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SubjectRe: [PATCH v4 2/2] mmc: dw_mmc: add reset support to dwmmc host controller
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Hi Guodong,

On 08/11/2016 11:23 AM, Shawn Lin wrote:
> On 2016/8/10 16:03, Guodong Xu wrote:
>> Dwmmc host controller may in unknown state when entering kernel boot. One
>> example is when booting from eMMC, bootloader need initialize MMC host
>> controller into some state so it can read. In order to make sure MMC host
>> controller in a clean initial state, this reset support is added.
>>
>> With this patch, a 'resets' property can be added into dw_mmc device
>> tree node. The hardware logic is: dwmmc host controller IP receives a reset
>> signal from a 'reset provider' (eg. power management unit). The 'resets'
>> property points to this reset signal. So, during dwmmc driver probe,
>> it can use this signal to reset itself.
>>
>> Refer to [1] for more information.
>>
>> [1] Documentation/devicetree/bindings/reset/reset.txt
>>
>> Signed-off-by: Guodong Xu <guodong.xu@linaro.org>
>> Signed-off-by: Xinwei Kong <kong.kongxinwei@hisilicon.com>
>> Signed-off-by: Zhangfei Gao <zhangfei.gao@linaro.org>
>
> Looks good to me,
>
> Reviewed-by: Shawn Lin <shawn.lin@rock-chips.com>

Could you rebase on https://github.com/jh80chung/dw-mmc.git?
Otherwise, when i apply your patch, i will rebase.

Best Regards,
Jaehoon Chung

>
>> ---
>> drivers/mmc/host/dw_mmc.c | 23 ++++++++++++++++++++++-
>> include/linux/mmc/dw_mmc.h | 2 ++
>> 2 files changed, 24 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
>> index 32380d5..481d441 100644
>> --- a/drivers/mmc/host/dw_mmc.c
>> +++ b/drivers/mmc/host/dw_mmc.c
>> @@ -2915,6 +2915,13 @@ 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);
>> + }
>> +
>> /* find out number of slots supported */
>> of_property_read_u32(np, "num-slots", &pdata->num_slots);
>>
>> @@ -2986,7 +2993,9 @@ 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;
>> + } else if (IS_ERR(host->pdata)) {
>> dev_err(host->dev, "platform data not available\n");
>> return -EINVAL;
>> }
>> @@ -3040,6 +3049,12 @@ int dw_mci_probe(struct dw_mci *host)
>> }
>> }
>>
>> + if (!IS_ERR(host->pdata->rstc)) {
>> + reset_control_assert(host->pdata->rstc);
>> + usleep_range(10, 50);
>> + reset_control_deassert(host->pdata->rstc);
>> + }
>> +
>> setup_timer(&host->cmd11_timer,
>> dw_mci_cmd11_timer, (unsigned long)host);
>>
>> @@ -3189,6 +3204,9 @@ err_dmaunmap:
>> if (host->use_dma && host->dma_ops->exit)
>> host->dma_ops->exit(host);
>>
>> + if (!IS_ERR(host->pdata->rstc))
>> + reset_control_assert(host->pdata->rstc);
>> +
>> err_clk_ciu:
>> if (!IS_ERR(host->ciu_clk))
>> clk_disable_unprepare(host->ciu_clk);
>> @@ -3221,6 +3239,9 @@ void dw_mci_remove(struct dw_mci *host)
>> if (host->use_dma && host->dma_ops->exit)
>> host->dma_ops->exit(host);
>>
>> + if (!IS_ERR(host->pdata->rstc))
>> + reset_control_assert(host->pdata->rstc);
>> +
>> if (!IS_ERR(host->ciu_clk))
>> clk_disable_unprepare(host->ciu_clk);
>>
>> diff --git a/include/linux/mmc/dw_mmc.h b/include/linux/mmc/dw_mmc.h
>> index 83b0edfc..f5af2bd 100644
>> --- a/include/linux/mmc/dw_mmc.h
>> +++ b/include/linux/mmc/dw_mmc.h
>> @@ -17,6 +17,7 @@
>> #include <linux/scatterlist.h>
>> #include <linux/mmc/core.h>
>> #include <linux/dmaengine.h>
>> +#include <linux/reset.h>
>>
>> #define MAX_MCI_SLOTS 2
>>
>> @@ -259,6 +260,7 @@ struct dw_mci_board {
>> /* delay in mS before detecting cards after interrupt */
>> u32 detect_delay_ms;
>>
>> + struct reset_control *rstc;
>> struct dw_mci_dma_ops *dma_ops;
>> struct dma_pdata *data;
>> };
>>
>
>

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