[4/5,v2] watchdog: ftwdt010: Add clock support

Message ID 20171016205427.4297-4-linus.walleij@linaro.org
State New
Headers show
Series
  • [1/5,v2] watchdog: gemini/ftwdt010: rename DT bindings
Related show

Commit Message

Linus Walleij Oct. 16, 2017, 8:54 p.m.
The Gemini platform now provides a proper clock look-up for this
and other IPs, so add clock support to the driver. This also aids
in using the same driver with other platforms such as MOXA ART.

The IP has two clock inputs: PCLK (the IP peripheral clock) and
EXTCLK (an external clock). We are a bit elaborate around this:
on Gemini the EXTCLK is used by default today and it's 5MHz, and
on MOXA ART the PCLK is used. On Aspeed the EXTCLK is used and
it's 1MHz. So add some clever code to fall back to platform
defaults if PCLK or EXTCLK is not provided by the device tree.

Take this opportunity to implement .remove() for the driver that
stops the watchdog and disables the clocks.

Add credits that this code is inspired by MOXA ART.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

---
ChangeLog v1->v2:
- Strictly require the clock framework
- Sort header files in alphabetic order
- Fix the error path to properly disable the clocks
- Fix spelling in commit message
- Be minimalist with informational messages and cut down
  on error messages
---
 drivers/watchdog/Kconfig        |  1 +
 drivers/watchdog/ftwdt010_wdt.c | 79 ++++++++++++++++++++++++++++++++++++-----
 2 files changed, 71 insertions(+), 9 deletions(-)

-- 
2.13.6

--
To unsubscribe from this list: send the line "unsubscribe linux-watchdog" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Comments

Guenter Roeck Oct. 22, 2017, 5:30 p.m. | #1
On Mon, Oct 16, 2017 at 10:54:26PM +0200, Linus Walleij wrote:
> The Gemini platform now provides a proper clock look-up for this

> and other IPs, so add clock support to the driver. This also aids

> in using the same driver with other platforms such as MOXA ART.

> 

> The IP has two clock inputs: PCLK (the IP peripheral clock) and

> EXTCLK (an external clock). We are a bit elaborate around this:

> on Gemini the EXTCLK is used by default today and it's 5MHz, and

> on MOXA ART the PCLK is used. On Aspeed the EXTCLK is used and

> it's 1MHz. So add some clever code to fall back to platform

> defaults if PCLK or EXTCLK is not provided by the device tree.

> 

Am I missing something ? The code suggests that PCLK is mandatory.

+	gwdt->pclk = devm_clk_get(dev, "PCLK");
+	if (IS_ERR(gwdt->pclk))
+		return PTR_ERR(gwdt->pclk);

> Take this opportunity to implement .remove() for the driver that

> stops the watchdog and disables the clocks.

> 

> Add credits that this code is inspired by MOXA ART.

> 

> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

> ---

> ChangeLog v1->v2:

> - Strictly require the clock framework

> - Sort header files in alphabetic order

> - Fix the error path to properly disable the clocks

> - Fix spelling in commit message

> - Be minimalist with informational messages and cut down

>   on error messages

> ---

>  drivers/watchdog/Kconfig        |  1 +

>  drivers/watchdog/ftwdt010_wdt.c | 79 ++++++++++++++++++++++++++++++++++++-----

>  2 files changed, 71 insertions(+), 9 deletions(-)

> 

> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig

> index fd44a542036a..245cff03c992 100644

> --- a/drivers/watchdog/Kconfig

> +++ b/drivers/watchdog/Kconfig

> @@ -324,6 +324,7 @@ config 977_WATCHDOG

>  config FTWDT010_WATCHDOG

>  	tristate "Faraday Technology FTWDT010 watchdog"

>  	depends on ARM || COMPILE_TEST

> +	depends on COMMON_CLK

>  	select WATCHDOG_CORE

>  	default ARCH_GEMINI

>  	help

> diff --git a/drivers/watchdog/ftwdt010_wdt.c b/drivers/watchdog/ftwdt010_wdt.c

> index a9c2912ee280..21c3ac7f557a 100644

> --- a/drivers/watchdog/ftwdt010_wdt.c

> +++ b/drivers/watchdog/ftwdt010_wdt.c

> @@ -5,6 +5,8 @@

>   *

>   * Inspired by the out-of-tree drivers from OpenWRT:

>   * Copyright (C) 2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>

> + * Inspired by the MOXA ART driver from Jonas Jensen:

