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    SubjectRe: [PATCH v3 1/2] mmc: sdhci-of-arasan: Enable UHS-1 support for Keem Bay SOC
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    On 06. 10. 20 17:55, muhammad.husaini.zulkifli@intel.com wrote:
    > From: Muhammad Husaini Zulkifli <muhammad.husaini.zulkifli@intel.com>
    >
    > Voltage switching sequence is needed to support UHS-1 interface.
    > There are 2 places to control the voltage.
    > 1) By setting the AON register using firmware driver calling
    > system-level platform management layer (SMC) to set the register.
    > 2) By controlling the GPIO expander value to drive either 1.8V or 3.3V
    > for power mux input.
    >
    > Signed-off-by: Muhammad Husaini Zulkifli <muhammad.husaini.zulkifli@intel.com>
    > Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
    > Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
    > ---
    > drivers/mmc/host/sdhci-of-arasan.c | 127 +++++++++++++++++++++++++++++
    > 1 file changed, 127 insertions(+)
    >
    > diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
    > index f186fbd016b1..e681e6f860ba 100644
    > --- a/drivers/mmc/host/sdhci-of-arasan.c
    > +++ b/drivers/mmc/host/sdhci-of-arasan.c
    > @@ -16,6 +16,7 @@
    > */
    >
    > #include <linux/clk-provider.h>
    > +#include <linux/gpio/consumer.h>
    > #include <linux/mfd/syscon.h>
    > #include <linux/module.h>
    > #include <linux/of_device.h>
    > @@ -23,6 +24,7 @@
    > #include <linux/regmap.h>
    > #include <linux/of.h>
    > #include <linux/firmware/xlnx-zynqmp.h>
    > +#include <linux/firmware/intel/keembay_firmware.h>
    >
    > #include "cqhci.h"
    > #include "sdhci-pltfm.h"
    > @@ -150,6 +152,7 @@ struct sdhci_arasan_data {
    > struct regmap *soc_ctl_base;
    > const struct sdhci_arasan_soc_ctl_map *soc_ctl_map;
    > unsigned int quirks;
    > + struct gpio_desc *uhs_gpio;
    >
    > /* Controller does not have CD wired and will not function normally without */
    > #define SDHCI_ARASAN_QUIRK_FORCE_CDTEST BIT(0)
    > @@ -361,6 +364,113 @@ static int sdhci_arasan_voltage_switch(struct mmc_host *mmc,
    > return -EINVAL;
    > }
    >
    > +static int sdhci_arasan_keembay_voltage_switch(struct mmc_host *mmc,
    > + struct mmc_ios *ios)
    > +{
    > + struct sdhci_host *host = mmc_priv(mmc);
    > + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
    > + struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
    > + u16 ctrl_2;
    > + u16 clk;

    nit: put it to one line.

    > + int ret;
    > +
    > + switch (ios->signal_voltage) {
    > + case MMC_SIGNAL_VOLTAGE_180:
    > + clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);

    nit: double space

    > + clk &= ~SDHCI_CLOCK_CARD_EN;
    > + sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
    > +
    > + clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);

    nit: double space again.

