[PATCH v4 0/6] reset: gpio: ASoC: shared GPIO resets

[PATCH v4 0/6] reset: gpio: ASoC: shared GPIO resets

[Krzysztof Kozlowski]

Hi,

Patch #2 (cpufreq: do not open-code of_phandle_args_equal()) and patch #4
(reset: Instantiate reset GPIO controller for shared reset-gpios) depend on OF
change (patch #1).

Changes in v4
=============
1. New patches:
   of: add of_phandle_args_equal() helper
   cpufreq: do not open-code of_phandle_args_equal()

2. reset-gpio.c:
   - Drop unneeded comment (Bartosz), add Rb tag.
   - Do not assign of_node.

3. reset/core.c:
   - Implement most of Bartosz feedback (I responded to one which I did not
     implement) and comments from Philipp.
   - Expect either rcdev->of_args or rcdev->of_node.
   - Drop __reset_gpios_args_match() and use common helper (Philipp).
   - Move declarations of automatic-cleanup variables in
     __reset_add_reset_gpio_lookup() to place of use (Bartosz).
   - Separate gpio_device_get_label() and kstrdup() (Philipp).
   - Correct doc for __reset_add_reset_gpio_device(), rewrite few comments.
   - Drop unneeded "r" variable in __reset_find_rcdev() (Philipp).
   - Drop of_phandle_args initialization in __of_reset_control_get (Philipp).
   - Check if CONFIG_RESET_GPIO is enabled before trying to look up reset-gpios.

4. Drop Chris' patch: "i2c: muxes: pca954x: Allow sharing reset GPIO", because
   discussion is on going.

Changes in v3
=============
1. reset-gpio.c:
  - Add reset_gpio_of_xlate (Philipp).
  - reset_gpio_of_args_put->reset_gpio_of_node_put (Philipp).
  - Expect via platdata of_phandle_args.
  - Do not call device_set_node() to attach itself to reset consumer
    (the final device).  This was questionable idea in the first place.
    Bartosz suggested to use GPIO_LOOKUP to solve this.

2. reset/core.c, implement Philipp's feedback. That was a lot:
  - Commit msg fixes.
  - Add new platform_device earlier, when reset core found "reset-gpios" but
    not "resets".
  - Do not overwrite of_phandle_args.
  - Expect matching .of_reset_n_cells.
  - Pass of_phandle_args as platdata to reset-gpio.
  - Rename reset_gpio_device->reset_gpio_lookup and others. Fix few comments
    and code cleanup pointed on review.
  - From Bartosz:
    Use GPIO_LOOKUP and a lot of cleanup.h in __reset_add_reset_gpio_lookup().

3. Include here Chris' patch: "i2c: muxes: pca954x: Allow sharing reset GPIO".

Changes in v2
=============
1. wsa884x.c: add missing return in wsa884x_get_reset(), correct comment.
2. qcom,wsa8840.yaml: fix oneOf syntax.
3. reset-gpio.c:
   - Fix smatch warning on platdata evaluation.
   - Parse GPIO args and store them in rc.of_args.
4. reset/core.c:
   - Revise approach based on Bartosz comments: parse the reset-gpios phandle
     with arguments, do not use deprecated API and do not rely on gpio_desc
     pointer.
   - Create a list of instantiated platform devices to avoid any duplicates.
   - After creating reset-gpio platform device, try to get new reset controller
     or return EPROBE_DEFER.
   - Drop the "cookie" member and add new "of_args" to "struct
     reset_controller_dev".

Description
===========

We have at least few cases where hardware engineers decided to use one
powerdown/shutdown/reset GPIO line for multiple devices:

1. WSA884x (this and previous patch):
https://lore.kernel.org/all/b7aeda24-d638-45b7-8e30-80d287f498f8@sirena.org.uk/
2. https://lore.kernel.org/all/20231027033104.1348921-1-chris.packham@alliedtelesis.co.nz/
3. https://lore.kernel.org/lkml/20191030120440.3699-1-peter.ujfalusi@ti.com/
4. https://lore.kernel.org/all/20211018234923.1769028-1-sean.anderson@seco.com/
5. https://social.treehouse.systems/@marcan/111268780311634160

I try to solve my case, hopefuly Chris' (2), partially Sean's (4) and maybe
Hectors (5), using Rob's suggestion:

https://lore.kernel.org/all/YXi5CUCEi7YmNxXM@robh.at.kernel.org/

Best regards,
Krzysztof

Cc: Chris Packham <chris.packham@alliedtelesis.co.nz>
Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Sean Anderson <sean.anderson@seco.com>

Krzysztof Kozlowski (6):
  of: Add of_phandle_args_equal() helper
  cpufreq: do not open-code of_phandle_args_equal()
  reset: gpio: Add GPIO-based reset controller
  reset: Instantiate reset GPIO controller for shared reset-gpios
  ASoC: dt-bindings: qcom,wsa8840: Add reset-gpios for shared line
  ASoC: codecs: wsa884x: Allow sharing reset GPIO

 .../bindings/sound/qcom,wsa8840.yaml          |  11 +-
 MAINTAINERS                                   |   5 +
 drivers/reset/Kconfig                         |   9 +
 drivers/reset/Makefile                        |   1 +
 drivers/reset/core.c                          | 213 ++++++++++++++++--
 drivers/reset/reset-gpio.c                    | 119 ++++++++++
 include/linux/cpufreq.h                       |   3 +-
 include/linux/of.h                            |  16 ++
 include/linux/reset-controller.h              |   4 +
 sound/soc/codecs/wsa884x.c                    |  53 ++++-
 10 files changed, 408 insertions(+), 26 deletions(-)
 create mode 100644 drivers/reset/reset-gpio.c

-- 
2.34.1

[PATCH v4 1/6] of: Add of_phandle_args_equal() helper

[Krzysztof Kozlowski]

Add a helper comparing two "struct of_phandle_args" to avoid
reinventing the wheel.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

---

Dependency of cpufreq and reset change.
---
 include/linux/of.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/include/linux/of.h b/include/linux/of.h
index 6a9ddf20e79a..85bcc05b278d 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -1065,6 +1065,22 @@ static inline int of_parse_phandle_with_optional_args(const struct device_node *
 					    0, index, out_args);
 }
 
