On Thu, Jan 16, 2014 at 09:06:25AM +0100, Lothar Waßmann wrote: > The i.MX PWM controller supports inverting the polarity of the PWM > output. Make this feature available in the pxm-imx driver. > > Signed-off-by: Lothar Waßmann <LW@xxxxxxxxxxxxxxxxxxx> > --- > Documentation/devicetree/bindings/pwm/imx-pwm.txt | 5 +- > drivers/pwm/pwm-imx.c | 42 +++++++++++++++++++++ > 2 files changed, 45 insertions(+), 2 deletions(-) > > diff --git a/Documentation/devicetree/bindings/pwm/imx-pwm.txt b/Documentation/devicetree/bindings/pwm/imx-pwm.txt > index b50d7a6d..d0b04b5 100644 > --- a/Documentation/devicetree/bindings/pwm/imx-pwm.txt > +++ b/Documentation/devicetree/bindings/pwm/imx-pwm.txt > @@ -3,8 +3,9 @@ Freescale i.MX PWM controller > Required properties: > - compatible: should be "fsl,<soc>-pwm" > - reg: physical base address and length of the controller's registers > -- #pwm-cells: should be 2. See pwm.txt in this directory for a description of > - the cells format. > +- #pwm-cells: may be 2 for backwards compatibility or 3 to support > + switching the output polarity. See pwm.txt in this directory for a > + description of the cells format. > - interrupts: The interrupt for the pwm controller > > Example: > diff --git a/drivers/pwm/pwm-imx.c b/drivers/pwm/pwm-imx.c > index 3b00a82..05461bb 100644 > --- a/drivers/pwm/pwm-imx.c > +++ b/drivers/pwm/pwm-imx.c > @@ -36,6 +36,7 @@ > #define MX3_PWMCR_DOZEEN (1 << 24) > #define MX3_PWMCR_WAITEN (1 << 23) > #define MX3_PWMCR_DBGEN (1 << 22) > +#define MX3_PWMCR_POUTC (1 << 18) > #define MX3_PWMCR_CLKSRC_IPG_HIGH (2 << 16) > #define MX3_PWMCR_CLKSRC_IPG (1 << 16) > #define MX3_PWMCR_EN (1 << 0) > @@ -138,6 +139,9 @@ static int imx_pwm_config_v2(struct pwm_chip *chip, > if (test_bit(PWMF_ENABLED, &pwm->flags)) > cr |= MX3_PWMCR_EN; > > + if (pwm->polarity == PWM_POLARITY_INVERSED) > + cr |= MX3_PWMCR_POUTC; > + > writel(cr, imx->mmio_base + MX3_PWMCR); > > return 0; > @@ -155,6 +159,11 @@ static void imx_pwm_set_enable_v2(struct pwm_chip *chip, bool enable) > else > val &= ~MX3_PWMCR_EN; > > + if (chip->pwms[0].polarity == PWM_POLARITY_INVERSED) > + val |= MX3_PWMCR_POUTC; > + else > + val &= ~MX3_PWMCR_POUTC; > + > writel(val, imx->mmio_base + MX3_PWMCR); > } > > @@ -198,6 +207,17 @@ static void imx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) > clk_disable_unprepare(imx->clk_per); > } > > +static int imx_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm, > + enum pwm_polarity polarity) > +{ > + struct imx_chip *imx = to_imx_chip(chip); > + > + dev_dbg(imx->chip.dev, "%s: polarity set to %s\n", __func__, > + polarity == PWM_POLARITY_INVERSED ? "inverted" : "normal"); > + > + return 0; > +} > + > static struct pwm_ops imx_pwm_ops = { > .enable = imx_pwm_enable, > .disable = imx_pwm_disable, > @@ -209,6 +229,7 @@ struct imx_pwm_data { > int (*config)(struct pwm_chip *chip, > struct pwm_device *pwm, int duty_ns, int period_ns); > void (*set_enable)(struct pwm_chip *chip, bool enable); > + unsigned output_polarity:1; > }; > > static struct imx_pwm_data imx_pwm_data_v1 = { > @@ -219,6 +240,7 @@ static struct imx_pwm_data imx_pwm_data_v1 = { > static struct imx_pwm_data imx_pwm_data_v2 = { > .config = imx_pwm_config_v2, > .set_enable = imx_pwm_set_enable_v2, > + .output_polarity = 1, > }; > > static const struct of_device_id imx_pwm_dt_ids[] = { > @@ -271,6 +293,26 @@ static int imx_pwm_probe(struct platform_device *pdev) > return PTR_ERR(imx->mmio_base); > > data = of_id->data; > + if (data->output_polarity) { > + const struct device_node *np = pdev->dev.of_node; > + u32 num_cells; > + > + dev_dbg(&pdev->dev, "PWM supports output inversion\n"); > + ret = of_property_read_u32(np, "#pwm-cells", &num_cells); > + if (ret < 0) { > + dev_err(&pdev->dev, "missing property '#pwm-cells'\n"); > + return ret; > + } > + if (num_cells == 3) { > + imx_pwm_ops.set_polarity = imx_pwm_set_polarity; > + imx->chip.of_xlate = of_pwm_xlate_with_flags; > + } else if (num_cells != 2) { > + dev_err(&pdev->dev, "'#pwm-cells' must be <2> or <3>\n"); > + return -EINVAL; > + } > + imx->chip.of_pwm_n_cells = num_cells; > + } Can't this be done in the PWM core? Right now the PWM core checks for of_pwm_n_cells before calling ->of_xlate. IMO this check should be done in the of_xlate hook. Then of_pwm_simple_xlate and of_pwm_xlate_with_flags can be merged into something like: static struct pwm_device * of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args) { struct pwm_device *pwm; int ret; if (pc->of_pwm_n_cells < 2) return ERR_PTR(-EINVAL); if (args->args[0] >= pc->npwm) return ERR_PTR(-EINVAL); pwm = pwm_request_from_chip(pc, args->args[0], NULL); if (IS_ERR(pwm)) return pwm; if (pc->of_pwm_n_cells >= 3) { if (args->args[2] & PWM_POLARITY_INVERTED) ret = pwm_set_polarity(pwm, PWM_POLARITY_INVERSED); else ret = pwm_set_polarity(pwm, PWM_POLARITY_NORMAL); if (ret) return ret; } pwm_set_period(pwm, args->args[1]); return pwm; } Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html