[PATCH 0/3] Add bridged amplifiers to cs42l43

[PATCH 0/3] Add bridged amplifiers to cs42l43

[Charles Keepax]

On some cs42l43 systems a couple of cs35l56 amplifiers are attached
to the cs42l43's SPI and I2S. On Windows the cs42l43 is controlled
by a SDCA class driver and these two amplifiers are controlled by
firmware running on the cs42l43. However, under Linux the decision
was made to interact with the cs42l43 directly, affording the user
greater control over the audio system. However, this has resulted
in an issue where these two bridged cs35l56 amplifiers are not
populated in ACPI and must be added manually. There is at least an
SDCA extension unit DT entry we can key off.

The process of adding this is handled using a software node, firstly the
ability to add native chip selects to software nodes must be added.
Secondly, an additional flag for naming the SPI devices is added this
allows the machine driver to key to the correct amplifier. Then finally,
the cs42l43 SPI driver adds the two amplifiers directly onto its SPI
bus.

An additional series will follow soon to add the audio machine driver
parts (in the sof-sdw driver), however that is fairly orthogonal to
this part of the process, getting the actual amplifiers registered.

Thanks,
Charles

Series changes since v1:
 - Add missing statics in driver/spi/spi-cs42l43.c

Charles Keepax (2):
  gpio: swnode: Add ability to specify native chip selects for SPI
  spi: Add a mechanism to use the fwnode name for the SPI device

Maciej Strozek (1):
  spi: cs42l43: Add bridged cs35l56 amplifiers

 drivers/gpio/gpiolib-swnode.c |   8 ++
 drivers/gpio/gpiolib.c        |   9 ++
 drivers/spi/spi-cs42l43.c     | 152 +++++++++++++++++++++++++++++++++-
 drivers/spi/spi.c             |   7 ++
 include/linux/gpio/consumer.h |   4 +
 include/linux/spi/spi.h       |   2 +
 6 files changed, 181 insertions(+), 1 deletion(-)

-- 
2.39.2

[PATCH v2 1/3] gpio: swnode: Add ability to specify native chip selects for SPI

[Charles Keepax]

SPI devices can specify a cs-gpios property to enumerate their
chip selects. Under device tree, a zero entry in this property can
be used to specify that a particular chip select is using the SPI
controllers native chip select, for example:

        cs-gpios = <&gpio1 0 0>, <0>;

Here the second chip select is native. However, when using swnodes
there is currently no way to specify a native chip select. The
proposal here is to register a swnode_gpio_undefined software node,
that can be specified to allow the indication of a native chip
select. For example:

static const struct software_node_ref_args device_cs_refs[] = {
	{
		.node  = &device_gpiochip_swnode,
		.nargs = 2,
		.args  = { 0, GPIO_ACTIVE_LOW },
	},
	{
		.node  = &swnode_gpio_undefined,
		.nargs = 0,
	},
};

Register the swnode as the gpiolib is initialised and
check in swnode_get_gpio_device if the returned node matches
swnode_gpio_undefined and return -ENOENT, which matches the behaviour
of the device tree system when it encounters a 0 phandle.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
---

No changes since v1.

Thanks,
Charles

 drivers/gpio/gpiolib-swnode.c | 8 ++++++++
 drivers/gpio/gpiolib.c        | 9 +++++++++
 include/linux/gpio/consumer.h | 4 ++++
 3 files changed, 21 insertions(+)

diff --git a/drivers/gpio/gpiolib-swnode.c b/drivers/gpio/gpiolib-swnode.c
index fa52bdb1a29a3..801b5a660307f 100644
--- a/drivers/gpio/gpiolib-swnode.c
+++ b/drivers/gpio/gpiolib-swnode.c
@@ -17,6 +17,11 @@
 #include "gpiolib.h"
 #include "gpiolib-swnode.h"
 
+const struct software_node swnode_gpio_undefined = {
+	.name = "gpio-internal-undefined",
+};
+EXPORT_SYMBOL_GPL(swnode_gpio_undefined);
+
 static void swnode_format_propname(const char *con_id, char *propname,
 				   size_t max_size)
 {
@@ -40,6 +45,9 @@ static struct gpio_device *swnode_get_gpio_device(struct fwnode_handle *fwnode)
 	if (!gdev_node || !gdev_node->name)
 		return ERR_PTR(-EINVAL);
 
