On 2016/3/6 16:47, Guodong Xu wrote:
mmc registers may in abnormal state if mmc is used in bootloader,
eg. to support booting from eMMC. So we need reset mmc registers
when kernel boots up, instead of assuming mmc is in clean state.
With this patch, user can add a 'resets' property into dw_mmc dts
node. When driver parse_dt and probe, it calls reset API to
deassert the 'reset' of dw_mmc host controller. When probe error or
remove, it calls reset API to assert it.
Please also refer to Documentation/devicetree/bindings/reset/reset.txt
Signed-off-by: Guodong Xu <guodong.xu@xxxxxxxxxx>
Signed-off-by: Xinwei Kong <kong.kongxinwei@xxxxxxxxxxxxx>
Signed-off-by: Zhangfei Gao <zhangfei.gao@xxxxxxxxxx>
Really should V2 and add the changelog.
---
drivers/mmc/host/dw_mmc.c | 22 +++++++++++++++++++++-
1 file changed, 21 insertions(+), 1 deletion(-)
diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 242f9a0..281ea9c 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -2878,6 +2878,14 @@ static struct dw_mci_board *dw_mci_parse_dt(struct dw_mci *host)
if (!pdata)
return ERR_PTR(-ENOMEM);
+ /* find reset controller when exist */
+ pdata->rstc = devm_reset_control_get_optional(dev, NULL);
+ if (IS_ERR(pdata->rstc)) {
+ if (PTR_ERR(pdata->rstc) == -EPROBE_DEFER)
+ return ERR_PTR(-EPROBE_DEFER);
+ pdata->rstc = NULL;
maybe we can remove "pdata->rstc = NULL", and directly
use IS_ERR(..) for the following "if (host->pdata->rstc != NULL)"
statement
+ }
+
/* find out number of slots supported */
of_property_read_u32(np, "num-slots", &pdata->num_slots);
@@ -2949,7 +2957,9 @@ int dw_mci_probe(struct dw_mci *host)
if (!host->pdata) {
host->pdata = dw_mci_parse_dt(host);
- if (IS_ERR(host->pdata)) {
+ if (PTR_ERR(host->pdata) == -EPROBE_DEFER)
+ return -EPROBE_DEFER;
please fix the coding style here.
+ else if (IS_ERR(host->pdata)) {
dev_err(host->dev, "platform data not available\n");
return -EINVAL;
}
@@ -3012,6 +3022,9 @@ int dw_mci_probe(struct dw_mci *host)
}
}
+ if (host->pdata->rstc != NULL)
+ reset_control_deassert(host->pdata->rstc);
+
sorry, I can't follow your intention here. Shouldn't it be something
like "assert mmc -> may need delay -> deassert mmc". As your current
code, nothing happend right?
setup_timer(&host->cmd11_timer,
dw_mci_cmd11_timer, (unsigned long)host);
@@ -3164,6 +3177,9 @@ err_dmaunmap:
if (host->use_dma && host->dma_ops->exit)
host->dma_ops->exit(host);
+ if (host->pdata->rstc != NULL)
+ reset_control_assert(host->pdata->rstc);
+
err_clk_ciu:
if (!IS_ERR(host->ciu_clk))
clk_disable_unprepare(host->ciu_clk);
@@ -3196,11 +3212,15 @@ void dw_mci_remove(struct dw_mci *host)
if (host->use_dma && host->dma_ops->exit)
host->dma_ops->exit(host);
+ if (host->pdata->rstc != NULL)
+ reset_control_assert(host->pdata->rstc);
+
if (!IS_ERR(host->ciu_clk))
clk_disable_unprepare(host->ciu_clk);
if (!IS_ERR(host->biu_clk))
clk_disable_unprepare(host->biu_clk);
+
}
unnecessary new line here.
EXPORT_SYMBOL(dw_mci_remove);
--
Best Regards
Shawn Lin
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