[PATCH 1/2] pwm: Manage owner assignment implicitly for drivers
Laurent Pinchart
laurent.pinchart at ideasonboard.com
Thu Aug 3 14:53:00 PDT 2023
Hi Uwe,
Thank you for the patch.
On Thu, Aug 03, 2023 at 04:06:31PM +0200, Uwe Kleine-König wrote:
> Instead of requiring each driver to care for assigning the owner member
> of struct pwm_ops, handle that implicitly using a macro. Note that the
> owner member has to be moved to struct pwm_chip, as the ops structure
> usually lives in read-only memory and so cannot be modified.
While technically speaking the ops and pwm chip could be provided by
different modules, such a use case would likely require a high level of
self-inflicted pain, so I think the change is fine.
> The upside is that new lowlevel drivers cannot forget the assignment and
> save one line each. The pwm-crc driver didn't assign .owner, that's not
> a problem in practise though as the driver cannot be compiled as a
> module.
>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
> ---
> drivers/gpio/gpio-mvebu.c | 1 -
> drivers/gpu/drm/bridge/ti-sn65dsi86.c | 1 -
> drivers/leds/rgb/leds-qcom-lpg.c | 1 -
> drivers/pwm/core.c | 20 +++++++++++---------
> drivers/pwm/pwm-ab8500.c | 1 -
> drivers/pwm/pwm-apple.c | 1 -
> drivers/pwm/pwm-atmel-hlcdc.c | 1 -
> drivers/pwm/pwm-atmel-tcb.c | 1 -
> drivers/pwm/pwm-atmel.c | 1 -
> drivers/pwm/pwm-bcm-iproc.c | 1 -
> drivers/pwm/pwm-bcm-kona.c | 1 -
> drivers/pwm/pwm-bcm2835.c | 1 -
> drivers/pwm/pwm-berlin.c | 1 -
> drivers/pwm/pwm-brcmstb.c | 1 -
> drivers/pwm/pwm-clk.c | 1 -
> drivers/pwm/pwm-clps711x.c | 1 -
> drivers/pwm/pwm-cros-ec.c | 1 -
> drivers/pwm/pwm-dwc.c | 1 -
> drivers/pwm/pwm-ep93xx.c | 1 -
> drivers/pwm/pwm-fsl-ftm.c | 1 -
> drivers/pwm/pwm-hibvt.c | 1 -
> drivers/pwm/pwm-img.c | 1 -
> drivers/pwm/pwm-imx-tpm.c | 1 -
> drivers/pwm/pwm-imx1.c | 1 -
> drivers/pwm/pwm-imx27.c | 1 -
> drivers/pwm/pwm-intel-lgm.c | 1 -
> drivers/pwm/pwm-iqs620a.c | 1 -
> drivers/pwm/pwm-jz4740.c | 1 -
> drivers/pwm/pwm-keembay.c | 1 -
> drivers/pwm/pwm-lp3943.c | 1 -
> drivers/pwm/pwm-lpc18xx-sct.c | 1 -
> drivers/pwm/pwm-lpc32xx.c | 1 -
> drivers/pwm/pwm-lpss.c | 1 -
> drivers/pwm/pwm-mediatek.c | 1 -
> drivers/pwm/pwm-meson.c | 1 -
> drivers/pwm/pwm-microchip-core.c | 1 -
> drivers/pwm/pwm-mtk-disp.c | 1 -
> drivers/pwm/pwm-mxs.c | 1 -
> drivers/pwm/pwm-ntxec.c | 1 -
> drivers/pwm/pwm-omap-dmtimer.c | 1 -
> drivers/pwm/pwm-pca9685.c | 1 -
> drivers/pwm/pwm-pxa.c | 1 -
> drivers/pwm/pwm-raspberrypi-poe.c | 1 -
> drivers/pwm/pwm-rcar.c | 1 -
> drivers/pwm/pwm-renesas-tpu.c | 1 -
> drivers/pwm/pwm-rockchip.c | 1 -
> drivers/pwm/pwm-rz-mtu3.c | 1 -
> drivers/pwm/pwm-samsung.c | 1 -
> drivers/pwm/pwm-sifive.c | 1 -
> drivers/pwm/pwm-sl28cpld.c | 1 -
> drivers/pwm/pwm-spear.c | 1 -
> drivers/pwm/pwm-sprd.c | 1 -
> drivers/pwm/pwm-sti.c | 1 -
> drivers/pwm/pwm-stm32-lp.c | 1 -
> drivers/pwm/pwm-stm32.c | 1 -
> drivers/pwm/pwm-stmpe.c | 1 -
> drivers/pwm/pwm-sun4i.c | 1 -
> drivers/pwm/pwm-sunplus.c | 1 -
> drivers/pwm/pwm-tegra.c | 1 -
> drivers/pwm/pwm-tiecap.c | 1 -
> drivers/pwm/pwm-tiehrpwm.c | 1 -
> drivers/pwm/pwm-twl-led.c | 2 --
> drivers/pwm/pwm-twl.c | 2 --
> drivers/pwm/pwm-visconti.c | 1 -
> drivers/pwm/pwm-vt8500.c | 1 -
> drivers/pwm/pwm-xilinx.c | 1 -
> drivers/staging/greybus/pwm.c | 1 -
> include/linux/pwm.h | 8 +++++---
> 68 files changed, 16 insertions(+), 80 deletions(-)
[snip]
> diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
> index dc66e3405bf5..96069c6d3d69 100644
> --- a/drivers/pwm/core.c
> +++ b/drivers/pwm/core.c
> @@ -89,13 +89,13 @@ static int pwm_device_request(struct pwm_device *pwm, const char *label)
> if (test_bit(PWMF_REQUESTED, &pwm->flags))
> return -EBUSY;
>
> - if (!try_module_get(pwm->chip->ops->owner))
> + if (!try_module_get(pwm->chip->owner))
> return -ENODEV;
>
> if (pwm->chip->ops->request) {
> err = pwm->chip->ops->request(pwm->chip, pwm);
> if (err) {
> - module_put(pwm->chip->ops->owner);
> + module_put(pwm->chip->owner);
> return err;
> }
> }
> @@ -253,14 +253,14 @@ static bool pwm_ops_check(const struct pwm_chip *chip)
> }
>
> /**
> - * pwmchip_add() - register a new PWM chip
> + * __pwmchip_add() - register a new PWM chip
> * @chip: the PWM chip to add
Missing documentation for the new owner parameter.
