[PATCH v2 1/2] dt-bindings: i2c: Add custom properties for MAX7357/MAX7358

[PATCH v2 1/2] dt-bindings: i2c: Add custom properties for MAX7357/MAX7358

[Naresh Solanki]

From: Patrick Rudolph <patrick.rudolph@9elements.com>

Both chips have a configuration register to enable additional
features. These features aren't enabled by default & its up to
board designer to enable the same.

Add booleans for:
 - maxim,isolate-stuck-channel
 - maxim,send-flush-out-sequence
 - maxim,preconnection-wiggle-test-enable

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
---
Changes in V2:
- Update properties.
---
 .../bindings/i2c/i2c-mux-pca954x.yaml         | 31 +++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml b/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
index 2d7bb998b0e9..fa73eadfdf7b 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
+++ b/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
@@ -71,6 +71,23 @@ properties:
     description: A voltage regulator supplying power to the chip. On PCA9846
       the regulator supplies power to VDD2 (core logic) and optionally to VDD1.
 
+  maxim,isolate-stuck-channel:
+    type: boolean
+    description: Allows to use non faulty channels while a stuck channel is
+      isolated from the upstream bus. If not set all channels are isolated from
+      the upstream bus until the fault is cleared.
+
+  maxim,send-flush-out-sequence:
+    type: boolean
+    description: Send a flush-out sequence to stuck auxiliary buses
+      automatically after a stuck channel is being detected.
+
+  maxim,preconnection-wiggle-test-enable:
+    type: boolean
+    description: Send a STOP condition to the auxiliary buses when the switch
+      register activates a channel to detect a stuck high fault. On fault the
+      channel is isolated from the upstream bus.
+
 required:
   - compatible
   - reg
@@ -95,6 +112,20 @@ allOf:
         "#interrupt-cells": false
         interrupt-controller: false
 
+  - if:
+      not:
+        properties:
+          compatible:
+            contains:
+              enum:
+                - maxim,max7357
+                - maxim,max7358
+    then:
+      properties:
+        maxim,isolate-stuck-channel: false
+        maxim,send-flush-out-sequence: false
+        maxim,preconnection-wiggle-test-enable: false
+
 unevaluatedProperties: false
 
 examples:

base-commit: f9ea75e087b81081f33e34c4e1ba8b4abe841d9f
-- 
2.41.0

[PATCH v2 2/2] i2c: muxes: pca954x: Enable features on MAX7357/MAX7358

[Naresh Solanki]

From: Patrick Rudolph <patrick.rudolph@9elements.com>

Detect that max7357 is being used and run custom init sequence.
Enable additional features based on DT settings and unconditionally
release the shared interrupt pin after 1.6 seconds and allow to use
it as reset.

The init sequence is not run for max7358 that needs to be unlocked
first, but that would need the unimplemented function
i2c_probe_func_quick_write().

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
---
Changes in V2:
- Update comments
- Update check for DT properties
---
 drivers/i2c/muxes/i2c-mux-pca954x.c | 62 +++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c
index 2219062104fb..e4bf72122c9f 100644
--- a/drivers/i2c/muxes/i2c-mux-pca954x.c
+++ b/drivers/i2c/muxes/i2c-mux-pca954x.c
@@ -57,6 +57,23 @@
 
 #define PCA954X_IRQ_OFFSET 4
 
+/*
+ * MAX7357's configuration register is writeable after POR, but
+ * can be locked by setting the basic mode bit. MAX7358 configuration
+ * register is locked by default and needs to be unlocked first.
+ * The configuration register holds the following settings:
+ */
+#define MAX7357_CONF_INT_ENABLE			BIT(0)
+#define MAX7357_CONF_FLUSH_OUT			BIT(1)
+#define MAX7357_CONF_RELEASE_INT		BIT(2)
+#define MAX7357_CONF_LOCK_UP_CLEAR		BIT(3)
+#define MAX7357_CONF_DISCON_SINGLE_CHAN		BIT(4)
+#define MAX7357_CONF_BUS_LOCKUP_DETECT_DIS	BIT(5)
+#define MAX7357_CONF_ENABLE_BASIC_MODE		BIT(6)
+#define MAX7357_CONF_PRECONNECT_TEST		BIT(7)
+
+#define MAX7357_POR_DEFAULT_CONF		BIT(0)
+
 enum pca_type {
 	max_7356,
 	max_7357,
@@ -477,6 +494,43 @@ static int pca954x_init(struct i2c_client *client, struct pca954x *data)
 	return ret;
 }
 
