On 06/06/2014 03:12 AM, Michael Welling wrote:
[...]
+enum mcp49x2_supported_device_ids {
+ ID_MCP4902,
+ ID_MCP4912,
+ ID_MCP4922,
+};
+
+struct mcp49x2_state {
+ struct spi_device *spi;
+ unsigned int value[MCP49X2_NUM_CHANNELS];
+ unsigned int power_mode[MCP49X2_NUM_CHANNELS];
+ unsigned int vref_mv;
+ struct regulator *vref_reg;
+};
+
+#define MCP49X2_CHAN(chan, bits) { \
+ .type = IIO_VOLTAGE, \
+ .output = 1, \
+ .indexed = 1, \
+ .channel = chan, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+ .scan_type = IIO_ST('u', bits, 16, 12-bits), \
The IIO_ST macro was removed a while ago, this will not compile with the
latest IIO sources.
+}
+
+static int mcp49x2_spi_write(struct spi_device *spi, u8 addr, u32 val)
+{
+ u8 mosi[2] ____cacheline_aligned;
It is also important that the transfer buffer is not on the stack and
strictly speaking the buffer should also be allocated with GFP_DMA.
+
+ mosi[1] = val & 0xff;
+ mosi[0] = (addr == 0) ? 0x00 : 0x80;
+ mosi[0] |= 0x30 | ((val >> 8) & 0x0f);
+
+ return spi_write(spi, mosi, 2);
+}
[...]
+
+static int mcp49x2_probe(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev;
+ struct mcp49x2_state *state;
+ const struct spi_device_id *id;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*state));
+ if (indio_dev == NULL)
+ return -ENOMEM;
+
+ state = iio_priv(indio_dev);
+ state->spi = spi;
+ state->vref_reg = devm_regulator_get(&spi->dev, "vref");
+ if (!IS_ERR(state->vref_reg)) {
+ ret = regulator_enable(state->vref_reg);
+ if (ret) {
+ dev_err(&spi->dev, "Failed to enable vref regulator: %d\n",
+ ret);
+ return ret;
+ }
+
+ ret = regulator_get_voltage(state->vref_reg);
+ if (ret < 0) {
+ dev_err(&spi->dev, "Failed to read vref regulator: %d\n",
+ ret);
+ goto error_disable_reg;
+ }
+ state->vref_mv = ret / 1000;
+ } else {
+ dev_info(&spi->dev, "Vref regulator not specified assuming 2.5V\n");
+ state->vref_mv = 2500;
This is not a good idea, unless there is a built-in vref with 2.5V. If that
is the case use devm_regulator_get_optional() as devm_regulator_get() will
return a dummy regulator if no regulator was specified for the device.
+ }
+
+ spi_set_drvdata(spi, indio_dev);
+ id = spi_get_device_id(spi);
+ indio_dev->dev.parent = &spi->dev;
+ indio_dev->info = &mcp49x2_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = mcp49x2_channels[id->driver_data];
+ indio_dev->num_channels = MCP49X2_NUM_CHANNELS;
+ indio_dev->name = id->name;
+
+ ret = devm_iio_device_register(&spi->dev, indio_dev);
+ if (ret) {
+ dev_err(&spi->dev, "Failed to register iio device: %d\n",
+ ret);
+ goto error_disable_reg;
+ }
+
+ return 0;
+
+error_disable_reg:
+ if (!IS_ERR(state->vref_reg))
+ regulator_disable(state->vref_reg);
+
+ return ret;
+}
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