On Thu, 30 May 2019 16:18:10 +0300
Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx> wrote:
> The SPI gain amplifiers are simple devices, with 1 or 2 channels, to which
> are read-from/written-to.
>
> The gain computation in ad8366_write_raw() has been updated to compute gain
> in dB for negative values.
>
> This driver will be extended to support other chips as well.
> To do that, this rework handles the AD8366 device as a special-case (via
> switch-statements). This will make things easier when adding new chips.
>
> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx>
Looks good to me.
Applied to the togreg branch of iio.git and pushed out as testing for
the autobuilders to play with it.
thanks,
Jonathan
> ---
> drivers/iio/amplifiers/ad8366.c | 81 +++++++++++++++++++++++++--------
> 1 file changed, 62 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/iio/amplifiers/ad8366.c b/drivers/iio/amplifiers/ad8366.c
> index 24ff5475d9f2..1beda6409301 100644
> --- a/drivers/iio/amplifiers/ad8366.c
> +++ b/drivers/iio/amplifiers/ad8366.c
> @@ -18,11 +18,22 @@
> #include <linux/iio/iio.h>
> #include <linux/iio/sysfs.h>
>
> +enum ad8366_type {
> + ID_AD8366,
> +};
> +
> +struct ad8366_info {
> + int gain_min;
> + int gain_max;
> +};
> +
> struct ad8366_state {
> struct spi_device *spi;
> struct regulator *reg;
> struct mutex lock; /* protect sensor state */
> unsigned char ch[2];
> + enum ad8366_type type;
> + struct ad8366_info *info;
> /*
> * DMA (thus cache coherency maintenance) requires the
> * transfer buffers to live in their own cache lines.
> @@ -30,19 +41,30 @@ struct ad8366_state {
> unsigned char data[2] ____cacheline_aligned;
> };
>
> +static struct ad8366_info ad8366_infos[] = {
> + [ID_AD8366] = {
> + .gain_min = 4500,
> + .gain_max = 20500,
> + },
> +};
> +
> static int ad8366_write(struct iio_dev *indio_dev,
> unsigned char ch_a, unsigned char ch_b)
> {
> struct ad8366_state *st = iio_priv(indio_dev);
> int ret;
>
> - ch_a = bitrev8(ch_a & 0x3F);
> - ch_b = bitrev8(ch_b & 0x3F);
> + switch (st->type) {
> + case ID_AD8366:
> + ch_a = bitrev8(ch_a & 0x3F);
> + ch_b = bitrev8(ch_b & 0x3F);
>
> - st->data[0] = ch_b >> 4;
> - st->data[1] = (ch_b << 4) | (ch_a >> 2);
> + st->data[0] = ch_b >> 4;
> + st->data[1] = (ch_b << 4) | (ch_a >> 2);
> + break;
> + }
>
> - ret = spi_write(st->spi, st->data, ARRAY_SIZE(st->data));
> + ret = spi_write(st->spi, st->data, indio_dev->num_channels);
> if (ret < 0)
> dev_err(&indio_dev->dev, "write failed (%d)", ret);
>
> @@ -57,17 +79,22 @@ static int ad8366_read_raw(struct iio_dev *indio_dev,
> {
> struct ad8366_state *st = iio_priv(indio_dev);
> int ret;
> - unsigned code;
> + int code, gain = 0;
>
> mutex_lock(&st->lock);
> switch (m) {
> case IIO_CHAN_INFO_HARDWAREGAIN:
> code = st->ch[chan->channel];
>
> + switch (st->type) {
> + case ID_AD8366:
> + gain = code * 253 + 4500;
> + break;
> + }
> +
> /* Values in dB */
> - code = code * 253 + 4500;
> - *val = code / 1000;
> - *val2 = (code % 1000) * 1000;
> + *val = gain / 1000;
> + *val2 = (gain % 1000) * 1000;
>
> ret = IIO_VAL_INT_PLUS_MICRO_DB;
> break;
> @@ -86,19 +113,24 @@ static int ad8366_write_raw(struct iio_dev *indio_dev,
> long mask)
> {
> struct ad8366_state *st = iio_priv(indio_dev);
> - unsigned code;
> + struct ad8366_info *inf = st->info;
> + int code = 0, gain;
> int ret;
>
> - if (val < 0 || val2 < 0)
> - return -EINVAL;
> -
> /* Values in dB */
> - code = (((u8)val * 1000) + ((u32)val2 / 1000));
> + if (val < 0)
> + gain = (val * 1000) - (val2 / 1000);
> + else
> + gain = (val * 1000) + (val2 / 1000);
>
> - if (code > 20500 || code < 4500)
> + if (gain > inf->gain_max || gain < inf->gain_min)
> return -EINVAL;
>
> - code = (code - 4500) / 253;
> + switch (st->type) {
> + case ID_AD8366:
> + code = (gain - 4500) / 253;
> + break;
> + }
>
> mutex_lock(&st->lock);
> switch (mask) {
> @@ -154,13 +186,24 @@ static int ad8366_probe(struct spi_device *spi)
> spi_set_drvdata(spi, indio_dev);
> mutex_init(&st->lock);
> st->spi = spi;
> + st->type = spi_get_device_id(spi)->driver_data;
> +
> + switch (st->type) {
> + case ID_AD8366:
> + indio_dev->channels = ad8366_channels;
> + indio_dev->num_channels = ARRAY_SIZE(ad8366_channels);
> + break;
> + default:
> + dev_err(&spi->dev, "Invalid device ID\n");
> + ret = -EINVAL;
> + goto error_disable_reg;
> + }
>
> + st->info = &ad8366_infos[st->type];
> indio_dev->dev.parent = &spi->dev;
> indio_dev->name = spi_get_device_id(spi)->name;
> indio_dev->info = &ad8366_info;
> indio_dev->modes = INDIO_DIRECT_MODE;
> - indio_dev->channels = ad8366_channels;
> - indio_dev->num_channels = ARRAY_SIZE(ad8366_channels);
>
> ret = ad8366_write(indio_dev, 0 , 0);
> if (ret < 0)
> @@ -194,7 +237,7 @@ static int ad8366_remove(struct spi_device *spi)
> }
>
> static const struct spi_device_id ad8366_id[] = {
> - {"ad8366", 0},
> + {"ad8366", ID_AD8366},
> {}
> };
> MODULE_DEVICE_TABLE(spi, ad8366_id);
