Re: [PATCH v3 1/2] mmc: sdhci-of-arasan: Enable UHS-1 support for Keem Bay SOC

[Michal Simek]

On 06. 10. 20 17:55, muhammad.husaini.zulkifli@xxxxxxxxx wrote:
> From: Muhammad Husaini Zulkifli <muhammad.husaini.zulkifli@xxxxxxxxx>
> 
> 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@xxxxxxxxx>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxx>
> Reviewed-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> ---
>  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