[PATCH v11 0/3] Add support for Maxim MAX735x/MAX736x variants

[PATCH v11 0/3] Add support for Maxim MAX735x/MAX736x variants

[Patrick Rudolph]

v11:
- Fix dt-binding example

v10:
- Small updates to dt-bindings
- Make vdd-supply optional
- Drop MAX7357 enhanced mode configuration

v9:
- Fix 'then' not aligned with 'if' in dt-bindings
- Split enhanced mode configuration into separate patch
- Add MAX7357/MAX7358 register definitions
- Rename config register defines
- Update comments and explain non default config being applied on MAX7357
- Check for I2C_FUNC_SMBUS_WRITE_BYTE_DATA functionality

v8:
- Move allOf in dt-binding and use double negation

v7:
- Reworked the commit message, comments and renamed a struct
  field. No functional change.

v6:
- Fix typo in dt-bindings

v5:
- Remove optional and make vdd-supply mandatory

v4:
- Add missing maxitems dt-bindings property

v3:
- Merge dt-bindings into i2c-mux-pca954x.yaml

v2:
- Move dt-bindings to separate file
- Added support for MAX736x as they are very similar
- Fixed an issue found by kernel test robot
- Dropped max735x property and custom IRQ check
- Added MAX7357 config register defines instead of magic values
- Renamed vcc-supply to vdd-supply

Patrick Rudolph (3):
  dt-bindings: i2c: Add Maxim MAX735x/MAX736x variants
  i2c: muxes: pca954x: Add MAX735x/MAX736x support
  i2c: muxes: pca954x: Add regulator support

 .../bindings/i2c/i2c-mux-pca954x.yaml         | 45 +++++++--
 drivers/i2c/muxes/Kconfig                     |  6 +-
 drivers/i2c/muxes/i2c-mux-pca954x.c           | 95 +++++++++++++++++--
 3 files changed, 131 insertions(+), 15 deletions(-)

-- 
2.39.2

[PATCH v11 1/3] dt-bindings: i2c: Add Maxim MAX735x/MAX736x variants

[Patrick Rudolph]

Update the pca954x bindings to add support for the Maxim MAX735x/MAX736x
chips. The functionality will be provided by the exisintg pca954x driver.

While on it make the interrupts support conditionally as not all of the
existing chips have interrupts.

For chips that are powered off by default add an optional regulator
called vdd-supply.

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
---
 .../bindings/i2c/i2c-mux-pca954x.yaml         | 45 ++++++++++++++++---
 1 file changed, 39 insertions(+), 6 deletions(-)

diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml b/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
index 9f1726d0356b..6fed6eae9c9b 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
+++ b/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
@@ -4,21 +4,29 @@
 $id: http://devicetree.org/schemas/i2c/i2c-mux-pca954x.yaml#
 $schema: http://devicetree.org/meta-schemas/core.yaml#
 
-title: NXP PCA954x I2C bus switch
+title: NXP PCA954x I2C and compatible bus switches
 
 maintainers:
   - Laurent Pinchart <laurent.pinchart@ideasonboard.com>
 
 description:
-  The binding supports NXP PCA954x and PCA984x I2C mux/switch devices.
-
-allOf:
-  - $ref: /schemas/i2c/i2c-mux.yaml#
+  The NXP PCA954x and compatible devices are I2C bus
+  multiplexer/switches that share the same functionality
+  and register layout.
+  The devices usually have 4 or 8 child buses, which are
+  attached to the parent bus by using the SMBus "Send Byte"
+  command.
 
 properties:
   compatible:
     oneOf:
       - enum:
+          - maxim,max7356
+          - maxim,max7357
+          - maxim,max7358
+          - maxim,max7367
+          - maxim,max7368
+          - maxim,max7369
           - nxp,pca9540
           - nxp,pca9542
           - nxp,pca9543
@@ -59,10 +67,33 @@ properties:
     description: if present, overrides i2c-mux-idle-disconnect
     $ref: /schemas/mux/mux-controller.yaml#/properties/idle-state
 
