Re: [PATCH v2 6/6] ACPI: bus-multi-instantiate: Add SPI support

[Hans de Goede <hdegoede@xxxxxxxxxx>]

Hi,

On 12/21/21 19:32, Hans de Goede wrote:
> Hi,
> 
> On 12/10/21 16:40, Stefan Binding wrote:
>> Add support for spi bus in bus-multi-instantiate driver
>>
>> Some peripherals can have either a I2C or a SPI connection
>> to the host (but not both) but use the same HID for both
>> types. So it is not possible to use the HID to determine
>> whether it is I2C or SPI. The driver must check the node
>> to see if it contains I2cSerialBus or SpiSerialBus entries.
>>
>> For backwards-compatibility with the existing nodes I2C is
>> checked first and if such entries are found ONLY I2C devices
>> are created. Since some existing nodes that were already
>> handled by this driver could also contain unrelated
>> SpiSerialBus nodes that were previously ignored, and this
>> preserves that behavior. If there is ever a need to handle
>> a node where both I2C and SPI devices must be instantiated
>> this can be added in future.
>>
>> Signed-off-by: Stefan Binding <sbinding@xxxxxxxxxxxxxxxxxxxxx>
>> ---
>>  drivers/acpi/Kconfig                 |  10 +-
>>  drivers/acpi/bus-multi-instantiate.c | 345 ++++++++++++++++++++++++---
>>  drivers/acpi/scan.c                  |  13 +-
>>  3 files changed, 327 insertions(+), 41 deletions(-)
>>
>> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
>> index 6ba47dd39eb4..948f39d55595 100644
>> --- a/drivers/acpi/Kconfig
>> +++ b/drivers/acpi/Kconfig
>> @@ -296,12 +296,12 @@ config ACPI_PROCESSOR
>>  	  the module will be called processor.
>>  
>>  config ACPI_BUS_MULTI_INST
>> -	tristate "I2C multi instantiate pseudo device driver"
>> -	depends on I2C
>> +	tristate "I2C and SPI multi instantiate pseudo device driver"
>> +	depends on I2C && SPI
>>  	help
>> -	  Some ACPI-based systems list multiple i2c-devices in a single ACPI
>> -	  firmware-node. This driver will instantiate separate i2c-clients
>> -	  for each device in the firmware-node.
>> +	  Some ACPI-based systems list multiple i2c/spi devices in a
>> +	  single ACPI firmware-node. This driver will instantiate separate
>> +	  i2c-clients or spi-devices for each device in the firmware-node.
>>  
>>  	  To compile this driver as a module, choose M here: the module
>>  	  will be called bus-multi-instantiate.
>> diff --git a/drivers/acpi/bus-multi-instantiate.c b/drivers/acpi/bus-multi-instantiate.c
>> index 50f1540762e9..c1306a0ee13c 100644
>> --- a/drivers/acpi/bus-multi-instantiate.c
>> +++ b/drivers/acpi/bus-multi-instantiate.c
>> @@ -1,7 +1,7 @@
>>  // SPDX-License-Identifier: GPL-2.0+
>>  /*
>>   * Bus multi-instantiate driver, pseudo driver to instantiate multiple
>> - * i2c-clients from a single fwnode.
>> + * i2c-clients or spi-devices from a single fwnode.
>>   *
>>   * Copyright 2018 Hans de Goede <hdegoede@xxxxxxxxxx>
>>   */
>> @@ -14,6 +14,7 @@
>>  #include <linux/module.h>
>>  #include <linux/platform_device.h>
>>  #include <linux/property.h>
>> +#include <linux/spi/spi.h>
>>  #include <linux/types.h>
>>  
>>  #define IRQ_RESOURCE_TYPE	GENMASK(1, 0)
>> @@ -21,15 +22,38 @@
>>  #define IRQ_RESOURCE_GPIO	1
>>  #define IRQ_RESOURCE_APIC	2
>>  
>> +enum bmi_bus_type {
>> +	BMI_I2C,
>> +	BMI_SPI,
>> +	BMI_AUTO_DETEC,
> 
> you are missing the T of detec_t_ here.
