Hi,
I'm working on a SDHCI driver for linux kernel 3.4.
The IP that I have to control does not control the Driver Strength.
Driver Type B is always selected. On the other hand, I can control the
drive strength of the pads in software.
I would like to use the interface select_drive_strength of the
mmc_host_ops. Is it a good idea?
If so, I have an other issue.
This function doesn't have an mmc_host as parameter. It is an issue for
me since the drive strength parameters can be board specific.
A solution would be to add this parameter:
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 5674504..cb6d117 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -134,7 +134,7 @@ struct mmc_host_ops {
/* The tuning command opcode value is different for SD and eMMC
cards */
int (*execute_tuning)(struct mmc_host *host, u32 opcode);
void (*enable_preset_value)(struct mmc_host *host, bool enable);
- int (*select_drive_strength)(unsigned int max_dtr, int
host_drv, int card_drv);
+ int (*select_drive_strength)(struct mmc_host *host, unsigned
int max_dtr, int host_drv, int card_drv);
void (*hw_reset)(struct mmc_host *host);
};
Is this solution a good idea?
Also, the drive strength configuration might be different according to
the mode (not only UHS). So, I would like to control the drive strength
for the default speed and the high speed. Would it be relevant to add
this a call to this function in mmc_sd_switch_hs or in mmc_sd_init_card?
Thanks,
Jeremie Samuel
--
To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
