Re: [PATCH 3/3] platform/x86: Support Spi in i2c-multi-instantiate driver

[Hans de Goede]

Hi Stefan,

On 12/2/21 17:24, Stefan Binding wrote:
> Add support for spi bus in i2c-multi-instantiate driver
> and rename it for a multiple purpose driver name
> By adding spi support into this driver enables devices
> to use the same _HID string for i2c and spi uses and
> minimize the support for two drivers doing the same thing
> for different busses
> 
> Signed-off-by: Stefan Binding <sbinding@xxxxxxxxxxxxxxxxxxxxx>
> ---
>  MAINTAINERS                                  |   4 +-
>  drivers/acpi/scan.c                          |  19 +-
>  drivers/platform/x86/Kconfig                 |  14 +-
>  drivers/platform/x86/Makefile                |   2 +-
>  drivers/platform/x86/bus-multi-instantiate.c | 432 +++++++++++++++++++
>  drivers/platform/x86/i2c-multi-instantiate.c | 174 --------

git's rename detection is failing here. Please split this in 2
patches:

1. Just the rename without any code changes
   (outside of Kconfig + Makefile)
2. The actual code changes

This will make it much easier to review what has actually changed
and will also make git log --follow work properly.

I have one more remark below.




>  6 files changed, 452 insertions(+), 193 deletions(-)
>  create mode 100644 drivers/platform/x86/bus-multi-instantiate.c
>  delete mode 100644 drivers/platform/x86/i2c-multi-instantiate.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 5b1e79f8e3d8..f75600d917bc 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -387,11 +387,11 @@ L:	linux-arm-kernel@xxxxxxxxxxxxxxxxxxx (moderated for non-subscribers)
>  S:	Maintained
>  F:	drivers/acpi/arm64
>  
> -ACPI I2C MULTI INSTANTIATE DRIVER
> +ACPI BUS MULTI INSTANTIATE DRIVER
>  M:	Hans de Goede <hdegoede@xxxxxxxxxx>
>  L:	platform-driver-x86@xxxxxxxxxxxxxxx
>  S:	Maintained
> -F:	drivers/platform/x86/i2c-multi-instantiate.c
> +F:	drivers/platform/x86/bus-multi-instantiate.c
>  
>  ACPI PCC(Platform Communication Channel) MAILBOX DRIVER
>  M:	Sudeep Holla <sudeep.holla@xxxxxxx>
> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> index 5991dddbc9ce..2f7da1a08112 100644
> --- a/drivers/acpi/scan.c
> +++ b/drivers/acpi/scan.c
> @@ -1696,14 +1696,15 @@ 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/platform/x86/i2c-multi-instantiate.c driver, which knows
> -	 * which i2c_device_id to use for each resource.
> +	 * These devices have multiple I2cSerialBus/SpiSerialBusV2 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/platform/x86/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 i2c_multi_instantiate_ids[] = {
> +	static const struct acpi_device_id bus_multi_instantiate_ids[] = {
>  		{"BSG1160", },
>  		{"BSG2150", },
>  		{"INT33FE", },
> @@ -1721,8 +1722,8 @@ static bool acpi_device_enumeration_by_parent(struct acpi_device *device)
>  	     fwnode_property_present(&device->fwnode, "baud")))
>  		return true;
>  
> -	/* Instantiate a pdev for the i2c-multi-instantiate drv to bind to */
> -	if (!acpi_match_device_ids(device, i2c_multi_instantiate_ids))
> +	/* Instantiate a pdev for the bus-multi-instantiate drv to bind to */
> +	if (!acpi_match_device_ids(device, bus_multi_instantiate_ids))
>  		return false;
>  
>  	INIT_LIST_HEAD(&resource_list);
> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> index 97e87628eb35..5a413b123c01 100644
> --- a/drivers/platform/x86/Kconfig
> +++ b/drivers/platform/x86/Kconfig
> @@ -958,16 +958,16 @@ config TOPSTAR_LAPTOP
>  
>  	  If you have a Topstar laptop, say Y or M here.
>  
> -config I2C_MULTI_INSTANTIATE
> -	tristate "I2C multi instantiate pseudo device driver"
> -	depends on I2C && ACPI
> +config BUS_MULTI_INSTANTIATE
> +	tristate "Bus multi instantiate pseudo device driver"
> +	depends on I2C && SPI && ACPI
>  	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 i2c-multi-instantiate.
> +	  will be called bus-multi-instantiate.
>  
>  config MLX_PLATFORM
>  	tristate "Mellanox Technologies platform support"
> diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
> index 219478061683..639a50af0bec 100644
> --- a/drivers/platform/x86/Makefile
> +++ b/drivers/platform/x86/Makefile
> @@ -108,7 +108,7 @@ obj-$(CONFIG_TOPSTAR_LAPTOP)	+= topstar-laptop.o
>  
>  # Platform drivers
>  obj-$(CONFIG_FW_ATTR_CLASS)		+= firmware_attributes_class.o
> -obj-$(CONFIG_I2C_MULTI_INSTANTIATE)	+= i2c-multi-instantiate.o
> +obj-$(CONFIG_BUS_MULTI_INSTANTIATE)	+= bus-multi-instantiate.o
>  obj-$(CONFIG_MLX_PLATFORM)		+= mlx-platform.o
>  obj-$(CONFIG_TOUCHSCREEN_DMI)		+= touchscreen_dmi.o
>  obj-$(CONFIG_WIRELESS_HOTKEY)		+= wireless-hotkey.o
> diff --git a/drivers/platform/x86/bus-multi-instantiate.c b/drivers/platform/x86/bus-multi-instantiate.c
> new file mode 100644
> index 000000000000..1b55380a2057
> --- /dev/null
> +++ b/drivers/platform/x86/bus-multi-instantiate.c
> @@ -0,0 +1,432 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Bus multi-instantiate driver, pseudo driver to instantiate multiple
> + * i2c-clients or spi-devices from a single fwnode.
> + *
> + * Copyright 2018 Hans de Goede <hdegoede@xxxxxxxxxx>
> + */
> +
> +#include <linux/acpi.h>
> +#include <linux/bits.h>
> +#include <linux/i2c.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#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)
> +#define IRQ_RESOURCE_NONE		0
> +#define IRQ_RESOURCE_GPIO		1
> +#define IRQ_RESOURCE_APIC		2
> +#define MAX_RESOURCE_SOURCE_CHAR	30
> +
> +struct inst_data {
> +	const char *type;
> +	unsigned int flags;
> +	int irq_idx;
> +};
> +
> +struct multi_inst_data {
> +	int i2c_num;
> +	int spi_num;
> +	struct spi_device **spi_devs;
> +	struct i2c_client **i2c_devs;
> +};
> +
> +struct spi_acpi_data {
> +	char resource_source[MAX_RESOURCE_SOURCE_CHAR];
> +	struct acpi_resource_spi_serialbus sb;
> +};
> +
> +struct spi_serialbus_acpi_data {
> +	int count;
> +	struct spi_acpi_data acpi_data[];
> +};
> +
> +static int 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 spi_count_resources(struct acpi_device *adev)
> +{
> +	LIST_HEAD(r);
> +	int count = 0;
> +	int ret;
> +
> +	ret = acpi_dev_get_resources(adev, &r, spi_count, &count);
> +	if (ret < 0)
> +		return ret;
> +
> +	acpi_dev_free_resource_list(&r);
> +	return count;
> +}
> +
> +static int spi_save_res(struct acpi_resource *ares, void *data)
> +{
> +	struct acpi_resource_spi_serialbus *sb;
> +	struct spi_serialbus_acpi_data *resources = 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;
> +
> +	memcpy(&resources->acpi_data[resources->count].sb, sb, sizeof(*sb));
