linux-kernel - [PATCH 3.16 033/328] pwm: tiehrpwm: Don't use emulation mode bits to control PWM output

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Message-ID: <lsq.1544392233.895035047@decadent.org.uk>
Date:   Sun, 09 Dec 2018 21:50:33 +0000
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, "Vignesh R" <vigneshr@...com>,
        "Thierry Reding" <thierry.reding@...il.com>
Subject: [PATCH 3.16 033/328] pwm: tiehrpwm: Don't use emulation mode bits
 to control PWM output

3.16.62-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Vignesh R <vigneshr@...com>

commit aa49d628f6e016bcec8c6f8e704b9b18ee697329 upstream.

As per AM335x TRM SPRUH73P "15.2.2.11 ePWM Behavior During Emulation",
TBCTL[15:14] only have effect during emulation suspend events (IOW,
to stop PWM when debugging using a debugger). These bits have no effect
on PWM output during normal running of system. Hence, remove code
accessing these bits as they have no role in enabling/disabling PWMs.

Fixes: 19891b20e7c2 ("pwm: pwm-tiehrpwm: PWM driver support for EHRPWM")
Signed-off-by: Vignesh R <vigneshr@...com>
Signed-off-by: Thierry Reding <thierry.reding@...il.com>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
--- a/drivers/pwm/pwm-tiehrpwm.c
+++ b/drivers/pwm/pwm-tiehrpwm.c
@@ -35,10 +35,6 @@
 #define TBCTL			0x00
 #define TBPRD			0x0A
 
-#define TBCTL_RUN_MASK		(BIT(15) | BIT(14))
-#define TBCTL_STOP_NEXT		0
-#define TBCTL_STOP_ON_CYCLE	BIT(14)
-#define TBCTL_FREE_RUN		(BIT(15) | BIT(14))
 #define TBCTL_PRDLD_MASK	BIT(3)
 #define TBCTL_PRDLD_SHDW	0
 #define TBCTL_PRDLD_IMDT	BIT(3)
@@ -357,7 +353,7 @@ static int ehrpwm_pwm_enable(struct pwm_
 	/* Channels polarity can be configured from action qualifier module */
 	configure_polarity(pc, pwm->hwpwm);
 
-	/* Enable TBCLK before enabling PWM device */
+	/* Enable TBCLK */
 	ret = clk_enable(pc->tbclk);
 	if (ret) {
 		dev_err(chip->dev, "Failed to enable TBCLK for %s\n",
@@ -365,8 +361,6 @@ static int ehrpwm_pwm_enable(struct pwm_
 		return ret;
 	}
 
-	/* Enable time counter for free_run */
-	ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_RUN_MASK, TBCTL_FREE_RUN);
 	return 0;
 }
 
@@ -396,9 +390,6 @@ static void ehrpwm_pwm_disable(struct pw
 	/* Disabling TBCLK on PWM disable */
 	clk_disable(pc->tbclk);
 
-	/* Stop Time base counter */
-	ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_RUN_MASK, TBCTL_STOP_NEXT);
-
 	/* Disable clock on PWM disable */
 	pm_runtime_put_sync(chip->dev);
 }