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 <fcooper@ti.com>
---
Tested on: AM335x and AM437x GP evms.

 drivers/pwm/pwm-tiecap.c   | 28 --------------------------
 drivers/pwm/pwm-tiehrpwm.c | 29 ---------------------------
 drivers/pwm/pwm-tipwmss.c  | 49 ----------------------------------------------
 drivers/pwm/pwm-tipwmss.h  | 39 ------------------------------------
 4 files changed, 145 deletions(-)
 delete mode 100644 drivers/pwm/pwm-tipwmss.h

On 03/07/2016 01:33 PM, Franklin S Cooper Jr wrote:
> 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 <fcooper@ti.com>
> ---
> Tested on: AM335x and AM437x GP evms.
> 
>  drivers/pwm/pwm-tiecap.c   | 28 --------------------------
>  drivers/pwm/pwm-tiehrpwm.c | 29 ---------------------------
>  drivers/pwm/pwm-tipwmss.c  | 49 ----------------------------------------------
>  drivers/pwm/pwm-tipwmss.h  | 39 ------------------------------------
>  4 files changed, 145 deletions(-)
>  delete mode 100644 drivers/pwm/pwm-tipwmss.h
> 
> diff --git a/drivers/pwm/pwm-tiecap.c b/drivers/pwm/pwm-tiecap.c
> index 616af76..9e0865d7 100644
> --- a/drivers/pwm/pwm-tiecap.c
> +++ b/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);
>  }
> diff --git a/drivers/pwm/pwm-tiehrpwm.c b/drivers/pwm/pwm-tiehrpwm.c
> index 6a41e66..e09b1f0 100644
> --- a/drivers/pwm/pwm-tiehrpwm.c
> +++ b/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);
> diff --git a/drivers/pwm/pwm-tipwmss.c b/drivers/pwm/pwm-tipwmss.c
> index 5cf65a1..829f499 100644
> --- a/drivers/pwm/pwm-tipwmss.c
> +++ b/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
> diff --git a/drivers/pwm/pwm-tipwmss.h b/drivers/pwm/pwm-tipwmss.h
> deleted file mode 100644
> index 10ad804..0000000
> --- a/drivers/pwm/pwm-tipwmss.h
> +++ /dev/null
> @@ -1,39 +0,0 @@
> -/*
> - * TI PWM Subsystem driver
> - *
> - * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
> - *
> - * This program is free software; you can redistribute it and/or modify
> - * it under the terms of the GNU General Public License as published by
> - * the Free Software Foundation; either version 2 of the License, or
> - * (at your option) any later version.
> - *
> - * This program is distributed in the hope that it will be useful,
> - * but WITHOUT ANY WARRANTY; without even the implied warranty of
> - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> - * GNU General Public License for more details.
> - *
> - */
> -
> -#ifndef __TIPWMSS_H
> -#define __TIPWMSS_H
> -
> -/* PWM substem clock gating */
> -#define PWMSS_ECAPCLK_EN	BIT(0)
> -#define PWMSS_ECAPCLK_STOP_REQ	BIT(1)
> -#define PWMSS_EPWMCLK_EN	BIT(8)
> -#define PWMSS_EPWMCLK_STOP_REQ	BIT(9)
> -
> -#define PWMSS_ECAPCLK_EN_ACK	BIT(0)
> -#define PWMSS_EPWMCLK_EN_ACK	BIT(8)
> -
> -#ifdef CONFIG_PWM_TIPWMSS
> -extern u16 pwmss_submodule_state_change(struct device *dev, int set);
> -#else
> -static inline u16 pwmss_submodule_state_change(struct device *dev, int set)
> -{
> -	/* return success status value */
> -	return 0xFFFF;
> -}
> -#endif
> -#endif	/* __TIPWMSS_H */
> 


gentle ping on this.
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