Re: [RFC v4 07/10] pwm: dwc: make timer clock configurable

From: Uwe Kleine-König
Date: Wed Sep 14 2022 - 12:18:03 EST


Hello Ben,

On Tue, Aug 16, 2022 at 10:14:51PM +0100, Ben Dooks wrote:
> Add a configurable clock base rate for the pwm as when being built
> for non-PCI the block may be sourced from an internal clock.
>
> Signed-off-by: Ben Dooks <ben.dooks@xxxxxxxxxx>
> ---
> v4:
> - moved earlier before the of changes to make the of changes one patch
> v2:
> - removed the ifdef and merged the other clock patch in here
> ---
> drivers/pwm/pwm-dwc-pci.c | 1 +
> drivers/pwm/pwm-dwc.c | 10 ++++++----
> drivers/pwm/pwm-dwc.h | 2 ++
> 3 files changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/pwm/pwm-dwc-pci.c b/drivers/pwm/pwm-dwc-pci.c
> index 2213d0e7f3c8..949423e368f9 100644
> --- a/drivers/pwm/pwm-dwc-pci.c
> +++ b/drivers/pwm/pwm-dwc-pci.c
> @@ -20,6 +20,7 @@
> #include <linux/pci.h>
> #include <linux/pm_runtime.h>
> #include <linux/pwm.h>
> +#include <linux/clk.h>
>
> #include "pwm-dwc.h"
>

This hunk is strange. Why do you add a header but no user of a symbol
declared in that header? Maybe it should go to pwm-dwc.h?

> diff --git a/drivers/pwm/pwm-dwc.c b/drivers/pwm/pwm-dwc.c
> index 90a8ae1252a1..1251620ab771 100644
> --- a/drivers/pwm/pwm-dwc.c
> +++ b/drivers/pwm/pwm-dwc.c
> @@ -14,6 +14,7 @@
> #include <linux/kernel.h>
> #include <linux/module.h>
> #include <linux/pci.h>
> +#include <linux/clk.h>
> #include <linux/pm_runtime.h>
> #include <linux/pwm.h>
>
> @@ -47,13 +48,13 @@ static int __dwc_pwm_configure_timer(struct dwc_pwm *dwc,
> * periods and check are the result within HW limits between 1 and
> * 2^32 periods.
> */
> - tmp = DIV_ROUND_CLOSEST_ULL(state->duty_cycle, DWC_CLK_PERIOD_NS);
> + tmp = DIV_ROUND_CLOSEST_ULL(state->duty_cycle, dwc->clk_ns);
> if (tmp < 1 || tmp > (1ULL << 32))
> return -ERANGE;
> low = tmp - 1;
>
> tmp = DIV_ROUND_CLOSEST_ULL(state->period - state->duty_cycle,
> - DWC_CLK_PERIOD_NS);
> + dwc->clk_ns);
> if (tmp < 1 || tmp > (1ULL << 32))
> return -ERANGE;
> high = tmp - 1;
> @@ -128,12 +129,12 @@ static void dwc_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
>
> duty = dwc_pwm_readl(dwc, DWC_TIM_LD_CNT(pwm->hwpwm));
> duty += 1;
> - duty *= DWC_CLK_PERIOD_NS;
> + duty *= dwc->clk_ns;
> state->duty_cycle = duty;
>
> period = dwc_pwm_readl(dwc, DWC_TIM_LD_CNT2(pwm->hwpwm));
> period += 1;
> - period *= DWC_CLK_PERIOD_NS;
> + period *= dwc->clk_ns;
> period += duty;
> state->period = period;
>
> @@ -156,6 +157,7 @@ struct dwc_pwm *dwc_pwm_alloc(struct device *dev)
> if (!dwc)
> return NULL;
>
> + dwc->clk_ns = 10;
> dwc->chip.dev = dev;
> dwc->chip.ops = &dwc_pwm_ops;
> dwc->chip.npwm = DWC_TIMERS_TOTAL;

After this conversion all usage of DWC_CLK_PERIOD_NS is done so the
#define can go away?

> diff --git a/drivers/pwm/pwm-dwc.h b/drivers/pwm/pwm-dwc.h
> index 68f98eb76152..e5a1f7be7bc8 100644
> --- a/drivers/pwm/pwm-dwc.h
> +++ b/drivers/pwm/pwm-dwc.h
> @@ -41,6 +41,8 @@ struct dwc_pwm_ctx {
> struct dwc_pwm {
> struct pwm_chip chip;
> void __iomem *base;
> + struct clk *clk;
> + unsigned int clk_ns;
> struct dwc_pwm_ctx ctx[DWC_TIMERS_TOTAL];
> };
> #define to_dwc_pwm(p) (container_of((p), struct dwc_pwm, chip))
> --
> 2.35.1
>
>

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

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