watchdog: renesas_wdt: add another divider option

If we set RWTCSRB to 0, we can gain 4096 as another divider value. This
is supported by all R-Car Gen2 and Gen3 devices which we aim to support.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
This commit is contained in:
Wolfram Sang 2017-07-19 10:27:55 +02:00 committed by Wim Van Sebroeck
parent 82f64cd208
commit 03a196f25f

View file

@ -23,21 +23,22 @@
#define RWTCSRA_WOVF BIT(4)
#define RWTCSRA_WRFLG BIT(5)
#define RWTCSRA_TME BIT(7)
#define RWTCSRB 8
#define RWDT_DEFAULT_TIMEOUT 60U
/*
* In probe, clk_rate is checked to be not more than 16 bit * biggest clock
* divider (10 bits). d is only a factor to fully utilize the WDT counter and
* divider (12 bits). d is only a factor to fully utilize the WDT counter and
* will not exceed its 16 bits. Thus, no overflow, we stay below 32 bits.
*/
#define MUL_BY_CLKS_PER_SEC(p, d) \
DIV_ROUND_UP((d) * (p)->clk_rate, clk_divs[(p)->cks])
/* d is 16 bit, clk_divs 10 bit -> no 32 bit overflow */
/* d is 16 bit, clk_divs 12 bit -> no 32 bit overflow */
#define DIV_BY_CLKS_PER_SEC(p, d) ((d) * clk_divs[(p)->cks] / (p)->clk_rate)
static const unsigned int clk_divs[] = { 1, 4, 16, 32, 64, 128, 1024 };
static const unsigned int clk_divs[] = { 1, 4, 16, 32, 64, 128, 1024, 4096 };
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
@ -77,6 +78,7 @@ static int rwdt_start(struct watchdog_device *wdev)
clk_prepare_enable(priv->clk);
rwdt_write(priv, 0, RWTCSRB);
rwdt_write(priv, priv->cks, RWTCSRA);
rwdt_init_timeout(wdev);