Re: [PATCH v2 1/3] watchdog: jz4740: Use WDT clock provided by TCU driver

[Guenter Roeck]

On 11/16/19 9:50 AM, Paul Cercueil wrote:
> Hi Guenter,
>
> I noticed you already acked all the patches in the V1 but expected them to go through the MIPS tree; could you take them into your tree instead?
Hmm, I seem to recall there was a reason for it to go through the mips tree.
Maybe that reason no longer exists. I added the series to my watchdog-next
tree for Wim to pick up. We'll see what 0-day has to say.

Guenter

> Cheers,
> -Paul
>
>
> Le mer., oct. 23, 2019 at 19:47, Paul Cercueil <paul@xxxxxxxxxxxxxxx> a Ãcrit :
> > Instead of requesting the "ext" clock and handling the watchdog clock
> > divider and gating in the watchdog driver, we now request and use the
> > "wdt" clock that is supplied by the ingenic-timer "TCU" driver.
> >
> > The major benefit is that the watchdog's clock rate and parent can now
> > be specified from within devicetree, instead of hardcoded in the driver.
> >
> > Also, this driver won't poke anymore into the TCU registers to
> > enable/disable the clock, as this is now handled by the TCU driver.
> >
> > On the bad side, we break the ABI with devicetree - as we now request a
> > different clock. In this very specific case it is still okay, as every
> > Ingenic JZ47xx-based board out there compile the devicetree within the
> > kernel; so it's still time to push breaking changes, in order to get a
> > clean devicetree that won't break once it musn't.
> >
> > Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
> > Tested-by: Mathieu Malaterre <malat@xxxxxxxxxx>
> > Tested-by: Artur Rojek <contact@xxxxxxxxxxxxxx>
> > Acked-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> > ---
> >
> > Notes:
> > ÂÂÂ v2: Rebase on top of 5.4-rc4
> >
> > Âdrivers/watchdog/KconfigÂÂÂÂÂ |Â 1 +
> > Âdrivers/watchdog/jz4740_wdt.c | 75 ++++++++++++++---------------------
> > Â2 files changed, 31 insertions(+), 45 deletions(-)
> >
> > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> > index 58e7c100b6ad..6421187769cf 100644
> > --- a/drivers/watchdog/Kconfig
> > +++ b/drivers/watchdog/Kconfig
> > @@ -1642,6 +1642,7 @@ config INDYDOG
> > Âconfig JZ4740_WDT
> > ÂÂÂÂ tristate "Ingenic jz4740 SoC hardware watchdog"
> > ÂÂÂÂ depends on MACH_JZ4740 || MACH_JZ4780
> > +ÂÂÂ depends on COMMON_CLK
> > ÂÂÂÂ select WATCHDOG_CORE
> > ÂÂÂÂ help
> > ÂÂÂÂÂÂ Hardware driver for the built-in watchdog timer on Ingenic jz4740 SoCs.
> > diff --git a/drivers/watchdog/jz4740_wdt.c b/drivers/watchdog/jz4740_wdt.c
> > index c6052ae54f32..72920f09f4a7 100644
> > --- a/drivers/watchdog/jz4740_wdt.c
> > +++ b/drivers/watchdog/jz4740_wdt.c
> > @@ -18,19 +18,6 @@
> > Â#include <linux/err.h>
> > Â#include <linux/of.h>
> >
