On Fri, Nov 08, 2024 at 11:09:30AM +0000, Russell King (Oracle) wrote:
> On Wed, Nov 06, 2024 at 01:22:38PM +0100, Christian Marangi wrote:
> > +/* MII Registers Page 1 */
> > +#define AN8855_PHY_EXT_REG_14 0x14
> > +#define AN8855_PHY_EN_DOWN_SHFIT BIT(4)
>
> Shouldn't "AN8855_PHY_EN_DOWN_SHFIT" be "AN8855_PHY_EN_DOWN_SHIFT"
> (notice the I and F are swapped) ?
>
Typo from SDK that I didn't notice fun.
> > +static int an8855_get_downshift(struct phy_device *phydev, u8 *data)
> > +{
> > + int saved_page;
> > + int val;
> > + int ret;
> > +
> > + saved_page = phy_select_page(phydev, AN8855_PHY_PAGE_EXTENDED_1);
> > + if (saved_page >= 0)
> > + val = __phy_read(phydev, AN8855_PHY_EXT_REG_14);
> > + ret = phy_restore_page(phydev, saved_page, val);
> > + if (ret)
> > + return ret;
>
> This function is entirely broken.
>
> phy_restore_page() will return "val" if everything went successfully,
> so here you end up returning "val" via this very return statement
> without executing any further code in the function. The only time
> further code will be executed is if "val" was successfully read as
> zero.
>
> Please use the helpers provided:
>
> ret = phy_read_paged(phydev, AN8855_PHY_PAGE_EXTENDED_1,
> AN8855_PHY_EXT_REG_14);
> if (ret < 0)
> return ret;
>
> ret now contains what you're using as "val" below. No need to open code
> phy_read_paged().
Thanks for the explaination, totally got confused by reading the
restore_page code. Anyway yes I will use the helper.
>
> > +
> > + *data = val & AN8855_PHY_EXT_REG_14 ? DOWNSHIFT_DEV_DEFAULT_COUNT :
> > + DOWNSHIFT_DEV_DISABLE;
>
> Here, the test is against the register number rather than the bit that
> controls downshift. Shouldn't AN8855_PHY_EXT_REG_14 be
> AN8855_PHY_EN_DOWN_SH(F)I(F)T ?
Copy paste error, was already staged to fix, thanks for extra eye on
this.
>
> > +static int an8855_set_downshift(struct phy_device *phydev, u8 cnt)
> > +{
> > + int saved_page;
> > + int ret;
> > +
> > + saved_page = phy_select_page(phydev, AN8855_PHY_PAGE_EXTENDED_1);
> > + if (saved_page >= 0) {
> > + if (cnt != DOWNSHIFT_DEV_DISABLE)
> > + ret = __phy_set_bits(phydev, AN8855_PHY_EXT_REG_14,
> > + AN8855_PHY_EN_DOWN_SHFIT);
> > + else
> > + ret = __phy_clear_bits(phydev, AN8855_PHY_EXT_REG_14,
> > + AN8855_PHY_EN_DOWN_SHFIT);
> > + }
> > +
> > + return phy_restore_page(phydev, saved_page, ret);
>
> This entire thing can be simplified to:
>
> u16 ds = cnt != DOWNSHIFT_DEV_DISABLE ? AN8855_PHY_EN_DOWN_SHFIT: 0;
>
> return phy_modify_paged(phydev, AN8855_PHY_PAGE_EXTENDED_1,
> AN8855_PHY_EXT_REG_14, AN8855_PHY_EN_DOWN_SHFIT,
> ds);
Funnly in rechecking I produced the same exact change.
>
> Thanks.
Thanks to you for the review.
>
> --
> RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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