+  vdd-supply:
+    description: A voltage regulator supplying power to the chip.
+
 required:
   - compatible
   - reg
 
+allOf:
+  - $ref: /schemas/i2c/i2c-mux.yaml#
+  - if:
+      not:
+        properties:
+          compatible:
+            contains:
+              enum:
+                - maxim,max7367
+                - maxim,max7369
+                - nxp,pca9542
+                - nxp,pca9543
+                - nxp,pca9544
+                - nxp,pca9545
+    then:
+      properties:
+        interrupts: false
+        "#interrupt-cells": false
+        interrupt-controller: false
+
 unevaluatedProperties: false
 
 examples:
@@ -74,11 +105,13 @@ examples:
         #size-cells = <0>;
 
         i2c-mux@74 {
-            compatible = "nxp,pca9548";
+            compatible = "nxp,pca9545";
             #address-cells = <1>;
             #size-cells = <0>;
             reg = <0x74>;
 
+            vdd-supply = <&p3v3>;
+
             interrupt-parent = <&ipic>;
             interrupts = <17 IRQ_TYPE_LEVEL_LOW>;
             interrupt-controller;
-- 
2.39.2

[PATCH v11 2/3] i2c: muxes: pca954x: Add MAX735x/MAX736x support

[Patrick Rudolph]

Add support for the following Maxim chips using the existing PCA954x
driver:
- MAX7356
- MAX7357
- MAX7358
- MAX7367
- MAX7368
- MAX7369

All added Maxim chips behave like the PCA954x, where a single SMBUS byte
write selects up to 8 channels to be bridged to the primary bus.

While the MAX7357/MAX7358 have interrupt support, they don't act as
interrupt controller like the PCA9545 does. Thus don't enable IRQ support
and handle them like the PCA9548.

Tested using the MAX7357.

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
---
 drivers/i2c/muxes/Kconfig           |  6 +--
 drivers/i2c/muxes/i2c-mux-pca954x.c | 60 ++++++++++++++++++++++++++++-
 2 files changed, 62 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig
index ea838dbae32e..db1b9057612a 100644
--- a/drivers/i2c/muxes/Kconfig
+++ b/drivers/i2c/muxes/Kconfig
@@ -65,11 +65,11 @@ config I2C_MUX_PCA9541
 	  will be called i2c-mux-pca9541.
 
 config I2C_MUX_PCA954x
-	tristate "NXP PCA954x and PCA984x I2C Mux/switches"
+	tristate "NXP PCA954x/PCA984x and Maxim MAX735x/MAX736x I2C Mux/switches"
 	depends on GPIOLIB || COMPILE_TEST
 	help
-	  If you say yes here you get support for the NXP PCA954x
-	  and PCA984x I2C mux/switch devices.
+	  If you say yes here you get support for NXP PCA954x/PCA984x
+	  and Maxim MAX735x/MAX736x I2C mux/switch devices.
 
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-mux-pca954x.
diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c
index 0ccee2ae5720..39f313658b18 100644
--- a/drivers/i2c/muxes/i2c-mux-pca954x.c
+++ b/drivers/i2c/muxes/i2c-mux-pca954x.c
@@ -4,6 +4,7 @@
  *
  * Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it>
  * Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it>
+ * Copyright (c) 2022 9elements GmbH <patrick.rudolph@9elements.com>
  *
  * This module supports the PCA954x and PCA984x series of I2C multiplexer/switch
  * chips made by NXP Semiconductors.
@@ -11,6 +12,12 @@
  *	 PCA9540, PCA9542, PCA9543, PCA9544, PCA9545, PCA9546, PCA9547,
  *	 PCA9548, PCA9846, PCA9847, PCA9848 and PCA9849.
  *
+ * It's also compatible to Maxims MAX735x I2C switch chips, which are controlled
+ * as the NXP PCA9548 and the MAX736x chips that act like the PCA9544.
+ *
+ * This includes the:
+ *	 MAX7356, MAX7357, MAX7358, MAX7367, MAX7368 and MAX7369
+ *
  * These chips are all controlled via the I2C bus itself, and all have a
  * single 8-bit register. The upstream "parent" bus fans out to two,
  * four, or eight downstream busses or channels; which of these
@@ -51,6 +58,12 @@
 #define PCA954X_IRQ_OFFSET 4
 
 enum pca_type {
+	max_7367,
+	max_7368,
+	max_7369,
+	max_7356,
+	max_7357,
+	max_7358,
 	pca_9540,
 	pca_9542,
 	pca_9543,
@@ -90,8 +103,41 @@ struct pca954x {
 	raw_spinlock_t lock;
 };
 
-/* Provide specs for the PCA954x types we know about */
+/* Provide specs for the MAX735x, PCA954x and PCA984x types we know about */
 static const struct chip_desc chips[] = {
+	[max_7356] = {
+		.nchans = 8,
+		.muxtype = pca954x_isswi,
+		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
+	},
+	[max_7357] = {
+		.nchans = 8,
+		.muxtype = pca954x_isswi,
+		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
+	},
+	[max_7358] = {
+		.nchans = 8,
+		.muxtype = pca954x_isswi,
+		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
+	},
+	[max_7367] = {
+		.nchans = 4,
+		.muxtype = pca954x_isswi,
+		.has_irq = 1,
+		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
+	},
+	[max_7368] = {
+		.nchans = 4,
+		.muxtype = pca954x_isswi,
+		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
+	},
+	[max_7369] = {
+		.nchans = 4,
+		.enable = 0x4,
+		.muxtype = pca954x_ismux,
+		.has_irq = 1,
+		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
+	},
 	[pca_9540] = {
 		.nchans = 2,
 		.enable = 0x4,
@@ -177,6 +223,12 @@ static const struct chip_desc chips[] = {
 };
 
 static const struct i2c_device_id pca954x_id[] = {
+	{ "max7356", max_7356 },
+	{ "max7357", max_7357 },
+	{ "max7358", max_7358 },
+	{ "max7367", max_7367 },
+	{ "max7368", max_7368 },
+	{ "max7369", max_7369 },
 	{ "pca9540", pca_9540 },
 	{ "pca9542", pca_9542 },
 	{ "pca9543", pca_9543 },
@@ -194,6 +246,12 @@ static const struct i2c_device_id pca954x_id[] = {
 MODULE_DEVICE_TABLE(i2c, pca954x_id);
 
 static const struct of_device_id pca954x_of_match[] = {
+	{ .compatible = "maxim,max7356", .data = &chips[max_7356] },
+	{ .compatible = "maxim,max7357", .data = &chips[max_7357] },
+	{ .compatible = "maxim,max7358", .data = &chips[max_7358] },
+	{ .compatible = "maxim,max7367", .data = &chips[max_7367] },
+	{ .compatible = "maxim,max7368", .data = &chips[max_7368] },
+	{ .compatible = "maxim,max7369", .data = &chips[max_7369] },
 	{ .compatible = "nxp,pca9540", .data = &chips[pca_9540] },
 	{ .compatible = "nxp,pca9542", .data = &chips[pca_9542] },
 	{ .compatible = "nxp,pca9543", .data = &chips[pca_9543] },
-- 
2.39.2

[PATCH v11 3/3] i2c: muxes: pca954x: Add regulator support

[Patrick Rudolph]

Add a vdd regulator and enable it for boards that have the
mux powered off by default.

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
---
 drivers/i2c/muxes/i2c-mux-pca954x.c | 35 ++++++++++++++++++++++++-----
 1 file changed, 30 insertions(+), 5 deletions(-)

diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c
index 39f313658b18..0d966a55b727 100644
--- a/drivers/i2c/muxes/i2c-mux-pca954x.c
+++ b/drivers/i2c/muxes/i2c-mux-pca954x.c
@@ -49,6 +49,7 @@
 #include <linux/module.h>
 #include <linux/pm.h>
 #include <linux/property.h>
+#include <linux/regulator/consumer.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <dt-bindings/mux/mux.h>
@@ -101,6 +102,7 @@ struct pca954x {
 	struct irq_domain *irq;
 	unsigned int irq_mask;
 	raw_spinlock_t lock;
+	struct regulator *supply;
 };
 
