[v6,3/8] pwm: sun4i: Prefer "mod" clock to unnamed
diff mbox series

Message ID 20191118110034.19444-4-peron.clem@gmail.com
State New
Headers show
Series
  • Add support for H6 PWM
Related show

Commit Message

Clément Péron Nov. 18, 2019, 11 a.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(-)

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)) {