path: root/drivers/pwm/pwm-imx.c
diff options
authorSascha Hauer <s.hauer@pengutronix.de>2017-01-29 22:54:06 +0100
committerThierry Reding <thierry.reding@gmail.com>2017-01-30 09:12:18 +0100
commit9fb27fac39f47632aa32ffd787b4de1dbd0b8655 (patch)
treeb37543333010fa074c7971ddb55d1eff29c74f7d /drivers/pwm/pwm-imx.c
parentae2520540cb0090eb8cdba559bcb6a82266f0308 (diff)
pwm: imx: Remove ipg clock and enable per clock when required
The use of the ipg clock was introduced with commit 7b27c160c681 ("pwm: i.MX: fix clock lookup"). In the commit message it was claimed that the ipg clock is enabled for register accesses. This is true for the ->config() callback, but not for the ->set_enable() callback. Given that the ipg clock is not consistently enabled for all register accesses we can assume that either it is not required at all or that the current code does not work. Remove the ipg clock code for now so that it's no longer in the way of refactoring the driver. On the other hand, the i.MX 7 IP requires the peripheral clock to be enabled before accessing its registers. Since ->config() can be called when the PWM is disabled (in which case, the peripheral clock is also disabled), we need to surround the imx->config() with clk_prepare_enable(per_clk)/clk_disable_unprepare(per_clk) calls. Note that the driver was working fine for the i.MX 7 IP so far because the ipg and peripheral clock use the same hardware clock gate, which guaranteed peripheral clock activation even when ->config() was called when the PWM was disabled. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> Cc: Philipp Zabel <p.zabel@pengutronix.de> Reviewed-by: Stefan Agner <stefan@agner.ch> Tested-by: Stefan Agner <stefan@agner.ch> Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Diffstat (limited to 'drivers/pwm/pwm-imx.c')
1 files changed, 2 insertions, 10 deletions
diff --git a/drivers/pwm/pwm-imx.c b/drivers/pwm/pwm-imx.c
index 177fb81c916d..bb64122a74be 100644
--- a/drivers/pwm/pwm-imx.c
+++ b/drivers/pwm/pwm-imx.c
@@ -49,7 +49,6 @@
struct imx_chip {
struct clk *clk_per;
- struct clk *clk_ipg;
void __iomem *mmio_base;
@@ -206,13 +205,13 @@ static int imx_pwm_config(struct pwm_chip *chip,
struct imx_chip *imx = to_imx_chip(chip);
int ret;
- ret = clk_prepare_enable(imx->clk_ipg);
+ ret = clk_prepare_enable(imx->clk_per);
if (ret)
return ret;
ret = imx->config(chip, pwm, duty_ns, period_ns);
- clk_disable_unprepare(imx->clk_ipg);
+ clk_disable_unprepare(imx->clk_per);
return ret;
@@ -293,13 +292,6 @@ static int imx_pwm_probe(struct platform_device *pdev)
return PTR_ERR(imx->clk_per);
- 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;
imx->chip.base = -1;

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