From: Sean Anderson <seanga2@gmail.com>
To: u-boot@lists.denx.de, Leo Liang <ycliang@andestech.com>
Cc: Bin Meng <bmeng.cn@gmail.com>,
Damien Le Moal <Damien.LeMoal@wdc.com>,
Lukasz Majewski <lukma@denx.de>,
Sean Anderson <seanga2@gmail.com>, Simon Glass <sjg@chromium.org>
Subject: [PATCH v2 4/4] clk: k210: Try harder to get the best config
Date: Sat, 11 Sep 2021 13:20:03 -0400 [thread overview]
Message-ID: <20210911172003.899301-4-seanga2@gmail.com> (raw)
In-Reply-To: <20210911172003.899301-1-seanga2@gmail.com>
In some cases, the best config cannot be used because the VCO would be
out-of-spec. In these cases, we may need to try a worse combination of r/od
in order to find the best representable config. This also adds a few test
cases to catch this and other (possible) unlikely errors.
Signed-off-by: Sean Anderson <seanga2@gmail.com>
---
(no changes since v1)
drivers/clk/clk_kendryte.c | 24 ++++++++++++++++++++++++
test/dm/k210_pll.c | 4 ++++
2 files changed, 28 insertions(+)
diff --git a/drivers/clk/clk_kendryte.c b/drivers/clk/clk_kendryte.c
index 69691c4a04..97efda5b6f 100644
--- a/drivers/clk/clk_kendryte.c
+++ b/drivers/clk/clk_kendryte.c
@@ -816,6 +816,30 @@ again:
i--;
}
+ /*
+ * Try looking back to see if there is a worse ratio
+ * that we could try anyway
+ */
+ while (i > 0) {
+ i--;
+ new_r = UNPACK_R(factors[i]);
+ new_od = UNPACK_OD(factors[i]);
+ /*
+ * Don't loop over factors for the same product
+ * to avoid getting stuck because of the above
+ * clause
+ */
+ if (r * od != new_r * new_od) {
+ if (new_r * new_od > last_r * last_od) {
+ r = new_r;
+ od = new_od;
+ swapped = false;
+ goto again;
+ }
+ break;
+ }
+ }
+
/* We ran out of things to try */
continue;
}
diff --git a/test/dm/k210_pll.c b/test/dm/k210_pll.c
index 5574ac96fa..f55379f336 100644
--- a/test/dm/k210_pll.c
+++ b/test/dm/k210_pll.c
@@ -84,6 +84,10 @@ static int dm_test_k210_pll(struct unit_test_state *uts)
compare(400000000, 26000000);
compare(27000000, 26000000);
compare(26000000, 27000000);
+ compare(13300000 * 64, 13300000);
+ compare(21250000, 21250000 * 70);
+ compare(21250000, 1750000000);
+ compare(1750000000, 1750000000);
return 0;
}
--
2.33.0
next prev parent reply other threads:[~2021-09-11 17:21 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-11 17:20 [PATCH v2 1/4] clk: k210: Fix checking if ulongs are less than 0 Sean Anderson
2021-09-11 17:20 ` [PATCH v2 2/4] k210: clk: Refactor out_of_spec tests Sean Anderson
2021-09-14 8:45 ` Leo Liang
2021-09-11 17:20 ` [PATCH v2 3/4] test: dm: k210: Reduce duplication in test cases Sean Anderson
2021-09-14 8:48 ` Leo Liang
2021-09-11 17:20 ` Sean Anderson [this message]
2021-09-30 4:08 ` [PATCH v2 4/4] clk: k210: Try harder to get the best config Simon Glass
2021-09-14 8:39 ` [PATCH v2 1/4] clk: k210: Fix checking if ulongs are less than 0 Leo Liang
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210911172003.899301-4-seanga2@gmail.com \
--to=seanga2@gmail.com \
--cc=Damien.LeMoal@wdc.com \
--cc=bmeng.cn@gmail.com \
--cc=lukma@denx.de \
--cc=sjg@chromium.org \
--cc=u-boot@lists.denx.de \
--cc=ycliang@andestech.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).