> +	strscpy(resources->acpi_data[resources->count].resource_source,
> +		sb->resource_source.string_ptr,
> +		sizeof(resources->acpi_data[resources->count].resource_source));
> +	resources->count++;
> +
> +	return 1;
> +}
> +
> +static struct spi_serialbus_acpi_data *spi_get_resources(struct device *dev,
> +							 struct acpi_device *adev, int count)
> +{
> +	struct spi_serialbus_acpi_data *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, spi_save_res, resources);
> +	if (ret < 0)
> +		goto error;
> +
> +	acpi_dev_free_resource_list(&r);
> +
> +	return resources;
> +
> +error:
> +	kfree(resources);
> +	return NULL;
> +}
> +
> +static struct spi_controller *find_spi_controller(char *path)
> +{
> +	struct spi_controller *ctlr;
> +	acpi_handle parent_handle;
> +	acpi_status status;
> +	int i;
> +
> +	status = acpi_get_handle(NULL, path, &parent_handle);
> +	if (ACPI_FAILURE(status))
> +		return NULL;
> +
> +	/* There will be not more than 10 spi controller for a device */
> +	for (i = 0 ; i < 10 ; i++) {
> +		ctlr = spi_busnum_to_master(i);
> +		if (ctlr && ACPI_HANDLE(ctlr->dev.parent) == parent_handle)
> +			return ctlr;
> +	}
> +
> +	return NULL;
> +}
> +
> +static int spi_multi_inst_probe(struct platform_device *pdev, struct acpi_device *adev,
> +				const struct inst_data *inst_data, int count)
> +{
> +	struct spi_serialbus_acpi_data *acpi_data;
> +	struct device *dev = &pdev->dev;
> +	struct multi_inst_data *multi;
> +	struct spi_controller *ctlr;
> +	struct spi_device *spi_dev;
> +	char name[50];
> +	int i, ret;
> +
> +	multi = devm_kzalloc(dev, sizeof(*multi), GFP_KERNEL);
> +	if (!multi)
> +		return -ENOMEM;
> +
> +	multi->spi_devs = devm_kcalloc(dev, count, sizeof(*multi->spi_devs), GFP_KERNEL);
> +	if (!multi->spi_devs)
> +		return -ENOMEM;
> +
> +	acpi_data = spi_get_resources(dev, adev, count);
> +	if (!acpi_data)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < count && inst_data[i].type; i++) {
> +		ctlr = find_spi_controller(acpi_data->acpi_data[i].resource_source);
> +		if (!ctlr) {
> +			ret = -EPROBE_DEFER;
> +			goto probe_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 probe_error;
> +		}
> +
> +		strscpy(spi_dev->modalias, inst_data[i].type, sizeof(spi_dev->modalias));
> +
> +		if (ctlr->fw_translate_cs) {
> +			int cs = ctlr->fw_translate_cs(ctlr,
> +					acpi_data->acpi_data[i].sb.device_selection);
> +			if (cs < 0) {
> +				ret = cs;
> +				goto probe_error;
> +			}
> +			spi_dev->chip_select = cs;
> +		} 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;
> +
> +		switch (inst_data[i].flags & IRQ_RESOURCE_TYPE) {
> +		case IRQ_RESOURCE_GPIO:
> +			ret = acpi_dev_gpio_irq_get(adev, inst_data[i].irq_idx);
> +			if (ret < 0) {
> +				if (ret != -EPROBE_DEFER)
> +					dev_err(dev, "Error requesting irq at index %d: %d\n",
> +						inst_data[i].irq_idx, ret);
> +				goto probe_error;
> +			}
> +			spi_dev->irq = ret;
> +			break;
> +		case IRQ_RESOURCE_APIC:
> +			ret = platform_get_irq(pdev, inst_data[i].irq_idx);
> +			if (ret < 0) {
> +				dev_dbg(dev, "Error requesting irq at index %d: %d\n",
> +					inst_data[i].irq_idx, ret);
> +				goto probe_error;
> +			}
> +			spi_dev->irq = ret;
> +			break;
> +		default:
> +			spi_dev->irq = 0;
> +			break;
> +		}

This switch (inst_data[i].flags & IRQ_RESOURCE_TYPE) { } block is duplicated with the
i2c code, please put this in some get_irq helper, so that you end up writing:

		spi_dev->irq = multi_inst_get_irq(pdev, &inst_data[i]);

Here.




> +
> +		snprintf(name, sizeof(name), "%s.%u-%s-%s.%d", dev_name(&ctlr->dev),
> +			 spi_dev->chip_select, dev_name(dev), inst_data[i].type, i);
> +		spi_dev->dev.init_name = name;
> +
> +		if (spi_add_device(spi_dev)) {
> +			dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
> +				dev_name(&adev->dev));
> +			spi_dev_put(spi_dev);
> +			goto probe_error;
> +		}
> +
> +		multi->spi_devs[i] = spi_dev;
> +		multi->spi_num++;
> +	}
> +
> +	if (multi->spi_num < count) {
> +		dev_err(dev, "Error finding driver, idx %d\n", i);
> +		ret = -ENODEV;
> +		goto probe_error;
> +	}
> +
> +	dev_info(dev, "Instantiate %d devices.\n", multi->spi_num);
> +	platform_set_drvdata(pdev, multi);
> +	kfree(acpi_data);
> +
> +	return 0;
> +
> +probe_error:
> +	while (--i >= 0)
> +		spi_unregister_device(multi->spi_devs[i]);
> +
> +	kfree(acpi_data);
> +	return ret;
> +}
> +
> +static int i2c_multi_inst_probe(struct platform_device *pdev, struct acpi_device *adev,
> +				const struct inst_data *inst_data, int count)
> +{
> +	struct i2c_board_info board_info = {};
> +	struct device *dev = &pdev->dev;
> +	struct multi_inst_data *multi;
> +	char name[32];
> +	int i, ret;
> +
> +	multi = devm_kzalloc(dev, sizeof(*multi), GFP_KERNEL);
> +	if (!multi)
> +		return -ENOMEM;
> +
> +	multi->i2c_devs = devm_kcalloc(dev, count, sizeof(*multi->i2c_devs), GFP_KERNEL);
> +	if (!multi->i2c_devs)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < count && inst_data[i].type; i++) {
> +		memset(&board_info, 0, sizeof(board_info));
> +		strscpy(board_info.type, inst_data[i].type, I2C_NAME_SIZE);
> +		snprintf(name, sizeof(name), "%s-%s.%d", dev_name(dev), inst_data[i].type, i);
> +		board_info.dev_name = name;
> +		switch (inst_data[i].flags & IRQ_RESOURCE_TYPE) {
> +		case IRQ_RESOURCE_GPIO:
> +			ret = acpi_dev_gpio_irq_get(adev, inst_data[i].irq_idx);
> +			if (ret < 0) {
> +				if (ret != -EPROBE_DEFER)
> +					dev_err(dev, "Error requesting irq at index %d: %d\n",
> +						inst_data[i].irq_idx, ret);
> +				goto error;
> +			}
> +			board_info.irq = ret;
> +			break;
> +		case IRQ_RESOURCE_APIC:
> +			ret = platform_get_irq(pdev, inst_data[i].irq_idx);
> +			if (ret < 0) {
> +				dev_dbg(dev, "Error requesting irq at index %d: %d\n",
> +					inst_data[i].irq_idx, ret);
> +				goto error;
> +			}
> +			board_info.irq = ret;
> +			break;
> +		default:
> +			board_info.irq = 0;
> +			break;
> +		}
> +		multi->i2c_devs[i] = i2c_acpi_new_device(dev, i, &board_info);
> +		if (IS_ERR(multi->i2c_devs[i])) {
> +			ret = dev_err_probe(dev, PTR_ERR(multi->i2c_devs[i]),
> +					    "Error creating i2c-client, idx %d\n", i);
> +			goto error;
> +		}
> +		multi->i2c_num++;
> +	}
> +	if (multi->i2c_num < count) {
> +		dev_err(dev, "Error finding driver, idx %d\n", i);
> +		ret = -ENODEV;
> +		goto error;
> +	}
> +
> +	dev_info(dev, "Instantiate %d devices.\n", multi->i2c_num);
> +	platform_set_drvdata(pdev, multi);
> +
> +	return 0;
> +
> +error:
> +	while (--i >= 0)
> +		i2c_unregister_device(multi->i2c_devs[i]);
> +
> +	return ret;
> +}
> +
> +static int bus_multi_inst_probe(struct platform_device *pdev)
> +{
> +	const struct inst_data *inst_data;
> +	struct device *dev = &pdev->dev;
> +	struct acpi_device *adev;
> +	int count;
> +
> +	inst_data = device_get_match_data(dev);
> +	if (!inst_data) {
> +		dev_err(dev, "Error ACPI match data is missing\n");
> +		return -ENODEV;
> +	}
> +
> +	adev = ACPI_COMPANION(dev);

You should check that adev != NULL here, the old code relied on
i2c_acpi_client_count() returning an error for adev == NULL, but
since you are now just warning when that fails an explicit check
for this would be good.

> +
> +	/* Count number of i2c clients to instantiate */
> +	count = i2c_acpi_client_count(adev);
> +	if (count > 0)
> +		return i2c_multi_inst_probe(pdev, adev, inst_data, count);

What if an ACPI device has both i2c and spi resources ?

