[Intel-gfx] [PATCH] drm/i915: Get the i2c bus number from the ACPI

[Deepak, M]

This patch reads the i2c bus number from the _CRS table of the display module of the ACPI, which will be updated by the BIOS with the i2c info which is used for this module.

> -----Original Message-----
> From: Deepak, M
> Sent: Friday, February 19, 2016 7:26 PM
> To: intel-gfx at lists.freedesktop.org
> Cc: Deepak, M <m.deepak at intel.com>
> Subject: [PATCH] drm/i915: Get the i2c bus number from the ACPI
> 
> Currently for executing the i2c MIPI sequence, we are relaying on the i2c bus
> bunmber which is specified in the VBT.
> 
> Signed-off-by: Deepak M <m.deepak at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_dma.c   |  2 ++
>  drivers/gpu/drm/i915/i915_drv.h   |  7 ++++++
>  drivers/gpu/drm/i915/intel_acpi.c | 49
> +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 58 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_dma.c
> b/drivers/gpu/drm/i915/i915_dma.c index 1c6d227..8cd1d9d 100644
> --- a/drivers/gpu/drm/i915/i915_dma.c
> +++ b/drivers/gpu/drm/i915/i915_dma.c
> @@ -387,6 +387,8 @@ static int i915_load_modeset_init(struct drm_device
> *dev)
> 
>  	intel_register_dsm_handler();
> 
> +	intel_acpi_find_i2c(dev_priv);
> +
>  	ret = vga_switcheroo_register_client(dev->pdev,
> &i915_switcheroo_ops, false);
>  	if (ret)
>  		goto cleanup_vga_client;
> diff --git a/drivers/gpu/drm/i915/i915_drv.h
> b/drivers/gpu/drm/i915/i915_drv.h index 6644c2e..6fe8b64 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -47,6 +47,7 @@
>  #include <drm/intel-gtt.h>
>  #include <drm/drm_legacy.h> /* for struct drm_dma_handle */  #include
> <drm/drm_gem.h>
> +#include <linux/acpi.h>
>  #include <linux/backlight.h>
>  #include <linux/hashtable.h>
>  #include <linux/intel-iommu.h>
> @@ -1880,6 +1881,11 @@ struct drm_i915_private {
> 
>  	struct i915_workarounds workarounds;
> 
> +	struct {
> +		int i2c_bus_number;
> +		int i2c_slave_address;
> +	} acpi_data;
> +
>  	/* Reclocking support */
>  	bool render_reclock_avail;
> 
> @@ -3426,6 +3432,7 @@ intel_opregion_notify_adapter(struct drm_device
> *dev, pci_power_t state)  #ifdef CONFIG_ACPI  extern void
> intel_register_dsm_handler(void);  extern void
> intel_unregister_dsm_handler(void);
> +extern acpi_status intel_acpi_find_i2c(struct drm_i915_private
> +*dev_priv);
>  #else
>  static inline void intel_register_dsm_handler(void) { return; }  static inline
> void intel_unregister_dsm_handler(void) { return; } diff --git
> a/drivers/gpu/drm/i915/intel_acpi.c b/drivers/gpu/drm/i915/intel_acpi.c
> index eb638a1..f62be5c 100644
> --- a/drivers/gpu/drm/i915/intel_acpi.c
> +++ b/drivers/gpu/drm/i915/intel_acpi.c
> @@ -110,6 +110,55 @@ static void intel_dsm_platform_mux_info(void)
>  	ACPI_FREE(pkg);
>  }
> 
> +static int i2c_acpi_get_name(struct acpi_resource *ares, void *data) {
> +	struct drm_i915_private *dev_priv = data;
> +	struct acpi_resource_i2c_serialbus *sb;
> +	unsigned int val;
> +	char *resource;
> +	int error;
> +
> +	if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
> +		sb = &ares->data.i2c_serial_bus;
> +
> +		if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_I2C) {
> +			resource = sb->resource_source.string_ptr;
> +			resource = strstr(resource, "I2C");
> +			error = kstrtouint(resource+3, 0, &val);
> +			if (error)
> +				return error;
> +			dev_priv->acpi_data.i2c_bus_number = val;
> +			dev_priv->acpi_data.i2c_slave_address =
> +						sb->slave_address;
> +		}
> +	}
> +	return 1;
> +}
> +
> +acpi_status intel_acpi_find_i2c(struct drm_i915_private *dev_priv) {
> +	struct pci_dev *pdev = dev_priv->dev->pdev;
> +	struct list_head resource_list;
> +	struct acpi_device *adev;
> +	acpi_handle dhandle;
> +
> +	dhandle = ACPI_HANDLE(&pdev->dev);
> +	if (!dhandle)
> +		return false;
> +
> +	if (acpi_bus_get_device(dhandle, &adev))
> +		return AE_OK;
> +	if (acpi_bus_get_status(adev) || !adev->status.present)
> +		return AE_OK;
> +
> +	INIT_LIST_HEAD(&resource_list);
> +	acpi_dev_get_resources(adev, &resource_list,
> +			i2c_acpi_get_name, dev_priv);
> +	acpi_dev_free_resource_list(&resource_list);
> +
> +	return AE_OK;
> +}
> +
>  static bool intel_dsm_pci_probe(struct pci_dev *pdev)  {
>  	acpi_handle dhandle;
> --
> 1.9.1