 /* Provide specs for the MAX735x, PCA954x and PCA984x types we know about */
@@ -440,6 +442,9 @@ static void pca954x_cleanup(struct i2c_mux_core *muxc)
 	struct pca954x *data = i2c_mux_priv(muxc);
 	int c, irq;
 
+	if (data->supply)
+		regulator_disable(data->supply);
+
 	if (data->irq) {
 		for (c = 0; c < data->chip->nchans; c++) {
 			irq = irq_find_mapping(data->irq, c);
@@ -492,10 +497,28 @@ static int pca954x_probe(struct i2c_client *client)
 	i2c_set_clientdata(client, muxc);
 	data->client = client;
 
+	data->supply = devm_regulator_get_optional(dev, "vdd");
+	if (IS_ERR(data->supply)) {
+		ret = PTR_ERR(data->supply);
+		if (ret != -ENODEV)
+			return dev_err_probe(dev, ret,
+				"Failed to request regulator\n");
+		else
+			data->supply = NULL;
+	} else {
+		ret = regulator_enable(data->supply);
+		if (ret) {
+			dev_err(dev, "Failed to enable regulator: %d\n", ret);
+			return ret;
+		}
+	}
+
 	/* Reset the mux if a reset GPIO is specified. */
 	gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
-	if (IS_ERR(gpio))
-		return PTR_ERR(gpio);
+	if (IS_ERR(gpio)) {
+		ret = PTR_ERR(gpio);
+		goto fail_cleanup;
+	}
 	if (gpio) {
 		udelay(1);
 		gpiod_set_value_cansleep(gpio, 0);
@@ -512,7 +535,7 @@ static int pca954x_probe(struct i2c_client *client)
 
 		ret = i2c_get_device_id(client, &id);
 		if (ret && ret != -EOPNOTSUPP)
-			return ret;
+			goto fail_cleanup;
 
 		if (!ret &&
 		    (id.manufacturer_id != data->chip->id.manufacturer_id ||
@@ -520,7 +543,8 @@ static int pca954x_probe(struct i2c_client *client)
 			dev_warn(dev, "unexpected device id %03x-%03x-%x\n",
 				 id.manufacturer_id, id.part_id,
 				 id.die_revision);
-			return -ENODEV;
+			ret = -ENODEV;
+			goto fail_cleanup;
 		}
 	}
 
@@ -539,7 +563,8 @@ static int pca954x_probe(struct i2c_client *client)
 	ret = pca954x_init(client, data);
 	if (ret < 0) {
 		dev_warn(dev, "probe failed\n");
-		return -ENODEV;
+		ret = -ENODEV;
+		goto fail_cleanup;
 	}
 
 	ret = pca954x_irq_setup(muxc);
-- 
2.39.2

Re: [PATCH v11 3/3] i2c: muxes: pca954x: Add regulator support

[Mark Brown]

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On Fri, Apr 14, 2023 at 01:01:36PM +0200, Patrick Rudolph wrote:

> +	data->supply = devm_regulator_get_optional(dev, "vdd");
> +	if (IS_ERR(data->supply)) {
> +		ret = PTR_ERR(data->supply);

Unless the device can work without power it should be using a normal
regulator_get().

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Re: [PATCH v11 3/3] i2c: muxes: pca954x: Add regulator support

[Patrick Rudolph]

Hi Mark,
It was using the normal regulator_get() in the last revision, but
Sergey requested to make it optional.
Please advise me what to do here? Who is right?

Regards,
Patrick

On Fri, Apr 14, 2023 at 1:47 PM Mark Brown <broonie@kernel.org> wrote:
>
> On Fri, Apr 14, 2023 at 01:01:36PM +0200, Patrick Rudolph wrote:
>
> > +     data->supply = devm_regulator_get_optional(dev, "vdd");
> > +     if (IS_ERR(data->supply)) {
> > +             ret = PTR_ERR(data->supply);
>
> Unless the device can work without power it should be using a normal
> regulator_get().