Regards,

Hans



> +	else if (count < 0)
> +		dev_warn(dev, "I2C multi instantiate error %d\n", count);
> +
> +	/* Count number of spi devices to instantiate */
> +	count = spi_count_resources(adev);
> +	if (count > 0)
> +		return spi_multi_inst_probe(pdev, adev, inst_data, count);
> +	else if (count < 0)
> +		dev_warn(dev, "SPI multi instantiate error %d\n", count);
> +
> +	return -ENODEV;
> +}
> +
> +static int bus_multi_inst_remove(struct platform_device *pdev)
> +{
> +	struct multi_inst_data *multi = platform_get_drvdata(pdev);
> +	int i;
> +
> +	for (i = 0; i < multi->i2c_num; i++)
> +		i2c_unregister_device(multi->i2c_devs[i]);
> +
> +	for (i = 0; i < multi->spi_num; i++)
> +		spi_unregister_device(multi->spi_devs[i]);
> +
> +	return 0;
> +}
> +
> +static const struct inst_data bsg1160_data[]  = {
> +	{ "bmc150_accel", IRQ_RESOURCE_GPIO, 0 },
> +	{ "bmc150_magn" },
> +	{ "bmg160" },
> +	{}
> +};
> +
> +static const struct inst_data 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 inst_data int3515_data[]  = {
> +	{ "tps6598x", IRQ_RESOURCE_APIC, 0 },
> +	{ "tps6598x", IRQ_RESOURCE_APIC, 1 },
> +	{ "tps6598x", IRQ_RESOURCE_APIC, 2 },
> +	{ "tps6598x", IRQ_RESOURCE_APIC, 3 },
> +	{}
> +};
> +
> +/*
> + * Note new device-ids must also be added to bus_multi_instantiate_ids in
> + * drivers/acpi/scan.c: acpi_device_enumeration_by_parent().
> + */
> +static const struct acpi_device_id bus_multi_inst_acpi_ids[] = {
> +	{ "BSG1160", (unsigned long)bsg1160_data },
> +	{ "BSG2150", (unsigned long)bsg2150_data },
> +	{ "INT3515", (unsigned long)int3515_data },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(acpi, bus_multi_inst_acpi_ids);
> +
> +static struct platform_driver bus_multi_inst_driver = {
> +	.driver	= {
> +		.name = "Bus multi instantiate pseudo device driver",
> +		.acpi_match_table = bus_multi_inst_acpi_ids,
> +	},
> +	.probe = bus_multi_inst_probe,
> +	.remove = bus_multi_inst_remove,
> +};
> +module_platform_driver(bus_multi_inst_driver);
> +
> +MODULE_DESCRIPTION("Bus multi instantiate pseudo device driver");
> +MODULE_AUTHOR("Hans de Goede <hdegoede@xxxxxxxxxx>");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/platform/x86/i2c-multi-instantiate.c b/drivers/platform/x86/i2c-multi-instantiate.c
> deleted file mode 100644
> index 4956a1df5b90..000000000000
> --- a/drivers/platform/x86/i2c-multi-instantiate.c
> +++ /dev/null
> @@ -1,174 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0+
> -/*
> - * I2C multi-instantiate driver, pseudo driver to instantiate multiple
> - * i2c-clients from a single fwnode.
> - *
> - * Copyright 2018 Hans de Goede <hdegoede@xxxxxxxxxx>
> - */
> -
> -#include <linux/acpi.h>
> -#include <linux/bits.h>
> -#include <linux/i2c.h>
> -#include <linux/interrupt.h>
> -#include <linux/kernel.h>
> -#include <linux/module.h>
> -#include <linux/platform_device.h>
> -#include <linux/property.h>
> -#include <linux/types.h>
> -
> -#define IRQ_RESOURCE_TYPE	GENMASK(1, 0)
> -#define IRQ_RESOURCE_NONE	0
> -#define IRQ_RESOURCE_GPIO	1
> -#define IRQ_RESOURCE_APIC	2
> -
> -struct i2c_inst_data {
> -	const char *type;
> -	unsigned int flags;
> -	int irq_idx;
> -};
> -
> -struct i2c_multi_inst_data {
> -	int num_clients;
> -	struct i2c_client *clients[];
> -};
> -
> -static int i2c_multi_inst_probe(struct platform_device *pdev)
> -{
> -	struct i2c_multi_inst_data *multi;
> -	const struct i2c_inst_data *inst_data;
> -	struct i2c_board_info board_info = {};
> -	struct device *dev = &pdev->dev;
> -	struct acpi_device *adev;
> -	char name[32];
> -	int i, ret;
> -
> -	inst_data = device_get_match_data(dev);