> + * Copyright (C) 2013 Jonas Jensen <jonas.jensen@gmail.com>

>   *

>   * This program is free software; you can redistribute it and/or modify

>   * it under the terms of the GNU General Public License version 2 as

> @@ -12,12 +14,14 @@

>   */

>  

>  #include <linux/bitops.h>

> +#include <linux/clk.h>

>  #include <linux/init.h>

>  #include <linux/interrupt.h>

>  #include <linux/io.h>

>  #include <linux/kernel.h>

>  #include <linux/module.h>

>  #include <linux/of_device.h>

> +#include <linux/of.h>

>  #include <linux/platform_device.h>

>  #include <linux/slab.h>

>  #include <linux/watchdog.h>

> @@ -29,19 +33,21 @@

>  

>  #define WDRESTART_MAGIC		0x5AB9

>  

> -#define WDCR_CLOCK_5MHZ		BIT(4)

> +#define WDCR_EXTCLK		BIT(4)

>  #define WDCR_WDEXT		BIT(3)

>  #define WDCR_WDINTR		BIT(2)

>  #define WDCR_SYS_RST		BIT(1)

>  #define WDCR_ENABLE		BIT(0)

>  

> -#define WDT_CLOCK		5000000		/* 5 MHz */

> -

>  struct ftwdt010_wdt {

>  	struct watchdog_device	wdd;

>  	struct device		*dev;

>  	void __iomem		*base;

>  	bool			has_irq;

> +	struct clk		*pclk;

> +	struct clk		*extclk;

> +	unsigned int		clk_freq;

> +	bool			use_extclk;

>  };

>  

>  static inline

> @@ -55,10 +61,12 @@ static int ftwdt010_wdt_start(struct watchdog_device *wdd)

>  	struct ftwdt010_wdt *gwdt = to_ftwdt010_wdt(wdd);

>  	u32 enable;

>  

> -	writel(wdd->timeout * WDT_CLOCK, gwdt->base + FTWDT010_WDLOAD);

> +	writel(wdd->timeout * gwdt->clk_freq, gwdt->base + FTWDT010_WDLOAD);

>  	writel(WDRESTART_MAGIC, gwdt->base + FTWDT010_WDRESTART);

>  	/* set clock before enabling */

> -	enable = WDCR_CLOCK_5MHZ | WDCR_SYS_RST;

> +	enable = WDCR_SYS_RST;

> +	if (gwdt->use_extclk)

> +		enable |= WDCR_EXTCLK;

>  	writel(enable, gwdt->base + FTWDT010_WDCR);

>  	if (gwdt->has_irq)

>  		enable |= WDCR_WDINTR;

> @@ -124,6 +132,7 @@ static const struct watchdog_info ftwdt010_wdt_info = {

>  static int ftwdt010_wdt_probe(struct platform_device *pdev)

>  {

>  	struct device *dev = &pdev->dev;

> +	struct device_node *np = dev->of_node;

>  	struct resource *res;

>  	struct ftwdt010_wdt *gwdt;

>  	unsigned int reg;

> @@ -139,11 +148,40 @@ static int ftwdt010_wdt_probe(struct platform_device *pdev)

>  	if (IS_ERR(gwdt->base))

>  		return PTR_ERR(gwdt->base);

>  

> +	gwdt->use_extclk = of_property_read_bool(np, "faraday,use-extclk");


Documentation and Ack from Rob required.

> +

> +	gwdt->pclk = devm_clk_get(dev, "PCLK");

> +	if (IS_ERR(gwdt->pclk))

> +		return PTR_ERR(gwdt->pclk);

> +	ret = clk_prepare_enable(gwdt->pclk);

> +	if (ret)

> +		return ret;

> +	if (!gwdt->use_extclk)

> +		gwdt->clk_freq = clk_get_rate(gwdt->pclk);


else case to the is statement below ?

> +

> +	/* Only enable and get frequency from EXTCLK if it's in use */

> +	if (gwdt->use_extclk) {


Does this use case still require pclk ?

> +		gwdt->extclk = devm_clk_get(dev, "EXTCLK");

> +		if (IS_ERR(gwdt->extclk)) {

> +			ret = PTR_ERR(gwdt->extclk);

> +			goto out_disable_pclk;

> +		}

> +		ret = clk_prepare_enable(gwdt->extclk);

> +		if (ret)

> +			goto out_disable_pclk;

> +		gwdt->clk_freq = clk_get_rate(gwdt->extclk);

> +	}

> +

> +	if (gwdt->clk_freq == 0) {

> +		ret = -EINVAL;

> +		goto out_disable_extclk;


Yet another use case of the rejected devm_clk_prepare_enable() :-(.

> +	}

> +

>  	gwdt->dev = dev;

>  	gwdt->wdd.info = &ftwdt010_wdt_info;

>  	gwdt->wdd.ops = &ftwdt010_wdt_ops;

>  	gwdt->wdd.min_timeout = 1;

> -	gwdt->wdd.max_timeout = 0xFFFFFFFF / WDT_CLOCK;

> +	gwdt->wdd.max_timeout = UINT_MAX / gwdt->clk_freq;

>  	gwdt->wdd.parent = dev;

>  

>  	/*

> @@ -165,19 +203,41 @@ static int ftwdt010_wdt_probe(struct platform_device *pdev)

>  		ret = devm_request_irq(dev, irq, ftwdt010_wdt_interrupt, 0,

>  				       "watchdog bark", gwdt);

>  		if (ret)

> -			return ret;

> +			goto out_disable_extclk;

>  		gwdt->has_irq = true;

>  	}

>  

>  	ret = devm_watchdog_register_device(dev, &gwdt->wdd);

>  	if (ret) {

>  		dev_err(&pdev->dev, "failed to register watchdog\n");

> -		return ret;

> +		goto out_disable_extclk;

>  	}

>  

>  	/* Set up platform driver data */

>  	platform_set_drvdata(pdev, gwdt);

> -	dev_info(dev, "FTWDT010 watchdog driver enabled\n");

> +	dev_info(dev, "FTWDT010 watchdog driver @%uHz\n",

> +		 gwdt->clk_freq);

> +

> +	return 0;

> +

> +out_disable_extclk:

> +	if (gwdt->use_extclk)

> +		clk_disable_unprepare(gwdt->extclk);

> +out_disable_pclk:

> +	if (!IS_ERR(gwdt->pclk))

> +		clk_disable_unprepare(gwdt->pclk);

> +

> +	return ret;

> +}

> +

> +static int ftwdt010_wdt_remove(struct platform_device *pdev)

> +{

> +	struct ftwdt010_wdt *gwdt = platform_get_drvdata(pdev);

> +

> +	writel(0, gwdt->base + FTWDT010_WDCR);

> +	clk_disable_unprepare(gwdt->pclk);

> +	if (gwdt->use_extclk)

> +		clk_disable_unprepare(gwdt->extclk);

>  

>  	return 0;

>  }

> @@ -224,6 +284,7 @@ MODULE_DEVICE_TABLE(of, ftwdt010_wdt_match);

>  

>  static struct platform_driver ftwdt010_wdt_driver = {

>  	.probe		= ftwdt010_wdt_probe,

> +	.remove		= ftwdt010_wdt_remove,

>  	.driver		= {

>  		.name	= "ftwdt010-wdt",

>  		.of_match_table = of_match_ptr(ftwdt010_wdt_match),

--
To unsubscribe from this list: send the line "unsubscribe linux-watchdog" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Patch

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index fd44a542036a..245cff03c992 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -324,6 +324,7 @@  config 977_WATCHDOG
 config FTWDT010_WATCHDOG
 	tristate "Faraday Technology FTWDT010 watchdog"
 	depends on ARM || COMPILE_TEST
+	depends on COMMON_CLK
 	select WATCHDOG_CORE
 	default ARCH_GEMINI
 	help
diff --git a/drivers/watchdog/ftwdt010_wdt.c b/drivers/watchdog/ftwdt010_wdt.c
index a9c2912ee280..21c3ac7f557a 100644
--- a/drivers/watchdog/ftwdt010_wdt.c
+++ b/drivers/watchdog/ftwdt010_wdt.c
@@ -5,6 +5,8 @@ 
  *
  * Inspired by the out-of-tree drivers from OpenWRT:
  * Copyright (C) 2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
+ * Inspired by the MOXA ART driver from Jonas Jensen:
+ * Copyright (C) 2013 Jonas Jensen <jonas.jensen@gmail.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -12,12 +14,14 @@ 
  */
 
 #include <linux/bitops.h>
+#include <linux/clk.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
+#include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/watchdog.h>
@@ -29,19 +33,21 @@ 
 
 #define WDRESTART_MAGIC		0x5AB9
 
-#define WDCR_CLOCK_5MHZ		BIT(4)
+#define WDCR_EXTCLK		BIT(4)
 #define WDCR_WDEXT		BIT(3)
 #define WDCR_WDINTR		BIT(2)
 #define WDCR_SYS_RST		BIT(1)
 #define WDCR_ENABLE		BIT(0)
 
-#define WDT_CLOCK		5000000		/* 5 MHz */
-
 struct ftwdt010_wdt {
 	struct watchdog_device	wdd;
 	struct device		*dev;
 	void __iomem		*base;
 	bool			has_irq;
+	struct clk		*pclk;
+	struct clk		*extclk;
+	unsigned int		clk_freq;
+	bool			use_extclk;
 };
 
 static inline
@@ -55,10 +61,12 @@  static int ftwdt010_wdt_start(struct watchdog_device *wdd)
 	struct ftwdt010_wdt *gwdt = to_ftwdt010_wdt(wdd);
 	u32 enable;
 
