Re: [PATCH v5 7/9] platform/x86: serial-multi-instantiate: Add SPI support

Rafael J. Wysocki
2022-01-21T15:31:33Z

On Fri, Jan 21, 2022 at 3:33 PM Stefan Binding
<sbinding@opensource.cirrus.com> wrote:
>
> Add support for spi bus in serial-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@opensource.cirrus.com>
> ---
> drivers/acpi/scan.c | 13 +-
> drivers/platform/x86/Kconfig | 10 +-
> .../platform/x86/serial-multi-instantiate.c | 174 +++++++++++++++---
> 3 files changed, 161 insertions(+), 36 deletions(-)
>
> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> index 8b237eb4e029..38c4f55960f4 100644
> --- a/drivers/acpi/scan.c
> +++ b/drivers/acpi/scan.c
> @@ -1734,12 +1734,13 @@ static bool acpi_device_enumeration_by_parent(struct acpi_device *device)
> bool is_serial_bus_slave = false;
> static const struct acpi_device_id ignore_serial_bus_ids[] = {
> /*
> - * 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/serial-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/platform/x86/serial-multi-instantiate.c driver, which
> + * knows which i2c_device_id or spi_device_id to use for each resource.
> */
> {"BSG1160", },
> {"BSG2150", },
> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> index 5b65d687f046..28f5bbf0f27a 100644
> --- a/drivers/platform/x86/Kconfig
> +++ b/drivers/platform/x86/Kconfig
> @@ -991,12 +991,12 @@ config TOPSTAR_LAPTOP
> If you have a Topstar laptop, say Y or M here.
>
> config SERIAL_MULTI_INSTANTIATE
> - tristate "I2C multi instantiate pseudo device driver"
> - depends on I2C && ACPI
> + tristate "I2C and SPI multi instantiate pseudo device driver"
> + depends on I2C && SPI && ACPI

Should this be (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 serial-multi-instantiate.
> diff --git a/drivers/platform/x86/serial-multi-instantiate.c b/drivers/platform/x86/serial-multi-instantiate.c
> index 162ec20a861a..535c80789852 100644
> --- a/drivers/platform/x86/serial-multi-instantiate.c
> +++ b/drivers/platform/x86/serial-multi-instantiate.c
> @@ -1,7 +1,7 @@
> // SPDX-License-Identifier: GPL-2.0+
> /*
> * Serial 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@redhat.com>
> */
> @@ -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 +22,28 @@
> #define IRQ_RESOURCE_GPIO 1
> #define IRQ_RESOURCE_APIC 2
>
> +enum smi_bus_type {
> + SMI_I2C,
> + SMI_SPI,
> + SMI_AUTO_DETECT,
> +};
> +
> struct smi_instance {
> const char *type;
> unsigned int flags;
> int irq_idx;
> };
>
> +struct smi_node {
> + enum smi_bus_type bus_type;
> + struct smi_instance instances[];
> +};
> +
> struct smi {
> int i2c_num;
> + int spi_num;
> struct i2c_client **i2c_devs;
> + struct spi_device **spi_devs;
> };
>
> static int smi_get_irq(struct platform_device *pdev, struct acpi_device *adev,
> @@ -60,6 +74,93 @@ static void smi_devs_unregister(struct smi *smi)
> {
> while (smi->i2c_num > 0)
> i2c_unregister_device(smi->i2c_devs[--smi->i2c_num]);
> +
> + while (smi->spi_num > 0)
> + spi_unregister_device(smi->spi_devs[--smi->spi_num]);
> +}
> +
> +/**
> + * smi_spi_probe - Instantiate multiple SPI devices from inst array
> + * @pdev: Platform device
> + * @adev: ACPI device
> + * @smi: Internal struct for Serial multi instantiate driver
> + * @inst: Array of instances to probe

This is called inst_array below.

> + *
> + * Returns the number of SPI devices instantiate, Zero if none is found or a negative error code.
> + */
> +static int smi_spi_probe(struct platform_device *pdev, struct acpi_device *adev, struct smi *smi,
> + const struct smi_instance *inst_array)
> +{
> + struct device *dev = &pdev->dev;
> + struct spi_controller *ctlr;
> + struct spi_device *spi_dev;
> + char name[50];
> + int i, ret, count;
> +
> + ret = acpi_spi_count_resources(adev);
> + if (ret <= 0)
> + return ret == 0 ? -ENODEV : ret;
> +
> + count = ret;
> +
> + smi->spi_devs = devm_kcalloc(dev, count, sizeof(*smi->spi_devs), GFP_KERNEL);
> + if (!smi->spi_devs)
> + return -ENOMEM;
> +
> + for (i = 0; i < count && inst_array[i].type; i++) {
> +
> + spi_dev = acpi_spi_device_alloc(NULL, adev, i);
> + if (IS_ERR(spi_dev)) {
> + ret = PTR_ERR(spi_dev);
> + dev_err_probe(dev, ret, "failed to allocate SPI device %s from ACPI: %d\n",
> + dev_name(&adev->dev), ret);
> + goto error;
> + }
> +
> + ctlr = spi_dev->controller;
> +
> + strscpy(spi_dev->modalias, inst_array[i].type, sizeof(spi_dev->modalias));
> +
> + ret = smi_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_probe(&ctlr->dev, ret,
> + "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);
> +
> + smi->spi_devs[i] = spi_dev;
> + smi->spi_num++;
> + }
> +
> + if (smi->spi_num < count) {
> + dev_err(dev, "Error finding driver, idx %d\n", i);

Another kind of debug message.

> + ret = -ENODEV;
> + goto error;
> + }
> +
> + dev_info(dev, "Instantiated %d SPI devices.\n", smi->spi_num);
> +
> + return 0;
> +error:
> + smi_devs_unregister(smi);
> +
> + return ret;
> +
> }
>
> /**
> @@ -125,13 +226,13 @@ static int smi_i2c_probe(struct platform_device *pdev, struct acpi_device *adev,
>
> static int smi_probe(struct platform_device *pdev)
> {
> - const struct smi_instance *inst_array;
> struct device *dev = &pdev->dev;
> + const struct smi_node *node;
> struct acpi_device *adev;
> struct smi *smi;
>
> - 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;
> }
> @@ -146,7 +247,21 @@ static int smi_probe(struct platform_device *pdev)
>
> platform_set_drvdata(pdev, smi);
>
> - return smi_i2c_probe(pdev, adev, smi, inst_array);
> + switch (node->bus_type) {
> + case SMI_I2C:
> + return smi_i2c_probe(pdev, adev, smi, node->instances);
> + case SMI_SPI:
> + return smi_spi_probe(pdev, adev, smi, node->instances);
> + case SMI_AUTO_DETECT:
> + if (i2c_acpi_client_count(adev) > 0)
> + return smi_i2c_probe(pdev, adev, smi, node->instances);
> + else
> + return smi_spi_probe(pdev, adev, smi, node->instances);
> + default:
> + break;

Why is this needed?

> + }
> +
> + return 0; /* never reached */
> }
>
> static int smi_remove(struct platform_device *pdev)
> @@ -158,27 +273,36 @@ static int smi_remove(struct platform_device *pdev)
> return 0;
> }
>
> -static const struct smi_instance bsg1160_data[] = {
> - { "bmc150_accel", IRQ_RESOURCE_GPIO, 0 },
> - { "bmc150_magn" },
> - { "bmg160" },
> - {}
> +static const struct smi_node bsg1160_data = {
> + .instances = {
> + { "bmc150_accel", IRQ_RESOURCE_GPIO, 0 },
> + { "bmc150_magn" },
> + { "bmg160" },
> + {}
> + },
> + .bus_type = SMI_I2C,
> };
>
> -static const struct smi_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 smi_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" },
> + {}
> + },
> + .bus_type = SMI_I2C,
> };
>
> -static const struct smi_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 smi_node int3515_data = {
> + .instances = {
> + { "tps6598x", IRQ_RESOURCE_APIC, 0 },
> + { "tps6598x", IRQ_RESOURCE_APIC, 1 },
> + { "tps6598x", IRQ_RESOURCE_APIC, 2 },
> + { "tps6598x", IRQ_RESOURCE_APIC, 3 },
> + {}
> + },
> + .bus_type = SMI_I2C,
> };
>
> /*
> @@ -186,9 +310,9 @@ static const struct smi_instance int3515_data[] = {
> * drivers/acpi/scan.c: acpi_device_enumeration_by_parent().
> */
> static const struct acpi_device_id smi_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, smi_acpi_ids);
> --
> 2.25.1
>