[PATCH v2 08/10] pwm: pwm-tiehrpwm: Adding TBCLK gating support.

[Philip, Avinash]

Some platforms (like AM33XX) requires clock gating from control module
explicitly for TBCLK. Enabling of this clock required for the
functioning of the time base sub module in EHRPWM module. So adding
optional TBCLK handling if DT node populated with tbclkgating. This
helps the driver can coexist for Davinci platforms.

Signed-off-by: Philip, Avinash <avinashphilip at ti.com>
Cc:	Grant Likely <grant.likely at secretlab.ca>
Cc: Rob Herring <rob.herring at calxeda.com>
Cc: Rob Landley <rob at landley.net>
---
Changes since v1:
	- Moved TBCLK enable from probe to .pwm_enable & disable from
	  remove to .pwm_disable

:100644 100644 07911e6... 927a8ed... M	drivers/pwm/pwm-tiehrpwm.c
 drivers/pwm/pwm-tiehrpwm.c |   22 ++++++++++++++++++++++
 1 files changed, 22 insertions(+), 0 deletions(-)

diff --git a/drivers/pwm/pwm-tiehrpwm.c b/drivers/pwm/pwm-tiehrpwm.c
index 07911e6..927a8ed 100644
--- a/drivers/pwm/pwm-tiehrpwm.c
+++ b/drivers/pwm/pwm-tiehrpwm.c
@@ -126,6 +126,7 @@ struct ehrpwm_pwm_chip {
 	void __iomem	*mmio_base;
 	unsigned long period_cycles[NUM_PWM_CHANNEL];
 	enum pwm_polarity polarity[NUM_PWM_CHANNEL];
+	struct	clk	*tbclk;
 };
 
 static inline struct ehrpwm_pwm_chip *to_ehrpwm_pwm_chip(struct pwm_chip *chip)
@@ -346,6 +347,13 @@ static int ehrpwm_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 	/* Channels polarity can be configured from action qualifier module */
 	configure_polarity(pc, pwm->hwpwm);
 
+	/*
+	 * Platforms require explicit clock enabling of TBCLK has
+	 * to enable TBCLK explicitly before enabling PWM device
+	 */
+	if (pc->tbclk)
+		clk_enable(pc->tbclk);
+
 	/* Enable time counter for free_run */
 	ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_RUN_MASK, TBCTL_FREE_RUN);
 	return 0;
@@ -374,6 +382,10 @@ static void ehrpwm_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 
 	ehrpwm_modify(pc->mmio_base, AQCSFRC, aqcsfrc_mask, aqcsfrc_val);
 
+	/* Disabling TBCLK on PWM disable */
+	if (pc->tbclk)
+		clk_disable(pc->tbclk);
+
 	/* Stop Time base counter */
 	ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_RUN_MASK, TBCTL_STOP_NEXT);
 
@@ -464,6 +476,16 @@ static int __devinit ehrpwm_pwm_probe(struct platform_device *pdev)
 		dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
 		return ret;
 	}
+
+	/* Some platforms require explicit tbclk gating */
+	if (of_property_read_bool(pdev->dev.of_node, "tbclkgating")) {
+		pc->tbclk = clk_get(&pdev->dev, "tbclk");
+		if (IS_ERR(pc->tbclk)) {
+			dev_err(&pdev->dev, "Could not get EHRPWM TBCLK\n");
+			return PTR_ERR(pc->tbclk);
+		}
+	}
+
 	pm_runtime_enable(&pdev->dev);
 	pm_runtime_get_sync(&pdev->dev);
 	if (!(pwmss_submodule_state_change(pdev->dev.parent, EPWMCLK_EN) &
-- 
1.7.0.4