Re: [PATCH v3 13/13] platform/x86: intel_cht_int33fe: Replacing the old connections with references

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 12-04-19 15:41, Heikki Krogerus wrote:
> Now that the software nodes support references, and the
> device connection API support parsing fwnode references,
> replacing the old connection descriptions with software node
> references. Relying on device names when matching the
> connection would not have been possible to link the USB
> Type-C connector and the DisplayPort connector together, but
> with real references it's not problem.
> 
> The DisplayPort ACPI node is dag up, and the drivers own
> software node for the DisplayPort is set as the secondary
> node for it. The USB Type-C connector refers the software
> node, but it is now tied to the ACPI node, and therefore any
> device entry (struct drm_connector in practice) that the
> node combo is assigned to.
> 
> The USB role switch device does not have ACPI node, so we
> have to wait for the device to appear. Then we can simply
> assign our software node for the to the device.
> 
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

So as promised I've been testing this series and this commit
breaks type-c functionality on devices using this driver.

The problem is that typec_switch_get() and  typec_mux_get()
after this both return the same pointer, which is pointing
to the switch, so typec_mux_get() is returning the wrong
pointer.

This is not surprising since the references for both are
both pointing to the fwnode attached to the piusb30532 devices:

	args[0].fwnode = data->node[INT33FE_NODE_PI3USB30532];

So the class_find_device here:

static void *typec_switch_match(struct device_connection *con, int ep,
                                 void *data)
{
         struct device *dev;

         if (con->fwnode) {
                 if (con->id && !fwnode_property_present(con->fwnode, con->id))
                         return NULL;

                 dev = class_find_device(&typec_mux_class, NULL, con->fwnode,
                                         fwnode_match);
         } else {
                 dev = class_find_device(&typec_mux_class, NULL,
                                         con->endpoint[ep], name_match);
         }

         return dev ? to_typec_switch(dev) : ERR_PTR(-EPROBE_DEFER);
}

Simply returns the first typec_mux_class device registered.

I see 2 possible solutions to this problem:

1) Use separate typec_mux_class and typec_orientation_switch_class-es

2) Merge struct typec_switch and struct typec_mux into a single struct,
so that all typec_mux_class devices have the same memory layout, add
a subclass enum to this new merged struct and use that to identify
which of the typec_mux_class devices with the same fwnode pointer we
want.

Any other suggestions?