> > -#include <asm/mach-jz4740/timer.h>
> > -
> > -#define JZ_WDT_CLOCK_PCLK 0x1
> > -#define JZ_WDT_CLOCK_RTCÂ 0x2
> > -#define JZ_WDT_CLOCK_EXTÂ 0x4
> > -
> > -#define JZ_WDT_CLOCK_DIV_1ÂÂÂ (0 << TCU_TCSR_PRESCALE_LSB)
> > -#define JZ_WDT_CLOCK_DIV_4ÂÂÂ (1 << TCU_TCSR_PRESCALE_LSB)
> > -#define JZ_WDT_CLOCK_DIV_16ÂÂ (2 << TCU_TCSR_PRESCALE_LSB)
> > -#define JZ_WDT_CLOCK_DIV_64ÂÂ (3 << TCU_TCSR_PRESCALE_LSB)
> > -#define JZ_WDT_CLOCK_DIV_256Â (4 << TCU_TCSR_PRESCALE_LSB)
> > -#define JZ_WDT_CLOCK_DIV_1024 (5 << TCU_TCSR_PRESCALE_LSB)
> > -
> > Â#define DEFAULT_HEARTBEAT 5
> > Â#define MAX_HEARTBEATÂÂÂÂ 2048
> >
> > @@ -50,7 +37,8 @@ MODULE_PARM_DESC(heartbeat,
> > Âstruct jz4740_wdt_drvdata {
> > ÂÂÂÂ struct watchdog_device wdt;
> > ÂÂÂÂ void __iomem *base;
> > -ÂÂÂ struct clk *rtc_clk;
> > +ÂÂÂ struct clk *clk;
> > +ÂÂÂ unsigned long clk_rate;
> > Â};
> >
> > Âstatic int jz4740_wdt_ping(struct watchdog_device *wdt_dev)
> > @@ -65,32 +53,14 @@ static int jz4740_wdt_set_timeout(struct watchdog_device *wdt_dev,
> > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ unsigned int new_timeout)
> > Â{
> > ÂÂÂÂ struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
> > -ÂÂÂ unsigned int rtc_clk_rate;
> > -ÂÂÂ unsigned int timeout_value;
> > -ÂÂÂ unsigned short clock_div = JZ_WDT_CLOCK_DIV_1;
> > +ÂÂÂ u16 timeout_value = (u16)(drvdata->clk_rate * new_timeout);
> > ÂÂÂÂ u8 tcer;
> >
> > -ÂÂÂ rtc_clk_rate = clk_get_rate(drvdata->rtc_clk);
> > -
> > -ÂÂÂ timeout_value = rtc_clk_rate * new_timeout;
> > -ÂÂÂ while (timeout_value > 0xffff) {
> > -ÂÂÂÂÂÂÂ if (clock_div == JZ_WDT_CLOCK_DIV_1024) {
> > -ÂÂÂÂÂÂÂÂÂÂÂ /* Requested timeout too high;
> > -ÂÂÂÂÂÂÂÂÂÂÂ * use highest possible value. */
> > -ÂÂÂÂÂÂÂÂÂÂÂ timeout_value = 0xffff;
> > -ÂÂÂÂÂÂÂÂÂÂÂ break;
> > -ÂÂÂÂÂÂÂ }
> > -ÂÂÂÂÂÂÂ timeout_value >>= 2;
> > -ÂÂÂÂÂÂÂ clock_div += (1 << TCU_TCSR_PRESCALE_LSB);
> > -ÂÂÂ }
> > -
> > ÂÂÂÂ tcer = readb(drvdata->base + TCU_REG_WDT_TCER);
> > ÂÂÂÂ writeb(0x0, drvdata->base + TCU_REG_WDT_TCER);
> > -ÂÂÂ writew(clock_div, drvdata->base + TCU_REG_WDT_TCSR);
> >
> > ÂÂÂÂ writew((u16)timeout_value, drvdata->base + TCU_REG_WDT_TDR);
> > ÂÂÂÂ writew(0x0, drvdata->base + TCU_REG_WDT_TCNT);
> > -ÂÂÂ writew(clock_div | JZ_WDT_CLOCK_RTC, drvdata->base + TCU_REG_WDT_TCSR);
> >
> > ÂÂÂÂ if (tcer & TCU_WDT_TCER_TCEN)
> > ÂÂÂÂÂÂÂÂ writeb(TCU_WDT_TCER_TCEN, drvdata->base + TCU_REG_WDT_TCER);
> > @@ -102,11 +72,15 @@ static int jz4740_wdt_set_timeout(struct watchdog_device *wdt_dev,
> > Âstatic int jz4740_wdt_start(struct watchdog_device *wdt_dev)
> > Â{
> > ÂÂÂÂ struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
> > +ÂÂÂ int ret;
> > ÂÂÂÂ u8 tcer;
> >
> > +ÂÂÂ ret = clk_prepare_enable(drvdata->clk);
> > +ÂÂÂ if (ret)
> > +ÂÂÂÂÂÂÂ return ret;