+/**
+ * of_phandle_args_equal() - Compare two of_phandle_args
+ * @a1:		First of_phandle_args to compare
+ * @a2:		Second of_phandle_args to compare
+ *
+ * Return: True if a1 and a2 are the same (same node pointer, same phandle
+ * args), false otherwise.
+ */
+static inline bool of_phandle_args_equal(const struct of_phandle_args *a1,
+					 const struct of_phandle_args *a2)
+{
+	return a1->np == a2->np &&
+	       a1->args_count == a2->args_count &&
+	       !memcmp(a1->args, a2->args, sizeof(a1->args[0]) * a1->args_count);
+}
+
 /**
  * of_property_count_u8_elems - Count the number of u8 elements in a property
  *
-- 
2.34.1

Re: [PATCH v4 1/6] of: Add of_phandle_args_equal() helper

[Philipp Zabel]

On Di, 2024-01-23 at 15:13 +0100, Krzysztof Kozlowski wrote:
> Add a helper comparing two "struct of_phandle_args" to avoid
> reinventing the wheel.
> 
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>

regards
Philipp

[PATCH v4 2/6] cpufreq: do not open-code of_phandle_args_equal()

[Krzysztof Kozlowski]

Use newly added of_phandle_args_equal() helper to compare two
of_phandle_args.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

---

Depends on previous of change.
---
 include/linux/cpufreq.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index afda5f24d3dd..3cd06dafb04b 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -1149,8 +1149,7 @@ static inline int of_perf_domain_get_sharing_cpumask(int pcpu, const char *list_
 		if (ret < 0)
 			continue;
 
-		if (pargs->np == args.np && pargs->args_count == args.args_count &&
-		    !memcmp(pargs->args, args.args, sizeof(args.args[0]) * args.args_count))
+		if (of_phandle_args_equal(pargs, &args))
 			cpumask_set_cpu(cpu, cpumask);
 
 		of_node_put(args.np);
-- 
2.34.1

Re: [PATCH v4 2/6] cpufreq: do not open-code of_phandle_args_equal()

[Philipp Zabel]

On Di, 2024-01-23 at 15:13 +0100, Krzysztof Kozlowski wrote:
> Use newly added of_phandle_args_equal() helper to compare two
> of_phandle_args.
> 
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>

regards
Philipp

Re: [PATCH v4 2/6] cpufreq: do not open-code of_phandle_args_equal()

[Viresh Kumar]

On 23-01-24, 15:13, Krzysztof Kozlowski wrote:
> Use newly added of_phandle_args_equal() helper to compare two
> of_phandle_args.
> 
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> 
> ---
> 
> Depends on previous of change.
> ---
>  include/linux/cpufreq.h | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
> index afda5f24d3dd..3cd06dafb04b 100644
> --- a/include/linux/cpufreq.h
> +++ b/include/linux/cpufreq.h
> @@ -1149,8 +1149,7 @@ static inline int of_perf_domain_get_sharing_cpumask(int pcpu, const char *list_
>  		if (ret < 0)
>  			continue;
>  
> -		if (pargs->np == args.np && pargs->args_count == args.args_count &&
> -		    !memcmp(pargs->args, args.args, sizeof(args.args[0]) * args.args_count))
> +		if (of_phandle_args_equal(pargs, &args))
>  			cpumask_set_cpu(cpu, cpumask);
>  
>  		of_node_put(args.np);

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

-- 
viresh

[PATCH v4 3/6] reset: gpio: Add GPIO-based reset controller

[Krzysztof Kozlowski]

Add a simple driver to control GPIO-based resets using the reset
controller API for the cases when the GPIOs are shared and reset should
be coordinated.  The driver is expected to be used by reset core
framework for ad-hoc reset controllers.

Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Chris Packham <chris.packham@alliedtelesis.co.nz>
Cc: Sean Anderson <sean.anderson@seco.com>
Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
 MAINTAINERS                |   5 ++
 drivers/reset/Kconfig      |   9 +++
 drivers/reset/Makefile     |   1 +
 drivers/reset/reset-gpio.c | 119 +++++++++++++++++++++++++++++++++++++
 4 files changed, 134 insertions(+)
 create mode 100644 drivers/reset/reset-gpio.c

diff --git a/MAINTAINERS b/MAINTAINERS
index ddc5e1049921..91d45c6bade7 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8905,6 +8905,11 @@ F:	Documentation/i2c/muxes/i2c-mux-gpio.rst
 F:	drivers/i2c/muxes/i2c-mux-gpio.c
 F:	include/linux/platform_data/i2c-mux-gpio.h
 
+GENERIC GPIO RESET DRIVER
+M:	Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
+S:	Maintained
+F:	drivers/reset/reset-gpio.c
+
 GENERIC HDLC (WAN) DRIVERS
 M:	Krzysztof Halasa <khc@pm.waw.pl>
 S:	Maintained
diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index ccd59ddd7610..bb1b5a326eb7 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -66,6 +66,15 @@ config RESET_BRCMSTB_RESCAL
 	  This enables the RESCAL reset controller for SATA, PCIe0, or PCIe1 on
 	  BCM7216.
 
