Re: [PATCH v3 6/8] scsi: ufs: qcom: Expose the reset controller for PHY

Kishon Vijay Abraham I
2019-02-06T11:43:07Z

On 06/02/19 12:29 AM, Evan Green wrote:
> Expose a reset controller that the phy will later use to control its
> own PHY reset in the UFS controller. This will enable the combining
> of PHY init functionality into a single function.
>
> Signed-off-by: Evan Green <evgreen@chromium.org>

I'd like to get ACK from scsi/ufs/ MAINTAINER Vinayak for me merge it in PHY tree.

Thanks
Kishon
>
> ---
> Note: The remaining changes in this series need this change, since
> the PHYs now depend on getting the reset controller.
>
> Changes in v3:
> - Refactor to only expose the reset controller in one change (Stephen).
> - Add period to comment (Stephen).
> - Reset err to 0 in ignored error case (Stephen).
> - Add include of reset-controller.h (Stephen)
>
> Changes in v2:
> - Remove include of reset.h (Stephen)
> - Fix error print of phy_power_on (Stephen)
> - Comment for reset controller warnings on id != 0 (Stephen)
> - Add static to ufs_qcom_reset_ops (Stephen).
>
> drivers/scsi/ufs/Kconfig | 1 +
> drivers/scsi/ufs/ufs-qcom.c | 52 +++++++++++++++++++++++++++++++++++++
> drivers/scsi/ufs/ufs-qcom.h | 4 +++
> 3 files changed, 57 insertions(+)
>
> diff --git a/drivers/scsi/ufs/Kconfig b/drivers/scsi/ufs/Kconfig
> index 2ddbb26d9c26..63c5c4115981 100644
> --- a/drivers/scsi/ufs/Kconfig
> +++ b/drivers/scsi/ufs/Kconfig
> @@ -100,6 +100,7 @@ config SCSI_UFS_QCOM
> tristate "QCOM specific hooks to UFS controller platform driver"
> depends on SCSI_UFSHCD_PLATFORM && ARCH_QCOM
> select PHY_QCOM_UFS
> + select RESET_CONTROLLER
> help
> This selects the QCOM specific additions to UFSHCD platform driver.
> UFS host on QCOM needs some vendor specific configuration before
> diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c
> index 3aeadb14aae1..ab05ef5cfdcd 100644
> --- a/drivers/scsi/ufs/ufs-qcom.c
> +++ b/drivers/scsi/ufs/ufs-qcom.c
> @@ -16,6 +16,7 @@
> #include <linux/of.h>
> #include <linux/platform_device.h>
> #include <linux/phy/phy.h>
> +#include <linux/reset-controller.h>
>
> #include "ufshcd.h"
> #include "ufshcd-pltfrm.h"
> @@ -49,6 +50,11 @@ static void ufs_qcom_get_default_testbus_cfg(struct ufs_qcom_host *host);
> static int ufs_qcom_set_dme_vs_core_clk_ctrl_clear_div(struct ufs_hba *hba,
> u32 clk_cycles);
>
> +static struct ufs_qcom_host *rcdev_to_ufs_host(struct reset_controller_dev *rcd)
> +{
> + return container_of(rcd, struct ufs_qcom_host, rcdev);
> +}
> +
> static void ufs_qcom_dump_regs_wrapper(struct ufs_hba *hba, int offset, int len,
> const char *prefix, void *priv)
> {
> @@ -1147,6 +1153,41 @@ static int ufs_qcom_setup_clocks(struct ufs_hba *hba, bool on,
> return err;
> }
>
> +static int
> +ufs_qcom_reset_assert(struct reset_controller_dev *rcdev, unsigned long id)
> +{
> + struct ufs_qcom_host *host = rcdev_to_ufs_host(rcdev);
> +
> + /* Currently this code only knows about a single reset. */
> + WARN_ON(id);
> + ufs_qcom_assert_reset(host->hba);
> + /* provide 1ms delay to let the reset pulse propagate. */
> + usleep_range(1000, 1100);
> + return 0;
> +}
> +
> +static int
> +ufs_qcom_reset_deassert(struct reset_controller_dev *rcdev, unsigned long id)
> +{
> + struct ufs_qcom_host *host = rcdev_to_ufs_host(rcdev);
> +
> + /* Currently this code only knows about a single reset. */
> + WARN_ON(id);
> + ufs_qcom_deassert_reset(host->hba);
> +
> + /*
> + * after reset deassertion, phy will need all ref clocks,
> + * voltage, current to settle down before starting serdes.
> + */
> + usleep_range(1000, 1100);
> + return 0;
> +}
> +
> +static const struct reset_control_ops ufs_qcom_reset_ops = {
> + .assert = ufs_qcom_reset_assert,
> + .deassert = ufs_qcom_reset_deassert,
> +};
> +
> #define ANDROID_BOOT_DEV_MAX 30
> static char android_boot_dev[ANDROID_BOOT_DEV_MAX];
>
> @@ -1191,6 +1232,17 @@ static int ufs_qcom_init(struct ufs_hba *hba)
> host->hba = hba;
> ufshcd_set_variant(hba, host);
>
> + /* Fire up the reset controller. Failure here is non-fatal. */
> + host->rcdev.of_node = dev->of_node;
> + host->rcdev.ops = &ufs_qcom_reset_ops;
> + host->rcdev.owner = dev->driver->owner;
> + host->rcdev.nr_resets = 1;
> + err = devm_reset_controller_register(dev, &host->rcdev);
> + if (err) {
> + dev_warn(dev, "Failed to register reset controller\n");
> + err = 0;
> + }
> +
> /*
> * voting/devoting device ref_clk source is time consuming hence
> * skip devoting it during aggressive clock gating. This clock
> diff --git a/drivers/scsi/ufs/ufs-qcom.h b/drivers/scsi/ufs/ufs-qcom.h
> index c114826316eb..68a880185752 100644
> --- a/drivers/scsi/ufs/ufs-qcom.h
> +++ b/drivers/scsi/ufs/ufs-qcom.h
> @@ -14,6 +14,8 @@
> #ifndef UFS_QCOM_H_
> #define UFS_QCOM_H_
>
> +#include <linux/reset-controller.h>
> +
> #define MAX_UFS_QCOM_HOSTS 1
> #define MAX_U32 (~(u32)0)
> #define MPHY_TX_FSM_STATE 0x41
> @@ -237,6 +239,8 @@ struct ufs_qcom_host {
> /* Bitmask for enabling debug prints */
> u32 dbg_print_en;
> struct ufs_qcom_testbus testbus;
> +
> + struct reset_controller_dev rcdev;
> };
>
> static inline u32
>