pwms: pwm-ti*: Remove support for local clock gating

The PWMSS local clock gating registers have no real purpose on OMAP ARM
devices. These registers were left over registers from DSP IP where the
PRCM doesn't exist. There is a silicon bug where gating and ungating clocks
don't function properly. TRMs will be update to indicate that these
registers shouldn't be touched.

Therefore, all code that accesses the PWMSS_CLKCONFIG or PWMSS_CLKSTATUS
will be removed by this patch with zero loss of functionality by the ECAP
and EPWM drivers.

Signed-off-by: Franklin S Cooper Jr <[email protected]>
Signed-off-by: Sekhar Nori <[email protected]>

Author: fcooperti

drivers/pwm/pwm-tiecap.c

@@ -27,8 +27,6 @@
 #include <linux/pwm.h>
 #include <linux/of_device.h>
 
-#include "pwm-tipwmss.h"
-
 /* ECAP registers and bits definitions */
 #define CAP1			0x08
 #define CAP2			0x0C
@@ -206,7 +204,6 @@ static int ecap_pwm_probe(struct platform_device *pdev)
 	struct resource *r;
 	struct clk *clk;
 	struct ecap_pwm_chip *pc;
-	u16 status;
 
 	pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
 	if (!pc)
@@ -243,40 +240,15 @@ static int 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 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_disable(&pdev->dev);
 	return pwmchip_remove(&pc->chip);
 }

drivers/pwm/pwm-tiehrpwm.c

@@ -27,8 +27,6 @@
 #include <linux/pm_runtime.h>
 #include <linux/of_device.h>
 
-#include "pwm-tipwmss.h"
-
 /* EHRPWM registers and bits definitions */
 
 /* Time base module registers */
@@ -437,7 +435,6 @@ static int ehrpwm_pwm_probe(struct platform_device *pdev)
 	struct resource *r;
 	struct clk *clk;
 	struct ehrpwm_pwm_chip *pc;
-	u16 status;
 
 	pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
 	if (!pc)
@@ -487,27 +484,9 @@ static int 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);
-	clk_unprepare(pc->tbclk);
-	return ret;
 }
 
 static int ehrpwm_pwm_remove(struct platform_device *pdev)
@@ -516,14 +495,6 @@ static int ehrpwm_pwm_remove(struct platform_device *pdev)
 
 	clk_unprepare(pc->tbclk);
 
-	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);

drivers/pwm/pwm-tipwmss.c

@@ -22,32 +22,6 @@
 #include <linux/pm_runtime.h>
 #include <linux/of_device.h>
 
-#include "pwm-tipwmss.h"
-
-#define PWMSS_CLKCONFIG		0x8	/* Clock gating reg */
-#define PWMSS_CLKSTATUS		0xc	/* Clock gating status reg */
-
-struct pwmss_info {
-	void __iomem	*mmio_base;
-	struct mutex	pwmss_lock;
-	u16		pwmss_clkconfig;
-};
-
-u16 pwmss_submodule_state_change(struct device *dev, int set)
-{
-	struct pwmss_info *info = dev_get_drvdata(dev);
-	u16 val;
-
-	mutex_lock(&info->pwmss_lock);
-	val = readw(info->mmio_base + PWMSS_CLKCONFIG);
-	val |= set;
-	writew(val , info->mmio_base + PWMSS_CLKCONFIG);
-	mutex_unlock(&info->pwmss_lock);
-
-	return readw(info->mmio_base + PWMSS_CLKSTATUS);
-}
-EXPORT_SYMBOL(pwmss_submodule_state_change);
-
 static const struct of_device_id pwmss_of_match[] = {
 	{ .compatible	= "ti,am33xx-pwmss" },
 	{},
@@ -57,24 +31,10 @@ MODULE_DEVICE_TABLE(of, pwmss_of_match);
 static int pwmss_probe(struct platform_device *pdev)
 {
 	int ret;
-	struct resource *r;
-	struct pwmss_info *info;
 	struct device_node *node = pdev->dev.of_node;
 
-	info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
-	if (!info)
-		return -ENOMEM;
-
-	mutex_init(&info->pwmss_lock);
-
-	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	info->mmio_base = devm_ioremap_resource(&pdev->dev, r);
-	if (IS_ERR(info->mmio_base))
-		return PTR_ERR(info->mmio_base);
-
 	pm_runtime_enable(&pdev->dev);
 	pm_runtime_get_sync(&pdev->dev);
-	platform_set_drvdata(pdev, info);
 
 	/* Populate all the child nodes here... */
 	ret = of_platform_populate(node, NULL, NULL, &pdev->dev);
@@ -86,30 +46,21 @@ static int pwmss_probe(struct platform_device *pdev)
 
 static int pwmss_remove(struct platform_device *pdev)
 {
-	struct pwmss_info *info = platform_get_drvdata(pdev);
-
 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
-	mutex_destroy(&info->pwmss_lock);
 	return 0;
 }
 
 #ifdef CONFIG_PM_SLEEP
 static int pwmss_suspend(struct device *dev)
 {
-	struct pwmss_info *info = dev_get_drvdata(dev);
-
-	info->pwmss_clkconfig = readw(info->mmio_base + PWMSS_CLKCONFIG);
 	pm_runtime_put_sync(dev);
 	return 0;
 }
 
 static int pwmss_resume(struct device *dev)
 {
-	struct pwmss_info *info = dev_get_drvdata(dev);
-
 	pm_runtime_get_sync(dev);
-	writew(info->pwmss_clkconfig, info->mmio_base + PWMSS_CLKCONFIG);
 	return 0;
 }
 #endif