pwm: i.MX: fix clock lookup
The i.MX PWM core has two clocks: The ipg clock and the ipg highfreq
(peripheral) clock. The ipg clock has to be enabled for this hardware
to work. The actual PWM output can either be driven by the ipg clock
or the ipg highfreq. The ipg highfreq has the advantage that it runs
even when the SoC is in low power modes.
This patch requests both clocks and enables the ipg clock for accessing
registers and the peripheral clock to actually turn on the PWM.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Shawn Guo <shawn.guo@linaro.org>
Reviewed-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
diff --git a/drivers/pwm/pwm-imx.c b/drivers/pwm/pwm-imx.c
index 852de6c..8a5d3ae 100644
--- a/drivers/pwm/pwm-imx.c
+++ b/drivers/pwm/pwm-imx.c
@@ -40,7 +40,8 @@
#define MX3_PWMCR_EN (1 << 0)
struct imx_chip {
- struct clk *clk;
+ struct clk *clk_per;
+ struct clk *clk_ipg;
int enabled;
void __iomem *mmio_base;
@@ -106,7 +107,7 @@
unsigned long period_cycles, duty_cycles, prescale;
u32 cr;
- c = clk_get_rate(imx->clk);
+ c = clk_get_rate(imx->clk_per);
c = c * period_ns;
do_div(c, 1000000000);
period_cycles = c;
@@ -161,8 +162,17 @@
struct pwm_device *pwm, int duty_ns, int period_ns)
{
struct imx_chip *imx = to_imx_chip(chip);
+ int ret;
- return imx->config(chip, pwm, duty_ns, period_ns);
+ ret = clk_prepare_enable(imx->clk_ipg);
+ if (ret)
+ return ret;
+
+ ret = imx->config(chip, pwm, duty_ns, period_ns);
+
+ clk_disable_unprepare(imx->clk_ipg);
+
+ return ret;
}
static int imx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
@@ -170,7 +180,7 @@
struct imx_chip *imx = to_imx_chip(chip);
int ret;
- ret = clk_prepare_enable(imx->clk);
+ ret = clk_prepare_enable(imx->clk_per);
if (ret)
return ret;
@@ -187,7 +197,7 @@
imx->set_enable(chip, false);
- clk_disable_unprepare(imx->clk);
+ clk_disable_unprepare(imx->clk_per);
imx->enabled = 0;
}
@@ -239,10 +249,19 @@
return -ENOMEM;
}
- imx->clk = devm_clk_get(&pdev->dev, "pwm");
+ imx->clk_per = devm_clk_get(&pdev->dev, "per");
+ if (IS_ERR(imx->clk_per)) {
+ dev_err(&pdev->dev, "getting per clock failed with %ld\n",
+ PTR_ERR(imx->clk_per));
+ return PTR_ERR(imx->clk_per);
+ }
- if (IS_ERR(imx->clk))
- return PTR_ERR(imx->clk);
+ imx->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
+ if (IS_ERR(imx->clk_ipg)) {
+ dev_err(&pdev->dev, "getting ipg clock failed with %ld\n",
+ PTR_ERR(imx->clk_ipg));
+ return PTR_ERR(imx->clk_ipg);
+ }
imx->chip.ops = &imx_pwm_ops;
imx->chip.dev = &pdev->dev;