> *
> * Register a new PWM chip.
> *
> * Returns: 0 on success or a negative error code on failure.
> */
> -int pwmchip_add(struct pwm_chip *chip)
> +int __pwmchip_add(struct pwm_chip *chip, struct module *owner)
> {
> struct pwm_device *pwm;
> unsigned int i;
> @@ -272,6 +272,8 @@ int pwmchip_add(struct pwm_chip *chip)
> if (!pwm_ops_check(chip))
> return -EINVAL;
>
> + chip->owner = owner;
> +
> chip->pwms = kcalloc(chip->npwm, sizeof(*pwm), GFP_KERNEL);
> if (!chip->pwms)
> return -ENOMEM;
> @@ -306,7 +308,7 @@ int pwmchip_add(struct pwm_chip *chip)
>
> return 0;
> }
> -EXPORT_SYMBOL_GPL(pwmchip_add);
> +EXPORT_SYMBOL_GPL(__pwmchip_add);
>
> /**
> * pwmchip_remove() - remove a PWM chip
> @@ -338,17 +340,17 @@ static void devm_pwmchip_remove(void *data)
> pwmchip_remove(chip);
> }
>
> -int devm_pwmchip_add(struct device *dev, struct pwm_chip *chip)
> +int __devm_pwmchip_add(struct device *dev, struct pwm_chip *chip, struct module *owner)
> {
> int ret;
>
> - ret = pwmchip_add(chip);
> + ret = __pwmchip_add(chip, owner);
> if (ret)
> return ret;
>
> return devm_add_action_or_reset(dev, devm_pwmchip_remove, chip);
> }
> -EXPORT_SYMBOL_GPL(devm_pwmchip_add);
> +EXPORT_SYMBOL_GPL(__devm_pwmchip_add);
>
> /**
> * pwm_request_from_chip() - request a PWM device relative to a PWM chip
> @@ -979,7 +981,7 @@ void pwm_put(struct pwm_device *pwm)
> pwm_set_chip_data(pwm, NULL);
> pwm->label = NULL;
>
> - module_put(pwm->chip->ops->owner);
> + module_put(pwm->chip->owner);
> out:
> mutex_unlock(&pwm_lock);
> }
[snip]
> diff --git a/include/linux/pwm.h b/include/linux/pwm.h
> index d2f9f690a9c1..d9fa0114edfa 100644
> --- a/include/linux/pwm.h
> +++ b/include/linux/pwm.h
> @@ -278,7 +278,6 @@ struct pwm_ops {
> const struct pwm_state *state);
> int (*get_state)(struct pwm_chip *chip, struct pwm_device *pwm,
> struct pwm_state *state);
> - struct module *owner;
> };
>
> /**
Missing documentation update here too, for both pwm_ops and pwm_chip.
> @@ -295,6 +294,7 @@ struct pwm_ops {
> struct pwm_chip {
> struct device *dev;
> const struct pwm_ops *ops;
> + struct module *owner;
> int base;
> unsigned int npwm;
>
> @@ -386,10 +386,12 @@ int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
> int pwm_set_chip_data(struct pwm_device *pwm, void *data);
> void *pwm_get_chip_data(struct pwm_device *pwm);
>
> -int pwmchip_add(struct pwm_chip *chip);
> +int __pwmchip_add(struct pwm_chip *chip, struct module *owner);
> +#define pwmchip_add(chip) __pwmchip_add(chip, THIS_MODULE)
> void pwmchip_remove(struct pwm_chip *chip);
>
> -int devm_pwmchip_add(struct device *dev, struct pwm_chip *chip);
> +int __devm_pwmchip_add(struct device *dev, struct pwm_chip *chip, struct module *owner);
> +#define devm_pwmchip_add(dev, chip) __devm_pwmchip_add(dev, chip, THIS_MODULE)
>
> struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
> unsigned int index,
--
Regards,
Laurent Pinchart
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