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Commit b8416b2f authored by Bjorn Andersson's avatar Bjorn Andersson Committed by Martin K. Petersen
Browse files

scsi: ufs-qcom: Implement device_reset vops 

The UFS_RESET pin on Qualcomm SoCs are controlled by TLMM and exposed
through the GPIO framework. Acquire the device-reset GPIO and use this to
implement the device_reset vops, to allow resetting the attached memory.

Based on downstream support implemented by Subhash Jadavani
<subhashj@codeaurora.org>.

Link: https://lore.kernel.org/r/20190828191756.24312-3-bjorn.andersson@linaro.org


Signed-off-by: default avatarBjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: default avatarRob Herring <robh@kernel.org>
Acked-by: default avatarAvri Altman <Avri.Altman@wdc.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent d8d9f793

Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt

+2 −0
Original line number Diff line number Diff line
@@ -54,6 +54,8 @@ Optional properties: 
			  PHY reset from the UFS controller.

- resets            : reset node register

- reset-names       : describe reset node register, the "rst" corresponds to reset the whole UFS IP.

- reset-gpios       : A phandle and gpio specifier denoting the GPIO connected

		      to the RESET pin of the UFS memory device.



Note: If above properties are not defined it can be assumed that the supply

regulators or clocks are always on.

drivers/scsi/ufs/ufs-qcom.c

+36 −0
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 
#include <linux/of.h>

#include <linux/platform_device.h>

#include <linux/phy/phy.h>

#include <linux/gpio/consumer.h>

#include <linux/reset-controller.h>



#include "ufshcd.h"
@@ -1137,6 +1138,15 @@ static int ufs_qcom_init(struct ufs_hba *hba) 
		}

	}



	host->device_reset = devm_gpiod_get_optional(dev, "reset",

						     GPIOD_OUT_HIGH);

	if (IS_ERR(host->device_reset)) {

		err = PTR_ERR(host->device_reset);

		if (err != -EPROBE_DEFER)

			dev_err(dev, "failed to acquire reset gpio: %d\n", err);

		goto out_variant_clear;

	}



	err = ufs_qcom_bus_register(host);

	if (err)

		goto out_variant_clear;
@@ -1542,6 +1552,31 @@ static void ufs_qcom_dump_dbg_regs(struct ufs_hba *hba) 
	usleep_range(1000, 1100);

}



/**

 * ufs_qcom_device_reset() - toggle the (optional) device reset line

 * @hba: per-adapter instance

 *

 * Toggles the (optional) reset line to reset the attached device.

 */

static void ufs_qcom_device_reset(struct ufs_hba *hba)

{

	struct ufs_qcom_host *host = ufshcd_get_variant(hba);



	/* reset gpio is optional */

	if (!host->device_reset)

		return;



	/*

	 * The UFS device shall detect reset pulses of 1us, sleep for 10us to

	 * be on the safe side.

	 */

	gpiod_set_value_cansleep(host->device_reset, 1);

	usleep_range(10, 15);



	gpiod_set_value_cansleep(host->device_reset, 0);

	usleep_range(10, 15);

}



/**

 * struct ufs_hba_qcom_vops - UFS QCOM specific variant operations

 *
@@ -1562,6 +1597,7 @@ static const struct ufs_hba_variant_ops ufs_hba_qcom_vops = { 
	.suspend		= ufs_qcom_suspend,

	.resume			= ufs_qcom_resume,

	.dbg_register_dump	= ufs_qcom_dump_dbg_regs,

	.device_reset		= ufs_qcom_device_reset,

};



/**

drivers/scsi/ufs/ufs-qcom.h

+4 −0
Original line number Diff line number Diff line
@@ -195,6 +195,8 @@ struct ufs_qcom_testbus { 
	u8 select_minor;

};



struct gpio_desc;



struct ufs_qcom_host {

	/*

	 * Set this capability if host controller supports the QUniPro mode
@@ -232,6 +234,8 @@ struct ufs_qcom_host { 
	struct ufs_qcom_testbus testbus;



	struct reset_controller_dev rcdev;



	struct gpio_desc *device_reset;

};



static inline u32