Re: [PATCH 04/14] pwm: rockchip: Add support for hardware readout

[Boris Brezillon]

On Fri, 3 Jun 2016 13:20:06 -0700
Brian Norris <briannorris@xxxxxxxxxxxx> wrote:

> On Fri, Jun 03, 2016 at 10:23:02AM +0200, Boris Brezillon wrote:
> > Implement the ->get_state() function to expose initial state.
> > 
> > Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>
> > ---
> >  drivers/pwm/pwm-rockchip.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 67 insertions(+)
> > 
> > diff --git a/drivers/pwm/pwm-rockchip.c b/drivers/pwm/pwm-rockchip.c
> > index 68d72ce..dfacf7d 100644
> > --- a/drivers/pwm/pwm-rockchip.c
> > +++ b/drivers/pwm/pwm-rockchip.c
> > @@ -51,6 +51,8 @@ struct rockchip_pwm_data {
> >  
> >  	void (*set_enable)(struct pwm_chip *chip,
> >  			   struct pwm_device *pwm, bool enable);
> > +	void (*get_state)(struct pwm_chip *chip, struct pwm_device *pwm,
> > +			  struct pwm_state *state);
> >  };
> >  
> >  static inline struct rockchip_pwm_chip *to_rockchip_pwm_chip(struct pwm_chip *c)
> > @@ -75,6 +77,19 @@ static void rockchip_pwm_set_enable_v1(struct pwm_chip *chip,
> >  	writel_relaxed(val, pc->base + pc->data->regs.ctrl);
> >  }
> >  
> > +static void rockchip_pwm_get_state_v1(struct pwm_chip *chip,
> > +				      struct pwm_device *pwm,
> > +				      struct pwm_state *state)
> > +{
> > +	struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
> > +	u32 enable_conf = PWM_CTRL_OUTPUT_EN | PWM_CTRL_TIMER_EN;
> > +	u32 val;
> > +
> > +	val = readl(pc->base + pc->data->regs.ctrl);  
> 
> Nit: I just noticed you've been starting to use readl()/writel() in this
> series, where previously {readl,writel}_relaxed() were being used. Any
> reason?

Because I'm lazy and usually don't take the time to think whether it's
safe of not to use the _relaxed() versions :-). Not sure you'll have a
noticeable improvement by using _relaxed() for a PWM device by the
way, but I can change that ;-).

> 
> Anyway, LGTM:
> 
> Reviewed-by: Brian Norris <briannorris@xxxxxxxxxxxx>
> Tested-by: Brian Norris <briannorris@xxxxxxxxxxxx>
> 
> > +	if ((val & enable_conf) == enable_conf)
> > +		state->enabled = true;
> > +}
> > +
> >  static void rockchip_pwm_set_enable_v2(struct pwm_chip *chip,
> >  				       struct pwm_device *pwm, bool enable)
> >  {
> > @@ -98,6 +113,53 @@ static void rockchip_pwm_set_enable_v2(struct pwm_chip *chip,
> >  	writel_relaxed(val, pc->base + pc->data->regs.ctrl);
> >  }
> >  
> > +static void rockchip_pwm_get_state_v2(struct pwm_chip *chip,
> > +				      struct pwm_device *pwm,
> > +				      struct pwm_state *state)
> > +{
> > +	struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
> > +	u32 enable_conf = PWM_OUTPUT_LEFT | PWM_LP_DISABLE | PWM_ENABLE |
> > +			  PWM_CONTINUOUS;
> > +	u32 val;
> > +
> > +	val = readl(pc->base + pc->data->regs.ctrl);
> > +	if ((val & enable_conf) != enable_conf)
> > +		return;
> > +
> > +	state->enabled = true;
> > +
> > +	if (!(val & PWM_DUTY_POSITIVE))
> > +		state->polarity = PWM_POLARITY_INVERSED;
> > +}
> > +
> > +static void rockchip_pwm_get_state(struct pwm_chip *chip,
> > +				   struct pwm_device *pwm,
> > +				   struct pwm_state *state)
> > +{
> > +	struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
> > +	unsigned long clk_rate;
> > +	u64 tmp;
> > +	int ret;
> > +
> > +	ret = clk_enable(pc->clk);
> > +	if (ret)
> > +		return;
> > +
> > +	clk_rate = clk_get_rate(pc->clk);
> > +
> > +	tmp = readl(pc->base + pc->data->regs.period);
> > +	tmp *= pc->data->prescaler * NSEC_PER_SEC;
> > +	state->period = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
> > +
> > +	tmp = readl(pc->base + pc->data->regs.duty);
> > +	tmp *= pc->data->prescaler * NSEC_PER_SEC;
> > +	state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
> > +
> > +	pc->data->get_state(chip, pwm, state);
> > +
> > +	clk_disable(pc->clk);
> > +}
> > +
> >  static int rockchip_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
> >  			       int duty_ns, int period_ns)
> >  {
> > @@ -170,6 +232,7 @@ static void rockchip_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
> >  }
> >  
> >  static const struct pwm_ops rockchip_pwm_ops_v1 = {
> > +	.get_state = rockchip_pwm_get_state,
> >  	.config = rockchip_pwm_config,
> >  	.enable = rockchip_pwm_enable,
> >  	.disable = rockchip_pwm_disable,
> > @@ -177,6 +240,7 @@ static const struct pwm_ops rockchip_pwm_ops_v1 = {
> >  };
> >  
> >  static const struct pwm_ops rockchip_pwm_ops_v2 = {
> > +	.get_state = rockchip_pwm_get_state,
> >  	.config = rockchip_pwm_config,
> >  	.set_polarity = rockchip_pwm_set_polarity,
> >  	.enable = rockchip_pwm_enable,
> > @@ -194,6 +258,7 @@ static const struct rockchip_pwm_data pwm_data_v1 = {
> >  	.prescaler = 2,
> >  	.ops = &rockchip_pwm_ops_v1,
> >  	.set_enable = rockchip_pwm_set_enable_v1,
> > +	.get_state = rockchip_pwm_get_state_v1,
> >  };
> >  
> >  static const struct rockchip_pwm_data pwm_data_v2 = {
> > @@ -206,6 +271,7 @@ static const struct rockchip_pwm_data pwm_data_v2 = {
> >  	.prescaler = 1,
> >  	.ops = &rockchip_pwm_ops_v2,
> >  	.set_enable = rockchip_pwm_set_enable_v2,
> > +	.get_state = rockchip_pwm_get_state_v2,
> >  };
> >  
> >  static const struct rockchip_pwm_data pwm_data_vop = {
> > @@ -218,6 +284,7 @@ static const struct rockchip_pwm_data pwm_data_vop = {
> >  	.prescaler = 1,
> >  	.ops = &rockchip_pwm_ops_v2,
> >  	.set_enable = rockchip_pwm_set_enable_v2,
> > +	.get_state = rockchip_pwm_get_state_v2,
> >  };
> >  
> >  static const struct of_device_id rockchip_pwm_dt_ids[] = {
> > -- 
> > 2.7.4
> >   



-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com