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    SubjectRe: [PATCH v2 2/3] spi / ACPI: add ACPI enumeration support
    Date
    On Thursday, November 15, 2012 01:03:16 PM Mika Westerberg wrote:
    > ACPI 5 introduced SPISerialBus resource that allows us to enumerate and
    > configure the SPI slave devices behind the SPI controller. This patch adds
    > support for this to the SPI core.
    >
    > In addition we bind ACPI nodes to SPI devices. This makes it possible for
    > the slave drivers to get the ACPI handle for further configuration.
    >
    > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

    Does anyone has objections or comments? Do we need to change anything
    in this patch?

    Grant? Linus? Bjorn?

    Rafael


    > ---
    > drivers/spi/spi.c | 201 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
    > 1 file changed, 200 insertions(+), 1 deletion(-)
    >
    > diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
    > index 84c2861..e39a484 100644
    > --- a/drivers/spi/spi.c
    > +++ b/drivers/spi/spi.c
    > @@ -35,6 +35,8 @@
    > #include <linux/sched.h>
    > #include <linux/delay.h>
    > #include <linux/kthread.h>
    > +#include <linux/ioport.h>
    > +#include <linux/acpi.h>
    >
    > static void spidev_release(struct device *dev)
    > {
    > @@ -93,6 +95,10 @@ static int spi_match_device(struct device *dev, struct device_driver *drv)
    > if (of_driver_match_device(dev, drv))
    > return 1;
    >
    > + /* Then try ACPI */
    > + if (acpi_driver_match_device(dev, drv))
    > + return 1;
    > +
    > if (sdrv->id_table)
    > return !!spi_match_id(sdrv->id_table, spi);
    >
    > @@ -888,6 +894,196 @@ static void of_register_spi_devices(struct spi_master *master)
    > static void of_register_spi_devices(struct spi_master *master) { }
    > #endif
    >
    > +#ifdef CONFIG_ACPI
    > +static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
    > +{
    > + struct acpi_resource_spi_serialbus *sb;
    > + struct spi_device *spi = data;
    > +
    > + if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
    > + return 0;
    > +
    > + sb = &ares->data.spi_serial_bus;
    > + if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_SPI)
    > + return 0;
    > +
    > + spi->chip_select = sb->device_selection;
    > + spi->max_speed_hz = sb->connection_speed;
    > +
    > + if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
    > + spi->mode |= SPI_CPHA;
    > + if (sb->clock_polarity == ACPI_SPI_START_HIGH)
    > + spi->mode |= SPI_CPOL;
    > + if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
    > + spi->mode |= SPI_CS_HIGH;
    > +
    > + return 1;
    > +}
    > +
    > +static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
    > + void *data, void **return_value)
    > +{
    > + struct spi_master *master = data;
    > + struct resource_list_entry *rentry;
    > + struct list_head resource_list;
    > + struct acpi_device *adev;
    > + struct spi_device *spi;
    > + int ret;
    > +
    > + if (acpi_bus_get_device(handle, &adev))
    > + return AE_OK;
    > + if (acpi_bus_get_status(adev) || !adev->status.present)
    > + return AE_OK;
    > +
    > + spi = spi_alloc_device(master);
    > + if (!spi) {
    > + dev_err(&master->dev, "failed to allocate SPI device for %s\n",
    > + dev_name(&adev->dev));
    > + return AE_NO_MEMORY;
    > + }
    > +
    > + INIT_LIST_HEAD(&resource_list);
    > + ret = acpi_dev_get_resources(adev, &resource_list,
    > + acpi_spi_add_resource, spi);
    > + if (ret < 0)
    > + goto fail_put_dev;
    > +
    > + list_for_each_entry(rentry, &resource_list, node) {
    > + struct resource *r = &rentry->res;
    > +
    > + if (resource_type(r) == IORESOURCE_IRQ) {
    > + spi->irq = r->start;
    > + break;
    > + }
    > + }
    > +
    > + acpi_dev_free_resource_list(&resource_list);
    > +
    > + if (!spi->max_speed_hz)
    > + goto fail_put_dev;
    > +
    > + strlcpy(spi->modalias, dev_name(&adev->dev), sizeof(spi->modalias));
    > + if (spi_add_device(spi)) {
    > + dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
    > + dev_name(&adev->dev));
    > + goto fail_put_dev;
    > + }
    > +
    > + return AE_OK;
    > +
    > +fail_put_dev:
    > + spi_dev_put(spi);
    > +
    > + return AE_OK;
    > +}
    > +
    > +static void acpi_register_spi_devices(struct spi_master *master)
    > +{
    > + acpi_status status;
    > + acpi_handle handle;
    > +
    > + handle = master->dev.acpi_handle;
    > + if (!handle)
    > + return;
    > +
    > + status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
    > + acpi_spi_add_device, NULL,
    > + master, NULL);
    > + if (ACPI_FAILURE(status))
    > + dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
    > +}
    > +
    > +struct acpi_spi_find {
    > + acpi_handle handle;
    > + u16 chip_select;
    > + bool found;
    > +};
    > +
    > +static int acpi_spi_find_child_address(struct acpi_resource *ares, void *data)
    > +{
    > + struct acpi_resource_spi_serialbus *sb;
    > + struct acpi_spi_find *spi_find = 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;
    > +
    > + if (sb->device_selection == spi_find->chip_select)
    > + spi_find->found = true;
    > +
    > + return 1;
    > +}
    > +
    > +static acpi_status acpi_spi_find_child(acpi_handle handle, u32 level,
    > + void *data, void **return_value)
    > +{
    > + struct acpi_spi_find *spi_find = data;
    > + struct list_head resource_list;
    > + struct acpi_device *adev;
    > + int ret;
    > +
    > + if (acpi_bus_get_device(handle, &adev))
    > + return AE_OK;
    > + if (acpi_bus_get_status(adev) || !adev->status.present)
    > + return AE_OK;
    > +
    > + INIT_LIST_HEAD(&resource_list);
    > + ret = acpi_dev_get_resources(adev, &resource_list,
    > + acpi_spi_find_child_address, spi_find);
    > + if (ret < 0)
    > + return AE_OK;
    > +
    > + acpi_dev_free_resource_list(&resource_list);
    > +
    > + if (spi_find->found) {
    > + spi_find->handle = handle;
    > + return AE_CTRL_TERMINATE;
    > + }
    > + return AE_OK;
    > +}
    > +
    > +static int acpi_spi_find_device(struct device *dev, acpi_handle *handle)
    > +{
    > + struct spi_device *spi = to_spi_device(dev);
    > + struct spi_master *master = spi->master;
    > + struct acpi_spi_find spi_find;
    > + acpi_handle parent;
    > + acpi_status status;
    > +
    > + parent = master->dev.acpi_handle;
    > + if (!parent)
    > + return -ENODEV;
    > +
    > + memset(&spi_find, 0, sizeof(spi_find));
    > + spi_find.chip_select = spi->chip_select;
    > +
    > + status = acpi_walk_namespace(ACPI_TYPE_DEVICE, parent, 1,
    > + acpi_spi_find_child, NULL,
    > + &spi_find, NULL);
    > + if (ACPI_FAILURE(status) || !spi_find.handle)
    > + return -ENODEV;
    > +
    > + *handle = spi_find.handle;
    > + return 0;
    > +}
    > +
    > +static struct acpi_bus_type acpi_spi_bus = {
    > + .bus = &spi_bus_type,
    > + .find_device = acpi_spi_find_device,
    > +};
    > +
    > +static void acpi_spi_bus_register(void)
    > +{
    > + register_acpi_bus_type(&acpi_spi_bus);
    > +}
    > +#else
    > +static inline void acpi_register_spi_devices(struct spi_master *master) {}
    > +static inline void acpi_spi_bus_register(void) {}
    > +#endif /* CONFIG_ACPI */
    > +
    > static void spi_master_release(struct device *dev)
    > {
    > struct spi_master *master;
    > @@ -1023,8 +1219,9 @@ int spi_register_master(struct spi_master *master)
    > spi_match_master_to_boardinfo(master, &bi->board_info);
    > mutex_unlock(&board_lock);
    >
    > - /* Register devices from the device tree */
    > + /* Register devices from the device tree and ACPI */
    > of_register_spi_devices(master);
    > + acpi_register_spi_devices(master);
    > done:
    > return status;
    > }
    > @@ -1550,6 +1747,8 @@ static int __init spi_init(void)
    > status = class_register(&spi_master_class);
    > if (status < 0)
    > goto err2;
    > +
    > + acpi_spi_bus_register();
    > return 0;
    >
    > err2:
    >
    --
    I speak only for myself.
    Rafael J. Wysocki, Intel Open Source Technology Center.


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