> > +
> > ÂÂÂÂ tcer = readb(drvdata->base + TCU_REG_WDT_TCER);
> >
> > -ÂÂÂ jz4740_timer_enable_watchdog();
> > ÂÂÂÂ jz4740_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
> >
> > ÂÂÂÂ /* Start watchdog if it wasn't started already */
> > @@ -121,7 +95,7 @@ static int jz4740_wdt_stop(struct watchdog_device *wdt_dev)
> > ÂÂÂÂ struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
> >
> > ÂÂÂÂ writeb(0x0, drvdata->base + TCU_REG_WDT_TCER);
> > -ÂÂÂ jz4740_timer_disable_watchdog();
> > +ÂÂÂ clk_disable_unprepare(drvdata->clk);
> >
> > ÂÂÂÂ return 0;
> > Â}
> > @@ -162,21 +136,38 @@ static int jz4740_wdt_probe(struct platform_device *pdev)
> > ÂÂÂÂ struct device *dev = &pdev->dev;
> > ÂÂÂÂ struct jz4740_wdt_drvdata *drvdata;
> > ÂÂÂÂ struct watchdog_device *jz4740_wdt;
> > +ÂÂÂ long rate;
> > +ÂÂÂ int ret;
> >
> > ÂÂÂÂ drvdata = devm_kzalloc(dev, sizeof(struct jz4740_wdt_drvdata),
> > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ GFP_KERNEL);
> > ÂÂÂÂ if (!drvdata)
> > ÂÂÂÂÂÂÂÂ return -ENOMEM;
> >
> > -ÂÂÂ if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
> > -ÂÂÂÂÂÂÂ heartbeat = DEFAULT_HEARTBEAT;
> > +ÂÂÂ drvdata->clk = devm_clk_get(&pdev->dev, "wdt");
> > +ÂÂÂ if (IS_ERR(drvdata->clk)) {
> > +ÂÂÂÂÂÂÂ dev_err(&pdev->dev, "cannot find WDT clock\n");
> > +ÂÂÂÂÂÂÂ return PTR_ERR(drvdata->clk);
> > +ÂÂÂ }
> > +
> > +ÂÂÂ /* Set smallest clock possible */
> > +ÂÂÂ rate = clk_round_rate(drvdata->clk, 1);
> > +ÂÂÂ if (rate < 0)
> > +ÂÂÂÂÂÂÂ return rate;
> > +
> > +ÂÂÂ ret = clk_set_rate(drvdata->clk, rate);
> > +ÂÂÂ if (ret)
> > +ÂÂÂÂÂÂÂ return ret;
> >
> > +ÂÂÂ drvdata->clk_rate = rate;
> > ÂÂÂÂ jz4740_wdt = &drvdata->wdt;
> > ÂÂÂÂ jz4740_wdt->info = &jz4740_wdt_info;
> > ÂÂÂÂ jz4740_wdt->ops = &jz4740_wdt_ops;
> > -ÂÂÂ jz4740_wdt->timeout = heartbeat;
> > ÂÂÂÂ jz4740_wdt->min_timeout = 1;
> > -ÂÂÂ jz4740_wdt->max_timeout = MAX_HEARTBEAT;
> > +ÂÂÂ jz4740_wdt->max_timeout = 0xffff / rate;
> > +ÂÂÂ jz4740_wdt->timeout = clamp(heartbeat,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ jz4740_wdt->min_timeout,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ jz4740_wdt->max_timeout);
> > ÂÂÂÂ jz4740_wdt->parent = dev;
> > ÂÂÂÂ watchdog_set_nowayout(jz4740_wdt, nowayout);
> > ÂÂÂÂ watchdog_set_drvdata(jz4740_wdt, drvdata);
> > @@ -185,12 +176,6 @@ static int jz4740_wdt_probe(struct platform_device *pdev)
> > ÂÂÂÂ if (IS_ERR(drvdata->base))
> > ÂÂÂÂÂÂÂÂ return PTR_ERR(drvdata->base);
> >
> > -ÂÂÂ drvdata->rtc_clk = devm_clk_get(dev, "rtc");
> > -ÂÂÂ if (IS_ERR(drvdata->rtc_clk)) {
> > -ÂÂÂÂÂÂÂ dev_err(dev, "cannot find RTC clock\n");
> > -ÂÂÂÂÂÂÂ return PTR_ERR(drvdata->rtc_clk);
> > -ÂÂÂ }
> > -
> > ÂÂÂÂ return devm_watchdog_register_device(dev, &drvdata->wdt);
> > Â}
> >
> > --
> > 2.23.0