    > + if (clk & SDHCI_CLOCK_CARD_EN)
    > + return -EAGAIN;
    > +
    > + sdhci_writeb(host, SDHCI_POWER_ON | SDHCI_POWER_180,
    > + SDHCI_POWER_CONTROL);
    > +
    > + /*
    > + * Set VDDIO_B voltage to Low for 1.8V
    > + * which is controlling by GPIO Expander.
    > + */
    > + gpiod_set_value_cansleep(sdhci_arasan->uhs_gpio, 0);
    > +
    > + /*
    > + * This is like final gatekeeper. Need to ensure changed voltage
    > + * is settled before and after turn on this bit.
    > + */
    > + usleep_range(1000, 1100);
    > +
    > + ret = keembay_sd_voltage_selection(KEEMBAY_SET_1V8_VOLT);
    > + if (ret)
    > + return ret;
    > +
    > + usleep_range(1000, 1100);
    > +
    > + ctrl_2 = sdhci_readw(host, SDHCI_HOST_CONTROL2);
    > + ctrl_2 |= SDHCI_CTRL_VDD_180;
    > + sdhci_writew(host, ctrl_2, SDHCI_HOST_CONTROL2);
    > +
    > + /* Sleep for 5ms to stabilize 1.8V regulator */
    > + usleep_range(5000, 5500);
    > +
    > + /* 1.8V regulator output should be stable within 5 ms */
    > + ctrl_2 = sdhci_readw(host, SDHCI_HOST_CONTROL2);
    > + if (!(ctrl_2 & SDHCI_CTRL_VDD_180))
    > + return -EAGAIN;
    > +
    > + clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
    > + clk |= SDHCI_CLOCK_CARD_EN;
    > + sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
    > + break;
    > + case MMC_SIGNAL_VOLTAGE_330:
    > + /*
    > + * Set VDDIO_B voltage to High for 3.3V
    > + * which is controlling by GPIO Expander.
    > + */
    > + gpiod_set_value_cansleep(sdhci_arasan->uhs_gpio, 1);
    > +
    > + /*
    > + * This is like final gatekeeper. Need to ensure changed voltage
    > + * is settled before and after turn on this bit.
    > + */
    > + usleep_range(1000, 1100);
    > +
    > + ret = keembay_sd_voltage_selection(KEEMBAY_SET_3V3_VOLT);
    > + if (ret)
    > + return ret;
    > +
    > + usleep_range(1000, 1100);
    > +
    > + /* Set 1.8V Signal Enable in the Host Control2 register to 0 */
    > + ctrl_2 = sdhci_readw(host, SDHCI_HOST_CONTROL2);
    > + ctrl_2 &= ~SDHCI_CTRL_VDD_180;
    > + sdhci_writew(host, ctrl_2, SDHCI_HOST_CONTROL2);
    > +
    > + /* Sleep for 5ms to stabilize 3.3V regulator */
    > + usleep_range(5000, 5500);
    > +
    > + /* 3.3V regulator output should be stable within 5 ms */
    > + ctrl_2 = sdhci_readw(host, SDHCI_HOST_CONTROL2);
    > + if (ctrl_2 & SDHCI_CTRL_VDD_180)
    > + return -EAGAIN;
    > +
    > + break;
    > + default:
    > + return -EINVAL;
    > + }
    > +
    > + return 0;
    > +}
    > +
    > +static int sdhci_arasan_keembay_select_drive_strength(struct mmc_card *card,
    > + unsigned int max_dtr, int host_drv,
    > + int card_drv, int *drv_type)
    > +{
    > + if (card->host->ios.signal_voltage == MMC_SIGNAL_VOLTAGE_180)
    > + *drv_type = MMC_SET_DRIVER_TYPE_C;
    > +
    > + return 0;
    > +}
    > +
    > static const struct sdhci_ops sdhci_arasan_ops = {
    > .set_clock = sdhci_arasan_set_clock,
    > .get_max_clock = sdhci_pltfm_clk_get_max_clock,
    > @@ -1521,6 +1631,7 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
    > struct sdhci_pltfm_host *pltfm_host;
    > struct sdhci_arasan_data *sdhci_arasan;
    > struct device_node *np = pdev->dev.of_node;
    > + struct device *dev = &pdev->dev;

    nit: I got this but as I see 3 lines below maybe would be better to use
    it everywhere but it can be done in separate patch.

    > const struct sdhci_arasan_of_data *data;
    >
    > match = of_match_node(sdhci_arasan_of_match, pdev->dev.of_node);
    > @@ -1600,6 +1711,22 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
    > host->mmc->caps |= MMC_CAP_WAIT_WHILE_BUSY;
    > }
    >
    > + if (of_device_is_compatible(np, "intel,keembay-sdhci-5.1-sd")) {
    > + struct gpio_desc *uhs;
    > +
    > + uhs = devm_gpiod_get_optional(dev, "uhs", GPIOD_OUT_HIGH);

    I can't see change in dt binding to record uhs gpio.


    Better
    sdhci_arasan->uhs_gpio = devm_gpiod_get_optional(dev, "uhs",
    GPIOD_OUT_HIGH);

    then you can avoid uhs variable.

    > + if (IS_ERR(uhs))
    > + return dev_err_probe(dev, PTR_ERR(uhs), "can't get uhs gpio\n");
    > +
    > + sdhci_arasan->uhs_gpio = uhs;
    > +
    > + host->mmc_host_ops.start_signal_voltage_switch =
    > + sdhci_arasan_keembay_voltage_switch;
    > +
    > + host->mmc_host_ops.select_drive_strength =
    > + sdhci_arasan_keembay_select_drive_strength;
    > + }
    > +
    > sdhci_arasan_update_baseclkfreq(host);
    >
    > ret = sdhci_arasan_register_sdclk(sdhci_arasan, clk_xin, &pdev->dev);
    >

    Thanks,
    Michal

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