[PATCH v3 0/2] iio: adc: adi-axi-adc: make sure DRP is locked on enable

[PATCH v3 0/2] iio: adc: adi-axi-adc: make sure DRP is locked on enable

[Nuno Sa via B4 Relay]

Hi Jonathan,

Here it goes my v3. Just splits the fix (with a proper tag)  in it's own patch.

---
Changes in v3:
- Patch 1
  * New patch.
- Patch 2
  * No changes.
- Link to v2: https://lore.kernel.org/r/20240522-dev-axi-adc-drp-v2-1-b63c9790a48a@analog.com

---
Nuno Sa (2):
      iio: adc: adi-axi-adc: don't allow concurrent enable/disable calls
      iio: adc: adi-axi-adc: make sure DRP is locked on enable

 drivers/iio/adc/adi-axi-adc.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)
---
base-commit: 5e3c5871138da700796587aa5f096d39135f9d36
change-id: 20240506-dev-axi-adc-drp-ae6bd9d32617
--

Thanks!
- Nuno Sá

[PATCH v3 1/2] iio: adc: adi-axi-adc: don't allow concurrent enable/disable calls

[Nuno Sa via B4 Relay]

From: Nuno Sa <nuno.sa@analog.com>

Add proper mutex guards as we should not be able to disable
the core in the middle of enabling it.

Note there's no need to rush in backporting this as the only user of the
backend does not do anything crazy..

Fixes: 794ef0e57854 ("iio: adc: adi-axi-adc: move to backend framework")
Signed-off-by: Nuno Sa <nuno.sa@analog.com>
---
 drivers/iio/adc/adi-axi-adc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/iio/adc/adi-axi-adc.c b/drivers/iio/adc/adi-axi-adc.c
index 0cf0d81358fd..bf51d619ebbc 100644
--- a/drivers/iio/adc/adi-axi-adc.c
+++ b/drivers/iio/adc/adi-axi-adc.c
@@ -85,6 +85,7 @@ static int axi_adc_enable(struct iio_backend *back)
 	struct adi_axi_adc_state *st = iio_backend_get_priv(back);
 	int ret;
 
+	guard(mutex)(&st->lock);
 	ret = regmap_set_bits(st->regmap, ADI_AXI_REG_RSTN,
 			      ADI_AXI_REG_RSTN_MMCM_RSTN);
 	if (ret)
@@ -99,6 +100,7 @@ static void axi_adc_disable(struct iio_backend *back)
 {
 	struct adi_axi_adc_state *st = iio_backend_get_priv(back);
 
+	guard(mutex)(&st->lock);
 	regmap_write(st->regmap, ADI_AXI_REG_RSTN, 0);
 }
 

-- 
2.45.1

[PATCH v3 2/2] iio: adc: adi-axi-adc: make sure DRP is locked on enable

[Nuno Sa via B4 Relay]

From: Nuno Sa <nuno.sa@analog.com>

When enabling the core, make sure DRP (Dynamic Reconfiguration Port)
is locked. Most of the designs don't really use it but we still get the
lock bit set. So let's do it all the time so the code is generic.

While at it reduce the timeout time to 1 microsecond as it seems to be
enough and goes in line with what we have on the similar DAC core
(adi-axi-dac).

Signed-off-by: Nuno Sa <nuno.sa@analog.com>
---
 drivers/iio/adc/adi-axi-adc.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/adc/adi-axi-adc.c b/drivers/iio/adc/adi-axi-adc.c
index bf51d619ebbc..0f8bd1d75131 100644
--- a/drivers/iio/adc/adi-axi-adc.c
+++ b/drivers/iio/adc/adi-axi-adc.c
@@ -42,6 +42,9 @@
 #define ADI_AXI_ADC_REG_CTRL			0x0044
 #define    ADI_AXI_ADC_CTRL_DDR_EDGESEL_MASK	BIT(1)
 
+#define ADI_AXI_ADC_REG_DRP_STATUS		0x0074
+#define   ADI_AXI_ADC_DRP_LOCKED		BIT(17)
+
 /* ADC Channel controls */
 
 #define ADI_AXI_REG_CHAN_CTRL(c)		(0x0400 + (c) * 0x40)
@@ -83,6 +86,7 @@ struct adi_axi_adc_state {
 static int axi_adc_enable(struct iio_backend *back)
 {
 	struct adi_axi_adc_state *st = iio_backend_get_priv(back);
+	unsigned int __val;
 	int ret;
 
 	guard(mutex)(&st->lock);
@@ -91,7 +95,17 @@ static int axi_adc_enable(struct iio_backend *back)
 	if (ret)
 		return ret;
 
-	fsleep(10000);
+	/*
+	 * Make sure the DRP (Dynamic Reconfiguration Port) is locked. Not all
+	 * designs really use it but if they don't we still get the lock bit
+	 * set. So let's do it all the time so the code is generic.
+	 */
+	ret = regmap_read_poll_timeout(st->regmap, ADI_AXI_ADC_REG_DRP_STATUS,
+				       __val, __val & ADI_AXI_ADC_DRP_LOCKED,
+				       100, 1000);
+	if (ret)
+		return ret;
+
 	return regmap_set_bits(st->regmap, ADI_AXI_REG_RSTN,
 			       ADI_AXI_REG_RSTN_RSTN | ADI_AXI_REG_RSTN_MMCM_RSTN);
 }

-- 
2.45.1

Re: [PATCH v3 0/2] iio: adc: adi-axi-adc: make sure DRP is locked on enable

[Jonathan Cameron]

On Fri, 31 May 2024 11:41:53 +0200
Nuno Sa via B4 Relay <devnull+nuno.sa.analog.com@kernel.org> wrote:

> Hi Jonathan,
> 
> Here it goes my v3. Just splits the fix (with a proper tag)  in it's own patch.
Applied to the togreg branch of iio.git and pushed out as testing for
all the normal reasons.

Jonathan

> 
> ---
> Changes in v3:
> - Patch 1
>   * New patch.
> - Patch 2
>   * No changes.
> - Link to v2: https://lore.kernel.org/r/20240522-dev-axi-adc-drp-v2-1-b63c9790a48a@analog.com
> 
> ---
> Nuno Sa (2):
>       iio: adc: adi-axi-adc: don't allow concurrent enable/disable calls
>       iio: adc: adi-axi-adc: make sure DRP is locked on enable
> 
>  drivers/iio/adc/adi-axi-adc.c | 18 +++++++++++++++++-
>  1 file changed, 17 insertions(+), 1 deletion(-)
> ---
> base-commit: 5e3c5871138da700796587aa5f096d39135f9d36
> change-id: 20240506-dev-axi-adc-drp-ae6bd9d32617
> --
> 
> Thanks!
> - Nuno Sá
> 
>