Re: [PATCH] mmc: sdhci-xenon: add gpio hard reset support

Shawn Lin
2017-08-15T02:11:50Z

Hi

On 2017/8/15 6:19, Zhoujie Wu wrote:
> On some platforms, like armada3700, SD card need to
> do hard reset by gpio toggling to make it work properly
> after warm reset the board.

I don't get this that SD card need to do hard reset...

I assume what you talk about is either for eMMC or a power-cycle
for SD card.

> Add gpio hard reset feature for this purpose.
>
> Signed-off-by: Zhoujie Wu <zjwu@marvell.com>
> ---
> drivers/mmc/host/sdhci-xenon.c | 49 +++++++++++++++++++++++++++++++++++++++---
> drivers/mmc/host/sdhci-xenon.h | 4 ++++
> 2 files changed, 50 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-xenon.c b/drivers/mmc/host/sdhci-xenon.c
> index edd4d915..54a7057 100644
> --- a/drivers/mmc/host/sdhci-xenon.c
> +++ b/drivers/mmc/host/sdhci-xenon.c
> @@ -18,6 +18,8 @@
> #include <linux/ktime.h>
> #include <linux/module.h>
> #include <linux/of.h>
> +#include <linux/of_gpio.h>
> +
>
> #include "sdhci-pltfm.h"
> #include "sdhci-xenon.h"
> @@ -210,12 +212,25 @@ static void xenon_set_uhs_signaling(struct sdhci_host *host,
> sdhci_writew(host, ctrl_2, SDHCI_HOST_CONTROL2);
> }
>
> +static void xenon_hw_reset(struct sdhci_host *host)
> +{
> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> + struct xenon_priv *priv = sdhci_pltfm_priv(pltfm_host);
> +
> + if (priv->reset_gpio) {
> + gpiod_set_value_cansleep(priv->reset_gpio, 0);
> + msleep(30);
> + gpiod_set_value_cansleep(priv->reset_gpio, 1);
> + }
> +}
> +

If that is not a functional IO wired out from your controller,
and I would expect you $subject patch and could introduce pwrseq for you
DT instead of adding these....

Does that work for you?

> static const struct sdhci_ops sdhci_xenon_ops = {
> .set_clock = sdhci_set_clock,
> .set_bus_width = sdhci_set_bus_width,
> .reset = xenon_reset,
> .set_uhs_signaling = xenon_set_uhs_signaling,
> .get_max_clock = sdhci_pltfm_clk_get_max_clock,
> + .hw_reset = xenon_hw_reset,
> };
>
> static const struct sdhci_pltfm_data sdhci_xenon_pdata = {
> @@ -373,10 +388,15 @@ static int xenon_probe_dt(struct platform_device *pdev)
> struct device_node *np = pdev->dev.of_node;
> struct sdhci_host *host = platform_get_drvdata(pdev);
> struct mmc_host *mmc = host->mmc;
> + struct device *dev = mmc_dev(mmc);
> struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> struct xenon_priv *priv = sdhci_pltfm_priv(pltfm_host);
> u32 sdhc_id, nr_sdhc;
> u32 tuning_count;
> + int reset_gpio, ret;
> + enum of_gpio_flags flags;
> + char *reset_name;
> + unsigned long gpio_flags;
>
> /* Disable HS200 on Armada AP806 */
> if (of_device_is_compatible(np, "marvell,armada-ap806-sdhci"))
> @@ -387,7 +407,7 @@ static int xenon_probe_dt(struct platform_device *pdev)
> nr_sdhc = sdhci_readl(host, XENON_SYS_CFG_INFO);
> nr_sdhc &= XENON_NR_SUPPORTED_SLOT_MASK;
> if (unlikely(sdhc_id > nr_sdhc)) {
> - dev_err(mmc_dev(mmc), "SDHC Index %d exceeds Number of SDHCs %d\n",
> + dev_err(dev, "SDHC Index %d exceeds Number of SDHCs %d\n",
> sdhc_id, nr_sdhc);
> return -EINVAL;
> }
> @@ -398,14 +418,37 @@ static int xenon_probe_dt(struct platform_device *pdev)
> if (!of_property_read_u32(np, "marvell,xenon-tun-count",
> &tuning_count)) {
> if (unlikely(tuning_count >= XENON_TMR_RETUN_NO_PRESENT)) {
> - dev_err(mmc_dev(mmc), "Wrong Re-tuning Count. Set default value %d\n",
> + dev_err(dev, "Wrong Re-tuning Count. Set default value %d\n",
> XENON_DEF_TUNING_COUNT);
> tuning_count = XENON_DEF_TUNING_COUNT;
> }
> }
> priv->tuning_count = tuning_count;
>
> - return xenon_phy_parse_dt(np, host);
> + ret = xenon_phy_parse_dt(np, host);
> +
> + reset_gpio = of_get_named_gpio_flags(np, "reset-gpios", 0, &flags);
> + if (gpio_is_valid(reset_gpio)) {
> + if (flags & OF_GPIO_ACTIVE_LOW)
> + gpio_flags = GPIOF_ACTIVE_LOW | GPIOF_OUT_INIT_HIGH;
> + else
> + gpio_flags = GPIOF_OUT_INIT_LOW;
> +
> + reset_name = devm_kasprintf(dev, GFP_KERNEL, "%s-reset",
> + dev_name(dev));
> + if (!reset_name)
> + return -ENOMEM;
> + ret = devm_gpio_request_one(dev, reset_gpio, gpio_flags,
> + reset_name);
> + if (ret) {
> + dev_err(dev, "Failed to request reset gpio\n");
> + return ret;
> + }
> +
> + priv->reset_gpio = gpio_to_desc(reset_gpio);
> + }
> +
> + return ret;
> }
>
> static int xenon_sdhc_prepare(struct sdhci_host *host)
> diff --git a/drivers/mmc/host/sdhci-xenon.h b/drivers/mmc/host/sdhci-xenon.h
> index 73debb4..cffb0fe 100644
> --- a/drivers/mmc/host/sdhci-xenon.h
> +++ b/drivers/mmc/host/sdhci-xenon.h
> @@ -90,6 +90,10 @@ struct xenon_priv {
> */
> void *phy_params;
> struct xenon_emmc_phy_regs *emmc_phy_regs;
> + /*
> + * gpio pin for hw reset
> + */
> + struct gpio_desc *reset_gpio;
> };
>
> int xenon_phy_adj(struct sdhci_host *host, struct mmc_ios *ios);
>