| Message ID | 20241211-dlech-mainline-spi-engine-offload-2-v6-10-88ee574d5d03@baylibre.com |
|---|---|
| State | New |
| Headers | show |
| Series | spi: axi-spi-engine: add offload support | expand |
On Wed, 11 Dec 2024 14:54:47 -0600 David Lechner <dlechner@baylibre.com> wrote: > Replace use of storagebits with realbits for determining the number of > bytes needed for SPI transfers. > > When adding SPI offload support, storagebits will no longer be > guaranteed to be the "best fit" for 16-bit chips so we can no longer > rely on storagebits being the correct size expected by the SPI > framework. Instead, derive the correct size from realbits since it will > always be correct even when SPI offloads are used. A more specific example with widths etc might be useful addition to this commit message. > > Signed-off-by: David Lechner <dlechner@baylibre.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
On Wed, 2024-12-11 at 14:54 -0600, David Lechner wrote: > Replace use of storagebits with realbits for determining the number of > bytes needed for SPI transfers. > > When adding SPI offload support, storagebits will no longer be > guaranteed to be the "best fit" for 16-bit chips so we can no longer > rely on storagebits being the correct size expected by the SPI > framework. Instead, derive the correct size from realbits since it will > always be correct even when SPI offloads are used. > > Signed-off-by: David Lechner <dlechner@baylibre.com> > --- Reviewed-vy: Nuno Sa <nuno.sa@analog.com> > v6 changes: none > > v5 changes: none > > v4 changes: new patch in v4 > --- > drivers/iio/adc/ad7944.c | 16 +++++++++------- > 1 file changed, 9 insertions(+), 7 deletions(-) > > diff --git a/drivers/iio/adc/ad7944.c b/drivers/iio/adc/ad7944.c > index > a5aea4e9f1a7bdd8ca10f9f4580ad3216ddcdfcb..6d1202bd55a013b092ff803f2065fd128dfa > 9bdd 100644 > --- a/drivers/iio/adc/ad7944.c > +++ b/drivers/iio/adc/ad7944.c > @@ -98,6 +98,9 @@ struct ad7944_chip_info { > const struct iio_chan_spec channels[2]; > }; > > +/* get number of bytes for SPI xfer */ > +#define AD7944_SPI_BYTES(scan_type) ((scan_type).realbits > 16 ? 4 : 2) > + > /* > * AD7944_DEFINE_CHIP_INFO - Define a chip info structure for a specific chip > * @_name: The name of the chip > @@ -164,7 +167,7 @@ static int ad7944_3wire_cs_mode_init_msg(struct device > *dev, struct ad7944_adc * > > /* Then we can read the data during the acquisition phase */ > xfers[2].rx_buf = &adc->sample.raw; > - xfers[2].len = BITS_TO_BYTES(chan->scan_type.storagebits); > + xfers[2].len = AD7944_SPI_BYTES(chan->scan_type); > xfers[2].bits_per_word = chan->scan_type.realbits; > > spi_message_init_with_transfers(&adc->msg, xfers, 3); > @@ -193,7 +196,7 @@ static int ad7944_4wire_mode_init_msg(struct device *dev, > struct ad7944_adc *adc > xfers[0].delay.unit = SPI_DELAY_UNIT_NSECS; > > xfers[1].rx_buf = &adc->sample.raw; > - xfers[1].len = BITS_TO_BYTES(chan->scan_type.storagebits); > + xfers[1].len = AD7944_SPI_BYTES(chan->scan_type); > xfers[1].bits_per_word = chan->scan_type.realbits; > > spi_message_init_with_transfers(&adc->msg, xfers, 2); > @@ -228,7 +231,7 @@ static int ad7944_chain_mode_init_msg(struct device *dev, > struct ad7944_adc *adc > xfers[0].delay.unit = SPI_DELAY_UNIT_NSECS; > > xfers[1].rx_buf = adc->chain_mode_buf; > - xfers[1].len = BITS_TO_BYTES(chan->scan_type.storagebits) * > n_chain_dev; > + xfers[1].len = AD7944_SPI_BYTES(chan->scan_type) * n_chain_dev; > xfers[1].bits_per_word = chan->scan_type.realbits; > > spi_message_init_with_transfers(&adc->msg, xfers, 2); > @@ -274,12 +277,12 @@ static int ad7944_single_conversion(struct ad7944_adc > *adc, > return ret; > > if (adc->spi_mode == AD7944_SPI_MODE_CHAIN) { > - if (chan->scan_type.storagebits > 16) > + if (chan->scan_type.realbits > 16) > *val = ((u32 *)adc->chain_mode_buf)[chan- > >scan_index]; > else > *val = ((u16 *)adc->chain_mode_buf)[chan- > >scan_index]; > } else { > - if (chan->scan_type.storagebits > 16) > + if (chan->scan_type.realbits > 16) > *val = adc->sample.raw.u32; > else > *val = adc->sample.raw.u16; > @@ -409,8 +412,7 @@ static int ad7944_chain_mode_alloc(struct device *dev, > /* 1 word for each voltage channel + aligned u64 for timestamp */ > > chain_mode_buf_size = ALIGN(n_chain_dev * > - BITS_TO_BYTES(chan[0].scan_type.storagebits), sizeof(u64)) > - + sizeof(u64); > + AD7944_SPI_BYTES(chan[0].scan_type), sizeof(u64)) + > sizeof(u64); > buf = devm_kzalloc(dev, chain_mode_buf_size, GFP_KERNEL); > if (!buf) > return -ENOMEM; >
diff --git a/drivers/iio/adc/ad7944.c b/drivers/iio/adc/ad7944.c index a5aea4e9f1a7bdd8ca10f9f4580ad3216ddcdfcb..6d1202bd55a013b092ff803f2065fd128dfa9bdd 100644 --- a/drivers/iio/adc/ad7944.c +++ b/drivers/iio/adc/ad7944.c @@ -98,6 +98,9 @@ struct ad7944_chip_info { const struct iio_chan_spec channels[2]; }; +/* get number of bytes for SPI xfer */ +#define AD7944_SPI_BYTES(scan_type) ((scan_type).realbits > 16 ? 4 : 2) + /* * AD7944_DEFINE_CHIP_INFO - Define a chip info structure for a specific chip * @_name: The name of the chip @@ -164,7 +167,7 @@ static int ad7944_3wire_cs_mode_init_msg(struct device *dev, struct ad7944_adc * /* Then we can read the data during the acquisition phase */ xfers[2].rx_buf = &adc->sample.raw; - xfers[2].len = BITS_TO_BYTES(chan->scan_type.storagebits); + xfers[2].len = AD7944_SPI_BYTES(chan->scan_type); xfers[2].bits_per_word = chan->scan_type.realbits; spi_message_init_with_transfers(&adc->msg, xfers, 3); @@ -193,7 +196,7 @@ static int ad7944_4wire_mode_init_msg(struct device *dev, struct ad7944_adc *adc xfers[0].delay.unit = SPI_DELAY_UNIT_NSECS; xfers[1].rx_buf = &adc->sample.raw; - xfers[1].len = BITS_TO_BYTES(chan->scan_type.storagebits); + xfers[1].len = AD7944_SPI_BYTES(chan->scan_type); xfers[1].bits_per_word = chan->scan_type.realbits; spi_message_init_with_transfers(&adc->msg, xfers, 2); @@ -228,7 +231,7 @@ static int ad7944_chain_mode_init_msg(struct device *dev, struct ad7944_adc *adc xfers[0].delay.unit = SPI_DELAY_UNIT_NSECS; xfers[1].rx_buf = adc->chain_mode_buf; - xfers[1].len = BITS_TO_BYTES(chan->scan_type.storagebits) * n_chain_dev; + xfers[1].len = AD7944_SPI_BYTES(chan->scan_type) * n_chain_dev; xfers[1].bits_per_word = chan->scan_type.realbits; spi_message_init_with_transfers(&adc->msg, xfers, 2); @@ -274,12 +277,12 @@ static int ad7944_single_conversion(struct ad7944_adc *adc, return ret; if (adc->spi_mode == AD7944_SPI_MODE_CHAIN) { - if (chan->scan_type.storagebits > 16) + if (chan->scan_type.realbits > 16) *val = ((u32 *)adc->chain_mode_buf)[chan->scan_index]; else *val = ((u16 *)adc->chain_mode_buf)[chan->scan_index]; } else { - if (chan->scan_type.storagebits > 16) + if (chan->scan_type.realbits > 16) *val = adc->sample.raw.u32; else *val = adc->sample.raw.u16; @@ -409,8 +412,7 @@ static int ad7944_chain_mode_alloc(struct device *dev, /* 1 word for each voltage channel + aligned u64 for timestamp */ chain_mode_buf_size = ALIGN(n_chain_dev * - BITS_TO_BYTES(chan[0].scan_type.storagebits), sizeof(u64)) - + sizeof(u64); + AD7944_SPI_BYTES(chan[0].scan_type), sizeof(u64)) + sizeof(u64); buf = devm_kzalloc(dev, chain_mode_buf_size, GFP_KERNEL); if (!buf) return -ENOMEM;
Replace use of storagebits with realbits for determining the number of bytes needed for SPI transfers. When adding SPI offload support, storagebits will no longer be guaranteed to be the "best fit" for 16-bit chips so we can no longer rely on storagebits being the correct size expected by the SPI framework. Instead, derive the correct size from realbits since it will always be correct even when SPI offloads are used. Signed-off-by: David Lechner <dlechner@baylibre.com> --- v6 changes: none v5 changes: none v4 changes: new patch in v4 --- drivers/iio/adc/ad7944.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-)