On 10/29/2014 09:45 PM, Ezequiel Garcia wrote:
From: Phani Movva <Phani.Movva@xxxxxxxxxx>
This commit adds support for Cosmic Circuits 10001 10-bit ADC device.
Signed-off-by: Phani Movva <Phani.Movva@xxxxxxxxxx>
Signed-off-by: Naidu Tellapati <Naidu.Tellapati@xxxxxxxxxx>
[Ezequiel: code style cleaning]
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@xxxxxxxxxx>
Looks very good. Just a few very minor issues.
[...]
+static int cc_adc_poll_done(struct iio_dev *dev, int channel,
+ unsigned int delay)
+{
+ struct cc_10001_adc_device *adc_dev = iio_priv(dev);
+ int val = INVALID_SAMPLED_OUTPUT;
I'm not so sure that returning a fake sample is such a good idea. When
reading from sysfs we should definitely return an error if there is one. For
buffer reading dropping the sample is probably not such a good idea, but we
should agree on and document a standard representation of invalid samples.
+ int poll_count = 0;
+
+ while (!(cc_adc_read_reg(adc_dev, CC_10001_ADC_EOC) &
+ CC_10001_ADC_EOC_SET)) {
+
+ ndelay(delay);
+ if (poll_count++ == MAX_POLL_COUNT)
+ return val;
+ }
+
+ poll_count = 0;
+ while ((cc_adc_read_reg(adc_dev, CC_10001_ADC_CHSEL_SAMPLED) &
+ CC_10001_ADC_CH_MASK) != channel) {
+
+ ndelay(delay);
+ if (poll_count++ == MAX_POLL_COUNT)
+ return val;
+ }
+
+ /* Read the 10 bit output register */
+ return cc_adc_read_reg(adc_dev, CC_10001_ADC_DDATA_OUT);
+}
+
+static irqreturn_t cc_10001_adc_trigger_h(int irq, void *p)
+{
+ u16 *data;
+ u16 val = 0;
+ unsigned int delay_ns = 0;
+ struct iio_dev *dev;
+ struct iio_poll_func *pf = p;
+ struct cc_10001_adc_device *adc_dev;
+
+ dev = pf->indio_dev;
+ adc_dev = iio_priv(dev);
+
+ data = kmalloc(dev->scan_bytes, GFP_KERNEL);
+ if (!data)
+ goto done;
If you want to avoid having to run malloc/free for each captured sample you
can allocate the buffer in the update_scan_mode() callback.
+
+ mutex_lock(&adc_dev->lock);
+
+ /* Power-up ADC */
+ cc_adc_write_reg(adc_dev, CC_10001_ADC_POWER_DOWN, 1);
+
+ /* Wait for 8 (6+2) clock cycles before activating START */
+ ndelay(adc_dev->start_delay_ns);
+
+ /* Calculate delay step for eoc and sampled data */
+ delay_ns = (adc_dev->eoc_delay_ns / MAX_POLL_COUNT);
+
+ if (!bitmap_empty(dev->active_scan_mask, dev->masklength)) {
+ int i, j;
+ for (i = 0, j = 0;
+ i < bitmap_weight(dev->active_scan_mask, dev->masklength);
+ i++, j++) {
+
This looks like a open-coded for_each_set_bit()
+ j = find_next_bit(dev->active_scan_mask,
+ dev->masklength, j);
+
+ cc_adc_start(adc_dev, j);
+ val = cc_adc_poll_done(dev, j, delay_ns);
+ data[i] = val & CC_10001_ADC_DATA_MASK;
+ }
+ }
+
+ /* Power-down ADC */
+ cc_adc_write_reg(adc_dev, CC_10001_ADC_POWER_DOWN, 0);
+
+ mutex_unlock(&adc_dev->lock);
+
+ iio_push_to_buffers_with_timestamp(dev, data, iio_get_time_ns());
+
+ kfree(data);
+done:
+ /*
+ * Tell the core we are done with this trigger and ready for the
+ * next one.
+ */
+ iio_trigger_notify_done(dev->trig);
+ return IRQ_HANDLED;
+}
+
[...]
+static int cc_10001_adc_probe(struct platform_device *pdev)
+{
+ struct device_node *node = pdev->dev.of_node;
+ struct cc_10001_adc_device *adc_dev;
+ unsigned long adc_clk_rate;
+ struct resource *res;
+ struct iio_dev *dev;
+ int ret;
+
+ dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc_dev));
+ if (dev == NULL)
+ return -ENOMEM;
+
+ adc_dev = iio_priv(dev);
+
+ if (of_property_read_u32(node, "cosmic,adc-available-channels", &ret)) {
So, what does available channels in this case mean. Channels that are connected?
+ dev_err(&dev->dev, "Missing adc-available-channels property\n");
+ return -EINVAL;
+ }
[...]
+
+ ret = iio_triggered_buffer_setup(dev, NULL,
+ &cc_10001_adc_trigger_h, NULL);
ret is not checked.
+
+ ret = iio_device_register(dev);
+ if (ret < 0)
+ goto err_cleanup_buffer;
+
+ platform_set_drvdata(pdev, dev);
+
+ return 0;
+
+err_disable_reg:
+ regulator_disable(adc_dev->reg);
+err_disable_clk:
+ clk_disable_unprepare(adc_dev->adc_clk);
+err_cleanup_buffer:
+ iio_triggered_buffer_cleanup(dev);
+ return 0;
+}
[...]
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