pwm: tiecap: Add device-tree binding

This patch
1. Add support for device-tree binding for ECAP APWM driver.
2. Set size of pwm-cells set to 3 to support PWM channel number, PWM
   period & polarity configuration from device tree.
3. Add enable/disable clock gating in PWM subsystem common config space.
4. When here set .owner member in platform_driver structure to
   THIS_MODULE.
Signed-off-by: Philip, Avinash <avinashphilip@ti.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Rob Landley <rob@landley.net>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

Documentation/devicetree/bindings/pwm/pwm-tiecap.txt

+TI SOC ECAP based APWM controller
+
+Required properties:
+- compatible: Must be "ti,am33xx-ecap"
+- #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.
+- reg: physical base address and size of the registers map.
+
+Optional properties:
+- ti,hwmods: Name of the hwmod associated to the ECAP:
+  "ecap<x>", <x> being the 0-based instance number from the HW spec
+
+Example:
+
+ecap0: ecap@0 {
+	compatible = "ti,am33xx-ecap";
+	#pwm-cells = <3>;
+	reg = <0x48300100 0x80>;
+	ti,hwmods = "ecap0";
+};

drivers/pwm/pwm-tiecap.c

@@ -25,6 +25,9 @@
 #include <linux/clk.h>
 #include <linux/pm_runtime.h>
 #include <linux/pwm.h>
+#include <linux/of_device.h>
+
+#include "pwm-tipwmss.h"
 
 /* ECAP registers and bits definitions */
 #define CAP1			0x08
@@ -184,12 +187,19 @@ static const struct pwm_ops ecap_pwm_ops = {
 	.owner		= THIS_MODULE,
 };
 
+static const struct of_device_id ecap_of_match[] = {
+	{ .compatible	= "ti,am33xx-ecap" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ecap_of_match);
+
 static int __devinit ecap_pwm_probe(struct platform_device *pdev)
 {
 	int ret;
 	struct resource *r;
 	struct clk *clk;
 	struct ecap_pwm_chip *pc;
+	u16 status;
 
 	pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
 	if (!pc) {
@@ -211,6 +221,8 @@ static int __devinit ecap_pwm_probe(struct platform_device *pdev)
 
 	pc->chip.dev = &pdev->dev;
 	pc->chip.ops = &ecap_pwm_ops;
+	pc->chip.of_xlate = of_pwm_xlate_with_flags;
+	pc->chip.of_pwm_n_cells = 3;
 	pc->chip.base = -1;
 	pc->chip.npwm = 1;
 
@@ -231,14 +243,40 @@ static int __devinit ecap_pwm_probe(struct platform_device *pdev)
 	}
 
 	pm_runtime_enable(&pdev->dev);
+	pm_runtime_get_sync(&pdev->dev);
+
+	status = pwmss_submodule_state_change(pdev->dev.parent,
+			PWMSS_ECAPCLK_EN);
+	if (!(status & PWMSS_ECAPCLK_EN_ACK)) {
+		dev_err(&pdev->dev, "PWMSS config space clock enable failed\n");
+		ret = -EINVAL;
+		goto pwmss_clk_failure;
+	}
+
+	pm_runtime_put_sync(&pdev->dev);
+
 	platform_set_drvdata(pdev, pc);
 	return 0;
+
+pwmss_clk_failure:
+	pm_runtime_put_sync(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+	pwmchip_remove(&pc->chip);
+	return ret;
 }
 
 static int __devexit ecap_pwm_remove(struct platform_device *pdev)
 {
 	struct ecap_pwm_chip *pc = platform_get_drvdata(pdev);
 
+	pm_runtime_get_sync(&pdev->dev);
+	/*
+	 * Due to hardware misbehaviour, acknowledge of the stop_req
+	 * is missing. Hence checking of the status bit skipped.
+	 */
+	pwmss_submodule_state_change(pdev->dev.parent, PWMSS_ECAPCLK_STOP_REQ);
+	pm_runtime_put_sync(&pdev->dev);
+
 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 	return pwmchip_remove(&pc->chip);
@@ -246,7 +284,9 @@ static int __devexit ecap_pwm_remove(struct platform_device *pdev)
 
 static struct platform_driver ecap_pwm_driver = {
 	.driver = {
-		.name = "ecap",
+		.name	= "ecap",
+		.owner	= THIS_MODULE,
+		.of_match_table = ecap_of_match,
 	},
 	.probe = ecap_pwm_probe,
 	.remove = __devexit_p(ecap_pwm_remove),