[PATCH v5 0/2] PWM: PXA: add device tree support to PWM driver

[PATCH v5 0/2] PWM: PXA: add device tree support to PWM driver

[Mike Dunn]

This is now a patch set because the changes to pxa27x.dtsi have been moved to a
separate patch.  This was done so that it can go through the arm-soc tree.

Changle log:
v5:
- changes to pxa27x.dtsi moved to a separate patch
- minor changes in phrasing made to bindings documentation
- cast removed from void *
- dummy functions for !CONFIG_OF removed; called only if (IS_ENABLED(CONFIG_OF)
- if-else block in pxa_pwm_get_id_dt() replaced with ternary operator

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

Mike Dunn (2):
  PWM: PXA: add device tree support to PWM driver
  PXA: add PWM nodes to pxa27x.dtsi

 arch/arm/boot/dts/pxa27x.dtsi | 24 ++++++++++++++++++++
 drivers/pwm/pwm-pxa.c         | 52 ++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 75 insertions(+), 1 deletion(-)

-- 
1.8.1.5

[PATCH v5 1/2] PWM: PXA: add device tree support to PWM driver

[Mike Dunn]

This patch adds device tree support to the PXA's PWM driver.  Nothing
needs to be extracted from the device tree node by the PWM device.
Client devices need only specify the period; the per-chip index is
implicitly zero because one device node must be present for each PWM
output in use.  This approach is more convenient due to the wide
variability in the number of PWM channels present across the various PXA
variants, and is made possible by the fact that the register sets for
each PWM channel are segregated from each other.  An of_xlate() method
is added to parse this single-cell 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-kFrNdAxtuftBDgjK7y7TUQ@public.gmane.org>
---
 drivers/pwm/pwm-pxa.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 51 insertions(+), 1 deletion(-)

diff --git a/drivers/pwm/pwm-pxa.c b/drivers/pwm/pwm-pxa.c
index a4d2164..e928cc8 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 +125,45 @@ 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);
+#else
+static struct of_device_id *pwm_of_match;
+#endif
+
+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);
+	return id ? id->data : NULL;
+}
+
+static 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;
+}
+
 static int pwm_probe(struct platform_device *pdev)
 {
 	const struct platform_device_id *id = platform_get_device_id(pdev);
@@ -131,6 +171,12 @@ static int pwm_probe(struct platform_device *pdev)
 	struct resource *r;
 	int ret = 0;
 
+	if (IS_ENABLED(CONFIG_OF) && id == NULL)
+		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");
@@ -145,7 +191,10 @@ 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;
-
+	if (IS_ENABLED(CONFIG_OF)) {
+		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);
 	if (IS_ERR(pwm->mmio_base))
@@ -176,6 +225,7 @@ 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

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[PATCH v5 2/2] PXA: add PWM nodes to pxa27x.dtsi

[Mike Dunn]

This patch adds PWM nodes for each of the four channels present on the
pxa270.

Signed-off-by: Mike Dunn <mikedunn-kFrNdAxtuftBDgjK7y7TUQ@public.gmane.org>
---
 arch/arm/boot/dts/pxa27x.dtsi | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

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>;
+		};
 	};
 };
-- 
1.8.1.5

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