From f1e8bf56320a7fb32095b6c51b707459361b403b Mon Sep 17 00:00:00 2001 From: Zijun Hu Date: Tue, 24 Dec 2024 21:05:03 +0800 Subject: driver core: Constify API device_find_child() and adapt for various usages MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Constify the following API: struct device *device_find_child(struct device *dev, void *data, int (*match)(struct device *dev, void *data)); To : struct device *device_find_child(struct device *dev, const void *data, device_match_t match); typedef int (*device_match_t)(struct device *dev, const void *data); with the following reasons: - Protect caller's match data @*data which is for comparison and lookup and the API does not actually need to modify @*data. - Make the API's parameters (@match)() and @data have the same type as all of other device finding APIs (bus|class|driver)_find_device(). - All kinds of existing device match functions can be directly taken as the API's argument, they were exported by driver core. Constify the API and adapt for various existing usages. BTW, various subsystem changes are squashed into this commit to meet 'git bisect' requirement, and this commit has the minimal and simplest changes to complement squashing shortcoming, and that may bring extra code improvement. Reviewed-by: Alison Schofield Reviewed-by: Takashi Sakamoto Acked-by: Uwe Kleine-König # for drivers/pwm Signed-off-by: Zijun Hu Reviewed-by: Jonathan Cameron Reviewed-by: Mathieu Poirier Link: https://lore.kernel.org/r/20241224-const_dfc_done-v5-4-6623037414d4@quicinc.com Signed-off-by: Greg Kroah-Hartman --- drivers/pwm/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/pwm/core.c') diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 675b252d9c8c..14144d0fa38e 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -1276,7 +1276,7 @@ static int pwm_export_child(struct device *pwmchip_dev, struct pwm_device *pwm) return 0; } -static int pwm_unexport_match(struct device *pwm_dev, void *data) +static int pwm_unexport_match(struct device *pwm_dev, const void *data) { return pwm_from_dev(pwm_dev) == data; } -- cgit v1.2.3 From da6b353786997c0ffa67127355ad1d54ed3324c2 Mon Sep 17 00:00:00 2001 From: Uwe Kleine-König Date: Thu, 23 Jan 2025 18:27:07 +0100 Subject: pwm: Ensure callbacks exist before calling them MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit If one of the waveform functions is called for a chip that only supports .apply(), we want that an error code is returned and not a NULL pointer exception. Fixes: 6c5126c6406d ("pwm: Provide new consumer API functions for waveforms") Cc: stable@vger.kernel.org Signed-off-by: Uwe Kleine-König Tested-by: Trevor Gamblin Link: https://lore.kernel.org/r/20250123172709.391349-2-u.kleine-koenig@baylibre.com Signed-off-by: Uwe Kleine-König --- drivers/pwm/core.c | 13 +++++++++++-- include/linux/pwm.h | 17 +++++++++++++++++ 2 files changed, 28 insertions(+), 2 deletions(-) (limited to 'drivers/pwm/core.c') diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 9c733877e98e..1a36ee3cab91 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -242,6 +242,9 @@ int pwm_round_waveform_might_sleep(struct pwm_device *pwm, struct pwm_waveform * BUG_ON(WFHWSIZE < ops->sizeof_wfhw); + if (!pwmchip_supports_waveform(chip)) + return -EOPNOTSUPP; + if (!pwm_wf_valid(wf)) return -EINVAL; @@ -294,6 +297,9 @@ int pwm_get_waveform_might_sleep(struct pwm_device *pwm, struct pwm_waveform *wf BUG_ON(WFHWSIZE < ops->sizeof_wfhw); + if (!pwmchip_supports_waveform(chip) || !ops->read_waveform) + return -EOPNOTSUPP; + guard(pwmchip)(chip); if (!chip->operational) @@ -320,6 +326,9 @@ static int __pwm_set_waveform(struct pwm_device *pwm, BUG_ON(WFHWSIZE < ops->sizeof_wfhw); + if (!pwmchip_supports_waveform(chip)) + return -EOPNOTSUPP; + if (!pwm_wf_valid(wf)) return -EINVAL; @@ -592,7 +601,7 @@ static int __pwm_apply(struct pwm_device *pwm, const struct pwm_state *state) state->usage_power == pwm->state.usage_power) return 0; - if (ops->write_waveform) { + if (pwmchip_supports_waveform(chip)) { struct pwm_waveform wf; char wfhw[WFHWSIZE]; @@ -746,7 +755,7 @@ int pwm_get_state_hw(struct pwm_device *pwm, struct pwm_state *state) if (!chip->operational) return -ENODEV; - if (ops->read_waveform) { + if (pwmchip_supports_waveform(chip) && ops->read_waveform) { char wfhw[WFHWSIZE]; struct pwm_waveform wf; diff --git a/include/linux/pwm.h b/include/linux/pwm.h index 78827f312407..b8d78009e779 100644 --- a/include/linux/pwm.h +++ b/include/linux/pwm.h @@ -347,6 +347,23 @@ struct pwm_chip { struct pwm_device pwms[] __counted_by(npwm); }; +/** + * pwmchip_supports_waveform() - checks if the given chip supports waveform callbacks + * @chip: The pwm_chip to test + * + * Returns true iff the pwm chip support the waveform functions like + * pwm_set_waveform_might_sleep() and pwm_round_waveform_might_sleep() + */ +static inline bool pwmchip_supports_waveform(struct pwm_chip *chip) +{ + /* + * only check for .write_waveform(). If that is available, + * .round_waveform_tohw() and .round_waveform_fromhw() asserted to be + * available, too, in pwmchip_add(). + */ + return chip->ops->write_waveform != NULL; +} + static inline struct device *pwmchip_parent(const struct pwm_chip *chip) { return chip->dev.parent; -- cgit v1.2.3