[alsa-devel] [PATCH v5 2/2] watchdog: mtk_wdt: mt8183: Add reset controller

[Philipp Zabel]

On Fri, 2019-11-29 at 16:36 +0800, Yong Liang wrote:
> On Mon, 2019-11-25 at 17:51 +0800, Philipp Zabel wrote:
> > On Sun, 2019-11-24 at 22:16 -0800, Guenter Roeck wrote:
> > > On Mon, Nov 25, 2019 at 11:03:50AM +0800, Jiaxin Yu wrote:
> > > > From: "yong.liang" <yong.liang at mediatek.com>
> > > > 
> > > > Add reset controller API in watchdog driver.
> > > > Besides watchdog, MTK toprgu module also provide sub-system (eg, audio,
> > > > camera, codec and connectivity) software reset functionality.
> > > > 
> > > > Signed-off-by: yong.liang <yong.liang at mediatek.com>
> > > > Signed-off-by: jiaxin.yu <jiaxin.yu at mediatek.com>
> > > > Reviewed-by: Yingjoe Chen <yingjoe.chen at mediatek.com>
> > > > ---
> > > >  drivers/watchdog/Kconfig   |   1 +
> > > >  drivers/watchdog/mtk_wdt.c | 111 ++++++++++++++++++++++++++++++++++++-
> > > >  2 files changed, 111 insertions(+), 1 deletion(-)
> > > > 
> > > > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> > > > index 2e07caab9db2..629249fe5305 100644
> > > > --- a/drivers/watchdog/Kconfig
> > > > +++ b/drivers/watchdog/Kconfig
> > > > @@ -717,6 +717,7 @@ config MEDIATEK_WATCHDOG
> > > >  	tristate "Mediatek SoCs watchdog support"
> > > >  	depends on ARCH_MEDIATEK || COMPILE_TEST
> > > >  	select WATCHDOG_CORE
> > > > +	select RESET_CONTROLLER
> > > >  	help
> > > >  	  Say Y here to include support for the watchdog timer
> > > >  	  in Mediatek SoCs.
> > > > diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
> > > > index 9c3d0033260d..d29484c7940a 100644
> > > > --- a/drivers/watchdog/mtk_wdt.c
> > > > +++ b/drivers/watchdog/mtk_wdt.c
> > > > @@ -9,6 +9,9 @@
> > > >   * Based on sunxi_wdt.c
> > > >   */
> > > >  
> > > > +#include <dt-bindings/reset-controller/mt2712-resets.h>
> > > > +#include <dt-bindings/reset-controller/mt8183-resets.h>
> > > > +#include <linux/delay.h>
> > > >  #include <linux/err.h>
> > > >  #include <linux/init.h>
> > > >  #include <linux/io.h>
> > > > @@ -16,10 +19,12 @@
> > > >  #include <linux/module.h>
> > > >  #include <linux/moduleparam.h>
> > > >  #include <linux/of.h>
> > > > +#include <linux/of_device.h>
> > > >  #include <linux/platform_device.h>
> > > > +#include <linux/reset-controller.h>
> > > > +#include <linux/slab.h>
> > > >  #include <linux/types.h>
> > > >  #include <linux/watchdog.h>
> > > > -#include <linux/delay.h>
> > > >  
> > > >  #define WDT_MAX_TIMEOUT		31
> > > >  #define WDT_MIN_TIMEOUT		1
> > > > @@ -44,6 +49,9 @@
> > > >  #define WDT_SWRST		0x14
> > > >  #define WDT_SWRST_KEY		0x1209
> > > >  
> > > > +#define WDT_SWSYSRST		0x18U
> > > > +#define WDT_SWSYS_RST_KEY	0x88000000
> > > > +
> > > >  #define DRV_NAME		"mtk-wdt"
> > > >  #define DRV_VERSION		"1.0"
> > > >  
> > > > @@ -53,8 +61,99 @@ static unsigned int timeout;
> > > >  struct mtk_wdt_dev {
> > > >  	struct watchdog_device wdt_dev;
> > > >  	void __iomem *wdt_base;
> > > > +	spinlock_t lock; /* protects WDT_SWSYSRST reg */
> > > > +	struct reset_controller_dev rcdev;
> > > > +};
> > > > +
> > > > +struct mtk_wdt_data {
> > > > +	int sw_rst_num;
> > > >  };
> > > >  
> > > > +static const struct mtk_wdt_data mt2712_data = {
> > > > +	.sw_rst_num = MT2712_TOPRGU_SW_RST_NUM,
> > > > +};
> > > > +
> > > > +static const struct mtk_wdt_data mt8183_data = {
> > > > +	.sw_rst_num = MT8183_TOPRGU_SW_RST_NUM,
> > > > +};
> > > 
> > > The number of resets can be set in .data directly; there is no need
> > > for the structures.
> 
>     We want to put all properities in mtxxxx-resets.h and it easy to
> manager. If there are new properity in the feture, we can put it in
> mtk_wdt_data mtxxxx_data

Do you expect there will be more properties in the future?

> > > > +static int toprgu_reset_deassert(struct reset_controller_dev *rcdev,
> > > > +				 unsigned long id)
> > > > +{
> > > > +	unsigned int tmp;
> > > > +	unsigned long flags;
> > > > +	struct mtk_wdt_dev *data =
> > > > +		 container_of(rcdev, struct mtk_wdt_dev, rcdev);
> > > > +
> > > > +	spin_lock_irqsave(&data->lock, flags);
> > > > +
> > > > +	tmp = __raw_readl(data->wdt_base + WDT_SWSYSRST);
> > > > +	tmp &= ~BIT(id);
> > > > +	tmp |= WDT_SWSYS_RST_KEY;
> > > > +	writel(tmp, data->wdt_base + WDT_SWSYSRST);
> > > > +
> > > > +	spin_unlock_irqrestore(&data->lock, flags);
> > > > +
> > > > +	return 0;
> > > > +}
> > > 
> > > There is a lot of duplication in those functions. Only one line
> > > is different. I think this is a good example where a helper function
> > > with an additional argument indicating set or reset would be helpful.
> > > 
>     .assert and .dessert are two numbers of struct reset_control_ops.
>      I think it's better to define both of them.

The suggestion was to have two very short _assert and _deassert
functions that only contain a single call to a common helper function.
See the reset-a10sr.c driver for an example.

regards
Philipp