This adds two new HS400 tuning operations:
* hs400_downgrade
* hs400_complete
These supplement the existing HS400 operation:
* prepare_hs400_tuning
This is motivated by a requirement of Renesas SDHI for the following:
1. Disabling SCC before selecting to HS if selection of HS400 has occurred.
This can be done in an implementation of prepare_hs400_tuning_downgrade
2. Updating registers after switching to HS400
This can be done in an implementation of complete_hs400_tuning
If hs400_downgrade or hs400_complete are not implemented then they are not
called. Thus means there should be no affect for existing drivers as none
implemt these ops.
Signed-off-by: Simon Horman <horms+renesas@xxxxxxxxxxxx>
---
v5
* Reworked as per feedback from Ulf Hansson
- Call ops from mmc_hs400_to_hs200() and mmc_select_hs400()
rather than mmc_retune() and mmc_select_timing().
This moves card code further away from core code and
makes the patch somewhat tider.
- Use shorter names for new ops.
v4
* New patch
---
drivers/mmc/core/mmc.c | 10 ++++++++++
include/linux/mmc/host.h | 7 +++++++
2 files changed, 17 insertions(+)
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 4466f5de54d4..63a52379e8ab 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1169,6 +1169,10 @@ static int mmc_select_hs400(struct mmc_card *card)
/* Set host controller to HS timing */
mmc_set_timing(card->host, MMC_TIMING_MMC_HS);
+ /* Prepare host to downgrade to HS timing */
+ if (host->ops->hs400_downgrade)
+ host->ops->hs400_downgrade(host);
+
/* Reduce frequency to HS frequency */
max_dtr = card->ext_csd.hs_max_dtr;
mmc_set_clock(host, max_dtr);
@@ -1209,6 +1213,9 @@ static int mmc_select_hs400(struct mmc_card *card)
if (err)
goto out_err;
+ if (host->ops->hs400_complete)
+ host->ops->hs400_complete(host);
+
return 0;
out_err:
@@ -1256,6 +1263,9 @@ int mmc_hs400_to_hs200(struct mmc_card *card)
mmc_set_timing(host, MMC_TIMING_MMC_HS);
+ if (host->ops->hs400_downgrade)
+ host->ops->hs400_downgrade(host);
+
err = mmc_switch_status(card);
if (err)
goto out_err;
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 64300a48dcce..a39e2925c84c 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -146,6 +146,13 @@ struct mmc_host_ops {
/* Prepare HS400 target operating frequency depending host driver */
int (*prepare_hs400_tuning)(struct mmc_host *host, struct mmc_ios *ios);
+
+ /* Prepare for switching from HS400 to HS200 */
+ void (*hs400_downgrade)(struct mmc_host *host);
+
+ /* Complete selection of HS400 */
+ void (*hs400_complete)(struct mmc_host *host);
+
/* Prepare enhanced strobe depending host driver */
void (*hs400_enhanced_strobe)(struct mmc_host *host,
struct mmc_ios *ios);
--
2.11.0
