diff options
author | Tony Prisk <linux@prisktech.co.nz> | 2013-01-02 19:44:16 (GMT) |
---|---|---|
committer | Thierry Reding <thierry.reding@avionic-design.de> | 2013-01-09 07:17:12 (GMT) |
commit | 3ccb1c1702ed4bb07006d20c8173899a69dae242 (patch) | |
tree | ef55173274b60bec942b0dcfc15f1df3614029fe | |
parent | 8ab432caa46413c9f3ca81d82ea9fa5bae07c3c1 (diff) | |
download | linux-fsl-qoriq-3ccb1c1702ed4bb07006d20c8173899a69dae242.tar.xz |
pwm: vt8500: Add polarity support
Add support to set polarity on PWM devices, allowing for inverted
duty cycles.
Also update the binding document to #pwm-cells = <3> to allow
passing the flags from devicetree.
Signed-off-by: Tony Prisk <linux@prisktech.co.nz>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
-rw-r--r-- | Documentation/devicetree/bindings/pwm/vt8500-pwm.txt | 9 | ||||
-rw-r--r-- | drivers/pwm/pwm-vt8500.c | 23 |
2 files changed, 29 insertions, 3 deletions
diff --git a/Documentation/devicetree/bindings/pwm/vt8500-pwm.txt b/Documentation/devicetree/bindings/pwm/vt8500-pwm.txt index bcc6367..d21d82d 100644 --- a/Documentation/devicetree/bindings/pwm/vt8500-pwm.txt +++ b/Documentation/devicetree/bindings/pwm/vt8500-pwm.txt @@ -3,14 +3,17 @@ VIA/Wondermedia VT8500/WM8xxx series SoC PWM controller Required properties: - compatible: should be "via,vt8500-pwm" - reg: physical base address and length of the controller's registers -- #pwm-cells: should be 2. The first cell specifies the per-chip index - of the PWM to use and the second cell is the period in nanoseconds. +- #pwm-cells: Should be 3. Number of cells being used to specify PWM property. + First cell specifies the per-chip index of the PWM to use, the second + cell is the period in nanoseconds and bit 0 in the third cell is used to + encode the polarity of PWM output. Set bit 0 of the third in PWM specifier + to 1 for inverse polarity & set to 0 for normal polarity. - clocks: phandle to the PWM source clock Example: pwm1: pwm@d8220000 { - #pwm-cells = <2>; + #pwm-cells = <3>; compatible = "via,vt8500-pwm"; reg = <0xd8220000 0x1000>; clocks = <&clkpwm>; diff --git a/drivers/pwm/pwm-vt8500.c b/drivers/pwm/pwm-vt8500.c index bbc3750..98d79e9 100644 --- a/drivers/pwm/pwm-vt8500.c +++ b/drivers/pwm/pwm-vt8500.c @@ -164,10 +164,31 @@ static void vt8500_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) clk_disable(vt8500->clk); } +static int vt8500_pwm_set_polarity(struct pwm_chip *chip, + struct pwm_device *pwm, + enum pwm_polarity polarity) +{ + struct vt8500_chip *vt8500 = to_vt8500_chip(chip); + u32 val; + + val = readl(vt8500->base + REG_CTRL(pwm->hwpwm)); + + if (polarity == PWM_POLARITY_INVERSED) + val |= CTRL_INVERT; + else + val &= ~CTRL_INVERT; + + writel(val, vt8500->base + REG_CTRL(pwm->hwpwm)); + pwm_busy_wait(vt8500, pwm->hwpwm, STATUS_CTRL_UPDATE); + + return 0; +} + static struct pwm_ops vt8500_pwm_ops = { .enable = vt8500_pwm_enable, .disable = vt8500_pwm_disable, .config = vt8500_pwm_config, + .set_polarity = vt8500_pwm_set_polarity, .owner = THIS_MODULE, }; @@ -197,6 +218,8 @@ static int vt8500_pwm_probe(struct platform_device *pdev) chip->chip.dev = &pdev->dev; chip->chip.ops = &vt8500_pwm_ops; + chip->chip.of_xlate = of_pwm_xlate_with_flags; + chip->chip.of_pwm_n_cells = 3; chip->chip.base = -1; chip->chip.npwm = VT8500_NR_PWMS; |