From 40c31955e4e9ff268d21c0a8009e35f4cfaa167c Mon Sep 17 00:00:00 2001 From: Maxime Ripard Date: Thu, 27 Oct 2022 14:52:43 +0200 Subject: firmware: raspberrypi: Provide a helper to query a clock max rate The firmware allows to query for its clocks the operating range of a given clock. We'll need this for some drivers (KMS, in particular) to infer the state of some configuration options, so let's create a function to do so. Acked-by: Stephen Boyd Reviewed-by: Florian Fainelli Acked-by: Florian Fainelli Link: https://lore.kernel.org/r/20220815-rpi-fix-4k-60-v5-3-fe9e7ac8b111@cerno.tech Signed-off-by: Maxime Ripard --- drivers/firmware/raspberrypi.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'drivers/firmware/raspberrypi.c') diff --git a/drivers/firmware/raspberrypi.c b/drivers/firmware/raspberrypi.c index 932a8bef22fb..b15aa6fce0e9 100644 --- a/drivers/firmware/raspberrypi.c +++ b/drivers/firmware/raspberrypi.c @@ -228,6 +228,26 @@ static void rpi_register_clk_driver(struct device *dev) -1, NULL, 0); } +unsigned int rpi_firmware_clk_get_max_rate(struct rpi_firmware *fw, unsigned int id) +{ + struct rpi_firmware_clk_rate_request msg = + RPI_FIRMWARE_CLK_RATE_REQUEST(id); + int ret; + + ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_MAX_CLOCK_RATE, + &msg, sizeof(msg)); + if (ret) + /* + * If our firmware doesn't support that operation, or fails, we + * assume the maximum clock rate is absolute maximum we can + * store over our type. + */ + return UINT_MAX; + + return le32_to_cpu(msg.rate); +} +EXPORT_SYMBOL_GPL(rpi_firmware_clk_get_max_rate); + static void rpi_firmware_delete(struct kref *kref) { struct rpi_firmware *fw = container_of(kref, struct rpi_firmware, -- cgit v1.2.3