+	if (!strcmp(gdev_node->name, "gpio-internal-undefined"))
+		return ERR_PTR(-ENOENT);
+
 	gdev = gpio_device_find_by_label(gdev_node->name);
 	return gdev ?: ERR_PTR(-EPROBE_DEFER);
 }
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index ce94e37bcbee7..e3a7e2a3a323e 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -4892,8 +4892,17 @@ DEFINE_SEQ_ATTRIBUTE(gpiolib);
 
 static int __init gpiolib_debugfs_init(void)
 {
+	int ret;
+
+	ret = software_node_register(&swnode_gpio_undefined);
+	if (ret < 0) {
+		pr_err("gpiolib: failed to register swnode: %d\n", ret);
+		return ret;
+	}
+
 	/* /sys/kernel/debug/gpio */
 	debugfs_create_file("gpio", 0444, NULL, NULL, &gpiolib_fops);
+
 	return 0;
 }
 subsys_initcall(gpiolib_debugfs_init);
diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
index db2dfbae8edbd..e685fac43398d 100644
--- a/include/linux/gpio/consumer.h
+++ b/include/linux/gpio/consumer.h
@@ -12,6 +12,8 @@ struct fwnode_handle;
 struct gpio_array;
 struct gpio_desc;
 
+struct software_node;
+
 /**
  * struct gpio_descs - Struct containing an array of descriptors that can be
  *                     obtained using gpiod_get_array()
@@ -54,6 +56,8 @@ enum gpiod_flags {
 	GPIOD_OUT_HIGH_OPEN_DRAIN = GPIOD_OUT_HIGH | GPIOD_FLAGS_BIT_OPEN_DRAIN,
 };
 
+extern const struct software_node swnode_gpio_undefined;
+
 #ifdef CONFIG_GPIOLIB
 
 /* Return the number of GPIOs associated with a device / function */
-- 
2.39.2

[PATCH v2 2/3] spi: Add a mechanism to use the fwnode name for the SPI device

[Charles Keepax]

Add a mechanism to force the use of the fwnode name for the name of the
SPI device itself. This is useful when devices need to be manually added
within the kernel.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
---

No changes since v1.

Thanks,
Charles

 drivers/spi/spi.c       | 7 +++++++
 include/linux/spi/spi.h | 2 ++
 2 files changed, 9 insertions(+)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index a2f01116ba092..a38a4960032b8 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -598,6 +598,12 @@ EXPORT_SYMBOL_GPL(spi_alloc_device);
 static void spi_dev_set_name(struct spi_device *spi)
 {
 	struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
+	struct fwnode_handle *fwnode = dev_fwnode(&spi->dev);
+
+	if (spi->use_fwnode_name && fwnode) {
+		dev_set_name(&spi->dev, "spi-%s", fwnode_get_name(fwnode));
+		return;
+	}
 
 	if (adev) {
 		dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
@@ -830,6 +836,7 @@ struct spi_device *spi_new_device(struct spi_controller *ctlr,
 	 * spi->cs_index_mask as 0x01.
 	 */
 	proxy->cs_index_mask = 0x01;
+	proxy->use_fwnode_name = chip->use_fwnode_name;
 
 	if (chip->swnode) {
 		status = device_add_software_node(&proxy->dev, chip->swnode);
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index b589e25474393..265f5d0c15304 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -222,6 +222,7 @@ struct spi_device {
 	struct spi_delay	cs_setup;
 	struct spi_delay	cs_hold;
 	struct spi_delay	cs_inactive;
+	bool			use_fwnode_name;
 
 	/* The statistics */
 	struct spi_statistics __percpu	*pcpu_statistics;
@@ -1603,6 +1604,7 @@ struct spi_board_info {
 	char		modalias[SPI_NAME_SIZE];
 	const void	*platform_data;
 	const struct software_node *swnode;
+	bool		use_fwnode_name;
 	void		*controller_data;
 	int		irq;
 
-- 
2.39.2

[PATCH v2 3/3] spi: cs42l43: Add bridged cs35l56 amplifiers

[Charles Keepax]

From: Maciej Strozek <mstrozek@opensource.cirrus.com>

On some cs42l43 systems a couple of cs35l56 amplifiers are attached
to the cs42l43's SPI and I2S. On Windows the cs42l43 is controlled
by a SDCA class driver and these two amplifiers are controlled by
firmware running on the cs42l43. However, under Linux the decision
was made to interact with the cs42l43 directly, affording the user
greater control over the audio system. However, this has resulted
in an issue where these two bridged cs35l56 amplifiers are not
populated in ACPI and must be added manually.

Check for the presence of the "01fa-cirrus-sidecar-instances" property
in the SDCA extension unit's ACPI properties to confirm the presence
of these two amplifiers and if they exist add them manually onto the
SPI bus.

