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firmware: raspberrypi: Provide a helper to query a clock max rate

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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>
This commit is contained in:
Maxime Ripard 2022-10-27 14:52:43 +02:00
parent d0cde9b3b0
commit 40c31955e4
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GPG Key ID: E3EF0D6F671851C5
2 changed files with 46 additions and 0 deletions
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20
drivers/firmware/raspberrypi.c
View File

@ -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,

26
include/soc/bcm2835/raspberrypi-firmware.h
View File

@ -155,12 +155,32 @@ enum rpi_firmware_clk_id {
RPI_FIRMWARE_NUM_CLK_ID,
};
/**
* struct rpi_firmware_clk_rate_request - Firmware Request for a rate
* @id: ID of the clock being queried
* @rate: Rate in Hertz. Set by the firmware.
*
* Used by @RPI_FIRMWARE_GET_CLOCK_RATE, @RPI_FIRMWARE_GET_CLOCK_MEASURED,
* @RPI_FIRMWARE_GET_MAX_CLOCK_RATE and @RPI_FIRMWARE_GET_MIN_CLOCK_RATE.
*/
struct rpi_firmware_clk_rate_request {
__le32 id;
__le32 rate;
} __packed;
#define RPI_FIRMWARE_CLK_RATE_REQUEST(_id) \
{ \
.id = _id, \
}
#if IS_ENABLED(CONFIG_RASPBERRYPI_FIRMWARE)
int rpi_firmware_property(struct rpi_firmware *fw,
u32 tag, void *data, size_t len);
int rpi_firmware_property_list(struct rpi_firmware *fw,
void *data, size_t tag_size);
void rpi_firmware_put(struct rpi_firmware *fw);
unsigned int rpi_firmware_clk_get_max_rate(struct rpi_firmware *fw,
unsigned int id);
struct device_node *rpi_firmware_find_node(void);
struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node);
struct rpi_firmware *devm_rpi_firmware_get(struct device *dev,
@ -180,6 +200,12 @@ static inline int rpi_firmware_property_list(struct rpi_firmware *fw,
static inline void rpi_firmware_put(struct rpi_firmware *fw) { }
static inline unsigned int rpi_firmware_clk_get_max_rate(struct rpi_firmware *fw,
unsigned int id)
{
return UINT_MAX;
}
static inline struct device_node *rpi_firmware_find_node(void)
{
return NULL;