev;
+	idev->name = dev_name(&pdev->dev);
+	idev->modes = INDIO_DIRECT_MODE;
+	idev->info = &tiadc_info;
+
+	adc_step_config(adc_dev);
+
+	err = tiadc_channel_init(idev, adc_dev->channels);
+	if (err < 0)
+		goto err_free_device;
+
+	err = iio_device_register(idev);
+	if (err)
+		goto err_free_channels;
+
+	dev_info(&pdev->dev, "attached adc driver\n");

I'd remove that line, it's just noise.

+	platform_set_drvdata(pdev, idev);
+
+	return 0;
+
+err_free_channels:
+	tiadc_channels_remove(idev);
+err_free_device:
+	iio_device_free(idev);
+err_ret:
+	return err;
+}
+

[...]

The struct name might be a bit to generic.

+	int adc_channels;

It does not really matter, but considering that there hardly ever going to
be a negative number of channels I'd make this unsigned.

+};
+
+#endif