> 
>> +};
>> +
>> +struct bmi_spi_acpi {
>> +	char *resource_source;
>> +	struct acpi_resource_spi_serialbus sb;
>> +};
>> +
>> +struct bmi_spi_sb_acpi {
>> +	int count;
>> +	struct bmi_spi_acpi acpi_data[];
>> +};
>> +
>>  struct bmi_instance {
>>  	const char *type;
>>  	unsigned int flags;
>>  	int irq_idx;
>>  };
>>  
>> +struct bmi_node {
>> +	enum bmi_bus_type bus_type;
>> +	struct bmi_instance instances[];
>> +};
>> +
>>  struct bmi {
>>  	int i2c_num;
>> +	int spi_num;
>>  	struct i2c_client **i2c_devs;
>> +	struct spi_device **spi_devs;
>>  };
>>  
>>  static int bmi_get_irq(struct platform_device *pdev, struct acpi_device *adev,
>> @@ -60,6 +84,230 @@ static void bmi_devs_unregister(struct bmi *bmi)
>>  {
>>  	while (bmi->i2c_num > 0)
>>  		i2c_unregister_device(bmi->i2c_devs[--bmi->i2c_num]);
>> +
>> +	while (bmi->spi_num > 0)
>> +		spi_unregister_device(bmi->spi_devs[--bmi->spi_num]);
>> +}
>> +
>> +static int bmi_spi_count(struct acpi_resource *ares, void *data)
>> +{
>> +	struct acpi_resource_spi_serialbus *sb;
>> +	int *count = data;
>> +
>> +	if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
>> +		return 1;
>> +
>> +	sb = &ares->data.spi_serial_bus;
>> +	if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_SPI)
>> +		return 1;
>> +
>> +	*count = *count + 1;
>> +
>> +	return 1;
>> +}
>> +
>> +static int bmi_spi_count_resources(struct acpi_device *adev)
>> +{
>> +	LIST_HEAD(r);
>> +	int count = 0;
>> +	int ret;
>> +
>> +	ret = acpi_dev_get_resources(adev, &r, bmi_spi_count, &count);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	acpi_dev_free_resource_list(&r);
>> +
>> +	return count;
>> +}
>> +
>> +static int bmi_spi_save_res(struct acpi_resource *ares, void *data)
>> +{
>> +	struct acpi_resource_spi_serialbus *sb;
>> +	struct bmi_spi_sb_acpi *resources = data;
>> +	struct bmi_spi_acpi *acpi_data;
>> +
>> +	if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
>> +		return 1;
>> +
>> +	sb = &ares->data.spi_serial_bus;
>> +	if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_SPI)
>> +		return 1;
>> +
>> +	acpi_data = &resources->acpi_data[resources->count];
>> +	memcpy(&acpi_data->sb, sb, sizeof(*sb));
>> +	acpi_data->resource_source = kstrndup(sb->resource_source.string_ptr,
>> +					      sb->resource_source.string_length, GFP_KERNEL);
>> +	if (!acpi_data->resource_source)
>> +		return 1;
>> +	resources->count++;
>> +
>> +	return 1;
>> +}
>> +
>> +static void bmi_spi_res_free(struct bmi_spi_sb_acpi *resources)
>> +{
>> +	if (!resources)
>> +		return;
>> +
>> +	while (resources->count)
>> +		kfree(resources->acpi_data[--resources->count].resource_source);
>> +	kfree(resources);
>> +}
> 
> This save + free dance here seems over complicated, see below for more on this ...
