[v7,3/8] pwm: sun4i: Prefer "mod" clock to unnamed
diff mbox series

Message ID 20191119175319.16561-4-peron.clem@gmail.com
State New
Headers show
Series
  • Add support for H6 PWM
Related show

Commit Message

Clément Péron Nov. 19, 2019, 5:53 p.m. UTC
New device tree bindings called the source clock of the module
"mod" when several clocks are defined.

Try to get a clock called "mod" if nothing is found try to get
an unnamed clock.

Signed-off-by: Clément Péron <peron.clem@gmail.com>
---
 drivers/pwm/pwm-sun4i.c | 29 +++++++++++++++++++++++++++--
 1 file changed, 27 insertions(+), 2 deletions(-)

Comments

Uwe Kleine-König Nov. 21, 2019, 7:26 a.m. UTC | #1
On Tue, Nov 19, 2019 at 06:53:14PM +0100, Clément Péron wrote:
> New device tree bindings called the source clock of the module
> "mod" when several clocks are defined.
> 
> Try to get a clock called "mod" if nothing is found try to get
> an unnamed clock.
> 
> Signed-off-by: Clément Péron <peron.clem@gmail.com>

Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

Thanks
Uwe

Patch
diff mbox series

diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
index c17935805690..6d97fef4ed43 100644
--- a/drivers/pwm/pwm-sun4i.c
+++ b/drivers/pwm/pwm-sun4i.c
@@ -362,9 +362,34 @@  static int sun4i_pwm_probe(struct platform_device *pdev)
 	if (IS_ERR(pwm->base))
 		return PTR_ERR(pwm->base);
 
-	pwm->clk = devm_clk_get(&pdev->dev, NULL);
-	if (IS_ERR(pwm->clk))
+	/*
+	 * All hardware variants need a source clock that is divided and
+	 * then feeds the counter that defines the output wave form. In the
+	 * device tree this clock is either unnamed or called "mod".
+	 * Some variants (e.g. H6) need another clock to access the
+	 * hardware registers; this is called "bus".
+	 * So we request "mod" first (and ignore the corner case that a
+	 * parent provides a "mod" clock while the right one would be the
+	 * unnamed one of the PWM device) and if this is not found we fall
+	 * back to the first clock of the PWM.
+	 */
+	pwm->clk = devm_clk_get_optional(&pdev->dev, "mod");
+	if (IS_ERR(pwm->clk)) {
+		if (PTR_ERR(pwm->rst) != -EPROBE_DEFER)
+			dev_err(&pdev->dev, "get mod clock failed %pe\n",
+				pwm->clk);
 		return PTR_ERR(pwm->clk);
+	}
+
+	if (!pwm->clk) {
+		pwm->clk = devm_clk_get(&pdev->dev, NULL);
+		if (IS_ERR(pwm->clk)) {
+			if (PTR_ERR(pwm->rst) != -EPROBE_DEFER)
+				dev_err(&pdev->dev, "get unnamed clock failed %pe\n",
+					pwm->clk);
+			return PTR_ERR(pwm->clk);
+		}
+	}
 
 	pwm->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL);
 	if (IS_ERR(pwm->rst)) {