On Wed, Feb 20, 2013 at 06:25:13PM +0100, Stephen Warren wrote: > On 02/20/2013 06:26 AM, Laxman Dewangan wrote: > > On Wednesday 20 February 2013 06:41 PM, Mark Brown wrote: > >> * PGP Signed by an unknown key > >> > >> On Wed, Feb 20, 2013 at 05:59:03PM +0530, Laxman Dewangan wrote: > >>>>> + tspi->clk = devm_clk_get(&pdev->dev, "spi"); > >>>> Does this HW block use multiple clocks? If not, I think s/"spi"/NULL/ > >>>> there, just like the Tegra20 driver. > >>> No, spi controller uses the only one clock. I will change to NULL. > >> I'm never convinced that NULL is a helpful clock name to pick, it's not > >> awesome if you ever acquire a second clock. > > > > I had other idea of okeeping clock name here for power optimization. > > Spi controller can take the power source ffrom different clock source > > say clk_m (crystal) and pllp. > > > > I want to set the parent clock dynamically based on required speed so > > that if the desire speed can be meet from clk_m, no need to increase pll > > count and possible we may endup with siwtchng off pllp which can save > > power. > > > > So for this I may require > > > > spi_clk = devm_clk_get(&pdev->dev, "spi"); > > spi_clkm = devm_clk_get(&pdev->dev, "clmkm"); > > spi_pllp = devm_clk_get(&pdev->dev, "pllp"); > > > > and call clk_set_parent(spi_clk, spi_clkm) or clk_set_parent(spi_clk, > > spi_pllp). > > OK, so that's certainly an argument for requesting a specific clock name > rather than NULL. > The list of possible parents for each clock is determined by the SoC and is already known to CCF, so maybe we just need to add a function to CCF to allow the drivers to query the list of possible parents? Cheers, Peter. -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
