From: Sean Nyekjaer <sean@geanix.com>
To: Jonathan Cameron <jic23@kernel.org>
Cc: linux-iio@vger.kernel.org, martin@geanix.com,
Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>,
Denis CIOCCA <denis.ciocca@st.com>
Subject: Re: [PATCH 2/2] iio: imu: st_lsm6dsx: add iio trigger and buffer support
Date: Sat, 11 May 2019 14:38:09 +0200 [thread overview]
Message-ID: <893b615d-693a-3a48-9c91-97559bd247e1@geanix.com> (raw)
In-Reply-To: <20190511123755.2d220233@archlinux>
On 11/05/2019 13.37, Jonathan Cameron wrote:
> On Tue, 7 May 2019 10:02:25 +0200
> Sean Nyekjaer <sean@geanix.com> wrote:
>
>> This adds support for using iio triggers, this is needed because
>> our hardware guys forgot to connect the irq pins from imu device
>> to the SoC.
>>
>> Signed-off-by: Sean Nyekjaer <sean@geanix.com>
> Hi Sean
>
> A small question on the size of the buffer needed inline. Otherwise looks
> good to me.
>> ---
>> drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c | 37 ++++++++++++++++++++
>> 1 file changed, 37 insertions(+)
>>
>> diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
>> index 1ca69598678f..65ab853202de 100644
>> --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
>> +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
>> @@ -40,8 +40,11 @@
>> #include <linux/kernel.h>
>> #include <linux/module.h>
>> #include <linux/delay.h>
>> +#include <linux/iio/buffer.h>
>> #include <linux/iio/iio.h>
>> #include <linux/iio/sysfs.h>
>> +#include <linux/iio/trigger_consumer.h>
>> +#include <linux/iio/triggered_buffer.h>
>> #include <linux/pm.h>
>> #include <linux/regmap.h>
>> #include <linux/bitfield.h>
>> @@ -945,6 +948,30 @@ static int st_lsm6dsx_init_hw_timer(struct st_lsm6dsx_hw *hw)
>> return 0;
>> }
>>
>> +static irqreturn_t st_lsm6dsx_trigger_handler(int irq, void *p)
>> +{
>> + struct iio_poll_func *pf = p;
>> + struct iio_dev *indio_dev = pf->indio_dev;
>> + struct st_lsm6dsx_sensor *sensor = iio_priv(indio_dev);
>> + u16 buffer[4 * sizeof(s64)/sizeof(u16)];
> The size may well be correct, but that particular way of expressing it doesn't make
> it terribly clear.
>
> It seems a bit large... You need the space for the timestamp, so it needs to be
> padded to a u64, but that would still require your other channels to need
> more than 2*sizeof(s64)/sizeof(u16) u16s which is 9 or more of them.
Right now we have u16[16], so that quite at bit large :-)
So maybe something like:
/* 3x s16 + 1x s16(padding) + 1x s64 timestamp */
u16 buffer[2 * sizeof(s64)/sizeof(u16)];
Would do it?
>
>> + int tmp, bit;
>> +
>> + memset(buffer, 0, sizeof(buffer));
>> +
>> + for_each_set_bit(bit, indio_dev->active_scan_mask, indio_dev->masklength) {
>> + st_lsm6dsx_read_oneshot(sensor,
>> + indio_dev->channels[bit].address, &tmp);
>> + buffer[bit] = tmp;
>> + }
As you pointed out in the
"[PATCH 1/2] iio: adc: ti-ads8688: save values correct in buffer"
When taking this approach it will not shift down.
>> +
>> + iio_push_to_buffers_with_timestamp(indio_dev, buffer,
>> + iio_get_time_ns(indio_dev));
>> +
>> + iio_trigger_notify_done(indio_dev->trig);
>> +
>> + return IRQ_HANDLED;
>> +}
>> +
>> static int st_lsm6dsx_init_device(struct st_lsm6dsx_hw *hw)
>> {
>> u8 drdy_int_reg;
>> @@ -1093,6 +1120,16 @@ int st_lsm6dsx_probe(struct device *dev, int irq, int hw_id, const char *name,
>> err = st_lsm6dsx_fifo_setup(hw);
>> if (err < 0)
>> return err;
>> + } else {
>> + for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
>> + err = devm_iio_triggered_buffer_setup(hw->dev,
>> + hw->iio_devs[i], NULL,
>> + st_lsm6dsx_trigger_handler, NULL);
>> + if (err < 0) {
>> + dev_err(hw->dev, "iio triggered buffer setup failed\n");
>> + return err;
>> + }
>> + }
>> }
>>
>> for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
>
prev parent reply other threads:[~2019-05-11 12:38 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-07 8:02 [PATCH 1/2] iio: imu: st_lsm6dsx: only set available_scan_masks if using device fifo Sean Nyekjaer
2019-05-07 8:02 ` [PATCH 2/2] iio: imu: st_lsm6dsx: add iio trigger and buffer support Sean Nyekjaer
2019-05-11 11:37 ` Jonathan Cameron
2019-05-11 12:30 ` Lorenzo Bianconi
2019-05-11 12:54 ` Sean Nyekjaer
2019-05-11 17:00 ` Lorenzo Bianconi
2019-05-16 11:46 ` Sean Nyekjaer
2019-05-18 8:38 ` Jonathan Cameron
2019-05-11 12:38 ` Sean Nyekjaer [this message]
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