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authorPhilipp Zabel <p.zabel@pengutronix.de>2012-06-25 16:15:20 +0200
committerThierry Reding <thierry.reding@avionic-design.de>2012-09-12 14:25:07 +0200
commit7b27c160c68152581c702b9f1fe362338d2a0cad (patch)
tree0fb2f975f42b1aadcbddb2ff25b06f7c525b112e /drivers/pwm
parent8d1c24bfd20829f5943c76b85c4973db264dd666 (diff)
downloadop-kernel-dev-7b27c160c68152581c702b9f1fe362338d2a0cad.zip
op-kernel-dev-7b27c160c68152581c702b9f1fe362338d2a0cad.tar.gz
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>
Diffstat (limited to 'drivers/pwm')
-rw-r--r--drivers/pwm/pwm-imx.c35
1 files changed, 27 insertions, 8 deletions
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 @@ static int imx_pwm_config_v2(struct pwm_chip *chip,
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 @@ static int imx_pwm_config(struct pwm_chip *chip,
struct pwm_device *pwm, int duty_ns, int period_ns)
{
struct imx_chip *imx = to_imx_chip(chip);
+ int ret;
+
+ ret = clk_prepare_enable(imx->clk_ipg);
+ if (ret)
+ return ret;
- return imx->config(chip, pwm, duty_ns, period_ns);
+ 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 @@ static int imx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
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 @@ static void imx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
imx->set_enable(chip, false);
- clk_disable_unprepare(imx->clk);
+ clk_disable_unprepare(imx->clk_per);
imx->enabled = 0;
}
@@ -239,10 +249,19 @@ static int __devinit imx_pwm_probe(struct platform_device *pdev)
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;
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