linux-kernel - [PATCH v2] serial: sifive: enable clocks for UART when probed

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Date:   Tue, 20 Sep 2022 09:00:18 -0700
From:   Olof Johansson <olof@...om.net>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Jiri Slaby <jirislaby@...nel.org>, linux-serial@...r.kernel.org,
        linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Olof Johansson <olof@...om.net>,
        Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>,
        Emil Renner Berthing <emil.renner.berthing@...onical.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Paul Walmsley <paul.walmsley@...ive.com>
Subject: [PATCH v2] serial: sifive: enable clocks for UART when probed

When the PWM driver was changed to disable clocks if no PWMs are enabled,
it ended up also disabling the shared parent with the UART, since the
UART doesn't do any clock enablement on its own.

To avoid these surprises, switch to clk_get_enabled().

Fixes: ace41d7564e655 ("pwm: sifive: Ensure the clk is enabled exactly once per running PWM")
Cc: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
Cc: Emil Renner Berthing <emil.renner.berthing@...onical.com>
Cc: Palmer Dabbelt <palmer@...belt.com>
Cc: Paul Walmsley <paul.walmsley@...ive.com>
Signed-off-by: Olof Johansson <olof@...om.net>

---

v2: Switch to devm_clk_enabled() per Uwe's suggestion.

---
 drivers/tty/serial/sifive.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/sifive.c b/drivers/tty/serial/sifive.c
index 5c3a07546a58..4b1d4fe8458e 100644
--- a/drivers/tty/serial/sifive.c
+++ b/drivers/tty/serial/sifive.c
@@ -945,7 +945,7 @@ static int sifive_serial_probe(struct platform_device *pdev)
 		return PTR_ERR(base);
 	}
 
-	clk = devm_clk_get(&pdev->dev, NULL);
+	clk = devm_clk_get_enabled(&pdev->dev, NULL);
 	if (IS_ERR(clk)) {
 		dev_err(&pdev->dev, "unable to find controller clock\n");
 		return PTR_ERR(clk);
-- 
2.30.2