From mboxrd@z Thu Jan 1 00:00:00 1970 From: maxime.ripard@free-electrons.com (Maxime Ripard) Date: Fri, 26 Aug 2016 22:49:14 +0200 Subject: [PATCH v2 1/5] ethernet: add sun8i-emac driver In-Reply-To: <20160824120221.GB29212@Red> References: <1469001800-11615-1-git-send-email-clabbe.montjoie@gmail.com> <1469001800-11615-2-git-send-email-clabbe.montjoie@gmail.com> <20160725195455.GQ7419@lukather> <20160824120221.GB29212@Red> Message-ID: <20160826204914.GD3165@lukather> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, On Wed, Aug 24, 2016 at 02:02:21PM +0200, LABBE Corentin wrote: > > > +/* Set Management Data Clock, must be call after device reset */ > > > +static void sun8i_emac_set_mdc(struct net_device *ndev) > > > +{ > > > + struct sun8i_emac_priv *priv = netdev_priv(ndev); > > > + unsigned long rate; > > > + u32 reg; > > > + > > > + rate = clk_get_rate(priv->ahb_clk); > > > + if (rate > 160000000) > > > + reg = 0x3 << 20; /* AHB / 128 */ > > > + else if (rate > 80000000) > > > + reg = 0x2 << 20; /* AHB / 64 */ > > > + else if (rate > 40000000) > > > + reg = 0x1 << 20; /* AHB / 32 */ > > > + else > > > + reg = 0x0 << 20; /* AHB / 16 */ > > > + netif_dbg(priv, link, ndev, "MDC auto : %x\n", reg); > > > + writel(reg, priv->base + SUN8I_EMAC_MDIO_CMD); > > > > You could also expose that as a clock. > > > > For which purpose ? > No ethernet driver expose the MDC as clock and I dont see any interest: > - I dont think that tuning it give any gain > - Knowing it's value is of little interest You don't have to implement anything, you can just register a clk_div driver, and everything works, and you would use the proper clock APIs (ie. clk_set_rate, and that's it). That would be exposed just like any other clock, including in debugfs, which would remove the need for the debug call. But this really was just a suggestion. Maxime -- Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 819 bytes Desc: not available URL: