pwm: tiehrpwm: Add device-tree binding

This patch
1. Add support for device-tree binding for EHRWPM 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>

2 files changed, 64 insertions, 1 deletions

diff --git a/Documentation/devicetree/bindings/pwm/pwm-tiehrpwm.txt b/Documentation/devicetree/bindings/pwm/pwm-tiehrpwm.txt
new file mode 100644
index 000000000000..4fc7079d822e
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/pwm-tiehrpwm.txt
@@ -0,0 +1,23 @@
+TI SOC EHRPWM based PWM controller
+
+Required properties:
+- compatible : Must be "ti,am33xx-ehrpwm"
+- #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 EHRPWM:
+  "ehrpwm<x>", <x> being the 0-based instance number from the HW spec
+
+Example:
+
+ehrpwm0: ehrpwm@0 {
+        compatible = "ti,am33xx-ehrpwm";
+        #pwm-cells = <3>;
+        reg = <0x48300200 0x100>;
+        ti,hwmods = "ehrpwm0";
+};
diff --git a/drivers/pwm/pwm-tiehrpwm.c b/drivers/pwm/pwm-tiehrpwm.c
index 565f96ad2787..ee7a8b3dbed9 100644
--- a/drivers/pwm/pwm-tiehrpwm.c
+++ b/drivers/pwm/pwm-tiehrpwm.c
@@ -25,6 +25,9 @@
 #include <linux/err.h>
 #include <linux/clk.h>
 #include <linux/pm_runtime.h>
+#include <linux/of_device.h>
+
+#include "pwm-tipwmss.h"
 
 /* EHRPWM registers and bits definitions */
 
@@ -399,12 +402,19 @@ static const struct pwm_ops ehrpwm_pwm_ops = {
         .owner          = THIS_MODULE,
 };
 
+static const struct of_device_id ehrpwm_of_match[] = {
+        { .compatible   = "ti,am33xx-ehrpwm" },
+        {},
+};
+MODULE_DEVICE_TABLE(of, ehrpwm_of_match);
+
 static int __devinit ehrpwm_pwm_probe(struct platform_device *pdev)
 {
         int ret;
         struct resource *r;
         struct clk *clk;
         struct ehrpwm_pwm_chip *pc;
+        u16 status;
 
         pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
         if (!pc) {
@@ -426,6 +436,8 @@ static int __devinit ehrpwm_pwm_probe(struct platform_device *pdev)
 
         pc->chip.dev = &pdev->dev;
         pc->chip.ops = &ehrpwm_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 = NUM_PWM_CHANNEL;
 
@@ -453,14 +465,40 @@ static int __devinit ehrpwm_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_EPWMCLK_EN);
+        if (!(status & PWMSS_EPWMCLK_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 ehrpwm_pwm_remove(struct platform_device *pdev)
 {
         struct ehrpwm_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_EPWMCLK_STOP_REQ);
+        pm_runtime_put_sync(&pdev->dev);
+
         pm_runtime_put_sync(&pdev->dev);
         pm_runtime_disable(&pdev->dev);
         return pwmchip_remove(&pc->chip);
@@ -468,7 +506,9 @@ static int __devexit ehrpwm_pwm_remove(struct platform_device *pdev)
 
 static struct platform_driver ehrpwm_pwm_driver = {
         .driver = {
-                .name = "ehrpwm",
+                .name   = "ehrpwm",
+                .owner  = THIS_MODULE,
+                .of_match_table = ehrpwm_of_match,
         },
         .probe = ehrpwm_pwm_probe,
         .remove = __devexit_p(ehrpwm_pwm_remove),