Re: [PATCH v3 2/3] ata: ahci_platform: Manage SATA PHY

On Thursday 09 January 2014, Roger Quadros wrote:

quoted

quoted

if (!IS_ERR(hpriv->phy)) {
        rc = phy_init(hpriv->phy);
        if (rc)
                goto disable_unprepare_clk;

        rc = phy_power_on(hpriv->phy);
        if (rc) {
                phy_exit(hpriv->phy);
                goto disable_unprepare_clk;
        }
}

As I said, I'd prefer to set hpriv->phy to NULL in case of -ENODEV,
but functionally it seems right (with the fixup from your other mail).

Why do you prefer setting hpriv->phy to NULL instead of using IS_ERR() check
before hpriv->phy is used?
The latter seems to be the norm at least among clock framework users.

Two reasons:

1. It feels more natural to read "if (clk)" in driver code as a check for
   "a clock exists" than "if (!IS_ERR(clk))".
2. It clarifies that this code path is only there to check for the
   clk-not-present case, not for other errors.

Obviously the first check after clk_get needs to be IS_ERR() because that
is the documented interface, but then you should decide on the action
based on the specific error.

	Arnd