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| author | Maxime Ripard <maxime@cerno.tech> | 2022-10-27 15:52:43 +0300 |
|---|---|---|
| committer | Maxime Ripard <maxime@cerno.tech> | 2022-10-28 14:03:19 +0300 |
| commit | 40c31955e4e9ff268d21c0a8009e35f4cfaa167c (patch) | |
| tree | c6151e11dd3620fef12ce29984d8e4d2b7c31a80 /drivers | |
| parent | d0cde9b3b0cae06f5998f6d3936e90a80d05b2ec (diff) | |
| download | linux-40c31955e4e9ff268d21c0a8009e35f4cfaa167c.tar.xz | |
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 <sboyd@kernel.org>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20220815-rpi-fix-4k-60-v5-3-fe9e7ac8b111@cerno.tech
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/firmware/raspberrypi.c | 20 |
1 files changed, 20 insertions, 0 deletions
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, |