> 
>> +
>> +static struct bmi_spi_sb_acpi *bmi_spi_get_resources(struct device *dev,
>> +						     struct acpi_device *adev, int count)
>> +{
>> +	struct bmi_spi_sb_acpi *resources;
>> +	LIST_HEAD(r);
>> +	int ret;
>> +
>> +	resources = kmalloc(struct_size(resources, acpi_data, count), GFP_KERNEL);
>> +	if (!resources)
>> +		return NULL;
>> +
>> +	ret = acpi_dev_get_resources(adev, &r, bmi_spi_save_res, resources);
>> +	if (ret < 0)
>> +		goto error;
>> +
>> +	acpi_dev_free_resource_list(&r);
>> +
>> +	return resources;
>> +
>> +error:
>> +	bmi_spi_res_free(resources);
>> +	return NULL;
>> +}
>> +
>> +static struct spi_controller *bmi_find_spi_controller(char *path)
>> +{
>> +	acpi_handle parent_handle;
>> +	struct acpi_device *adev;
>> +	acpi_status status;
>> +
>> +	status = acpi_get_handle(NULL, path, &parent_handle);
>> +	if (ACPI_FAILURE(status))
>> +		return NULL;
>> +
>> +	if (acpi_bus_get_device(parent_handle, &adev))
>> +		return NULL;
>> +
>> +	return acpi_spi_find_controller_by_adev(adev);
>> +}
>> +
>> +/**
>> + * bmi_spi_probe - Instantiate multiple SPI devices from inst array
>> + * @pdev:	Platform device
>> + * @adev:	ACPI device
>> + * @bmi:	Internal struct for Bus multi instantiate driver
>> + * @inst:	Array of instances to probe
>> + *
>> + * Returns the number of SPI devices instantiate, Zero if none is found or a negative error code.
>> + */
>> +static int bmi_spi_probe(struct platform_device *pdev, struct acpi_device *adev, struct bmi *bmi,
>> +			 const struct bmi_instance *inst_array)
>> +{
>> +	struct bmi_spi_sb_acpi *acpi_data;
>> +	struct device *dev = &pdev->dev;
>> +	struct spi_controller *ctlr;
>> +	struct spi_device *spi_dev;
>> +	char name[50];
>> +	int i, ret, count;
>> +
> 
> 
> 
>> +	ret = bmi_spi_count_resources(adev);
>> +	if (ret <= 0)
>> +		return ret;
>> +	count = ret;
> 
> Ok, so why not do the following here instead (and drop a whole bunch of
> functions above):
> 
> 	ret = acpi_dev_get_resources(adev, &r, bmi_spi_count, &count);
> 	if (ret < 0)
> 		return ret;
> 
> 	if (count <= 0) {
> 		acpi_dev_free_resource_list(&r);
> 		return count;
> 	}
> 
> 	/* Note we are not freeing the resource list yet here !!! */
> 	
>> +
>> +	bmi->spi_devs = devm_kcalloc(dev, count, sizeof(*bmi->spi_devs), GFP_KERNEL);
>> +	if (!bmi->spi_devs)
>> +		return -ENOMEM;
>> +
>> +	acpi_data = bmi_spi_get_resources(dev, adev, count);
>> +	if (!acpi_data)
>> +		return -ENOMEM;
> 
> Remove the bmi_spi_get_resources() call here.
> 
>> +
>> +	for (i = 0; i < count && inst_array[i].type; i++) {
> 
> Write a new:
> 
> int bmi_get_spi_resource_by_index(list_head *resource_list, struct acpi_resource_spi_serialbus *sb_ret, int index)
> {}
> 
> Helper which walks the list and fills in *sb_ret with the Nth (matching index) SpiSerialBus resource found in the
> list.
> 
> And then do:
> 
> 		ret = bmi_get_spi_resource_by_index(&r, &sb, i);
> 		if (ret)
> 			return ret;
> 
> 		ctrl = bmi_find_spi_controller(sb.resource_source.string_ptr);
> 
> 
>> +		ctlr = bmi_find_spi_controller(acpi_data->acpi_data[i].resource_source);
>> +		if (!ctlr) {
>> +			ret = -EPROBE_DEFER;
>> +			goto error;
>> +		}
>> +
>> +		spi_dev = spi_alloc_device(ctlr);
>> +		if (!spi_dev) {
>> +			dev_err(&ctlr->dev, "failed to allocate SPI device for %s\n",
>> +				dev_name(&adev->dev));
>> +			ret = -ENOMEM;
>> +			goto error;
>> +		}
>> +
>> +		strscpy(spi_dev->modalias, inst_array[i].type, sizeof(spi_dev->modalias));
>> +
> 
> And replace all the "acpi_data->acpi_data[i].sb." reference below with simple "sb.".
