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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Jiri Slaby <jirislaby@kernel.org>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Dennis Giaya <dgiaya@whoi.edu>
Subject: [PATCH v2 1/1] serial: max310x: Use clock-names property matching to recognize EXTCLK
Date: Fri, 23 Jul 2021 15:59:43 +0300	[thread overview]
Message-ID: <20210723125943.22039-1-andriy.shevchenko@linux.intel.com> (raw)

Dennis reported that on ACPI-based systems the clock frequency
isn't enough to configure device properly. We have to respect
the clock source as well. To achieve this match the clock-names
property against "osc" to recognize external clock connection.
On DT-based system this doesn't change anything.

Reported-and-tested-by: Dennis Giaya <dgiaya@whoi.edu>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
v2: added Tested-by tag (Dennis), inverted comparison to leave original flow
 drivers/tty/serial/max310x.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c
index ef11860cd69e..3df0788ddeb0 100644
--- a/drivers/tty/serial/max310x.c
+++ b/drivers/tty/serial/max310x.c
@@ -1271,18 +1271,13 @@ static int max310x_probe(struct device *dev, const struct max310x_devtype *devty
 	/* Always ask for fixed clock rate from a property. */
 	device_property_read_u32(dev, "clock-frequency", &uartclk);
 
-	s->clk = devm_clk_get_optional(dev, "osc");
+	xtal = device_property_match_string(dev, "clock-names", "osc") < 0;
+	if (xtal)
+		s->clk = devm_clk_get_optional(dev, "xtal");
+	else
+		s->clk = devm_clk_get_optional(dev, "osc");
 	if (IS_ERR(s->clk))
 		return PTR_ERR(s->clk);
-	if (s->clk) {
-		xtal = false;
-	} else {
-		s->clk = devm_clk_get_optional(dev, "xtal");
-		if (IS_ERR(s->clk))
-			return PTR_ERR(s->clk);
-
-		xtal = true;
-	}
 
 	ret = clk_prepare_enable(s->clk);
 	if (ret)
-- 
2.30.2


             reply	other threads:[~2021-07-23 12:59 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-23 12:59 Andy Shevchenko [this message]
2021-07-28 14:52 ` Dennis Giaya
2021-07-28 15:19   ` andriy.shevchenko

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