+config RESET_GPIO
+	tristate "GPIO reset controller"
+	help
+	  This enables a generic reset controller for resets attached via
+	  GPIOs.  Typically for OF platforms this driver expects "reset-gpios"
+	  property.
+
+	  If compiled as module, it will be called reset-gpio.
+
 config RESET_HSDK
 	bool "Synopsys HSDK Reset Driver"
 	depends on HAS_IOMEM
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 8270da8a4baa..fd8b49fa46fc 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_RESET_BCM6345) += reset-bcm6345.o
 obj-$(CONFIG_RESET_BERLIN) += reset-berlin.o
 obj-$(CONFIG_RESET_BRCMSTB) += reset-brcmstb.o
 obj-$(CONFIG_RESET_BRCMSTB_RESCAL) += reset-brcmstb-rescal.o
+obj-$(CONFIG_RESET_GPIO) += reset-gpio.o
 obj-$(CONFIG_RESET_HSDK) += reset-hsdk.o
 obj-$(CONFIG_RESET_IMX7) += reset-imx7.o
 obj-$(CONFIG_RESET_INTEL_GW) += reset-intel-gw.o
diff --git a/drivers/reset/reset-gpio.c b/drivers/reset/reset-gpio.c
new file mode 100644
index 000000000000..2290b25b6703
--- /dev/null
+++ b/drivers/reset/reset-gpio.c
@@ -0,0 +1,119 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/gpio/consumer.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+
+struct reset_gpio_priv {
+	struct reset_controller_dev rc;
+	struct gpio_desc *reset;
+};
+
+static inline struct reset_gpio_priv
+*rc_to_reset_gpio(struct reset_controller_dev *rc)
+{
+	return container_of(rc, struct reset_gpio_priv, rc);
+}
+
+static int reset_gpio_assert(struct reset_controller_dev *rc, unsigned long id)
+{
+	struct reset_gpio_priv *priv = rc_to_reset_gpio(rc);
+
+	gpiod_set_value_cansleep(priv->reset, 1);
+
+	return 0;
+}
+
+static int reset_gpio_deassert(struct reset_controller_dev *rc,
+			       unsigned long id)
+{
+	struct reset_gpio_priv *priv = rc_to_reset_gpio(rc);
+
+	gpiod_set_value_cansleep(priv->reset, 0);
+
+	return 0;
+}
+
+static int reset_gpio_status(struct reset_controller_dev *rc, unsigned long id)
+{
+	struct reset_gpio_priv *priv = rc_to_reset_gpio(rc);
+
+	return gpiod_get_value_cansleep(priv->reset);
+}
+
+static const struct reset_control_ops reset_gpio_ops = {
+	.assert = reset_gpio_assert,
+	.deassert = reset_gpio_deassert,
+	.status = reset_gpio_status,
+};
+
+static int reset_gpio_of_xlate(struct reset_controller_dev *rcdev,
+			       const struct of_phandle_args *reset_spec)
+{
+	return reset_spec->args[0];
+}
+
+static void reset_gpio_of_node_put(void *data)
+{
+	of_node_put(data);
+}
+
+static int reset_gpio_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct of_phandle_args *platdata = dev_get_platdata(dev);
+	struct reset_gpio_priv *priv;
+	int ret;
+
+	if (!platdata)
+		return -EINVAL;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, &priv->rc);
+
+	priv->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(priv->reset))
+		return dev_err_probe(dev, PTR_ERR(priv->reset),
+				     "Could not get reset gpios\n");
+
+	priv->rc.ops = &reset_gpio_ops;
+	priv->rc.owner = THIS_MODULE;
+	priv->rc.dev = dev;
+	priv->rc.of_args = platdata;
+	ret = devm_add_action_or_reset(dev, reset_gpio_of_node_put,
+				       priv->rc.of_node);
+	if (ret)
+		return ret;
+
+	/* Cells to match GPIO specifier, but it's not really used */
+	priv->rc.of_reset_n_cells = 2;
+	priv->rc.of_xlate = reset_gpio_of_xlate;
+	priv->rc.nr_resets = 1;
+
+	return devm_reset_controller_register(dev, &priv->rc);
+}
+
+static const struct platform_device_id reset_gpio_ids[] = {
+	{ .name = "reset-gpio", },
+	{}
+};
+MODULE_DEVICE_TABLE(platform, reset_gpio_ids);
+
+static struct platform_driver reset_gpio_driver = {
+	.probe		= reset_gpio_probe,
+	.id_table	= reset_gpio_ids,
+	.driver	= {
+		.name = "reset-gpio",
+	},
+};
+module_platform_driver(reset_gpio_driver);
+
+MODULE_AUTHOR("Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>");
+MODULE_DESCRIPTION("Generic GPIO reset driver");
+MODULE_LICENSE("GPL");
-- 
2.34.1

[PATCH v4 4/6] reset: Instantiate reset GPIO controller for shared reset-gpios

[Krzysztof Kozlowski]

Devices sharing a reset GPIO could use the reset framework for
coordinated handling of that shared GPIO line.  We have several cases of
such needs, at least for Devicetree-based platforms.

If Devicetree-based device requests a reset line, while "resets"
Devicetree property is missing but there is a "reset-gpios" one,
instantiate a new "reset-gpio" platform device which will handle such
reset line.  This allows seamless handling of such shared reset-gpios
without need of changing Devicetree binding [1].

To avoid creating multiple "reset-gpio" platform devices, store the
Devicetree "reset-gpios" GPIO specifiers used for new devices on a
linked list.  Later such Devicetree GPIO specifier (phandle to GPIO
controller, GPIO number and GPIO flags) is used to check if reset
controller for given GPIO was already registered.

If two devices have conflicting "reset-gpios" property, e.g. with
different ACTIVE_xxx flags, this would allow to spawn two separate
"reset-gpio" devices, where the second would fail probing on busy GPIO
request.

Link: https://lore.kernel.org/all/YXi5CUCEi7YmNxXM@robh.at.kernel.org/ [1]
Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Chris Packham <chris.packham@alliedtelesis.co.nz>
Cc: Sean Anderson <sean.anderson@seco.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

---

Depends on previous of change.
---
 drivers/reset/core.c             | 213 +++++++++++++++++++++++++++++--
 include/linux/reset-controller.h |   4 +
 2 files changed, 204 insertions(+), 13 deletions(-)

diff --git a/drivers/reset/core.c b/drivers/reset/core.c
index 4d5a78d3c085..6e81b8d35055 100644
--- a/drivers/reset/core.c
+++ b/drivers/reset/core.c
@@ -10,9 +10,13 @@
 #include <linux/export.h>
 #include <linux/kernel.h>
 #include <linux/kref.h>
+#include <linux/gpio/driver.h>
+#include <linux/gpio/machine.h>
+#include <linux/idr.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/acpi.h>
+#include <linux/platform_device.h>
 #include <linux/reset.h>
 #include <linux/reset-controller.h>
 #include <linux/slab.h>
@@ -23,6 +27,11 @@ static LIST_HEAD(reset_controller_list);
 static DEFINE_MUTEX(reset_lookup_mutex);
 static LIST_HEAD(reset_lookup_list);
 
+/* Protects reset_gpio_lookup_list */
+static DEFINE_MUTEX(reset_gpio_lookup_mutex);
+static LIST_HEAD(reset_gpio_lookup_list);
+static DEFINE_IDA(reset_gpio_ida);
+
 /**
  * struct reset_control - a reset control
  * @rcdev: a pointer to the reset controller device
@@ -63,6 +72,16 @@ struct reset_control_array {
 	struct reset_control *rstc[] __counted_by(num_rstcs);
 };
 
+/**
+ * struct reset_gpio_lookup - lookup key for ad-hoc created reset-gpio devices
+ * @of_args: phandle to the reset controller with all the args like GPIO number
+ * @list: list entry for the reset_gpio_lookup_list
+ */
+struct reset_gpio_lookup {
+	struct of_phandle_args of_args;
+	struct list_head list;
+};
+
 static const char *rcdev_name(struct reset_controller_dev *rcdev)
 {
 	if (rcdev->dev)
@@ -71,6 +90,9 @@ static const char *rcdev_name(struct reset_controller_dev *rcdev)
 	if (rcdev->of_node)
 		return rcdev->of_node->full_name;
 
+	if (rcdev->of_args)
+		return rcdev->of_args->np->full_name;
+
 	return NULL;
 }
 
@@ -99,6 +121,9 @@ static int of_reset_simple_xlate(struct reset_controller_dev *rcdev,
  */
 int reset_controller_register(struct reset_controller_dev *rcdev)
 {
+	if (rcdev->of_node && rcdev->of_args)
+		return -EINVAL;
+
 	if (!rcdev->of_xlate) {
 		rcdev->of_reset_n_cells = 1;
 		rcdev->of_xlate = of_reset_simple_xlate;
@@ -813,12 +838,161 @@ static void __reset_control_put_internal(struct reset_control *rstc)
 	kref_put(&rstc->refcnt, __reset_control_release);
 }
 
+static int __reset_add_reset_gpio_lookup(int id, struct device_node *np,
+					 unsigned int gpio,
+					 unsigned int of_flags)
+{
+	unsigned int lookup_flags;
+	const char *label_tmp;
+
+	/*
+	 * Later we map GPIO flags between OF and Linux, however not all
+	 * constants from include/dt-bindings/gpio/gpio.h and
+	 * include/linux/gpio/machine.h match each other.
+	 */
+	if (of_flags > GPIO_ACTIVE_LOW) {
+		pr_err("reset-gpio code does not support GPIO flags %u for GPIO %u\n",
+			of_flags, gpio);
+		return -EINVAL;
+	}
+
+	struct gpio_device *gdev __free(gpio_device_put) = gpio_device_find_by_fwnode(of_fwnode_handle(np));
+	if (!gdev)
+		return -EPROBE_DEFER;
+
+	label_tmp = gpio_device_get_label(gdev);
+	if (!label_tmp)
+		return -EINVAL;
+
+	char *label __free(kfree) = kstrdup(label_tmp, GFP_KERNEL);
+	if (!label)
+		return -ENOMEM;
+
+	/* Size: one lookup entry plus sentinel */
+	struct gpiod_lookup_table *lookup __free(kfree) = kzalloc(struct_size(lookup, table, 2),
+								  GFP_KERNEL);
+	if (!lookup)
+		return -ENOMEM;
+
+	lookup->dev_id = kasprintf(GFP_KERNEL, "reset-gpio.%d", id);
+	if (!lookup->dev_id)
+		return -ENOMEM;
+
+	lookup_flags = GPIO_PERSISTENT;
+	lookup_flags |= of_flags & GPIO_ACTIVE_LOW;
+	lookup->table[0] = GPIO_LOOKUP(no_free_ptr(label), gpio, "reset",
+				       lookup_flags);
+
+	/* Not freed on success, because it is persisent subsystem data. */
+	gpiod_add_lookup_table(no_free_ptr(lookup));
+
+	return 0;
+}
+
+/*
+ * @args:	phandle to the GPIO provider with all the args like GPIO number
+ */
+static int __reset_add_reset_gpio_device(const struct of_phandle_args *args)
+{
+	struct reset_gpio_lookup *rgpio_dev;
+	struct platform_device *pdev;
+	int id, ret;
+
+	/*
+	 * Registering reset-gpio device might cause immediate
+	 * bind, resulting in its probe() registering new reset controller thus
+	 * taking reset_list_mutex lock via reset_controller_register().
+	 */
+	lockdep_assert_not_held(&reset_list_mutex);
+
+	mutex_lock(&reset_gpio_lookup_mutex);
+
+	list_for_each_entry(rgpio_dev, &reset_gpio_lookup_list, list) {
+		if (args->np == rgpio_dev->of_args.np) {
+			if (of_phandle_args_equal(args, &rgpio_dev->of_args))
+				goto out; /* Already on the list, done */
+		}
+	}
+
+	id = ida_alloc(&reset_gpio_ida, GFP_KERNEL);
+	if (id < 0) {
+		ret = id;
+		goto err_unlock;
+	}
+
+	/* Not freed on success, because it is persisent subsystem data. */
+	rgpio_dev = kzalloc(sizeof(*rgpio_dev), GFP_KERNEL);
+	if (!rgpio_dev) {
+		ret = -ENOMEM;
+		goto err_ida_free;
+	}
+
+	ret = __reset_add_reset_gpio_lookup(id, args->np, args->args[0],
+					    args->args[1]);
+	if (ret < 0)
+		goto err_kfree;
+
+	rgpio_dev->of_args = *args;
+	/*
+	 * We keep the device_node reference, but of_args.np is put at the end
+	 * of __of_reset_control_get(), so get it one more time.
+	 * Hold reference as long as rgpio_dev memory is valid.
+	 */
+	of_node_get(rgpio_dev->of_args.np);
+	pdev = platform_device_register_data(NULL, "reset-gpio", id,
+					     &rgpio_dev->of_args,
+					     sizeof(rgpio_dev->of_args));
+	ret = PTR_ERR_OR_ZERO(pdev);
+	if (ret)
+		goto err_put;
+
+	list_add(&rgpio_dev->list, &reset_gpio_lookup_list);
+
+out:
+	mutex_unlock(&reset_gpio_lookup_mutex);
+
+	return 0;
+
+err_put:
+	of_node_put(rgpio_dev->of_args.np);
+err_kfree:
+	kfree(rgpio_dev);
+err_ida_free:
+	ida_free(&reset_gpio_ida, id);
+err_unlock:
+	mutex_unlock(&reset_gpio_lookup_mutex);
+
+	return ret;
+}
+
+static struct reset_controller_dev *__reset_find_rcdev(const struct of_phandle_args *args,
+						       bool gpio_fallback)
+{
+	struct reset_controller_dev *rcdev;
+
+	lockdep_assert_held(&reset_list_mutex);
+
+	list_for_each_entry(rcdev, &reset_controller_list, list) {
+		if (gpio_fallback) {
+			if (rcdev->of_args && of_phandle_args_equal(args,
+								    rcdev->of_args))
+				return rcdev;
+		} else {
+			if (args->np == rcdev->of_node)
+				return rcdev;
+		}
+	}
+
+	return NULL;
+}
+
 struct reset_control *
 __of_reset_control_get(struct device_node *node, const char *id, int index,
 		       bool shared, bool optional, bool acquired)
 {
+	bool gpio_fallback = false;
 	struct reset_control *rstc;
-	struct reset_controller_dev *r, *rcdev;
+	struct reset_controller_dev *rcdev;
 	struct of_phandle_args args;
 	int rstc_id;
 	int ret;
@@ -839,39 +1013,52 @@ __of_reset_control_get(struct device_node *node, const char *id, int index,
 					 index, &args);
 	if (ret == -EINVAL)
 		return ERR_PTR(ret);
-	if (ret)
-		return optional ? NULL : ERR_PTR(ret);
+	if (ret) {
+		if (!IS_ENABLED(CONFIG_RESET_GPIO))
+			return optional ? NULL : ERR_PTR(ret);
 
-	mutex_lock(&reset_list_mutex);
-	rcdev = NULL;
-	list_for_each_entry(r, &reset_controller_list, list) {
-		if (args.np == r->of_node) {
-			rcdev = r;
-			break;
+		/*
+		 * There can be only one reset-gpio for regular devices, so
+		 * don't bother with the "reset-gpios" phandle index.
+		 */
+		ret = of_parse_phandle_with_args(node, "reset-gpios", "#gpio-cells",
+						 0, &args);
+		if (ret)
+			return optional ? NULL : ERR_PTR(ret);
+
+		gpio_fallback = true;
+
+		ret = __reset_add_reset_gpio_device(&args);
+		if (ret) {
+			rstc = ERR_PTR(ret);
+			goto out_put;
 		}
 	}
 
+	mutex_lock(&reset_list_mutex);
+	rcdev = __reset_find_rcdev(&args, gpio_fallback);
 	if (!rcdev) {
 		rstc = ERR_PTR(-EPROBE_DEFER);
-		goto out;
+		goto out_unlock;
 	}
 
 	if (WARN_ON(args.args_count != rcdev->of_reset_n_cells)) {
 		rstc = ERR_PTR(-EINVAL);
-		goto out;
+		goto out_unlock;
 	}
 
 	rstc_id = rcdev->of_xlate(rcdev, &args);
 	if (rstc_id < 0) {
 		rstc = ERR_PTR(rstc_id);
-		goto out;
+		goto out_unlock;
 	}
 
 	/* reset_list_mutex also protects the rcdev's reset_control list */
 	rstc = __reset_control_get_internal(rcdev, rstc_id, shared, acquired);
 
-out:
+out_unlock:
 	mutex_unlock(&reset_list_mutex);
+out_put:
 	of_node_put(args.np);
 
 	return rstc;
diff --git a/include/linux/reset-controller.h b/include/linux/reset-controller.h
index 0fa4f60e1186..357df16ede32 100644
--- a/include/linux/reset-controller.h
+++ b/include/linux/reset-controller.h
@@ -60,6 +60,9 @@ struct reset_control_lookup {
  * @reset_control_head: head of internal list of requested reset controls
  * @dev: corresponding driver model device struct
  * @of_node: corresponding device tree node as phandle target
+ * @of_args: for reset-gpios controllers: corresponding phandle args with
+ *           of_node and GPIO number complementing of_node; either this or
+ *           of_node should be present
  * @of_reset_n_cells: number of cells in reset line specifiers
  * @of_xlate: translation function to translate from specifier as found in the
  *            device tree to id as given to the reset control ops, defaults
@@ -73,6 +76,7 @@ struct reset_controller_dev {
 	struct list_head reset_control_head;
 	struct device *dev;
 	struct device_node *of_node;
+	const struct of_phandle_args *of_args;
 	int of_reset_n_cells;
 	int (*of_xlate)(struct reset_controller_dev *rcdev,
 			const struct of_phandle_args *reset_spec);
-- 
2.34.1

Re: [PATCH v4 4/6] reset: Instantiate reset GPIO controller for shared reset-gpios

[Philipp Zabel]

On Di, 2024-01-23 at 15:13 +0100, Krzysztof Kozlowski wrote:
> Devices sharing a reset GPIO could use the reset framework for
> coordinated handling of that shared GPIO line.  We have several cases of
> such needs, at least for Devicetree-based platforms.
> 
> If Devicetree-based device requests a reset line, while "resets"
> Devicetree property is missing but there is a "reset-gpios" one,
> instantiate a new "reset-gpio" platform device which will handle such
> reset line.  This allows seamless handling of such shared reset-gpios
> without need of changing Devicetree binding [1].
> 
> To avoid creating multiple "reset-gpio" platform devices, store the
> Devicetree "reset-gpios" GPIO specifiers used for new devices on a
> linked list.  Later such Devicetree GPIO specifier (phandle to GPIO
> controller, GPIO number and GPIO flags) is used to check if reset
> controller for given GPIO was already registered.
> 
> If two devices have conflicting "reset-gpios" property, e.g. with
> different ACTIVE_xxx flags, this would allow to spawn two separate
> "reset-gpio" devices, where the second would fail probing on busy GPIO
> request.
> 
> Link: https://lore.kernel.org/all/YXi5CUCEi7YmNxXM@robh.at.kernel.org/ [1]
> Cc: Bartosz Golaszewski <brgl@bgdev.pl>
> Cc: Chris Packham <chris.packham@alliedtelesis.co.nz>
> Cc: Sean Anderson <sean.anderson@seco.com>
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

I'm nearly out of complaints, two tiny cosmetic issues remaining:

[...]
> diff --git a/drivers/reset/core.c b/drivers/reset/core.c
> index 4d5a78d3c085..6e81b8d35055 100644
> --- a/drivers/reset/core.c
> +++ b/drivers/reset/core.c
[...]
> @@ -813,12 +838,161 @@ static void __reset_control_put_internal(struct reset_control *rstc)
>  	kref_put(&rstc->refcnt, __reset_control_release);
>  }
>  
> +static int __reset_add_reset_gpio_lookup(int id, struct device_node *np,
> +					 unsigned int gpio,
> +					 unsigned int of_flags)
> +{
> +	unsigned int lookup_flags;
> +	const char *label_tmp;
> +
> +	/*
> +	 * Later we map GPIO flags between OF and Linux, however not all
> +	 * constants from include/dt-bindings/gpio/gpio.h and
> +	 * include/linux/gpio/machine.h match each other.
> +	 */
> +	if (of_flags > GPIO_ACTIVE_LOW) {
> +		pr_err("reset-gpio code does not support GPIO flags %u for GPIO %u\n",
> +			of_flags, gpio);

Alignment to parenthesis is slightly off.

> +		return -EINVAL;
> +	}
> +
> +	struct gpio_device *gdev __free(gpio_device_put) = gpio_device_find_by_fwnode(of_fwnode_handle(np));

Adding a local fwnode variable would make this fit in the 100 character
limit again.

regards
Philipp

Re: [PATCH v4 4/6] reset: Instantiate reset GPIO controller for shared reset-gpios

[Krzysztof Kozlowski]

On 23/01/2024 16:06, Philipp Zabel wrote:
> On Di, 2024-01-23 at 15:13 +0100, Krzysztof Kozlowski wrote:
>> Devices sharing a reset GPIO could use the reset framework for
>> coordinated handling of that shared GPIO line.  We have several cases of
>> such needs, at least for Devicetree-based platforms.
>>
>> If Devicetree-based device requests a reset line, while "resets"
>> Devicetree property is missing but there is a "reset-gpios" one,
>> instantiate a new "reset-gpio" platform device which will handle such
>> reset line.  This allows seamless handling of such shared reset-gpios
>> without need of changing Devicetree binding [1].
>>
>> To avoid creating multiple "reset-gpio" platform devices, store the
>> Devicetree "reset-gpios" GPIO specifiers used for new devices on a
>> linked list.  Later such Devicetree GPIO specifier (phandle to GPIO
>> controller, GPIO number and GPIO flags) is used to check if reset
>> controller for given GPIO was already registered.
>>
>> If two devices have conflicting "reset-gpios" property, e.g. with
>> different ACTIVE_xxx flags, this would allow to spawn two separate
>> "reset-gpio" devices, where the second would fail probing on busy GPIO
>> request.
>>
>> Link: https://lore.kernel.org/all/YXi5CUCEi7YmNxXM@robh.at.kernel.org/ [1]
>> Cc: Bartosz Golaszewski <brgl@bgdev.pl>
>> Cc: Chris Packham <chris.packham@alliedtelesis.co.nz>
>> Cc: Sean Anderson <sean.anderson@seco.com>
>> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> 
> I'm nearly out of complaints, two tiny cosmetic issues remaining:
> 
> [...]
>> diff --git a/drivers/reset/core.c b/drivers/reset/core.c
>> index 4d5a78d3c085..6e81b8d35055 100644
>> --- a/drivers/reset/core.c
>> +++ b/drivers/reset/core.c
> [...]
>> @@ -813,12 +838,161 @@ static void __reset_control_put_internal(struct reset_control *rstc)
>>  	kref_put(&rstc->refcnt, __reset_control_release);
>>  }
>>  
>> +static int __reset_add_reset_gpio_lookup(int id, struct device_node *np,
>> +					 unsigned int gpio,
>> +					 unsigned int of_flags)
>> +{
>> +	unsigned int lookup_flags;
>> +	const char *label_tmp;
>> +
>> +	/*
>> +	 * Later we map GPIO flags between OF and Linux, however not all
>> +	 * constants from include/dt-bindings/gpio/gpio.h and
>> +	 * include/linux/gpio/machine.h match each other.
>> +	 */
>> +	if (of_flags > GPIO_ACTIVE_LOW) {
>> +		pr_err("reset-gpio code does not support GPIO flags %u for GPIO %u\n",
>> +			of_flags, gpio);
> 
> Alignment to parenthesis is slightly off.

Ack

> 
>> +		return -EINVAL;
>> +	}
>> +
>> +	struct gpio_device *gdev __free(gpio_device_put) = gpio_device_find_by_fwnode(of_fwnode_handle(np));
> 
> Adding a local fwnode variable would make this fit in the 100 character
> limit again.

Ack

Best regards,
Krzysztof

Re: [PATCH v4 4/6] reset: Instantiate reset GPIO controller for shared reset-gpios

[Philipp Zabel]

On Di, 2024-01-23 at 15:13 +0100, Krzysztof Kozlowski wrote:
> Devices sharing a reset GPIO could use the reset framework for
> coordinated handling of that shared GPIO line.  We have several cases of
> such needs, at least for Devicetree-based platforms.
> 
> If Devicetree-based device requests a reset line, while "resets"
> Devicetree property is missing but there is a "reset-gpios" one,
> instantiate a new "reset-gpio" platform device which will handle such
> reset line.  This allows seamless handling of such shared reset-gpios
> without need of changing Devicetree binding [1].
> 
> To avoid creating multiple "reset-gpio" platform devices, store the
> Devicetree "reset-gpios" GPIO specifiers used for new devices on a
> linked list.  Later such Devicetree GPIO specifier (phandle to GPIO
> controller, GPIO number and GPIO flags) is used to check if reset
> controller for given GPIO was already registered.
> 
> If two devices have conflicting "reset-gpios" property, e.g. with
> different ACTIVE_xxx flags, this would allow to spawn two separate
> "reset-gpio" devices, where the second would fail probing on busy GPIO
> request.
> 
> Link: https://lore.kernel.org/all/YXi5CUCEi7YmNxXM@robh.at.kernel.org/ [1]
> Cc: Bartosz Golaszewski <brgl@bgdev.pl>
> Cc: Chris Packham <chris.packham@alliedtelesis.co.nz>
> Cc: Sean Anderson <sean.anderson@seco.com>
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> 
> ---
> 
> Depends on previous of change.
> ---
>  drivers/reset/core.c             | 213 +++++++++++++++++++++++++++++--
>  include/linux/reset-controller.h |   4 +
>  2 files changed, 204 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/reset/core.c b/drivers/reset/core.c
> index 4d5a78d3c085..6e81b8d35055 100644
> --- a/drivers/reset/core.c
> +++ b/drivers/reset/core.c
> @@ -10,9 +10,13 @@

Oh, and

#include <linux/cleanup.h>

>  #include <linux/export.h>
>  #include <linux/kernel.h>
>  #include <linux/kref.h>
> +#include <linux/gpio/driver.h>
> +#include <linux/gpio/machine.h>
> +#include <linux/idr.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/acpi.h>
> +#include <linux/platform_device.h>
>  #include <linux/reset.h>
>  #include <linux/reset-controller.h>
>  #include <linux/slab.h>

regards
Philipp

Re: [PATCH v4 4/6] reset: Instantiate reset GPIO controller for shared reset-gpios

[Krzysztof Kozlowski]

On 23/01/2024 16:58, Philipp Zabel wrote:
>>
>> Depends on previous of change.
>> ---
>>  drivers/reset/core.c             | 213 +++++++++++++++++++++++++++++--
>>  include/linux/reset-controller.h |   4 +
>>  2 files changed, 204 insertions(+), 13 deletions(-)
>>
>> diff --git a/drivers/reset/core.c b/drivers/reset/core.c
>> index 4d5a78d3c085..6e81b8d35055 100644
>> --- a/drivers/reset/core.c
>> +++ b/drivers/reset/core.c
>> @@ -10,9 +10,13 @@
> 
> Oh, and
> 
> #include <linux/cleanup.h>

Ack, I thought I did it, but that must have been a dream...

