This patch adds device tree support to the PXA's PWM driver. Only an OF match table is added; nothing needs to be extracted from the device tree node. The existing ID table is reused for the match table data. Tested on a Palm Treo 680 (both platform data and DT cases). Signed-off-by: Mike Dunn <mikedunn@xxxxxxxxxxx> --- Thanks Stephen for the reviews and explanations. Changle log: v4: - add second "compatible" string to pxa27x.dtsi - change phrasing in binding doc pxa-pwm.txt to "one or more of" v3: - remove support for the polarity flag - remove per-chip pwm index cell; define custom of_xlate() (now #pwm-cells = <1>) - "compatible" strings for all devices added to OF match table - various stylistic changes recommended by reviewers v2: - of_match_table contains only the "pxa250-pwm" compatible string; require one device instance per pwm - add Documentation/devicetree/bindings/pwm/pxa-pwm.txt - add support for polarity flag in DT and implement set_polarity() method (the treo 680 inverts the signal between pwm out and backlight) - return -EINVAL instead of -ENODEV if platform data or DT node not found - output dev_info string if platform data missing - expanded CC list of patch Documentation/devicetree/bindings/pwm/pxa-pwm.txt | 31 ++++++++++++ arch/arm/boot/dts/pxa27x.dtsi | 24 +++++++++ drivers/pwm/pwm-pxa.c | 62 +++++++++++++++++++++++ 3 files changed, 117 insertions(+) create mode 100644 Documentation/devicetree/bindings/pwm/pxa-pwm.txt diff --git a/Documentation/devicetree/bindings/pwm/pxa-pwm.txt b/Documentation/devicetree/bindings/pwm/pxa-pwm.txt new file mode 100644 index 0000000..01aca2e --- /dev/null +++ b/Documentation/devicetree/bindings/pwm/pxa-pwm.txt @@ -0,0 +1,31 @@ +Marvell PWM controller + +Required properties: +- compatible: should be one or more of: + - "marvell,pxa250-pwm" + - "marvell,pxa270-pwm" + - "marvell,pxa168-pwm" + - "marvell,pxa910-pwm" +- reg: physical base address and length of the registers used by the PWM channel + NB: One device instance must be created for each PWM that is used, so the + length covers only the register window for one PWM output, not that of the + entire PWM controller. Currently length is 0x10 for all supported devices. +- #pwm-cells: should be 1. This cell is used to specify the period in + nanoseconds. (Because one device instance is created for each PWM output, + the per-chip index is superflous and not used.) + +Example PWM device node: + +pwm0: pwm@40b00000 { + compatible = "marvell,pxa250-pwm"; + reg = <0x40b00000 0x10>; + #pwm-cells = <1>; +}; + +Example PWM client node: + +backlight { + compatible = "pwm-backlight"; + pwms = <&pwm0 5000000>; + ... +} diff --git a/arch/arm/boot/dts/pxa27x.dtsi b/arch/arm/boot/dts/pxa27x.dtsi index d7c5d72..a705469 100644 --- a/arch/arm/boot/dts/pxa27x.dtsi +++ b/arch/arm/boot/dts/pxa27x.dtsi @@ -10,5 +10,29 @@ marvell,intc-priority; marvell,intc-nr-irqs = <34>; }; + + pwm0: pwm@40b00000 { + compatible = "marvell,pxa270-pwm", "marvell,pxa250-pwm"; + reg = <0x40b00000 0x10>; + #pwm-cells = <1>; + }; + + pwm1: pwm@40b00010 { + compatible = "marvell,pxa270-pwm", "marvell,pxa250-pwm"; + reg = <0x40b00010 0x10>; + #pwm-cells = <1>; + }; + + pwm2: pwm@40c00000 { + compatible = "marvell,pxa270-pwm", "marvell,pxa250-pwm"; + reg = <0x40c00000 0x10>; + #pwm-cells = <1>; + }; + + pwm3: pwm@40c00010 { + compatible = "marvell,pxa270-pwm", "marvell,pxa250-pwm"; + reg = <0x40c00010 0x10>; + #pwm-cells = <1>; + }; }; }; diff --git a/drivers/pwm/pwm-pxa.c b/drivers/pwm/pwm-pxa.c index a4d2164..91b1cff 100644 --- a/drivers/pwm/pwm-pxa.c +++ b/drivers/pwm/pwm-pxa.c @@ -19,6 +19,7 @@ #include <linux/clk.h> #include <linux/io.h> #include <linux/pwm.h> +#include <linux/of_device.h> #include <asm/div64.h> @@ -124,6 +125,59 @@ static struct pwm_ops pxa_pwm_ops = { .owner = THIS_MODULE, }; +#ifdef CONFIG_OF +/* + * Device tree users must create one device instance for each pwm channel. + * Hence we dispense with the HAS_SECONDARY_PWM and "tell" the original driver + * code that this is a single channel pxa25x-pwm. Currently all devices are + * supported identically. + */ +static struct of_device_id pwm_of_match[] = { + { .compatible = "marvell,pxa250-pwm", .data = &pwm_id_table[0]}, + { .compatible = "marvell,pxa270-pwm", .data = &pwm_id_table[0]}, + { .compatible = "marvell,pxa168-pwm", .data = &pwm_id_table[0]}, + { .compatible = "marvell,pxa910-pwm", .data = &pwm_id_table[0]}, + { } +}; +MODULE_DEVICE_TABLE(of, pwm_of_match); + +static const struct platform_device_id *pxa_pwm_get_id_dt(struct device *dev) +{ + const struct of_device_id *id = of_match_device(pwm_of_match, dev); + if (id) + return (const struct platform_device_id *)id->data; + else + return NULL; +} + +struct pwm_device * +pxa_pwm_of_xlate(struct pwm_chip *pc, const struct of_phandle_args *args) +{ + struct pwm_device *pwm; + + pwm = pwm_request_from_chip(pc, 0, NULL); + if (IS_ERR(pwm)) + return pwm; + + pwm_set_period(pwm, args->args[0]); + + return pwm; +} + +#else /* !CONFIG_OF */ +static const struct platform_device_id *pxa_pwm_get_id_dt(struct device *dev) +{ + dev_err(dev, "missing platform data\n"); + return NULL; +} + +struct pwm_device * +pxa_pwm_of_xlate(struct pwm_chip *pc, const struct of_phandle_args *args) +{ + return NULL; +} +#endif + static int pwm_probe(struct platform_device *pdev) { const struct platform_device_id *id = platform_get_device_id(pdev); @@ -131,6 +185,11 @@ static int pwm_probe(struct platform_device *pdev) struct resource *r; int ret = 0; + if (id == NULL) /* using device tree */ + id = pxa_pwm_get_id_dt(&pdev->dev); + if (id == NULL) + return -EINVAL; + pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL); if (pwm == NULL) { dev_err(&pdev->dev, "failed to allocate memory\n"); @@ -145,6 +204,8 @@ static int pwm_probe(struct platform_device *pdev) pwm->chip.ops = &pxa_pwm_ops; pwm->chip.base = -1; pwm->chip.npwm = (id->driver_data & HAS_SECONDARY_PWM) ? 2 : 1; + pwm->chip.of_xlate = pxa_pwm_of_xlate; + pwm->chip.of_pwm_n_cells = 1; r = platform_get_resource(pdev, IORESOURCE_MEM, 0); pwm->mmio_base = devm_ioremap_resource(&pdev->dev, r); @@ -176,6 +237,7 @@ static struct platform_driver pwm_driver = { .driver = { .name = "pxa25x-pwm", .owner = THIS_MODULE, + .of_match_table = of_match_ptr(pwm_of_match), }, .probe = pwm_probe, .remove = pwm_remove, -- 1.8.1.5 -- 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