> 
> 
>> +		if (ctlr->fw_translate_cs) {
>> +			ret = ctlr->fw_translate_cs(ctlr,
>> +						    acpi_data->acpi_data[i].sb.device_selection);
>> +			if (ret < 0) {
>> +				spi_dev_put(spi_dev);
>> +				goto error;
>> +			}
>> +			spi_dev->chip_select = ret;
>> +		} else {
>> +			spi_dev->chip_select = acpi_data->acpi_data[i].sb.device_selection;
>> +		}
>> +
>> +		spi_dev->max_speed_hz = acpi_data->acpi_data[i].sb.connection_speed;
>> +		spi_dev->bits_per_word = acpi_data->acpi_data[i].sb.data_bit_length;
>> +
>> +		if (acpi_data->acpi_data[i].sb.clock_phase == ACPI_SPI_SECOND_PHASE)
>> +			spi_dev->mode |= SPI_CPHA;
>> +		if (acpi_data->acpi_data[i].sb.clock_polarity == ACPI_SPI_START_HIGH)
>> +			spi_dev->mode |= SPI_CPOL;
>> +		if (acpi_data->acpi_data[i].sb.device_polarity == ACPI_SPI_ACTIVE_HIGH)
>> +			spi_dev->mode |= SPI_CS_HIGH;
>> +
>> +		ret = bmi_get_irq(pdev, adev, &inst_array[i]);
>> +		if (ret < 0) {
>> +			spi_dev_put(spi_dev);
>> +			goto error;
>> +		}
>> +		spi_dev->irq = ret;
>> +
>> +		snprintf(name, sizeof(name), "%s-%s-%s.%d", dev_name(&ctlr->dev), dev_name(dev),
>> +			 inst_array[i].type, i);
>> +		spi_dev->dev.init_name = name;
>> +
>> +		ret = spi_add_device(spi_dev);
>> +		if (ret) {
>> +			dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI: %d\n",
>> +				dev_name(&adev->dev), ret);
>> +			spi_dev_put(spi_dev);
>> +			goto error;
>> +		}
>> +
>> +		dev_dbg(dev, "SPI device %s using chip select %u", name, spi_dev->chip_select);
>> +
>> +		bmi->spi_devs[i] = spi_dev;
>> +		bmi->spi_num++;
>> +	}
>> +
>> +	if (bmi->spi_num < count) {
>> +		dev_err(dev, "Error finding driver, idx %d\n", i);
>> +		ret = -ENODEV;
>> +		goto error;
>> +	}
>> +
>> +	dev_info(dev, "Instantiate %d SPI devices.\n", bmi->spi_num);
> 
> And here replace the bmi_spi_res_free(acpi_data); call in both exit paths with:
> acpi_dev_free_resource_list(&r); .
> 
> To me this way, simply using the already allocated resources from the list,
> rather then making a temp copy of them and throwing that away seems like
> a simpler solution ?
> 
> If you go this route, please also remove the struct bmi_spi_acpi and
> struct bmi_spi_sb_acpi data types which you now no longer need.

So thinking a bit more about this, then looking up the nth SpiSerialBus
resource, and then turning that into a spi_client is something which
the SPI core ACPI code should already be doing for index==0. So I think
that you should be able to modify the SPI core ACPI code to take index
as a parameter and then have it export a helper for this which you
can use rather then duplicate the SPI core ACPI code  ? Note this is
also what the I2C code is already doing.

And if you go that route you may also want to consider to add the SPI
equivalent of the i2c_acpi_client_count() helper.