Regards,

Hans





> ---
>   drivers/platform/x86/intel_cht_int33fe.c | 93 +++++++++++++++++++-----
>   1 file changed, 76 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/platform/x86/intel_cht_int33fe.c b/drivers/platform/x86/intel_cht_int33fe.c
> index 7711667a3454..e6a1ea7f33af 100644
> --- a/drivers/platform/x86/intel_cht_int33fe.c
> +++ b/drivers/platform/x86/intel_cht_int33fe.c
> @@ -39,15 +39,22 @@ enum {
>   	INT33FE_NODE_MAX,
>   };
>   
> +enum {
> +	INT33FE_REF_ORIENTATION,
> +	INT33FE_REF_MODE_MUX,
> +	INT33FE_REF_DISPLAYPORT,
> +	INT33FE_REF_ROLE_SWITCH,
> +	INT33FE_REF_MAX,
> +};
> +
>   struct cht_int33fe_data {
>   	struct i2c_client *max17047;
>   	struct i2c_client *fusb302;
>   	struct i2c_client *pi3usb30532;
> -	/* Contain a list-head must be per device */
> -	struct device_connection connections[4];
>   
>   	struct fwnode_handle *dp;
>   	struct fwnode_handle *node[INT33FE_NODE_MAX];
> +	struct software_node_reference *ref[INT33FE_REF_MAX];
>   };
>   
>   /*
> @@ -280,6 +287,65 @@ static int cht_int33fe_add_nodes(struct cht_int33fe_data *data)
>   	return ret;
>   }
>   
> +static void cht_int33fe_remove_references(struct cht_int33fe_data *data)
> +{
> +	int i;
> +
> +	for (i = 0; i < INT33FE_REF_MAX; i++)
> +		fwnode_remove_software_node_reference(data->ref[i]);
> +}
> +
> +static int cht_int33fe_add_references(struct cht_int33fe_data *data)
> +{
> +	struct fwnode_reference_args args[2] = { };
> +	struct software_node_reference *ref;
> +	struct fwnode_handle *con;
> +
> +	con = data->node[INT33FE_NODE_USB_CONNECTOR];
> +
> +	/* USB Type-C muxes */
> +	args[0].fwnode = data->node[INT33FE_NODE_PI3USB30532];
> +	args[1].fwnode = NULL;
> +
> +	ref = fwnode_create_software_node_reference(con, "orientation-switch",
> +						    args);
> +	if (IS_ERR(ref))
> +		return PTR_ERR(ref);
> +	data->ref[INT33FE_REF_ORIENTATION] = ref;
> +
> +	ref = fwnode_create_software_node_reference(con, "mode-switch", args);
> +	if (IS_ERR(ref)) {
> +		cht_int33fe_remove_references(data);
> +		return PTR_ERR(ref);
> +	}
> +	data->ref[INT33FE_REF_MODE_MUX] = ref;
> +
> +	/* USB role switch */
> +	args[0].fwnode = data->node[INT33FE_NODE_ROLE_SWITCH];
> +	args[1].fwnode = NULL;
> +
> +	ref = fwnode_create_software_node_reference(con, "usb-role-switch",
> +						    args);
> +	if (IS_ERR(ref)) {
> +		cht_int33fe_remove_references(data);
> +		return PTR_ERR(ref);
> +	}
> +	data->ref[INT33FE_REF_ROLE_SWITCH] = ref;
> +
> +	/* DisplayPort */
> +	args[0].fwnode = data->node[INT33FE_NODE_DISPLAYPORT];
> +	args[1].fwnode = NULL;
> +
> +	ref = fwnode_create_software_node_reference(con, "displayport", args);
> +	if (IS_ERR(ref)) {
> +		cht_int33fe_remove_references(data);
> +		return PTR_ERR(ref);
> +	}
> +	data->ref[INT33FE_REF_DISPLAYPORT] = ref;
> +
> +	return 0;
> +}
> +
>   static int cht_int33fe_probe(struct platform_device *pdev)
>   {
>   	struct device *dev = &pdev->dev;
> @@ -348,22 +414,14 @@ static int cht_int33fe_probe(struct platform_device *pdev)
>   	if (ret)
>   		return ret;
>   
> -	/* Work around BIOS bug, see comment on cht_int33fe_check_for_max17047 */
> -	ret = cht_int33fe_register_max17047(dev, data);
> +	ret = cht_int33fe_add_references(data);
>   	if (ret)
>   		goto out_remove_nodes;
>   
> -	data->connections[0].endpoint[0] = "port0";
> -	data->connections[0].endpoint[1] = "i2c-pi3usb30532-switch";
> -	data->connections[0].id = "orientation-switch";
> -	data->connections[1].endpoint[0] = "port0";
> -	data->connections[1].endpoint[1] = "i2c-pi3usb30532-mux";
> -	data->connections[1].id = "mode-switch";
> -	data->connections[2].endpoint[0] = "i2c-fusb302";
> -	data->connections[2].endpoint[1] = "intel_xhci_usb_sw-role-switch";
> -	data->connections[2].id = "usb-role-switch";
> -
> -	device_connections_add(data->connections);
> +	/* Work around BIOS bug, see comment on cht_int33fe_check_for_max17047 */
> +	ret = cht_int33fe_register_max17047(dev, data);
> +	if (ret)
> +		goto out_remove_references;
>   
>   	memset(&board_info, 0, sizeof(board_info));
>   	strlcpy(board_info.type, "typec_fusb302", I2C_NAME_SIZE);
> @@ -398,7 +456,8 @@ static int cht_int33fe_probe(struct platform_device *pdev)
>   out_unregister_max17047:
>   	i2c_unregister_device(data->max17047);
>   
> -	device_connections_remove(data->connections);
> +out_remove_references:
> +	cht_int33fe_remove_references(data);
>   
>   out_remove_nodes:
>   	cht_int33fe_remove_nodes(data);
> @@ -414,7 +473,7 @@ static int cht_int33fe_remove(struct platform_device *pdev)
>   	i2c_unregister_device(data->fusb302);
>   	i2c_unregister_device(data->max17047);
>   
> -	device_connections_remove(data->connections);
> +	cht_int33fe_remove_references(data);
>   	cht_int33fe_remove_nodes(data);
>   
>   	return 0;
>