[PATCH 05/12] mmc: sdhci: add a pre voltage switch callback function

Hi Adrian,
 
 On lun., juin 13 2016, Adrian Hunter [off-list ref] wrote:

On 09/06/16 10:10, Gregory CLEMENT wrote:

quoted

From: Victor Gu <redacted>

Some host controller such as Xenon needs additional setting when
switching signal voltage in eMMC mode. They also need to re-enable
internal clock before a voltage switch.

This commit adds a callback routine "voltage_switch_pre" in the struct
sdhci_ops, which is used by some host controllers which need re-enable
the internal clock before a voltage switch.

Don't want to add sdhci host ops for the "do something before a mmc host op"
case.

Instead, export sdhci_start_signal_voltage_switch() and  hook
host->mmc_host_ops.start_signal_voltage_switch. Then in sdhci-xenon.c:

int xenon__start_signal_voltage_switch(struct mmc_host *mmc,
				       struct mmc_ios *ios)
{
	blah blah
	return sdhci_start_signal_voltage_switch(mmc, ios);
}

OK I see your point.

Thanks,

Gregory

quoted

[gregory.clement at free-electrons.com: split the initial commit and
reformulate the log]

Signed-off-by: Victor Gu <redacted>
Signed-off-by: Marcin Wojtas <redacted>
Signed-off-by: Gregory CLEMENT <redacted>
---
 drivers/mmc/host/sdhci.c | 4 ++++
 drivers/mmc/host/sdhci.h | 1 +
 2 files changed, 5 insertions(+)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index b07219426d39..cad03ffa9d9b 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c

@@ -1729,6 +1729,10 @@ static int sdhci_start_signal_voltage_switch(struct mmc_host *mmc,
 	if (host->version < SDHCI_SPEC_300)
 		return 0;
 
+	/* Some controller need to do more before switching */
+	if (host->ops->voltage_switch_pre)
+		host->ops->voltage_switch_pre(host);
+
 	ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
 
 	switch (ios->signal_voltage) {

diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index 49c6c5b0e33b..6bec1b0368d2 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h

@@ -550,6 +550,7 @@ struct sdhci_ops {
 					 unsigned int max_dtr, int host_drv,
 					 int card_drv, int *drv_type);
 	void	(*init_card)(struct sdhci_host *host, struct mmc_card *card);
+	void	(*voltage_switch_pre)(struct sdhci_host *host);
 };
 
 #ifdef CONFIG_MMC_SDHCI_IO_ACCESSORS

-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com