Regards,

hans



> 
>> +	bmi_spi_res_free(acpi_data);
>> +
>> +	return bmi->spi_num;
>> +error:
>> +	bmi_spi_res_free(acpi_data);
>> +	bmi_devs_unregister(bmi);
>> +	dev_err_probe(dev, ret, "SPI error %d\n", ret);
>> +
>> +	return ret;
>> +
>>  }
>>  
>>  /**
>> @@ -125,14 +373,14 @@ static int bmi_i2c_probe(struct platform_device *pdev, struct acpi_device *adev,
>>  
>>  static int bmi_probe(struct platform_device *pdev)
>>  {
>> -	const struct bmi_instance *inst_array;
>>  	struct device *dev = &pdev->dev;
>> +	const struct bmi_node *node;
>>  	struct acpi_device *adev;
>>  	struct bmi *bmi;
>> -	int ret;
>> +	int i2c_ret = 0, spi_ret = 0;
>>  
>> -	inst_array = device_get_match_data(dev);
>> -	if (!inst_array) {
>> +	node = device_get_match_data(dev);
>> +	if (!node) {
>>  		dev_err(dev, "Error ACPI match data is missing\n");
>>  		return -ENODEV;
>>  	}
>> @@ -147,13 +395,44 @@ static int bmi_probe(struct platform_device *pdev)
>>  
>>  	platform_set_drvdata(pdev, bmi);
>>  
>> -	ret = bmi_i2c_probe(pdev, adev, bmi, inst_array);
>> -	if (ret > 0)
>> +	/* Each time this driver probes only one type of bus will be chosen.
>> +	 * And I2C has preference, which means that if find a I2cSerialBus it assumes
>> +	 * that all following devices will also be I2C.
>> +	 * In case there are zero I2C devices, it assumes that all following devices are SPI.
>> +	 */
>> +	if (node->bus_type != BMI_SPI) {
>> +		i2c_ret = bmi_i2c_probe(pdev, adev, bmi, node->instances);
>> +		if (i2c_ret > 0)
>> +			return 0;
>> +		else if (i2c_ret == -EPROBE_DEFER)
>> +			return i2c_ret;
>> +		if (node->bus_type == BMI_I2C) {
>> +			if (i2c_ret == 0)
>> +				return -ENODEV;
>> +			else
>> +				return i2c_ret;
>> +		}
>> +	}
>> +	/* BMI_SPI or BMI_AUTO_DETEC */
> 
> auto-detec_t_
> 
>> +	spi_ret = bmi_spi_probe(pdev, adev, bmi, node->instances);
>> +	if (spi_ret > 0)
>>  		return 0;
>> -	if (ret == 0)
>> -		ret = -ENODEV;
>> +	else if (spi_ret == -EPROBE_DEFER)
>> +		return -EPROBE_DEFER;
>> +	if (node->bus_type == BMI_SPI) {
>> +		if (spi_ret == 0)
>> +			return -ENODEV;
>> +		else
>> +			return spi_ret;
>> +	}
>>  
>> -	return ret;
>> +	/* The only way to get here is BMI_AUTO_DETEC and i2c_ret <= 0 and spi_ret <= 0 */
>> +	if (i2c_ret == 0 && spi_ret == 0)
>> +		return -ENODEV;
>> +	else if (i2c_ret == 0 && spi_ret)
>> +		return spi_ret;
>> +
>> +	return i2c_ret;
>>  }
>>  
>>  static int bmi_remove(struct platform_device *pdev)
>> @@ -165,27 +444,33 @@ static int bmi_remove(struct platform_device *pdev)
>>  	return 0;
>>  }
>>  
>> -static const struct bmi_instance bsg1160_data[]  = {
>> -	{ "bmc150_accel", IRQ_RESOURCE_GPIO, 0 },
>> -	{ "bmc150_magn" },
>> -	{ "bmg160" },
>> -	{}
>> +static const struct bmi_node bsg1160_data = {
> 
> Please explicitly set ".type = BMI_I2C" here and for all the
> other already existing  bmi_node structs.
