> From: Matthijs Kooijman [mailto:[email protected]] > Sent: Wednesday, July 17, 2013 8:10 AM > > Various register fields wider than one bit have constants defined for > their value. Previously, these registers would define the values as they > appear in the register, so shifted to the right to the position the > value appears in the register. > > This commit changes those constants to their natural values (e.g, 0, 1, > 2, etc.), as they are after shifting the register value to the right. > This also changes all relevant code to shift the values before comparing > them with constants. > > This has the advantage that the values can be stored in smaller > variables (now they always require a u32) and makes the handling of > these values more consistent with other register fields that represent > natural numbers instead of enumerations (e.g., number of host channels).
Hi Matthijs, Are you sure the advantages outweigh the drawbacks and the amount of code churn here? There are a lot of changes similar to this: > - u32 hs_phy_type = hsotg->hwcfg2 & GHWCFG2_HS_PHY_TYPE_MASK; > - u32 fs_phy_type = hsotg->hwcfg2 & GHWCFG2_FS_PHY_TYPE_MASK; > + u32 hs_phy_type = (hsotg->hwcfg2 & GHWCFG2_HS_PHY_TYPE_MASK) >> > + GHWCFG2_HS_PHY_TYPE_SHIFT; > + u32 fs_phy_type = (hsotg->hwcfg2 & GHWCFG2_FS_PHY_TYPE_MASK) >> > + GHWCFG2_FS_PHY_TYPE_SHIFT; I.e we went from two lines of code to four. Other than saving a tiny amount of RAM by being able to store the config values in a smaller variable, are there any other advantages? -- Paul -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
