sdhci: Be more strict with get_min_clock() usage

PATCH New Anton Vorontsov 1 participant 1 message Aug 4, 2009 2 messages not in the archive

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MMC, SD and SDIO Secure digital host controller interface (SDHCI) driver

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Anton Vorontsov

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2009-08-04 17:20 UTC #2 lore raw

PATCH 1/1 sdhci: Be more strict with get_min_clock() usage

get_min_clock() makes sense only with NONSTANDARD_CLOCK quirk and when set_clock() callback is specified.

The patch should cause no functional changes, it just makes the code self-documented and avoids any possible misuse of get_min_clock().

Signed-off-by Anton Vorontsov <[email protected]>

---

On Sat, Aug 01, 2009 at 10:04:43AM +0200, Pierre Ossman wrote:
[...]

Quoted 2 lines

Hmm... I don't think this is quite right. Right now you kill the warning without verifying that there is a mechanism to go lower.

[...]

Quoted 10 lines

Review
Quoted 7 lines
(quoted diff) +4 -1
-	mmc->f_min = host->max_clk / 256;
+	if (host->ops->get_min_clock)
+		mmc->f_min = host->ops->get_min_clock(host);
+	else
+		mmc->f_min = host->max_clk / 256;
 	mmc->f_max = host->max_clk;
 	mmc->caps = MMC_CAP_SDIO_IRQ;
You should be checking ops->set_clock and SDHCI_QUIRK_NONSTANDARD_CLOCK here.

Well, it makes no sense to specify .get_min_clock() w/o .set_clock().

But okay, to make things self documented and to avoid misuses, we'd better add these checks.

Thanks Pierre!

 drivers/mmc/host/sdhci.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

drivers/mmc/host/sdhci.c +2 -1

index fc96f8c..7f7f45b 100644
@@ -1772,7 +1772,8 @@ int sdhci_add_host(struct sdhci_host *host)
 	 * Set host parameters.
 	 */
 	mmc->ops = &sdhci_ops;
-	if (host->ops->get_min_clock)
+	if (host->quirks & SDHCI_QUIRK_NONSTANDARD_CLOCK &&
+			host->ops->set_clock && host->ops->get_min_clock)
 		mmc->f_min = host->ops->get_min_clock(host);
 	else
 		mmc->f_min = host->max_clk / 256;

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