Re: [PATCH 1/7] pwm: jz4740: Obtain regmap from parent node

From: Uwe Kleine-König
Date: Mon Aug 12 2019 - 02:18:19 EST


Hello Paul,

On Fri, Aug 09, 2019 at 07:04:56PM +0200, Paul Cercueil wrote:
> Le ven. 9 août 2019 à 18:51, Uwe =?iso-8859-1?q?Kleine-K=F6nig?=
> <u.kleine-koenig@xxxxxxxxxxxxxx> a écrit :
> > On Fri, Aug 09, 2019 at 02:30:25PM +0200, Paul Cercueil wrote:
> > > The TCU registers are shared between a handful of drivers, accessing
> > > them through the same regmap.
> > >
> > > While this driver is devicetree-compatible, it is never (as of now)
> > > probed from devicetree, so this change does not introduce a ABI
> > > problem
> > > with current devicetree files.
> >
> > If you adapt the binding also update the binding doc please.
>
> It's already updated, in mips-next, so it'll be in the next -rc1.

This is a useful information for the commit log.

> > > Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
> > > Tested-by: Mathieu Malaterre <malat@xxxxxxxxxx>
> > > Tested-by: Artur Rojek <contact@xxxxxxxxxxxxxx>
> >
> > nitpick: put your S-o-b line after the other tags you added.
> >
> > > ---
> > > drivers/pwm/Kconfig | 1 +
> > > drivers/pwm/pwm-jz4740.c | 80 ++++++++++++++++++++++++++--------------
> > > 2 files changed, 53 insertions(+), 28 deletions(-)
> > >
> > > diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
> > > index a7e57516959e..cc4df0ec978a 100644
> > > --- a/drivers/pwm/Kconfig
> > > +++ b/drivers/pwm/Kconfig
> > > @@ -225,6 +225,7 @@ config PWM_IMX_TPM
> > > config PWM_JZ4740
> > > tristate "Ingenic JZ47xx PWM support"
> > > depends on MACH_INGENIC
> > > + select MFD_SYSCON
> > > help
> > > Generic PWM framework driver for Ingenic JZ47xx based
> > > machines.
> > > diff --git a/drivers/pwm/pwm-jz4740.c b/drivers/pwm/pwm-jz4740.c
> > > index f901e8a0d33d..7aea5e0c6e18 100644
> > > --- a/drivers/pwm/pwm-jz4740.c
> > > +++ b/drivers/pwm/pwm-jz4740.c
> > > @@ -8,18 +8,20 @@
> > > #include <linux/err.h>
> > > #include <linux/gpio.h>
> > > #include <linux/kernel.h>
> > > +#include <linux/mfd/ingenic-tcu.h>
> > > +#include <linux/mfd/syscon.h>
> > > #include <linux/module.h>
> > > #include <linux/of_device.h>
> > > #include <linux/platform_device.h>
> > > #include <linux/pwm.h>
> > > -
> > > -#include <asm/mach-jz4740/timer.h>
> > > +#include <linux/regmap.h>
> > >
> > > #define NUM_PWM 8
> > >
> > > struct jz4740_pwm_chip {
> > > struct pwm_chip chip;
> > > struct clk *clk;
> > > + struct regmap *map;
> > > };
> > >
> > > static inline struct jz4740_pwm_chip *to_jz4740(struct pwm_chip *chip)
> > > @@ -29,6 +31,8 @@ static inline struct jz4740_pwm_chip *to_jz4740(struct pwm_chip *chip)
> > >
> > > static int jz4740_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
> > > {
> > > + struct jz4740_pwm_chip *jz = to_jz4740(chip);
> > > +
> > > /*
> > > * Timers 0 and 1 are used for system tasks, so they are unavailable
> > > * for use as PWMs.
> > > @@ -36,50 +40,53 @@ static int jz4740_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
> > > if (pwm->hwpwm < 2)
> > > return -EBUSY;
> > >
> > > - jz4740_timer_start(pwm->hwpwm);
> > > + regmap_write(jz->map, TCU_REG_TSCR, BIT(pwm->hwpwm));
> >
> > jz4740_timer_start does
> >
> > writel(BIT(timer), jz4740_timer_base + JZ_REG_TIMER_STOP_CLEAR);
> >
> > with
> >
> > #define JZ_REG_TIMER_STOP_CLEAR 0x2C
> >
> > and
> >
> > #define TCU_REG_TSCR 0x3c
> >
> > I wonder why the offsets are different.
>
> The offset are different because the base is different.

This is a useful information for the commit log.

> > >
> > > return 0;
> > > }
> > >
> > > static void jz4740_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
> > > {
> > > - jz4740_timer_set_ctrl(pwm->hwpwm, 0);
> > > + struct jz4740_pwm_chip *jz = to_jz4740(chip);
> > >
> > > - jz4740_timer_stop(pwm->hwpwm);
> > > + regmap_write(jz->map, TCU_REG_TSCR, BIT(pwm->hwpwm));
> >
> > jz4740_timer_set_ctrl writes to offset (((pwm->hwpwm) * 0x10) + 0x3C)
> > and jz4740_timer_stop to offset 0x1c. The regmap_write doesn't do both
> > of them but instead writes to offset 0x3c.
>
> I guess it should have been TCU_REG_TSSR ("Timer Stop Set Register") and
> I didn't notice because the next patch drops this write anyway.
>
> I'll do as you suggested in your other reply and swap the two patches if
> it makes things easier, it'll get rid of this write.

ok.

Best regards
Uwe

--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |