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Commit ebc5a1bf authored by harish_kandiga@mentor.com's avatar harish_kandiga@mentor.com Committed by Ulf Hansson
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mmc: core: Add a new quirk for limiting clock rate 



This patch adds a quirk to limit clock rate which
can be used to reduce the SDIO clock rate for some
chips with broken UHS.

Signed-off-by: default avatarHarish Jenny K N <harish_kandiga@mentor.com>
Reviewed-by: default avatarShawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent d39b1b2a

drivers/mmc/core/card.h

+6 −0
Original line number Diff line number Diff line
@@ -149,6 +149,12 @@ static inline void __maybe_unused remove_quirk(struct mmc_card *card, int data) 
	card->quirks &= ~data;

}



static inline void __maybe_unused add_limit_rate_quirk(struct mmc_card *card,

						       int data)

{

	card->quirk_max_rate = data;

}



/*

 * Quirk add/remove for MMC products.

 */

drivers/mmc/core/sdio.c

+5 −1
Original line number Diff line number Diff line
@@ -444,6 +444,7 @@ static int sdio_set_bus_speed_mode(struct mmc_card *card) 
	unsigned int bus_speed, timing;

	int err;

	unsigned char speed;

	unsigned int max_rate;



	/*

	 * If the host doesn't support any of the UHS-I modes, fallback on
@@ -500,9 +501,12 @@ static int sdio_set_bus_speed_mode(struct mmc_card *card) 
	if (err)

		return err;



	max_rate = min_not_zero(card->quirk_max_rate,

				card->sw_caps.uhs_max_dtr);



	if (bus_speed) {

		mmc_set_timing(card->host, timing);

		mmc_set_clock(card->host, card->sw_caps.uhs_max_dtr);

		mmc_set_clock(card->host, max_rate);

	}



	return 0;

include/linux/mmc/card.h

+1 −0
Original line number Diff line number Diff line
@@ -252,6 +252,7 @@ struct mmc_card { 
#define MMC_TYPE_SD_COMBO	3		/* SD combo (IO+mem) card */

	unsigned int		state;		/* (our) card state */

	unsigned int		quirks; 	/* card quirks */

	unsigned int		quirk_max_rate;	/* max rate set by quirks */

#define MMC_QUIRK_LENIENT_FN0	(1<<0)		/* allow SDIO FN0 writes outside of the VS CCCR range */

#define MMC_QUIRK_BLKSZ_FOR_BYTE_MODE (1<<1)	/* use func->cur_blksize */

						/* for byte mode */