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

[adrian.hunter@intel.com (Adrian Hunter)]

On 09/06/16 10:10, Gregory CLEMENT wrote:
> From: Victor Gu <xigu@marvell.com>
> 
> 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);
}


> 
> [gregory.clement at free-electrons.com: split the initial commit and
> reformulate the log]
> 
> Signed-off-by: Victor Gu <xigu@marvell.com>
> Signed-off-by: Marcin Wojtas <mw@semihalf.com>
> Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
> ---
>  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
>