Re: [PATCH v2 3/8] watchdog: at91rm9200: use the regmap from mfd

Guenter Roeck
2015-01-10T00:39:52Z

On 01/09/2015 01:51 AM, Alexandre Belloni wrote:
> The system timer MFD driver is providing a regmap. Use it to access the
> registers.
>
> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
> ---
> drivers/watchdog/Kconfig | 2 +-
> drivers/watchdog/at91rm9200_wdt.c | 27 +++++++++------------------
> 2 files changed, 10 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 08f41add1461..18c73bc159fc 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -154,7 +154,7 @@ config ARM_SP805_WATCHDOG
>
> config AT91RM9200_WATCHDOG
> tristate "AT91RM9200 watchdog"
> - depends on SOC_AT91RM9200
> + depends on SOC_AT91RM9200 && MFD_ATMEL_ST
> help
> Watchdog timer embedded into AT91RM9200 chips. This will reboot your
> system when the timeout is reached.
> diff --git a/drivers/watchdog/at91rm9200_wdt.c b/drivers/watchdog/at91rm9200_wdt.c
> index d244112d5b6f..a493fe4b0dfc 100644
> --- a/drivers/watchdog/at91rm9200_wdt.c
> +++ b/drivers/watchdog/at91rm9200_wdt.c
> @@ -14,25 +14,22 @@
> #include <linux/bitops.h>
> #include <linux/errno.h>
> #include <linux/fs.h>
> -#include <linux/init.h>
> -#include <linux/io.h>
> #include <linux/kernel.h>
> +#include <linux/mfd/atmel-st.h>
> #include <linux/miscdevice.h>
> #include <linux/module.h>
> #include <linux/moduleparam.h>
> #include <linux/platform_device.h>
> -#include <linux/types.h>
> +#include <linux/regmap.h>
> #include <linux/watchdog.h>
> #include <linux/uaccess.h>
> -#include <linux/of.h>
> -#include <linux/of_device.h>
> -#include <mach/at91_st.h>
>
> #define WDT_DEFAULT_TIME 5 /* seconds */
> #define WDT_MAX_TIME 256 /* seconds */
>
> static int wdt_time = WDT_DEFAULT_TIME;
> static bool nowayout = WATCHDOG_NOWAYOUT;
> +static struct regmap *regmap_st;
>
> module_param(wdt_time, int, 0);
> MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
> @@ -55,7 +52,7 @@ static unsigned long at91wdt_busy;
> */
> static inline void at91_wdt_stop(void)
> {
> - at91_st_write(AT91_ST_WDMR, AT91_ST_EXTEN);
> + regmap_write(regmap_st, AT91_ST_WDMR, AT91_ST_EXTEN);
> }
>
> /*
> @@ -63,9 +60,9 @@ static inline void at91_wdt_stop(void)
> */
> static inline void at91_wdt_start(void)
> {
> - at91_st_write(AT91_ST_WDMR, AT91_ST_EXTEN | AT91_ST_RSTEN |
> + regmap_write(regmap_st, AT91_ST_WDMR, AT91_ST_EXTEN | AT91_ST_RSTEN |
> (((65536 * wdt_time) >> 8) & AT91_ST_WDV));
> - at91_st_write(AT91_ST_CR, AT91_ST_WDRST);
> + regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
> }
>
> /*
> @@ -73,7 +70,7 @@ static inline void at91_wdt_start(void)
> */
> static inline void at91_wdt_reload(void)
> {
> - at91_st_write(AT91_ST_CR, AT91_ST_WDRST);
> + regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
> }
>
> /* ......................................................................... */
> @@ -204,6 +201,7 @@ static struct miscdevice at91wdt_miscdev = {
> static int at91wdt_probe(struct platform_device *pdev)
> {
> int res;
> + regmap_st = dev_get_drvdata(pdev->dev.parent);
>

Is it guaranteed that parent is never NULL, and that the parent's
drvdata is always set ?

Also, it seems that regmap_st will be overwritten if the device
is already open (see code below). That may not be a good idea.

Guenter

> if (at91wdt_miscdev.parent)
> return -EBUSY;
> @@ -254,12 +252,6 @@ static int at91wdt_resume(struct platform_device *pdev)
> #define at91wdt_resume NULL
> #endif
>
> -static const struct of_device_id at91_wdt_dt_ids[] = {
> - { .compatible = "atmel,at91rm9200-wdt" },
> - { /* sentinel */ }
> -};
> -MODULE_DEVICE_TABLE(of, at91_wdt_dt_ids);
> -
> static struct platform_driver at91wdt_driver = {
> .probe = at91wdt_probe,
> .remove = at91wdt_remove,
> @@ -267,8 +259,7 @@ static struct platform_driver at91wdt_driver = {
> .suspend = at91wdt_suspend,
> .resume = at91wdt_resume,
> .driver = {
> - .name = "at91_wdt",
> - .of_match_table = at91_wdt_dt_ids,
> + .name = "atmel_st_watchdog",
> },
> };
>
>