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

[Deepak, M]

> -----Original Message-----
> From: Ville Syrjälä [mailto:ville.syrjala at linux.intel.com]
> Sent: Friday, February 19, 2016 7:38 PM
> To: Deepak, M <m.deepak at intel.com>
> Cc: intel-gfx at lists.freedesktop.org
> Subject: Re: [Intel-gfx] [PATCH] drm/i915: Get the i2c bus number from the
> ACPI
> 
> On Fri, Feb 19, 2016 at 07:25:57PM +0530, Deepak M wrote:
> > 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;
> 
> The naming is rather vague. i2c bus for what?
> 
> Also is one bus always enough? The VBT i2c stuff could use multiple i2c
> busses. Also how do we map this to the bus number that the VBT has?
> 
[Deepak, M] Most of the cases I have seen only one i2c being used, If there are multiple i2c busses used then need to check which i2c is used for what purpose and is there a protocol which is followed by BIOS team when more than one i2c bus is used.
> > +
> >  	/* 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
> >
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> --
> Ville Syrjälä
> Intel OTC