+static int max7357_init(struct i2c_client *client, struct pca954x *data)
+{
+	struct i2c_adapter *adap = client->adapter;
+	u8 conf = MAX7357_POR_DEFAULT_CONF;
+	int ret;
+
+	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) {
+		dev_warn(&client->dev, "Device not configured: SMBUS_WRITE_BYTE_DATA is unsupported\n");
+		return pca954x_init(client, data);
+	}
+
+	if (data->idle_state >= 0)
+		data->last_chan = pca954x_regval(data, data->idle_state);
+	else
+		data->last_chan = 0; /* Disconnect multiplexer */
+
+	/*
+	 * The interrupt signal is shared with the reset pin. Release the
+	 * interrupt after 1.6 seconds to allow using the pin as reset.
+	 * The interrupt isn't serviced yet.
+	 */
+	conf |= MAX7357_CONF_RELEASE_INT;
+
+	if (device_property_read_bool(&client->dev, "maxim,isolate-stuck-channel"))
+		conf |= MAX7357_CONF_DISCON_SINGLE_CHAN;
+	if (device_property_read_bool(&client->dev, "maxim,send-flush-out-sequence"))
+		conf |= MAX7357_CONF_FLUSH_OUT;
+	if (device_property_read_bool(&client->dev, "maxim,preconnection-wiggle-test-enable"))
+		conf |= MAX7357_CONF_PRECONNECT_TEST;
+
+	ret = i2c_smbus_write_byte_data(client, data->last_chan, conf);
+	if (ret < 0)
+		data->last_chan = 0;
+
+	return ret;
+}
+
 /*
  * I2C init/probing/exit functions
  */
@@ -485,6 +539,7 @@ static int pca954x_probe(struct i2c_client *client)
 	const struct i2c_device_id *id = i2c_client_get_device_id(client);
 	struct i2c_adapter *adap = client->adapter;
 	struct device *dev = &client->dev;
+	struct device_node *node = dev->of_node;
 	struct gpio_desc *gpio;
 	struct i2c_mux_core *muxc;
 	struct pca954x *data;
@@ -560,6 +615,13 @@ static int pca954x_probe(struct i2c_client *client)
 	 * initializes the mux to a channel
 	 * or disconnected state.
 	 */
+	if ((node && of_device_is_compatible(node, "maxim,max7357")) ||
+	    id->driver_data == max_7357)
+		ret = max7357_init(client, data);
+	else if ((node && of_device_is_compatible(node, "maxim,max7358")) ||
+		 id->driver_data == max_7358)
+		dev_warn(dev, "Device not configured: unlock sequence not implemented\n");
+
 	ret = pca954x_init(client, data);
 	if (ret < 0) {
 		dev_warn(dev, "probe failed\n");
-- 
2.41.0

Re: [PATCH v2 1/2] dt-bindings: i2c: Add custom properties for MAX7357/MAX7358

[Krzysztof Kozlowski]

On 31/08/2023 12:15, Naresh Solanki wrote:
> From: Patrick Rudolph <patrick.rudolph@9elements.com>
> 
> Both chips have a configuration register to enable additional
> features. These features aren't enabled by default & its up to
> board designer to enable the same.
> 
> Add booleans for:
>  - maxim,isolate-stuck-channel
>  - maxim,send-flush-out-sequence
>  - maxim,preconnection-wiggle-test-enable
> 
> Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
> Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>

Subject: still did not improve. You waited exactly 30 minutes for my
feedback after sending your response.



> ---
> Changes in V2:
> - Update properties.
> ---
>  .../bindings/i2c/i2c-mux-pca954x.yaml         | 31 +++++++++++++++++++
>  1 file changed, 31 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml b/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
> index 2d7bb998b0e9..fa73eadfdf7b 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
> +++ b/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
> @@ -71,6 +71,23 @@ properties:
>      description: A voltage regulator supplying power to the chip. On PCA9846
>        the regulator supplies power to VDD2 (core logic) and optionally to VDD1.
>  
> +  maxim,isolate-stuck-channel:
> +    type: boolean
> +    description: Allows to use non faulty channels while a stuck channel is
> +      isolated from the upstream bus. If not set all channels are isolated from
> +      the upstream bus until the fault is cleared.

Nothing improved here. As I said, please provide arguments or drop this
property.

> +
> +  maxim,send-flush-out-sequence:
> +    type: boolean
> +    description: Send a flush-out sequence to stuck auxiliary buses
> +      automatically after a stuck channel is being detected.

Ditto

> +
> +  maxim,preconnection-wiggle-test-enable:
> +    type: boolean
> +    description: Send a STOP condition to the auxiliary buses when the switch
> +      register activates a channel to detect a stuck high fault. On fault the
> +      channel is isolated from the upstream bus.

Ditto


Best regards,
Krzysztof

Re: [PATCH v2 1/2] dt-bindings: i2c: Add custom properties for MAX7357/MAX7358

[Naresh Solanki]

Hi

On Thu, 31 Aug 2023 at 17:33, Krzysztof Kozlowski
<krzysztof.kozlowski@linaro.org> wrote:
>
> On 31/08/2023 12:15, Naresh Solanki wrote:
> > From: Patrick Rudolph <patrick.rudolph@9elements.com>
> >
> > Both chips have a configuration register to enable additional
> > features. These features aren't enabled by default & it's up to
> > board designer to enable the same.
> >
> > Add booleans for:
> >  - maxim,isolate-stuck-channel
> >  - maxim,send-flush-out-sequence
> >  - maxim,preconnection-wiggle-test-enable
> >
> > Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
> > Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
>
> Subject: still did not improve. You waited exactly 30 minutes for my
> feedback after sending your response.
Will update the subject prefix to: 'dt-bindings: i2c: pca954x:'
Also I'm adding three properties here so I guess 'Add custom
properties..' should be fine.
If you have a better suggestion then please let me know.