> 
>> +	.instances = {
>> +		{ "bmc150_accel", IRQ_RESOURCE_GPIO, 0 },
>> +		{ "bmc150_magn" },
>> +		{ "bmg160" },
>> +		{}
>> +	},
>>  };
>>  
>> -static const struct bmi_instance bsg2150_data[]  = {
>> -	{ "bmc150_accel", IRQ_RESOURCE_GPIO, 0 },
>> -	{ "bmc150_magn" },
>> -	/* The resources describe a 3th client, but it is not really there. */
>> -	{ "bsg2150_dummy_dev" },
>> -	{}
>> +static const struct bmi_node bsg2150_data = {
>> +	.instances = {
>> +		{ "bmc150_accel", IRQ_RESOURCE_GPIO, 0 },
>> +		{ "bmc150_magn" },
>> +		/* The resources describe a 3th client, but it is not really there. */
>> +		{ "bsg2150_dummy_dev" },
>> +		{}
>> +	},
>>  };
>>  
>> -static const struct bmi_instance int3515_data[]  = {
>> -	{ "tps6598x", IRQ_RESOURCE_APIC, 0 },
>> -	{ "tps6598x", IRQ_RESOURCE_APIC, 1 },
>> -	{ "tps6598x", IRQ_RESOURCE_APIC, 2 },
>> -	{ "tps6598x", IRQ_RESOURCE_APIC, 3 },
>> -	{}
>> +static const struct bmi_node int3515_data = {
>> +	.instances = {
>> +		{ "tps6598x", IRQ_RESOURCE_APIC, 0 },
>> +		{ "tps6598x", IRQ_RESOURCE_APIC, 1 },
>> +		{ "tps6598x", IRQ_RESOURCE_APIC, 2 },
>> +		{ "tps6598x", IRQ_RESOURCE_APIC, 3 },
>> +		{}
>> +	},
>>  };
>>  
>>  /*
>> @@ -193,9 +478,9 @@ static const struct bmi_instance int3515_data[]  = {
>>   * drivers/acpi/scan.c: acpi_device_enumeration_by_parent().
>>   */
>>  static const struct acpi_device_id bmi_acpi_ids[] = {
>> -	{ "BSG1160", (unsigned long)bsg1160_data },
>> -	{ "BSG2150", (unsigned long)bsg2150_data },
>> -	{ "INT3515", (unsigned long)int3515_data },
>> +	{ "BSG1160", (unsigned long)&bsg1160_data },
>> +	{ "BSG2150", (unsigned long)&bsg2150_data },
>> +	{ "INT3515", (unsigned long)&int3515_data },
>>  	{ }
>>  };
>>  MODULE_DEVICE_TABLE(acpi, bmi_acpi_ids);
>> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
>> index 969d8138d019..8b937fc20d23 100644
>> --- a/drivers/acpi/scan.c
>> +++ b/drivers/acpi/scan.c
>> @@ -1696,12 +1696,13 @@ static bool acpi_device_enumeration_by_parent(struct acpi_device *device)
>>  	struct list_head resource_list;
>>  	bool is_serial_bus_slave = false;
>>  	/*
>> -	 * These devices have multiple I2cSerialBus resources and an i2c-client
>> -	 * must be instantiated for each, each with its own i2c_device_id.
>> -	 * Normally we only instantiate an i2c-client for the first resource,
>> -	 * using the ACPI HID as id. These special cases are handled by the
>> -	 * drivers/acpi/bus-multi-instantiate.c driver, which knows
>> -	 * which i2c_device_id to use for each resource.
>> +	 * These devices have multiple I2cSerialBus/SpiSerialBus resources
>> +	 * and an (i2c/spi)-client must be instantiated for each, each with
>> +	 * its own i2c_device_id/spi_device_id.
>> +	 * Normally we only instantiate an (i2c/spi)-client for the first
>> +	 * resource, using the ACPI HID as id. These special cases are handled
>> +	 * by the drivers/acpi/bus-multi-instantiate.c driver, which
>> +	 * knows which i2c_device_id or spi_device_id to use for each resource.
>>  	 */
>>  	static const struct acpi_device_id bus_multi_instantiate_ids[] = {
>>  		{"BSG1160", },
>>
> 
> 
> Regards,
> 
> Hans
>