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Date: Fri, 16 Nov 2012 11:06:47 +0100
From: "Rafael J. Wysocki" <rjw@...k.pl>
To: Mika Westerberg <mika.westerberg@...ux.intel.com>,
grant.likely@...retlab.ca, linus.walleij@...aro.org,
bhelgaas@...gle.com
Cc: linux-kernel@...r.kernel.org, lenb@...nel.org,
rafael.j.wysocki@...el.com, broonie@...nsource.wolfsonmicro.com,
khali@...ux-fr.org, ben-linux@...ff.org, w.sang@...gutronix.de,
mathias.nyman@...ux.intel.com, linux-acpi@...r.kernel.org
Subject: Re: [PATCH v2 2/3] spi / ACPI: add ACPI enumeration support
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@...ux.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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