Re: [PATCH v11 3/3] i2c: muxes: pca954x: Add regulator support

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 793 bytes --]

On Fri, Apr 14, 2023 at 02:01:09PM +0200, Patrick Rudolph wrote:

> It was using the normal regulator_get() in the last revision, but
> Sergey requested to make it optional.
> Please advise me what to do here? Who is right?

As I said regulator_get_optional() is strictly for the case where the
supply may be physically absent and shouldn not be used in any other
situation.  Using the wrong variant will break error handling.

> 
> Regards,
> Patrick
> 
> On Fri, Apr 14, 2023 at 1:47 PM Mark Brown <broonie@kernel.org> wrote:


Please don't top post, reply in line with needed context.  This allows
readers to readily follow the flow of conversation and understand what
you are talking about and also helps ensure that everything in the
discussion is being addressed.

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Re: [PATCH v11 1/3] dt-bindings: i2c: Add Maxim MAX735x/MAX736x variants

[Krzysztof Kozlowski]

On 14/04/2023 13:01, Patrick Rudolph wrote:
> Update the pca954x bindings to add support for the Maxim MAX735x/MAX736x
> chips. The functionality will be provided by the exisintg pca954x driver.

Typo: existing


> 
> While on it make the interrupts support conditionally as not all of the
> existing chips have interrupts.
> 
> For chips that are powered off by default add an optional regulator
> called vdd-supply.
> 
> Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
> ---
>  .../bindings/i2c/i2c-mux-pca954x.yaml         | 45 ++++++++++++++++---
>  1 file changed, 39 insertions(+), 6 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml b/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
> index 9f1726d0356b..6fed6eae9c9b 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
> +++ b/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
> @@ -4,21 +4,29 @@
>  $id: http://devicetree.org/schemas/i2c/i2c-mux-pca954x.yaml#
>  $schema: http://devicetree.org/meta-schemas/core.yaml#
>  
> -title: NXP PCA954x I2C bus switch
> +title: NXP PCA954x I2C and compatible bus switches
>  
>  maintainers:
>    - Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>  
>  description:
> -  The binding supports NXP PCA954x and PCA984x I2C mux/switch devices.
> -
> -allOf:
> -  - $ref: /schemas/i2c/i2c-mux.yaml#
> +  The NXP PCA954x and compatible devices are I2C bus
> +  multiplexer/switches that share the same functionality
> +  and register layout.
> +  The devices usually have 4 or 8 child buses, which are
> +  attached to the parent bus by using the SMBus "Send Byte"
> +  command.
>  
>  properties:
>    compatible:
>      oneOf:
>        - enum:
> +          - maxim,max7356
> +          - maxim,max7357
> +          - maxim,max7358
> +          - maxim,max7367
> +          - maxim,max7368
> +          - maxim,max7369
>            - nxp,pca9540
>            - nxp,pca9542
>            - nxp,pca9543
> @@ -59,10 +67,33 @@ properties:
>      description: if present, overrides i2c-mux-idle-disconnect
>      $ref: /schemas/mux/mux-controller.yaml#/properties/idle-state
>  
> +  vdd-supply:
> +    description: A voltage regulator supplying power to the chip.
> +
>  required:
>    - compatible
>    - reg
>  
> +allOf:
> +  - $ref: /schemas/i2c/i2c-mux.yaml#
> +  - if:
> +      not:
> +        properties:
> +          compatible:
> +            contains:
> +              enum:
> +                - maxim,max7367
> +                - maxim,max7369
> +                - nxp,pca9542
> +                - nxp,pca9543
> +                - nxp,pca9544
> +                - nxp,pca9545

That's independent change. You add here support for Maxim devices, not
customize PCA. Please split it to new patch (first in the series).

> +    then:
> +      properties:
> +        interrupts: false
> +        "#interrupt-cells": false
> +        interrupt-controller: false
> +
>  unevaluatedProperties: false
>  
>  examples:
> @@ -74,11 +105,13 @@ examples:
>          #size-cells = <0>;
>  
>          i2c-mux@74 {
> -            compatible = "nxp,pca9548";
> +            compatible = "nxp,pca9545";

Best regards,
Krzysztof