From: "Clément Péron" <peron.clem@gmail.com>
To: "Thierry Reding" <thierry.reding@gmail.com>,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
"Rob Herring" <robh+dt@kernel.org>,
"Mark Rutland" <mark.rutland@arm.com>,
"Maxime Ripard" <mripard@kernel.org>,
"Chen-Yu Tsai" <wens@csie.org>,
"Philipp Zabel" <pza@pengutronix.de>
Cc: linux-pwm@vger.kernel.org, devicetree@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-sunxi@googlegroups.com,
"Clément Péron" <peron.clem@gmail.com>
Subject: [PATCH v7 3/8] pwm: sun4i: Prefer "mod" clock to unnamed
Date: Tue, 19 Nov 2019 18:53:14 +0100 [thread overview]
Message-ID: <20191119175319.16561-4-peron.clem@gmail.com> (raw)
In-Reply-To: <20191119175319.16561-1-peron.clem@gmail.com>
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(-)
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)) {
--
2.20.1
next prev parent reply other threads:[~2019-11-19 17:54 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-19 17:53 [PATCH v7 0/8] Add support for H6 PWM Clément Péron
2019-11-19 17:53 ` [PATCH v7 1/8] dt-bindings: pwm: allwinner: Add H6 PWM description Clément Péron
2019-11-19 17:53 ` [PATCH v7 2/8] pwm: sun4i: Add an optional probe for reset line Clément Péron
2019-11-19 17:53 ` Clément Péron [this message]
2019-11-21 7:26 ` [PATCH v7 3/8] pwm: sun4i: Prefer "mod" clock to unnamed Uwe Kleine-König
2019-11-19 17:53 ` [PATCH v7 4/8] pwm: sun4i: Add an optional probe for bus clock Clément Péron
2019-11-21 7:28 ` Uwe Kleine-König
2019-11-21 11:14 ` Clément Péron
2019-11-19 17:53 ` [PATCH v7 5/8] pwm: sun4i: Add support to output source clock directly Clément Péron
2019-11-21 7:36 ` Uwe Kleine-König
2019-11-21 11:38 ` Clément Péron
2019-11-19 17:53 ` [PATCH v7 6/8] pwm: sun4i: Add support for H6 PWM Clément Péron
2019-11-19 17:53 ` [PATCH v7 7/8] arm64: dts: allwinner: h6: Add PWM node Clément Péron
2019-11-19 17:53 ` [PATCH v7 8/8] [DO NOT MERGE] arm64: allwinner: h6: enable Beelink GS1 PWM Clément Péron
2019-11-21 7:24 ` [PATCH v7 0/8] Add support for H6 PWM Maxime Ripard
2019-12-10 16:48 ` Rob Herring
2019-12-10 17:20 ` Clément Péron
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