> -	if (!inst_data) {
> -		dev_err(dev, "Error ACPI match data is missing\n");
> -		return -ENODEV;
> -	}
> -
> -	adev = ACPI_COMPANION(dev);
> -
> -	/* Count number of clients to instantiate */
> -	ret = i2c_acpi_client_count(adev);
> -	if (ret < 0)
> -		return ret;
> -
> -	multi = devm_kmalloc(dev, struct_size(multi, clients, ret), GFP_KERNEL);
> -	if (!multi)
> -		return -ENOMEM;
> -
> -	multi->num_clients = ret;
> -
> -	for (i = 0; i < multi->num_clients && inst_data[i].type; i++) {
> -		memset(&board_info, 0, sizeof(board_info));
> -		strlcpy(board_info.type, inst_data[i].type, I2C_NAME_SIZE);
> -		snprintf(name, sizeof(name), "%s-%s.%d", dev_name(dev),
> -			 inst_data[i].type, i);
> -		board_info.dev_name = name;
> -		switch (inst_data[i].flags & IRQ_RESOURCE_TYPE) {
> -		case IRQ_RESOURCE_GPIO:
> -			ret = acpi_dev_gpio_irq_get(adev, inst_data[i].irq_idx);
> -			if (ret < 0) {
> -				dev_err(dev, "Error requesting irq at index %d: %d\n",
> -					inst_data[i].irq_idx, ret);
> -				goto error;
> -			}
> -			board_info.irq = ret;
> -			break;
> -		case IRQ_RESOURCE_APIC:
> -			ret = platform_get_irq(pdev, inst_data[i].irq_idx);
> -			if (ret < 0) {
> -				dev_dbg(dev, "Error requesting irq at index %d: %d\n",
> -					inst_data[i].irq_idx, ret);
> -				goto error;
> -			}
> -			board_info.irq = ret;
> -			break;
> -		default:
> -			board_info.irq = 0;
> -			break;
> -		}
> -		multi->clients[i] = i2c_acpi_new_device(dev, i, &board_info);
> -		if (IS_ERR(multi->clients[i])) {
> -			ret = dev_err_probe(dev, PTR_ERR(multi->clients[i]),
> -					    "Error creating i2c-client, idx %d\n", i);
> -			goto error;
> -		}
> -	}
> -	if (i < multi->num_clients) {
> -		dev_err(dev, "Error finding driver, idx %d\n", i);
> -		ret = -ENODEV;
> -		goto error;
> -	}
> -
> -	platform_set_drvdata(pdev, multi);
> -	return 0;
> -
> -error:
> -	while (--i >= 0)
> -		i2c_unregister_device(multi->clients[i]);
> -
> -	return ret;
> -}
> -
> -static int i2c_multi_inst_remove(struct platform_device *pdev)
> -{
> -	struct i2c_multi_inst_data *multi = platform_get_drvdata(pdev);
> -	int i;
> -
> -	for (i = 0; i < multi->num_clients; i++)
> -		i2c_unregister_device(multi->clients[i]);
> -
> -	return 0;
> -}
> -
> -static const struct i2c_inst_data bsg1160_data[]  = {
> -	{ "bmc150_accel", IRQ_RESOURCE_GPIO, 0 },
> -	{ "bmc150_magn" },
> -	{ "bmg160" },
> -	{}
> -};
> -
> -static const struct i2c_inst_data 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 i2c_inst_data int3515_data[]  = {
> -	{ "tps6598x", IRQ_RESOURCE_APIC, 0 },
> -	{ "tps6598x", IRQ_RESOURCE_APIC, 1 },
> -	{ "tps6598x", IRQ_RESOURCE_APIC, 2 },
> -	{ "tps6598x", IRQ_RESOURCE_APIC, 3 },
> -	{}
> -};
> -
> -/*
> - * Note new device-ids must also be added to i2c_multi_instantiate_ids in
> - * drivers/acpi/scan.c: acpi_device_enumeration_by_parent().
> - */
> -static const struct acpi_device_id i2c_multi_inst_acpi_ids[] = {
> -	{ "BSG1160", (unsigned long)bsg1160_data },
> -	{ "BSG2150", (unsigned long)bsg2150_data },
> -	{ "INT3515", (unsigned long)int3515_data },
> -	{ }
> -};
> -MODULE_DEVICE_TABLE(acpi, i2c_multi_inst_acpi_ids);
> -
> -static struct platform_driver i2c_multi_inst_driver = {
> -	.driver	= {
> -		.name = "I2C multi instantiate pseudo device driver",
> -		.acpi_match_table = i2c_multi_inst_acpi_ids,
> -	},
> -	.probe = i2c_multi_inst_probe,
> -	.remove = i2c_multi_inst_remove,
> -};
> -module_platform_driver(i2c_multi_inst_driver);
> -
> -MODULE_DESCRIPTION("I2C multi instantiate pseudo device driver");
> -MODULE_AUTHOR("Hans de Goede <hdegoede@xxxxxxxxxx>");
> -MODULE_LICENSE("GPL");
>