Introduce a helper for v4l2 sensor drivers on both DT- and ACPI-based platforms to retrieve a reference to the clock producer from firmware. This helper behaves the same as clk_get_optional() except where there is no clock producer like ACPI-based platforms. For ACPI-based platforms the function will read the "clock-frequency" ACPI _DSD property and register a fixed frequency clock with the frequency indicated in the property. Signed-off-by: Mehdi Djait <mehdi.djait@xxxxxxxxxxxxxxx> --- Link for discussion (where this patch was proposed): https://lore.kernel.org/linux-media/20250220154909.152538-1-mehdi.djait@xxxxxxxxxxxxxxx/ v1 -> v2: Suggested by Sakari: - removed clk_name - removed the IS_ERR() check - improved the kernel-doc comment and commit msg Link for v1: https://lore.kernel.org/linux-media/20250227092643.113939-1-mehdi.djait@xxxxxxxxxxxxxxx drivers/media/v4l2-core/v4l2-common.c | 35 +++++++++++++++++++++++++++ include/media/v4l2-common.h | 18 ++++++++++++++ 2 files changed, 53 insertions(+) diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c index 0a2f4f0d0a07..99d826acb213 100644 --- a/drivers/media/v4l2-core/v4l2-common.c +++ b/drivers/media/v4l2-core/v4l2-common.c @@ -34,6 +34,9 @@ * Added Gerd Knorrs v4l1 enhancements (Justin Schoeman) */ +#include <linux/clk.h> +#include <linux/clkdev.h> +#include <linux/clk-provider.h> #include <linux/module.h> #include <linux/types.h> #include <linux/kernel.h> @@ -636,3 +639,35 @@ int v4l2_link_freq_to_bitmap(struct device *dev, const u64 *fw_link_freqs, return 0; } EXPORT_SYMBOL_GPL(v4l2_link_freq_to_bitmap); + +struct clk *devm_v4l2_sensor_clk_get(struct device *dev, const char *id) +{ + struct clk_hw *clk_hw; + struct clk *clk; + u32 rate; + int ret; + + clk = devm_clk_get_optional(dev, id); + if (clk) + return clk; + + if (!is_acpi_node(dev_fwnode(dev))) + return ERR_PTR(-ENOENT); + + ret = device_property_read_u32(dev, "clock-frequency", &rate); + if (ret) + return ERR_PTR(ret); + + if (!id) { + id = devm_kasprintf(dev, GFP_KERNEL, "clk-%s", dev_name(dev)); + if (!id) + return ERR_PTR(-ENOMEM); + } + + clk_hw = devm_clk_hw_register_fixed_rate(dev, id, NULL, 0, rate); + if (IS_ERR(clk_hw)) + return ERR_CAST(clk_hw); + + return clk_hw->clk; +} +EXPORT_SYMBOL_GPL(devm_v4l2_sensor_clk_get); diff --git a/include/media/v4l2-common.h b/include/media/v4l2-common.h index 63ad36f04f72..35b9ac698e8a 100644 --- a/include/media/v4l2-common.h +++ b/include/media/v4l2-common.h @@ -573,6 +573,24 @@ int v4l2_link_freq_to_bitmap(struct device *dev, const u64 *fw_link_freqs, unsigned int num_of_driver_link_freqs, unsigned long *bitmap); +/** + * devm_v4l2_sensor_clk_get - lookup and obtain a reference to an optional clock + * producer for a camera sensor. + * + * @dev: device for v4l2 sensor clock "consumer" + * @id: clock consumer ID + * + * This function behaves the same way as clk_get_optional() except where there + * is no clock producer like in ACPI-based platforms. + * For ACPI-based platforms, the function will read the "clock-frequency" + * ACPI _DSD property and register a fixed-clock with the frequency indicated + * in the property. + * + * Return: + * * pointer to a struct clk on success or an error code on failure. + */ +struct clk *devm_v4l2_sensor_clk_get(struct device *dev, const char *id); + static inline u64 v4l2_buffer_get_timestamp(const struct v4l2_buffer *buf) { /* -- 2.48.1
