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SubjectRe: [PATCH v5 2/2] phy: cadence-torrent: Use kernel PHY API to set PHY attributes
Hi Swapnil,

Thank you for the patch.

On Mon, Aug 24, 2020 at 08:28:31PM +0200, Swapnil Jakhade wrote:
> Use generic PHY framework function phy_set_attrs() to set number
> of lanes and maximum link rate supported by PHY.
>
> Signed-off-by: Swapnil Jakhade <sjakhade@cadence.com>
> Acked-by: Kishon Vijay Abraham I <kishon@ti.com>
> ---
> drivers/phy/cadence/phy-cadence-torrent.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/drivers/phy/cadence/phy-cadence-torrent.c b/drivers/phy/cadence/phy-cadence-torrent.c
> index 7116127358ee..eca71467c4a8 100644
> --- a/drivers/phy/cadence/phy-cadence-torrent.c
> +++ b/drivers/phy/cadence/phy-cadence-torrent.c
> @@ -1710,6 +1710,7 @@ static int cdns_torrent_phy_probe(struct platform_device *pdev)
> struct cdns_torrent_phy *cdns_phy;
> struct device *dev = &pdev->dev;
> struct phy_provider *phy_provider;
> + struct phy_attrs torrent_attr;
> const struct of_device_id *match;
> struct cdns_torrent_data *data;
> struct device_node *child;
> @@ -1852,6 +1853,12 @@ static int cdns_torrent_phy_probe(struct platform_device *pdev)
> cdns_phy->phys[node].num_lanes,
> cdns_phy->max_bit_rate / 1000,
> cdns_phy->max_bit_rate % 1000);
> +
> + torrent_attr.bus_width = cdns_phy->phys[node].num_lanes;
> + torrent_attr.max_link_rate = cdns_phy->max_bit_rate;
> + torrent_attr.mode = PHY_MODE_DP;
> +
> + phy_set_attrs(gphy, &torrent_attr);

Why is this better than accessing the attributes manually as follows ?

gphy->attrs.bus_width = cdns_phy->phys[node].num_lanes;
gphy->attrs.max_link_rate = cdns_phy->max_bit_rate;
gphy->attrs.mode = PHY_MODE_DP;

This is called in cdns_torrent_phy_probe(), before the PHY provider is
registered, so nothing can access the PHY yet. What race condition are
you trying to protect against with usage of phy_set_attrs() ?

> } else {
> dev_err(dev, "Driver supports only PHY_TYPE_DP\n");
> ret = -ENOTSUPP;

--
Regards,

Laurent Pinchart

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