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Date: Mon, 12 Oct 2015 13:46:49 +0300
From: Mika Westerberg <mika.westerberg@...ux.intel.com>
To: Dustin Byford <dustin@...ulusnetworks.com>
Cc: Wolfram Sang <wsa@...-dreams.de>, linux-i2c@...r.kernel.org,
linux-kernel@...r.kernel.org, rjw@...ysocki.net,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: Re: [PATCH 1/2] i2c: scan entire ACPI namespace for I2C connections
On Fri, Oct 09, 2015 at 05:41:46PM -0700, Dustin Byford wrote:
> An I2cSerialBus connection resource descriptor may indicate a
> ResourceSource (a string uniquely identifying the I2C bus controller)
> anywhere in the ACPI namespace. However, when enumerating connections to a
> I2C bus controller, i2c-core.c:acpi_i2c_register_devices() as only
> searching devices that are descendants of the bus controller.
>
> This change corrects acpi_i2c_register_devices() to walk the entire ACPI
> namespace searching for I2C connections.
>
> Suggested-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
> Signed-off-by: Dustin Byford <dustin@...ulusnetworks.com>
This patch is already included in Andy's latest series adding support
for Intel Galileo here:
https://patchwork.ozlabs.org/patch/527231/
Maybe we can add your Tested-by/Reviewed-by to that patch instead?
> ---
> drivers/i2c/i2c-core.c | 82 ++++++++++++++++++++++++++++++++++++--------------
> 1 file changed, 59 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> index 5f89f1e..3a4c54e 100644
> --- a/drivers/i2c/i2c-core.c
> +++ b/drivers/i2c/i2c-core.c
> @@ -99,27 +99,40 @@ struct gsb_buffer {
> };
> } __packed;
>
> -static int acpi_i2c_add_resource(struct acpi_resource *ares, void *data)
> +struct acpi_i2c_lookup {
> + struct i2c_board_info *info;
> + acpi_handle adapter_handle;
> + acpi_handle device_handle;
> +};
> +
> +static int acpi_i2c_find_address(struct acpi_resource *ares, void *data)
> {
> - struct i2c_board_info *info = data;
> + struct acpi_i2c_lookup *lookup = data;
> + struct i2c_board_info *info = lookup->info;
> + struct acpi_resource_i2c_serialbus *sb;
> + acpi_handle adapter_handle;
> + acpi_status status;
>
> - if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
> - struct acpi_resource_i2c_serialbus *sb;
> + if (info->addr || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
> + return 1;
>
> - sb = &ares->data.i2c_serial_bus;
> - if (!info->addr && sb->type == ACPI_RESOURCE_SERIAL_TYPE_I2C) {
> - info->addr = sb->slave_address;
> - if (sb->access_mode == ACPI_I2C_10BIT_MODE)
> - info->flags |= I2C_CLIENT_TEN;
> - }
> - } else if (!info->irq) {
> - struct resource r;
> + sb = &ares->data.i2c_serial_bus;
> + if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C)
> + return 1;
>
> - if (acpi_dev_resource_interrupt(ares, 0, &r))
> - info->irq = r.start;
> + /*
> + * Extract the ResourceSource and make sure that the handle matches
> + * with the I2C adapter handle.
> + */
> + status = acpi_get_handle(lookup->device_handle,
> + sb->resource_source.string_ptr,
> + &adapter_handle);
> + if (ACPI_SUCCESS(status) && adapter_handle == lookup->adapter_handle) {
> + info->addr = sb->slave_address;
> + if (sb->access_mode == ACPI_I2C_10BIT_MODE)
> + info->flags |= I2C_CLIENT_TEN;
> }
>
> - /* Tell the ACPI core to skip this resource */
> return 1;
> }
>
> @@ -128,6 +141,8 @@ static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level,
> {
> struct i2c_adapter *adapter = data;
> struct list_head resource_list;
> + struct acpi_i2c_lookup lookup;
> + struct resource_entry *entry;
> struct i2c_board_info info;
> struct acpi_device *adev;
> int ret;
> @@ -140,14 +155,37 @@ static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level,
> memset(&info, 0, sizeof(info));
> info.fwnode = acpi_fwnode_handle(adev);
>
> + memset(&lookup, 0, sizeof(lookup));
> + lookup.adapter_handle = ACPI_HANDLE(adapter->dev.parent);
> + lookup.device_handle = handle;
> + lookup.info = &info;
> +
> + /*
> + * Look up for I2cSerialBus resource with ResourceSource that
> + * matches with this adapter.
> + */
> INIT_LIST_HEAD(&resource_list);
> ret = acpi_dev_get_resources(adev, &resource_list,
> - acpi_i2c_add_resource, &info);
> + acpi_i2c_find_address, &lookup);
> acpi_dev_free_resource_list(&resource_list);
>
> if (ret < 0 || !info.addr)
> return AE_OK;
>
> + /* Then fill IRQ number if any */
> + ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
> + if (ret < 0)
> + return AE_OK;
> +
> + resource_list_for_each_entry(entry, &resource_list) {
> + if (resource_type(entry->res) == IORESOURCE_IRQ) {
> + info.irq = entry->res->start;
> + break;
> + }
> + }
> +
> + acpi_dev_free_resource_list(&resource_list);
> +
> adev->power.flags.ignore_parent = true;
> strlcpy(info.type, dev_name(&adev->dev), sizeof(info.type));
> if (!i2c_new_device(adapter, &info)) {
> @@ -160,6 +198,8 @@ static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level,
> return AE_OK;
> }
>
> +#define ACPI_I2C_MAX_SCAN_DEPTH 32
> +
> /**
> * acpi_i2c_register_devices - enumerate I2C slave devices behind adapter
> * @adap: pointer to adapter
> @@ -170,17 +210,13 @@ static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level,
> */
> static void acpi_i2c_register_devices(struct i2c_adapter *adap)
> {
> - acpi_handle handle;
> acpi_status status;
>
> - if (!adap->dev.parent)
> - return;
> -
> - handle = ACPI_HANDLE(adap->dev.parent);
> - if (!handle)
> + if (!adap->dev.parent || !has_acpi_companion(adap->dev.parent))
> return;
>
> - status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
> + status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
> + ACPI_I2C_MAX_SCAN_DEPTH,
> acpi_i2c_add_device, NULL,
> adap, NULL);
> if (ACPI_FAILURE(status))
> --
> 2.1.4
--
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