From: Laurent Pinchart Date: Tue, 12 Aug 2025 21:45:53 +0000 (+0300) Subject: media: v4l2-common: Add legacy camera sensor clock helper X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=dd235b07b65e123c0fdadc2883b9c16aa4749164;p=users%2Fhch%2Fmisc.git media: v4l2-common: Add legacy camera sensor clock helper The recently introduced devm_v4l2_sensor_clk_get() helper aims at simplifying sensor drivers by centralizing clock handling code, as well as reducing cargo-cult and deprecated behaviour. A set of drivers implement external clock handling in a non-standard way. This can't be changed as there is a high risk of breaking existing platforms, but keeping the code as-is creates a risk of new drivers copying deprecated behaviour. To fix this, introduce a new devm_v4l2_sensor_clk_get_legacy() helper and use it in those driver. Compared to devm_v4l2_sensor_clk_get(), the new helper takes the "clock-frequency" property into account and sets the external clock rate on OF platforms, and adds the ability to specify a fixed default or fallback clock rate in case the "clock-frequency" property is not present. Signed-off-by: Laurent Pinchart Reviewed-by: Niklas Söderlund Signed-off-by: Sakari Ailus Reviewed-by: Mehdi Djait Signed-off-by: Hans Verkuil --- diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c index 6f8bce4d6b62..b367d479d6b3 100644 --- a/drivers/media/v4l2-core/v4l2-common.c +++ b/drivers/media/v4l2-core/v4l2-common.c @@ -708,24 +708,40 @@ int v4l2_link_freq_to_bitmap(struct device *dev, const u64 *fw_link_freqs, } EXPORT_SYMBOL_GPL(v4l2_link_freq_to_bitmap); -struct clk *devm_v4l2_sensor_clk_get(struct device *dev, const char *id) +struct clk *__devm_v4l2_sensor_clk_get(struct device *dev, const char *id, + bool legacy, bool fixed_rate, + unsigned long clk_rate) { + bool of_node = is_of_node(dev_fwnode(dev)); const char *clk_id __free(kfree) = NULL; struct clk_hw *clk_hw; struct clk *clk; - bool of_node; - u32 rate; - int ret; + u32 rate = clk_rate; + int ret = 0; clk = devm_clk_get_optional(dev, id); if (IS_ERR(clk)) return clk; - ret = device_property_read_u32(dev, "clock-frequency", &rate); - of_node = is_of_node(dev_fwnode(dev)); + /* + * If the caller didn't request a fixed rate, retrieve it from the + * clock-frequency property. -EINVAL indicates the property is absent, + * and is not a failure. Other errors, or success with a clock-frequency + * value of 0, are hard failures. + */ + if (!fixed_rate || !clk_rate) { + ret = device_property_read_u32(dev, "clock-frequency", &rate); + if ((ret && ret != -EINVAL) || (!ret && !rate)) + return ERR_PTR(-EINVAL); + } if (clk) { - if (!ret && !of_node) { + /* + * On non-OF platforms, or when legacy behaviour is requested, + * set the clock rate if a rate has been specified by the caller + * or by the clock-frequency property. + */ + if (rate && (!of_node || legacy)) { ret = clk_set_rate(clk, rate); if (ret) { dev_err(dev, "Failed to set clock rate: %u\n", @@ -736,9 +752,14 @@ struct clk *devm_v4l2_sensor_clk_get(struct device *dev, const char *id) return clk; } - if (!IS_ENABLED(CONFIG_COMMON_CLK) || of_node) + /* + * Register a dummy fixed clock on non-OF platforms or when legacy + * behaviour is requested. This required the common clock framework. + */ + if (!IS_ENABLED(CONFIG_COMMON_CLK) || (of_node && !legacy)) return ERR_PTR(-ENOENT); + /* We need a rate to create a clock. */ if (ret) return ERR_PTR(ret == -EINVAL ? -EPROBE_DEFER : ret); @@ -755,4 +776,4 @@ struct clk *devm_v4l2_sensor_clk_get(struct device *dev, const char *id) return clk_hw->clk; } -EXPORT_SYMBOL_GPL(devm_v4l2_sensor_clk_get); +EXPORT_SYMBOL_GPL(__devm_v4l2_sensor_clk_get); diff --git a/include/media/v4l2-common.h b/include/media/v4l2-common.h index 594314459333..5c0a7f6b5bb6 100644 --- a/include/media/v4l2-common.h +++ b/include/media/v4l2-common.h @@ -612,6 +612,10 @@ int v4l2_link_freq_to_bitmap(struct device *dev, const u64 *fw_link_freqs, unsigned int num_of_driver_link_freqs, unsigned long *bitmap); +struct clk *__devm_v4l2_sensor_clk_get(struct device *dev, const char *id, + bool legacy, bool fixed_rate, + unsigned long clk_rate); + /** * devm_v4l2_sensor_clk_get - lookup and obtain a reference to a clock producer * for a camera sensor @@ -644,7 +648,42 @@ int v4l2_link_freq_to_bitmap(struct device *dev, const u64 *fw_link_freqs, * * Returns a pointer to a struct clk on success or an error pointer on failure. */ -struct clk *devm_v4l2_sensor_clk_get(struct device *dev, const char *id); +static inline struct clk * +devm_v4l2_sensor_clk_get(struct device *dev, const char *id) +{ + return __devm_v4l2_sensor_clk_get(dev, id, false, false, 0); +} + +/** + * devm_v4l2_sensor_clk_get_legacy - lookup and obtain a reference to a clock + * producer for a camera sensor. + * + * @dev: device for v4l2 sensor clock "consumer" + * @id: clock consumer ID + * @fixed_rate: interpret the @clk_rate as a fixed rate or default rate + * @clk_rate: the clock rate + * + * This function behaves the same way as devm_v4l2_sensor_clk_get() except that + * it extends the behaviour on ACPI platforms to all platforms. + * + * The function also provides the ability to set the clock rate to a fixed + * frequency by setting @fixed_rate to true and specifying the fixed frequency + * in @clk_rate, or to use a default clock rate when the "clock-frequency" + * property is absent by setting @fixed_rate to false and specifying the default + * frequency in @clk_rate. Setting @fixed_rate to true and @clk_rate to 0 is an + * error. + * + * This function is meant to support legacy behaviour in existing drivers only. + * It must not be used in any new driver. + * + * Returns a pointer to a struct clk on success or an error pointer on failure. + */ +static inline struct clk * +devm_v4l2_sensor_clk_get_legacy(struct device *dev, const char *id, + bool fixed_rate, unsigned long clk_rate) +{ + return __devm_v4l2_sensor_clk_get(dev, id, true, fixed_rate, clk_rate); +} static inline u64 v4l2_buffer_get_timestamp(const struct v4l2_buffer *buf) {