Signed-off-by: Maciej Strozek <mstrozek@opensource.cirrus.com>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
---

Changes since v1:
 - Add some missing statics

Thanks,
Charles

 drivers/spi/spi-cs42l43.c | 152 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 151 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-cs42l43.c b/drivers/spi/spi-cs42l43.c
index aabef9fc84bdf..c7ee9d49d9ef4 100644
--- a/drivers/spi/spi-cs42l43.c
+++ b/drivers/spi/spi-cs42l43.c
@@ -5,6 +5,8 @@
 // Copyright (C) 2022-2023 Cirrus Logic, Inc. and
 //                         Cirrus Logic International Semiconductor Ltd.
 
+#include <dt-bindings/gpio/gpio.h>
+#include <linux/acpi.h>
 #include <linux/bits.h>
 #include <linux/bitfield.h>
 #include <linux/device.h>
@@ -39,6 +41,59 @@ static const unsigned int cs42l43_clock_divs[] = {
 	2, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30
 };
 
+static const struct software_node ampl = {
+	.name			= "cs35l56-left",
+};
+
+static const struct software_node ampr = {
+	.name			= "cs35l56-right",
+};
+
+static struct spi_board_info ampl_info = {
+	.modalias		= "cs35l56",
+	.max_speed_hz		= 2000000,
+	.chip_select		= 0,
+	.mode			= SPI_MODE_0,
+	.swnode			= &ampl,
+	.use_fwnode_name	= true,
+};
+
+static struct spi_board_info ampr_info = {
+	.modalias		= "cs35l56",
+	.max_speed_hz		= 2000000,
+	.chip_select		= 1,
+	.mode			= SPI_MODE_0,
+	.swnode			= &ampr,
+	.use_fwnode_name	= true,
+};
+
+static const struct software_node cs42l43_gpiochip_swnode = {
+	.name			= "cs42l43-pinctrl",
+};
+
+static const struct software_node_ref_args cs42l43_cs_refs[] = {
+	{
+		.node		= &cs42l43_gpiochip_swnode,
+		.nargs		= 2,
+		.args		= { 0, GPIO_ACTIVE_LOW },
+	},
+	{
+		.node		= &swnode_gpio_undefined,
+		.nargs		= 0,
+	},
+};
+
+static const struct property_entry cs42l43_cs_props[] = {
+	{
+		.name		= "cs-gpios",
+		.length		= ARRAY_SIZE(cs42l43_cs_refs) *
+				  sizeof(struct software_node_ref_args),
+		.type		= DEV_PROP_REF,
+		.pointer	= cs42l43_cs_refs,
+	},
+	{}
+};
+
 static int cs42l43_spi_tx(struct regmap *regmap, const u8 *buf, unsigned int len)
 {
 	const u8 *end = buf + len;
@@ -203,6 +258,51 @@ static size_t cs42l43_spi_max_length(struct spi_device *spi)
 	return CS42L43_SPI_MAX_LENGTH;
 }
 
+#if IS_ENABLED(CONFIG_ACPI)
+static bool cs42l43_has_sidecar(struct fwnode_handle *fwnode)
+{
+	static const int func_smart_amp = 0x1;
+	struct fwnode_handle *child_fwnode, *ext_fwnode;
+	unsigned long long function;
+	unsigned int val;
+	int ret;
+
+	if (!is_acpi_node(fwnode))
+		return false;
+
+	fwnode_for_each_child_node(fwnode, child_fwnode) {
+		struct acpi_device *adev = to_acpi_device_node(child_fwnode);
+
+		ret = acpi_evaluate_integer(adev->handle, "_ADR", NULL, &function);
+		if (ACPI_FAILURE(ret))
+			continue;
+
+		if (function != func_smart_amp)
+			continue;
+
+		ext_fwnode = fwnode_get_named_child_node(child_fwnode,
+				"mipi-sdca-function-expansion-subproperties");
+		if (!ext_fwnode)
+			continue;
+
+		ret = fwnode_property_read_u32(ext_fwnode,
+					       "01fa-cirrus-sidecar-instances",
+					       &val);
+		if (ret)
+			continue;
+
+		return !!val;
+	}
+
+	return false;
+}
+#else
+static bool cs42l43_has_sidecar(struct fwnode_handle *fwnode)
+{
+	return false;
+}
+#endif
+
 static void cs42l43_release_of_node(void *data)
 {
 	fwnode_handle_put(data);
@@ -213,6 +313,7 @@ static int cs42l43_spi_probe(struct platform_device *pdev)
 	struct cs42l43 *cs42l43 = dev_get_drvdata(pdev->dev.parent);
 	struct cs42l43_spi *priv;
 	struct fwnode_handle *fwnode = dev_fwnode(cs42l43->dev);
+	bool has_sidecar = cs42l43_has_sidecar(fwnode);
 	int ret;
 
