Messages in this thread | | | From | Andy Shevchenko <> | Date | Sat, 7 Dec 2019 16:57:43 +0200 | Subject | Re: [PATCH v1 1/2] clk: intel: Add CGU clock driver for a new SoC |
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On Fri, Dec 6, 2019 at 7:06 AM Tanwar, Rahul <rahul.tanwar@linux.intel.com> wrote: > On 2/9/2019 8:24 PM, Andy Shevchenko wrote: > > On Mon, Sep 02, 2019 at 03:20:30PM +0300, Andy Shevchenko wrote: > >> On Mon, Sep 02, 2019 at 03:43:13PM +0800, Tanwar, Rahul wrote: > >>> On 28/8/2019 11:09 PM, Andy Shevchenko wrote: > >>>> On Wed, Aug 28, 2019 at 03:00:17PM +0800, Rahul Tanwar wrote:
> >>>>> + { .val = 0, .div = 1 }, > >>>>> + { .val = 1, .div = 2 }, > >>>>> + { .val = 2, .div = 3 }, > >> 1 > >> > >>>>> + { .val = 3, .div = 4 }, > >>>>> + { .val = 4, .div = 5 }, > >>>>> + { .val = 5, .div = 6 }, > >> 1 > >> > >>>>> + { .val = 6, .div = 8 }, > >>>>> + { .val = 7, .div = 10 }, > >>>>> + { .val = 8, .div = 12 }, > >> 2 > >> > >>>>> + { .val = 9, .div = 16 }, > >>>>> + { .val = 10, .div = 20 }, > >>>>> + { .val = 11, .div = 24 }, > >> 4 > >> > >>>>> + { .val = 12, .div = 32 }, > >>>>> + { .val = 13, .div = 40 }, > >>>>> + { .val = 14, .div = 48 }, > >> 8 > >> > >>>>> + { .val = 15, .div = 64 }, > >> 16 > >> > >> > >> So, now we see the pattern: > >> > >> div = val < 3 ? (val + 1) : (1 << ((val - 3) / 3)); > > It's not complete, but I think you got the idea. > > > >> So, can we eliminate table? > > In the desperation to eliminate table, below is what i can come up with: > > struct clk_div_table div_table[16];
But this is not an elimination, it's just a replacement from static to dynamically calculated one.
> int i, j; > > for (i = 0; i < 16; i++) > div_table[i].val = i; > > for (i = 0, j=0; i < 16; i+=3, j++) { > div_table[i].div = (i == 0) ? (1 << j) : (1 << (j + 1)); > if (i == 15) > break; > > div_table[i + 1].div = (i == 0) ? ((1 << j) + 1) : > (1 << (j + 1)) + (1 << (j - 1)); > div_table[i + 2].div = (3 << j); > } > > To me, table still looks a better approach. Also, table is more extendable & > consistent w.r.t. clk framework & other referenced clk drivers. > > Whats your opinion ?
Whatever CCF maintainers is fine with.
-- With Best Regards, Andy Shevchenko
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