> 
Best regards,
Krzysztof

[PATCH v4 5/6] ASoC: dt-bindings: qcom,wsa8840: Add reset-gpios for shared line

[Krzysztof Kozlowski]

On newer Qualcomm platforms, like X1E80100-CRD, the WSA884x speakers
share SD_N GPIOs between two speakers, thus a coordinated assertion is
needed.  Linux supports handling shared GPIO lines through "reset-gpios"
property, thus allow specifying either powerdown or reset GPIOs (these
are the same).

Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Sean Anderson <sean.anderson@seco.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---

If previous patches are fine, then this commit is independent and could
be taken via ASoC.
---
 .../devicetree/bindings/sound/qcom,wsa8840.yaml       | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/sound/qcom,wsa8840.yaml b/Documentation/devicetree/bindings/sound/qcom,wsa8840.yaml
index d717017b0fdb..22798d22d981 100644
--- a/Documentation/devicetree/bindings/sound/qcom,wsa8840.yaml
+++ b/Documentation/devicetree/bindings/sound/qcom,wsa8840.yaml
@@ -28,6 +28,10 @@ properties:
     description: Powerdown/Shutdown line to use (pin SD_N)
     maxItems: 1
 
+  reset-gpios:
+    description: Powerdown/Shutdown line to use (pin SD_N)
+    maxItems: 1
+
   '#sound-dai-cells':
     const: 0
 
@@ -37,11 +41,16 @@ properties:
 required:
   - compatible
   - reg
-  - powerdown-gpios
   - '#sound-dai-cells'
   - vdd-1p8-supply
   - vdd-io-supply
 
+oneOf:
+  - required:
+      - powerdown-gpios
+  - required:
+      - reset-gpios
+
 unevaluatedProperties: false
 
 examples:
-- 
2.34.1

[PATCH v4 6/6] ASoC: codecs: wsa884x: Allow sharing reset GPIO

[Krzysztof Kozlowski]

On some boards with multiple WSA8840/WSA8845 speakers, the reset
(shutdown) GPIO is shared between two speakers.  Use the reset
controller framework and its "reset-gpio" driver to handle this case.
This allows bring-up and proper handling of all WSA884x speakers on
X1E80100-CRD board.

Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Sean Anderson <sean.anderson@seco.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

---

If previous patches are fine, then this commit is independent and could
be taken via ASoC.
---
 sound/soc/codecs/wsa884x.c | 53 +++++++++++++++++++++++++++++++-------
 1 file changed, 43 insertions(+), 10 deletions(-)

diff --git a/sound/soc/codecs/wsa884x.c b/sound/soc/codecs/wsa884x.c
index f2653df84e4a..a9767ef0e39d 100644
--- a/sound/soc/codecs/wsa884x.c
+++ b/sound/soc/codecs/wsa884x.c
@@ -13,6 +13,7 @@
 #include <linux/pm_runtime.h>
 #include <linux/regmap.h>
 #include <linux/regulator/consumer.h>
+#include <linux/reset.h>
 #include <linux/slab.h>
 #include <linux/soundwire/sdw.h>
 #include <linux/soundwire/sdw_registers.h>
@@ -699,6 +700,7 @@ struct wsa884x_priv {
 	struct sdw_stream_runtime *sruntime;
 	struct sdw_port_config port_config[WSA884X_MAX_SWR_PORTS];
 	struct gpio_desc *sd_n;
+	struct reset_control *sd_reset;
 	bool port_prepared[WSA884X_MAX_SWR_PORTS];
 	bool port_enable[WSA884X_MAX_SWR_PORTS];
 	unsigned int variant;
@@ -1799,9 +1801,22 @@ static struct snd_soc_dai_driver wsa884x_dais[] = {
 	},
 };
 
-static void wsa884x_gpio_powerdown(void *data)
+static void wsa884x_reset_powerdown(void *data)
 {
-	gpiod_direction_output(data, 1);
+	struct wsa884x_priv *wsa884x = data;
+
+	if (wsa884x->sd_reset)
+		reset_control_assert(wsa884x->sd_reset);
+	else
+		gpiod_direction_output(wsa884x->sd_n, 1);
+}
+
+static void wsa884x_reset_deassert(struct wsa884x_priv *wsa884x)
+{
+	if (wsa884x->sd_reset)
+		reset_control_deassert(wsa884x->sd_reset);
+	else
+		gpiod_direction_output(wsa884x->sd_n, 0);
 }
 
 static void wsa884x_regulator_disable(void *data)
@@ -1809,6 +1824,27 @@ static void wsa884x_regulator_disable(void *data)
 	regulator_bulk_disable(WSA884X_SUPPLIES_NUM, data);
 }
 
+static int wsa884x_get_reset(struct device *dev, struct wsa884x_priv *wsa884x)
+{
+	wsa884x->sd_reset = devm_reset_control_get_optional_shared(dev, NULL);
+	if (IS_ERR(wsa884x->sd_reset))
+		return dev_err_probe(dev, PTR_ERR(wsa884x->sd_reset),
+				     "Failed to get reset\n");
+	else if (wsa884x->sd_reset)
+		return 0;
+	/*
+	 * else: NULL, so use the backwards compatible way for powerdown-gpios,
+	 * which does not handle sharing GPIO properly.
+	 */
+	wsa884x->sd_n = devm_gpiod_get_optional(dev, "powerdown",
+						GPIOD_OUT_HIGH);
+	if (IS_ERR(wsa884x->sd_n))
+		return dev_err_probe(dev, PTR_ERR(wsa884x->sd_n),
+				     "Shutdown Control GPIO not found\n");
+
+	return 0;
+}
+
 static int wsa884x_probe(struct sdw_slave *pdev,
 			 const struct sdw_device_id *id)
 {
@@ -1838,11 +1874,9 @@ static int wsa884x_probe(struct sdw_slave *pdev,
 	if (ret)
 		return ret;
 
