[RESEND,v4,3/3] mmc: mediatek: add optional module reset property

[Wenbin Mei]

Yes, I will add Philipp Zabels Reviewed-by tag in the next version.
On Thu, 2020-08-13 at 15:57 +0200, Matthias Brugger wrote:
> 
> On 13/08/2020 11:38, Wenbin Mei wrote:
> > This patch fixs eMMC-Access on mt7622/Bpi-64.
> > Before we got these Errors on mounting eMMC ion R64:
> > [   48.664925] blk_update_request: I/O error, dev mmcblk0, sector 204800 op 0x1:(WRITE)
> > flags 0x800 phys_seg 1 prio class 0
> > [   48.676019] Buffer I/O error on dev mmcblk0p1, logical block 0, lost sync page write
> > 
> > This patch adds a optional reset management for msdc.
> > Sometimes the bootloader does not bring msdc register
> > to default state, so need reset the msdc controller.
> > 
> > Cc: <stable at vger.kernel.org> # v5.4+
> > Fixes: 966580ad236e ("mmc: mediatek: add support for MT7622 SoC")
> > Signed-off-by: Wenbin Mei <wenbin.mei at mediatek.com>
> > Tested-by: Frank Wunderlich <frank-w at public-files.de>
> 
> I think you missed to add Philipp Zabels Reviewed-by tag.
> 
> Regards,
> Matthias
> 
> 
> > ---
> >   drivers/mmc/host/mtk-sd.c | 13 +++++++++++++
> >   1 file changed, 13 insertions(+)
> > 
> > diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
> > index 39e7fc54c438..fc97d5bf3a20 100644
> > --- a/drivers/mmc/host/mtk-sd.c
> > +++ b/drivers/mmc/host/mtk-sd.c
> > @@ -22,6 +22,7 @@
> >   #include <linux/slab.h>
> >   #include <linux/spinlock.h>
> >   #include <linux/interrupt.h>
> > +#include <linux/reset.h>
> >   
> >   #include <linux/mmc/card.h>
> >   #include <linux/mmc/core.h>
> > @@ -434,6 +435,7 @@ struct msdc_host {
> >   	struct msdc_save_para save_para; /* used when gate HCLK */
> >   	struct msdc_tune_para def_tune_para; /* default tune setting */
> >   	struct msdc_tune_para saved_tune_para; /* tune result of CMD21/CMD19 */
> > +	struct reset_control *reset;
> >   };
> >   
> >   static const struct mtk_mmc_compatible mt8135_compat = {
> > @@ -1516,6 +1518,12 @@ static void msdc_init_hw(struct msdc_host *host)
> >   	u32 val;
> >   	u32 tune_reg = host->dev_comp->pad_tune_reg;
> >   
> > +	if (host->reset) {
> > +		reset_control_assert(host->reset);
> > +		usleep_range(10, 50);
> > +		reset_control_deassert(host->reset);
> > +	}
> > +
> >   	/* Configure to MMC/SD mode, clock free running */
> >   	sdr_set_bits(host->base + MSDC_CFG, MSDC_CFG_MODE | MSDC_CFG_CKPDN);
> >   
> > @@ -2273,6 +2281,11 @@ static int msdc_drv_probe(struct platform_device *pdev)
> >   	if (IS_ERR(host->src_clk_cg))
> >   		host->src_clk_cg = NULL;
> >   
> > +	host->reset = devm_reset_control_get_optional_exclusive(&pdev->dev,
> > +								"hrst");
> > +	if (IS_ERR(host->reset))
> > +		return PTR_ERR(host->reset);
> > +
> >   	host->irq = platform_get_irq(pdev, 0);
> >   	if (host->irq < 0) {
> >   		ret = -EINVAL;
> >