[PATCH 4/5] BCM2835: add support (arch)
Sascha Hauer
s.hauer at pengutronix.de
Thu Oct 18 03:02:11 EDT 2012
On Thu, Oct 18, 2012 at 12:27:14AM +0200, Carlo Caione wrote:
>
> On Oct 16, 2012, at 11:24 PM, Sascha Hauer <s.hauer at pengutronix.de> wrote:
>
> > On Tue, Oct 16, 2012 at 08:04:44PM +0200, Carlo Caione wrote:
> >> +
> >> +static struct clk ref_3_clk = {
> >> + .rate = 3 * 1000 * 1000,
> >> +};
> >> +
> >> +static struct clk ref_1_clk = {
> >> + .rate = 1 * 1000 * 1000,
> >> +};
> >
> > Add a 'select COMMON_CLK' to your Kconfig and do a:
> >
> > clk_dummy = clk_fixed("dummy", 0);
> > clk_ref_3 = clk_fixed("ref3", 3 * 1000 * 1000);
> > clk_ref_1 = clk_fixed("ref1", 1 * 1000 * 1000);
> >
> > Then you can drop your clk code and get a clk_dump command
> > which you can use to see what clocks you have.
>
> RFC
>
> ok I ask here before submitting the whole set because I'm not sure if this is a convenient solution.
> I'm not sure if you are suggesting to have two different clock definition one for clk_fixed and the other one for clkdev,
> so I was thinking something like:
>
> enum brcm_clks {
> dummy, clk_ref_3, clk_ref_1, clks_max
> };
>
> static struct clk *clks[clks_max];
>
> int brmc_clk_create(struct clk *clk, const char *con_id, const char *dev_id)
> {
> struct clk_lookup *clkdev;
>
> clkdev = clkdev_alloc(clk, con_id, dev_id);
> if (!clkdev)
> return -ENOMEM;
> clkdev_add(clkdev);
> return 0;
> }
>
> static int bcm2835_clk_init(void)
> {
> int ret;
>
> clks[dummy] = clk_fixed("dummy", 0);
> ret = brmc_clk_create(clks[dummy], "apb_pclk", NULL);
> if (ret)
> goto clk_err;
>
> clks[clk_ref_3] = clk_fixed("ref3", 3 * 1000 * 1000);
> ret = brmc_clk_create(clks[clk_ref_3], NULL, "uart0-pl0110");
> if (ret)
> goto clk_err;
>
> clks[clk_ref_1] = clk_fixed("ref1", 1 * 1000 * 1000);
> ret = brmc_clk_create(clks[clk_ref_1], NULL, "bcm2835-cs");
> if (ret)
> goto clk_err;
The above is basically what I was thinking of. The only thing I see that
this *looks* like there is exactly one lookup per clock. This indeed is
the case currenty here, but this does not have to be true. A clock may
have multiple lookups, for example the ref3 clk may also be used by the
lcd controller or something else. So I suggest to first register all
clocks and the lookups afterwards.
What you have as brmc_clk_create could well be a generic helper
function, it will be useful for others aswell.
BTW error checking here is a good idea, but a rollback of the allocated
resources will be unnecessary as you are doomed anyway when something
fails here.
Sascha
--
Pengutronix e.K. | |
Industrial Linux Solutions | http://www.pengutronix.de/ |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
More information about the barebox
mailing list