Commit 93b6911a authored by Wolfram Sang's avatar Wolfram Sang Committed by Ulf Hansson

mmc: host: add note that set_ios needs to handle 0Hz properly

While here, refactor the comments so that they are before the
declaration they are referring to.
Signed-off-by: default avatarWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent 148634d2
...@@ -93,28 +93,39 @@ struct mmc_host_ops { ...@@ -93,28 +93,39 @@ struct mmc_host_ops {
void (*pre_req)(struct mmc_host *host, struct mmc_request *req, void (*pre_req)(struct mmc_host *host, struct mmc_request *req,
bool is_first_req); bool is_first_req);
void (*request)(struct mmc_host *host, struct mmc_request *req); void (*request)(struct mmc_host *host, struct mmc_request *req);
/*
* Avoid calling the next three functions too often or in a "fast
* path", since underlaying controller might implement them in an
* expensive and/or slow way. Also note that these functions might
* sleep, so don't call them in the atomic contexts!
*/
/*
* Notes to the set_ios callback:
* ios->clock might be 0. For some controllers, setting 0Hz
* as any other frequency works. However, some controllers
* explicitly need to disable the clock. Otherwise e.g. voltage
* switching might fail because the SDCLK is not really quiet.
*/
void (*set_ios)(struct mmc_host *host, struct mmc_ios *ios);
/* /*
* Avoid calling these three functions too often or in a "fast path",
* since underlaying controller might implement them in an expensive
* and/or slow way.
*
* Also note that these functions might sleep, so don't call them
* in the atomic contexts!
*
* Return values for the get_ro callback should be: * Return values for the get_ro callback should be:
* 0 for a read/write card * 0 for a read/write card
* 1 for a read-only card * 1 for a read-only card
* -ENOSYS when not supported (equal to NULL callback) * -ENOSYS when not supported (equal to NULL callback)
* or a negative errno value when something bad happened * or a negative errno value when something bad happened
* */
int (*get_ro)(struct mmc_host *host);
/*
* Return values for the get_cd callback should be: * Return values for the get_cd callback should be:
* 0 for a absent card * 0 for a absent card
* 1 for a present card * 1 for a present card
* -ENOSYS when not supported (equal to NULL callback) * -ENOSYS when not supported (equal to NULL callback)
* or a negative errno value when something bad happened * or a negative errno value when something bad happened
*/ */
void (*set_ios)(struct mmc_host *host, struct mmc_ios *ios);
int (*get_ro)(struct mmc_host *host);
int (*get_cd)(struct mmc_host *host); int (*get_cd)(struct mmc_host *host);
void (*enable_sdio_irq)(struct mmc_host *host, int enable); void (*enable_sdio_irq)(struct mmc_host *host, int enable);
......
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