-	writel(wdd->timeout * WDT_CLOCK, gwdt->base + FTWDT010_WDLOAD);
+	writel(wdd->timeout * gwdt->clk_freq, gwdt->base + FTWDT010_WDLOAD);
 	writel(WDRESTART_MAGIC, gwdt->base + FTWDT010_WDRESTART);
 	/* set clock before enabling */
-	enable = WDCR_CLOCK_5MHZ | WDCR_SYS_RST;
+	enable = WDCR_SYS_RST;
+	if (gwdt->use_extclk)
+		enable |= WDCR_EXTCLK;
 	writel(enable, gwdt->base + FTWDT010_WDCR);
 	if (gwdt->has_irq)
 		enable |= WDCR_WDINTR;
@@ -124,6 +132,7 @@  static const struct watchdog_info ftwdt010_wdt_info = {
 static int ftwdt010_wdt_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
 	struct resource *res;
 	struct ftwdt010_wdt *gwdt;
 	unsigned int reg;
@@ -139,11 +148,40 @@  static int ftwdt010_wdt_probe(struct platform_device *pdev)
 	if (IS_ERR(gwdt->base))
 		return PTR_ERR(gwdt->base);
 
+	gwdt->use_extclk = of_property_read_bool(np, "faraday,use-extclk");
+
+	gwdt->pclk = devm_clk_get(dev, "PCLK");
+	if (IS_ERR(gwdt->pclk))
+		return PTR_ERR(gwdt->pclk);
+	ret = clk_prepare_enable(gwdt->pclk);
+	if (ret)
+		return ret;
+	if (!gwdt->use_extclk)
+		gwdt->clk_freq = clk_get_rate(gwdt->pclk);
+
+	/* Only enable and get frequency from EXTCLK if it's in use */
+	if (gwdt->use_extclk) {
+		gwdt->extclk = devm_clk_get(dev, "EXTCLK");
+		if (IS_ERR(gwdt->extclk)) {
+			ret = PTR_ERR(gwdt->extclk);
+			goto out_disable_pclk;
+		}
+		ret = clk_prepare_enable(gwdt->extclk);
+		if (ret)
+			goto out_disable_pclk;
+		gwdt->clk_freq = clk_get_rate(gwdt->extclk);
+	}
+
+	if (gwdt->clk_freq == 0) {
+		ret = -EINVAL;
+		goto out_disable_extclk;
+	}
+
 	gwdt->dev = dev;
 	gwdt->wdd.info = &ftwdt010_wdt_info;
 	gwdt->wdd.ops = &ftwdt010_wdt_ops;
 	gwdt->wdd.min_timeout = 1;
-	gwdt->wdd.max_timeout = 0xFFFFFFFF / WDT_CLOCK;
+	gwdt->wdd.max_timeout = UINT_MAX / gwdt->clk_freq;
 	gwdt->wdd.parent = dev;
 
 	/*
@@ -165,19 +203,41 @@  static int ftwdt010_wdt_probe(struct platform_device *pdev)
 		ret = devm_request_irq(dev, irq, ftwdt010_wdt_interrupt, 0,
 				       "watchdog bark", gwdt);
 		if (ret)
-			return ret;
+			goto out_disable_extclk;
 		gwdt->has_irq = true;
 	}
 
 	ret = devm_watchdog_register_device(dev, &gwdt->wdd);
 	if (ret) {
 		dev_err(&pdev->dev, "failed to register watchdog\n");
-		return ret;
+		goto out_disable_extclk;
 	}
 
 	/* Set up platform driver data */
 	platform_set_drvdata(pdev, gwdt);
-	dev_info(dev, "FTWDT010 watchdog driver enabled\n");
+	dev_info(dev, "FTWDT010 watchdog driver @%uHz\n",
+		 gwdt->clk_freq);
+
+	return 0;
+
+out_disable_extclk:
+	if (gwdt->use_extclk)
+		clk_disable_unprepare(gwdt->extclk);
+out_disable_pclk:
+	if (!IS_ERR(gwdt->pclk))
+		clk_disable_unprepare(gwdt->pclk);
+
+	return ret;
+}
+
+static int ftwdt010_wdt_remove(struct platform_device *pdev)
+{
+	struct ftwdt010_wdt *gwdt = platform_get_drvdata(pdev);
+
+	writel(0, gwdt->base + FTWDT010_WDCR);
+	clk_disable_unprepare(gwdt->pclk);
+	if (gwdt->use_extclk)
+		clk_disable_unprepare(gwdt->extclk);
 
 	return 0;
 }
@@ -224,6 +284,7 @@  MODULE_DEVICE_TABLE(of, ftwdt010_wdt_match);
 
 static struct platform_driver ftwdt010_wdt_driver = {
 	.probe		= ftwdt010_wdt_probe,
+	.remove		= ftwdt010_wdt_remove,
 	.driver		= {
 		.name	= "ftwdt010-wdt",
 		.of_match_table = of_match_ptr(ftwdt010_wdt_match),