-	wsa884x->sd_n = devm_gpiod_get_optional(dev, "powerdown",
-						GPIOD_OUT_HIGH);
-	if (IS_ERR(wsa884x->sd_n))
-		return dev_err_probe(dev, PTR_ERR(wsa884x->sd_n),
-				     "Shutdown Control GPIO not found\n");
+	ret = wsa884x_get_reset(dev, wsa884x);
+	if (ret)
+		return ret;
 
 	dev_set_drvdata(dev, wsa884x);
 	wsa884x->slave = pdev;
@@ -1858,9 +1892,8 @@ static int wsa884x_probe(struct sdw_slave *pdev,
 	pdev->prop.sink_dpn_prop = wsa884x_sink_dpn_prop;
 	pdev->prop.scp_int1_mask = SDW_SCP_INT1_BUS_CLASH | SDW_SCP_INT1_PARITY;
 
-	/* Bring out of reset */
-	gpiod_direction_output(wsa884x->sd_n, 0);
-	ret = devm_add_action_or_reset(dev, wsa884x_gpio_powerdown, wsa884x->sd_n);
+	wsa884x_reset_deassert(wsa884x);
+	ret = devm_add_action_or_reset(dev, wsa884x_reset_powerdown, wsa884x);
 	if (ret)
 		return ret;
 
-- 
2.34.1

Re: [PATCH v4 6/6] ASoC: codecs: wsa884x: Allow sharing reset GPIO

[Philipp Zabel]

On Di, 2024-01-23 at 15:13 +0100, Krzysztof Kozlowski wrote:
> On some boards with multiple WSA8840/WSA8845 speakers, the reset
> (shutdown) GPIO is shared between two speakers.  Use the reset
> controller framework and its "reset-gpio" driver to handle this case.
> This allows bring-up and proper handling of all WSA884x speakers on
> X1E80100-CRD board.
> 
> Cc: Bartosz Golaszewski <brgl@bgdev.pl>
> Cc: Sean Anderson <sean.anderson@seco.com>
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>

regards
Philipp

Re: [PATCH v4 0/6] reset: gpio: ASoC: shared GPIO resets

[Chris Packham]

On 24/01/24 03:13, Krzysztof Kozlowski wrote:
> Hi,
>
> Patch #2 (cpufreq: do not open-code of_phandle_args_equal()) and patch #4
> (reset: Instantiate reset GPIO controller for shared reset-gpios) depend on OF
> change (patch #1).
>
> Changes in v4
> =============
> 1. New patches:
>     of: add of_phandle_args_equal() helper
>     cpufreq: do not open-code of_phandle_args_equal()
>
> 2. reset-gpio.c:
>     - Drop unneeded comment (Bartosz), add Rb tag.
>     - Do not assign of_node.
>
> 3. reset/core.c:
>     - Implement most of Bartosz feedback (I responded to one which I did not
>       implement) and comments from Philipp.
>     - Expect either rcdev->of_args or rcdev->of_node.
>     - Drop __reset_gpios_args_match() and use common helper (Philipp).
>     - Move declarations of automatic-cleanup variables in
>       __reset_add_reset_gpio_lookup() to place of use (Bartosz).
>     - Separate gpio_device_get_label() and kstrdup() (Philipp).
>     - Correct doc for __reset_add_reset_gpio_device(), rewrite few comments.
>     - Drop unneeded "r" variable in __reset_find_rcdev() (Philipp).
>     - Drop of_phandle_args initialization in __of_reset_control_get (Philipp).
>     - Check if CONFIG_RESET_GPIO is enabled before trying to look up reset-gpios.
>
> 4. Drop Chris' patch: "i2c: muxes: pca954x: Allow sharing reset GPIO", because
>     discussion is on going.

I actually think it would have been OK as-is with your latest change to 
return NULL when CONFIG_RESET_GPIO is not enabled. But I'm happy to 
submit it independently after this series lands. It'll give me a chance 
to do a bit more testing.

Re: [PATCH v4 0/6] reset: gpio: ASoC: shared GPIO resets

[Krzysztof Kozlowski]

On 23/01/2024 20:28, Chris Packham wrote:
> 
> On 24/01/24 03:13, Krzysztof Kozlowski wrote:
>> Hi,
>>
>> Patch #2 (cpufreq: do not open-code of_phandle_args_equal()) and patch #4
>> (reset: Instantiate reset GPIO controller for shared reset-gpios) depend on OF
>> change (patch #1).
>>
>> Changes in v4
>> =============
>> 1. New patches:
>>     of: add of_phandle_args_equal() helper
>>     cpufreq: do not open-code of_phandle_args_equal()
>>
>> 2. reset-gpio.c:
>>     - Drop unneeded comment (Bartosz), add Rb tag.
>>     - Do not assign of_node.
>>
>> 3. reset/core.c:
>>     - Implement most of Bartosz feedback (I responded to one which I did not
>>       implement) and comments from Philipp.
>>     - Expect either rcdev->of_args or rcdev->of_node.
>>     - Drop __reset_gpios_args_match() and use common helper (Philipp).
>>     - Move declarations of automatic-cleanup variables in
>>       __reset_add_reset_gpio_lookup() to place of use (Bartosz).
>>     - Separate gpio_device_get_label() and kstrdup() (Philipp).
>>     - Correct doc for __reset_add_reset_gpio_device(), rewrite few comments.
>>     - Drop unneeded "r" variable in __reset_find_rcdev() (Philipp).
>>     - Drop of_phandle_args initialization in __of_reset_control_get (Philipp).
>>     - Check if CONFIG_RESET_GPIO is enabled before trying to look up reset-gpios.
>>
>> 4. Drop Chris' patch: "i2c: muxes: pca954x: Allow sharing reset GPIO", because
>>     discussion is on going.
> 
> I actually think it would have been OK as-is with your latest change to 
> return NULL when CONFIG_RESET_GPIO is not enabled. But I'm happy to 
> submit it independently after this series lands. It'll give me a chance 
> to do a bit more testing.

Yeah, I wasn't sure if the concerns are really resolved. I think you can
send your patch separately because there is no clear dependency, so also
no clear benefits of me taking your patch into this patchset.

Best regards,
Krzysztof