 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
@@ -266,16 +367,64 @@ static int cs42l43_spi_probe(struct platform_device *pdev)
 		}
 	}
 
-	device_set_node(&priv->ctlr->dev, fwnode);
+	if (has_sidecar) {
+		ret = software_node_register(&cs42l43_gpiochip_swnode);
+		if (ret) {
+			dev_err(priv->dev, "Failed to register gpio swnode: %d\n", ret);
+			return ret;
+		}
+
+		ret = device_create_managed_software_node(&priv->ctlr->dev, cs42l43_cs_props, NULL);
+		if (ret) {
+			dev_err(priv->dev, "Failed to add swnode: %d\n", ret);
+			goto err;
+		}
+
+	} else {
+		device_set_node(&priv->ctlr->dev, fwnode);
+	}
 
 	ret = devm_spi_register_controller(priv->dev, priv->ctlr);
 	if (ret) {
 		dev_err(priv->dev, "Failed to register SPI controller: %d\n", ret);
+		goto err;
 	}
 
+	if (has_sidecar) {
+		if (!spi_new_device(priv->ctlr, &ampl_info)) {
+			ret = -ENODEV;
+			dev_err(priv->dev, "Failed to create left amp slave\n");
+			goto err;
+		}
+
+		if (!spi_new_device(priv->ctlr, &ampr_info)) {
+			ret = -ENODEV;
+			dev_err(priv->dev, "Failed to create right amp slave\n");
+			goto err;
+		}
+	}
+
+	return 0;
+
+err:
+	if (has_sidecar)
+		software_node_unregister(&cs42l43_gpiochip_swnode);
+
 	return ret;
 }
 
+static int cs42l43_spi_remove(struct platform_device *pdev)
+{
+	struct cs42l43 *cs42l43 = dev_get_drvdata(pdev->dev.parent);
+	struct fwnode_handle *fwnode = dev_fwnode(cs42l43->dev);
+	bool has_sidecar = cs42l43_has_sidecar(fwnode);
+
+	if (has_sidecar)
+		software_node_unregister(&cs42l43_gpiochip_swnode);
+
+	return 0;
+};
+
 static const struct platform_device_id cs42l43_spi_id_table[] = {
 	{ "cs42l43-spi", },
 	{}
@@ -288,6 +437,7 @@ static struct platform_driver cs42l43_spi_driver = {
 	},
 	.probe		= cs42l43_spi_probe,
 	.id_table	= cs42l43_spi_id_table,
+	.remove		= cs42l43_spi_remove,
 };
 module_platform_driver(cs42l43_spi_driver);
 
-- 
2.39.2

Re: [PATCH v2 3/3] spi: cs42l43: Add bridged cs35l56 amplifiers

[Dan Carpenter]

On Thu, Mar 28, 2024 at 02:01:19PM +0000, Charles Keepax wrote:
> +static bool cs42l43_has_sidecar(struct fwnode_handle *fwnode)
> +{
> +	static const int func_smart_amp = 0x1;
> +	struct fwnode_handle *child_fwnode, *ext_fwnode;
> +	unsigned long long function;
> +	unsigned int val;
> +	int ret;
> +
> +	if (!is_acpi_node(fwnode))
> +		return false;
> +
> +	fwnode_for_each_child_node(fwnode, child_fwnode) {
> +		struct acpi_device *adev = to_acpi_device_node(child_fwnode);
> +
> +		ret = acpi_evaluate_integer(adev->handle, "_ADR", NULL, &function);
> +		if (ACPI_FAILURE(ret))
> +			continue;
> +
> +		if (function != func_smart_amp)
> +			continue;
> +
> +		ext_fwnode = fwnode_get_named_child_node(child_fwnode,
> +				"mipi-sdca-function-expansion-subproperties");
> +		if (!ext_fwnode)
> +			continue;
> +
> +		ret = fwnode_property_read_u32(ext_fwnode,
> +					       "01fa-cirrus-sidecar-instances",
> +					       &val);
> +		if (ret)
> +			continue;
> +
> +		return !!val;

This should call fwnode_handle_put(child_fwnode) before returning.  An
alternative fix would be to use the new device_for_each_child_node_scoped()
macro.

regards,
dan carpenter

> +	}
> +
> +	return false;
> +}