>
>
>
> > ---
> > Changes in V2:
> > - Update properties.
> > ---
> >  .../bindings/i2c/i2c-mux-pca954x.yaml         | 31 +++++++++++++++++++
> >  1 file changed, 31 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml b/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
> > index 2d7bb998b0e9..fa73eadfdf7b 100644
> > --- a/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
> > +++ b/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
> > @@ -71,6 +71,23 @@ properties:
> >      description: A voltage regulator supplying power to the chip. On PCA9846
> >        the regulator supplies power to VDD2 (core logic) and optionally to VDD1.
> >
> > +  maxim,isolate-stuck-channel:
> > +    type: boolean
> > +    description: Allows to use non faulty channels while a stuck channel is
> > +      isolated from the upstream bus. If not set all channels are isolated from
> > +      the upstream bus until the fault is cleared.
>
> Nothing improved here. As I said, please provide arguments or drop this
> property.
These features cannot be enabled by default because doing so may lead
to unexpected behavior, such as bus disconnections(although that
wasn't expected).
These features should only be enabled after they have been validated
by the board designer.
Therefore, they cannot be enabled by default.

Regards,
Naresh
>
> > +
> > +  maxim,send-flush-out-sequence:
> > +    type: boolean
> > +    description: Send a flush-out sequence to stuck auxiliary buses
> > +      automatically after a stuck channel is being detected.
>
> Ditto
>
> > +
> > +  maxim,preconnection-wiggle-test-enable:
> > +    type: boolean
> > +    description: Send a STOP condition to the auxiliary buses when the switch
> > +      register activates a channel to detect a stuck high fault. On fault the
> > +      channel is isolated from the upstream bus.
>
> Ditto
>
>
> Best regards,
> Krzysztof
>

Re: [PATCH v2 1/2] dt-bindings: i2c: Add custom properties for MAX7357/MAX7358

[Krzysztof Kozlowski]

On 11/09/2023 12:31, Naresh Solanki wrote:

>>> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml b/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
>>> index 2d7bb998b0e9..fa73eadfdf7b 100644
>>> --- a/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
>>> +++ b/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
>>> @@ -71,6 +71,23 @@ properties:
>>>      description: A voltage regulator supplying power to the chip. On PCA9846
>>>        the regulator supplies power to VDD2 (core logic) and optionally to VDD1.
>>>
>>> +  maxim,isolate-stuck-channel:
>>> +    type: boolean
>>> +    description: Allows to use non faulty channels while a stuck channel is
>>> +      isolated from the upstream bus. If not set all channels are isolated from
>>> +      the upstream bus until the fault is cleared.
>>
>> Nothing improved here. As I said, please provide arguments or drop this
>> property.
> These features cannot be enabled by default because doing so may lead
> to unexpected behavior, such as bus disconnections(although that
> wasn't expected).
> These features should only be enabled after they have been validated
> by the board designer.
> Therefore, they cannot be enabled by default.

And what is needed to validate them for given board? IOW, what changes
in hardware design that it can or cannot be used?

Best regards,
Krzysztof

Re: [PATCH v2 1/2] dt-bindings: i2c: Add custom properties for MAX7357/MAX7358

[Naresh Solanki]

Hi


On Mon, 11 Sept 2023 at 16:13, Krzysztof Kozlowski
<krzysztof.kozlowski@linaro.org> wrote:
>
> On 11/09/2023 12:31, Naresh Solanki wrote:
>
> >>> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml b/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
> >>> index 2d7bb998b0e9..fa73eadfdf7b 100644
> >>> --- a/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
> >>> +++ b/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
> >>> @@ -71,6 +71,23 @@ properties:
> >>>      description: A voltage regulator supplying power to the chip. On PCA9846
> >>>        the regulator supplies power to VDD2 (core logic) and optionally to VDD1.
> >>>
> >>> +  maxim,isolate-stuck-channel:
> >>> +    type: boolean
> >>> +    description: Allows to use non faulty channels while a stuck channel is
> >>> +      isolated from the upstream bus. If not set all channels are isolated from
> >>> +      the upstream bus until the fault is cleared.
> >>
> >> Nothing improved here. As I said, please provide arguments or drop this
> >> property.
> > These features cannot be enabled by default because doing so may lead
> > to unexpected behavior, such as bus disconnections(although that
> > wasn't expected).
> > These features should only be enabled after they have been validated
> > by the board designer.
> > Therefore, they cannot be enabled by default.
>
> And what is needed to validate them for given board? IOW, what changes
> in hardware design that it can or cannot be used?
Enabling PRECONNECT_TEST in my setup didn't work
Although this wasn't expected.

Regards,
Naresh

>
> Best regards,
> Krzysztof
>