Patch "iio: adis: handle devices that cannot unmask the drdy pin" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    iio: adis: handle devices that cannot unmask the drdy pin

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     iio-adis-handle-devices-that-cannot-unmask-the-drdy-.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 6dd6393e890f074e86e2f03c648d9b5fcdf7906f
Author: Nuno Sá <nuno.sa@xxxxxxxxxx>
Date:   Fri Sep 3 16:14:20 2021 +0200

    iio: adis: handle devices that cannot unmask the drdy pin
    
    [ Upstream commit 31fa357ac809affd9f9a7d0b5d1991951e16beec ]
    
    Some devices can't mask/unmask the data ready pin and in those cases
    each driver was just calling '{dis}enable_irq()' to control the trigger
    state. This change, moves that handling into the library by introducing
    a new boolean in the data structure that tells the library that the
    device cannot unmask the pin.
    
    On top of controlling the trigger state, we can also use this flag to
    automatically request the IRQ with 'IRQF_NO_AUTOEN' in case it is set.
    So far, all users of the library want to start operation with IRQs/DRDY
    pin disabled so it should be fairly safe to do this inside the library.
    
    Signed-off-by: Nuno Sá <nuno.sa@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20210903141423.517028-3-nuno.sa@xxxxxxxxxx
    Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
    Stable-dep-of: 99c05e4283a1 ("iio: adis: add '__adis_enable_irq()' implementation")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/iio/imu/adis.c b/drivers/iio/imu/adis.c
index d4e692b187cd..cb0d66bf6561 100644
--- a/drivers/iio/imu/adis.c
+++ b/drivers/iio/imu/adis.c
@@ -286,6 +286,13 @@ int adis_enable_irq(struct adis *adis, bool enable)
 	if (adis->data->enable_irq) {
 		ret = adis->data->enable_irq(adis, enable);
 		goto out_unlock;
+	} else if (adis->data->unmasked_drdy) {
+		if (enable)
+			enable_irq(adis->spi->irq);
+		else
+			disable_irq(adis->spi->irq);
+
+		goto out_unlock;
 	}
 
 	ret = __adis_read_reg_16(adis, adis->data->msc_ctrl_reg, &msc);
@@ -430,7 +437,13 @@ int __adis_initial_startup(struct adis *adis)
 	if (ret)
 		return ret;
 
-	adis_enable_irq(adis, false);
+	/*
+	 * don't bother calling this if we can't unmask the IRQ as in this case
+	 * the IRQ is most likely not yet requested and we will request it
+	 * with 'IRQF_NO_AUTOEN' anyways.
+	 */
+	if (!adis->data->unmasked_drdy)
+		adis_enable_irq(adis, false);
 
 	if (!adis->data->prod_id_reg)
 		return 0;
diff --git a/drivers/iio/imu/adis_trigger.c b/drivers/iio/imu/adis_trigger.c
index 48eedc29b28a..c461bd1e8e69 100644
--- a/drivers/iio/imu/adis_trigger.c
+++ b/drivers/iio/imu/adis_trigger.c
@@ -30,6 +30,10 @@ static const struct iio_trigger_ops adis_trigger_ops = {
 static int adis_validate_irq_flag(struct adis *adis)
 {
 	unsigned long direction = adis->irq_flag & IRQF_TRIGGER_MASK;
+
+	/* We cannot mask the interrupt so ensure it's not enabled at request */
+	if (adis->data->unmasked_drdy)
+		adis->irq_flag |= IRQF_NO_AUTOEN;
 	/*
 	 * Typically this devices have data ready either on the rising edge or
 	 * on the falling edge of the data ready pin. This checks enforces that
diff --git a/include/linux/iio/imu/adis.h b/include/linux/iio/imu/adis.h
index cf49997d5903..7c02f5292eea 100644
--- a/include/linux/iio/imu/adis.h
+++ b/include/linux/iio/imu/adis.h
@@ -49,6 +49,7 @@ struct adis_timeout {
  * @status_error_mask: Bitmask of errors supported by the device
  * @timeouts: Chip specific delays
  * @enable_irq: Hook for ADIS devices that have a special IRQ enable/disable
+ * @unmasked_drdy: True for devices that cannot mask/unmask the data ready pin
  * @has_paging: True if ADIS device has paged registers
  * @burst_reg_cmd:	Register command that triggers burst
  * @burst_len:		Burst size in the SPI RX buffer. If @burst_max_len is defined,
@@ -78,6 +79,7 @@ struct adis_data {
 	unsigned int status_error_mask;
 
 	int (*enable_irq)(struct adis *adis, bool enable);
+	bool unmasked_drdy;
 
 	bool has_paging;