Re: [PATCH v3 1/2] usb: ohci-at91: Forcibly suspend ports while USB suspend

Rob Herring
2016-06-08T20:26:56Z

On Wed, Jun 08, 2016 at 12:15:10PM +0800, Wenyou Yang wrote:
> In order to the save power consumption, as a workaround, suspend
> forcibly the USB PORTA/B/C via set the SUSPEND_A/B/C bits of OHCI
> Interrupt Configuration Register in the SFRs while OHCI USB suspend.
>
> This suspend operation must be done before the USB clock is disabled,
> resume after the USB clock is enabled.
>
> Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
> ---
>
> Changes in v3:
> - Change the compatible description for more precise.
>
> Changes in v2:
> - Add compatible to support forcibly suspend the ports.
> - Add soc/at91/at91_sfr.h to accommodate the defines.
> - Add error checking for .sfr_regmap.
> - Remove unnecessary regmap_read() statement.
>
> .../devicetree/bindings/usb/atmel-usb.txt | 6 +-
> drivers/usb/host/ohci-at91.c | 80 +++++++++++++++++++++-
> include/soc/at91/at91_sfr.h | 29 ++++++++
> 3 files changed, 112 insertions(+), 3 deletions(-)
> create mode 100644 include/soc/at91/at91_sfr.h
>
> diff --git a/Documentation/devicetree/bindings/usb/atmel-usb.txt b/Documentation/devicetree/bindings/usb/atmel-usb.txt
> index 5883b73..888deaa 100644
> --- a/Documentation/devicetree/bindings/usb/atmel-usb.txt
> +++ b/Documentation/devicetree/bindings/usb/atmel-usb.txt
> @@ -3,8 +3,10 @@ Atmel SOC USB controllers
> OHCI
>
> Required properties:
> - - compatible: Should be "atmel,at91rm9200-ohci" for USB controllers
> - used in host mode.
> + - compatible: Should be one of the following
> + "atmel,at91rm9200-ohci" for USB controllers used in host mode.
> + "atmel,sama5d2-ohci" for USB controllers used in host mode
> + on SAMA5D2 which can force to suspend.

Guess I wasn't clear enough before. Drop "which can force to suspend".

> - reg: Address and length of the register set for the device
> - interrupts: Should contain ehci interrupt
> - clocks: Should reference the peripheral, host and system clocks
> diff --git a/drivers/usb/host/ohci-at91.c b/drivers/usb/host/ohci-at91.c
> index d177372..54e8feb 100644
> --- a/drivers/usb/host/ohci-at91.c
> +++ b/drivers/usb/host/ohci-at91.c
> @@ -21,8 +21,11 @@
> #include <linux/io.h>
> #include <linux/kernel.h>
> #include <linux/module.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/regmap.h>
> #include <linux/usb.h>
> #include <linux/usb/hcd.h>
> +#include <soc/at91/at91_sfr.h>
>
> #include "ohci.h"
>
> @@ -45,12 +48,18 @@ struct at91_usbh_data {
> u8 overcurrent_changed[AT91_MAX_USBH_PORTS];
> };
>
> +struct ohci_at91_caps {
> + bool suspend_ctrl;
> +};
> +
> struct ohci_at91_priv {
> struct clk *iclk;
> struct clk *fclk;
> struct clk *hclk;
> bool clocked;
> bool wakeup; /* Saved wake-up state for resume */
> + const struct ohci_at91_caps *caps;
> + struct regmap *sfr_regmap;
> };
> /* interface and function clocks; sometimes also an AHB clock */
>
> @@ -132,6 +141,17 @@ static void at91_stop_hc(struct platform_device *pdev)
>
> /*-------------------------------------------------------------------------*/
>
> +struct regmap *at91_dt_syscon_sfr(void)
> +{
> + struct regmap *regmap;
> +
> + regmap = syscon_regmap_lookup_by_compatible("atmel,sama5d2-sfr");
> + if (IS_ERR(regmap))
> + regmap = NULL;
> +
> + return regmap;
> +}
> +
> static void usb_hcd_at91_remove (struct usb_hcd *, struct platform_device *);
>
> /* configure so an HC device and id are always provided */
> @@ -197,6 +217,17 @@ static int usb_hcd_at91_probe(const struct hc_driver *driver,
> goto err;
> }
>
> + ohci_at91->caps = (const struct ohci_at91_caps *)
> + of_device_get_match_data(&pdev->dev);
> + if (!ohci_at91->caps)
> + return -ENODEV;
> +
> + if (ohci_at91->caps->suspend_ctrl) {
> + ohci_at91->sfr_regmap = at91_dt_syscon_sfr();
> + if (!ohci_at91->sfr_regmap)
> + dev_warn(dev, "failed to find sfr node\n");
> + }
> +
> board = hcd->self.controller->platform_data;
> ohci = hcd_to_ohci(hcd);
> ohci->num_ports = board->ports;
> @@ -440,8 +471,17 @@ static irqreturn_t ohci_hcd_at91_overcurrent_irq(int irq, void *data)
> return IRQ_HANDLED;
> }
>
> +static const struct ohci_at91_caps at91rm9200_caps = {
> + .suspend_ctrl = false,
> +};
> +
> +static const struct ohci_at91_caps sama5d2_caps = {
> + .suspend_ctrl = true,
> +};
> +
> static const struct of_device_id at91_ohci_dt_ids[] = {
> - { .compatible = "atmel,at91rm9200-ohci" },
> + { .compatible = "atmel,at91rm9200-ohci", .data = &at91rm9200_caps },
> + { .compatible = "atmel,sama5d2-ohci", .data = &sama5d2_caps },
> { /* sentinel */ }
> };
>
> @@ -581,6 +621,38 @@ static int ohci_hcd_at91_drv_remove(struct platform_device *pdev)
> return 0;
> }
>
> +static int ohci_at91_port_ctrl(struct regmap *regmap, bool enable)
> +{
> + u32 regval;
> + int ret;
> +
> + if (!regmap)
> + return -EINVAL;
> +
> + ret = regmap_read(regmap, SFR_OHCIICR, &regval);
> + if (ret)
> + return ret;
> +
> + if (enable)
> + regval &= ~SFR_OHCIICR_USB_SUSPEND;
> + else
> + regval |= SFR_OHCIICR_USB_SUSPEND;
> +
> + regmap_write(regmap, SFR_OHCIICR, regval);
> +
> + return 0;
> +}
> +
> +static int ohci_at91_port_suspend(struct regmap *regmap)
> +{
> + return ohci_at91_port_ctrl(regmap, false);
> +}
> +
> +static int ohci_at91_port_resume(struct regmap *regmap)
> +{
> + return ohci_at91_port_ctrl(regmap, true);
> +}
> +
> static int __maybe_unused
> ohci_hcd_at91_drv_suspend(struct device *dev)
> {
> @@ -618,6 +690,9 @@ ohci_hcd_at91_drv_suspend(struct device *dev)
> ohci_writel(ohci, ohci->hc_control, &ohci->regs->control);
> ohci->rh_state = OHCI_RH_HALTED;
>
> + if (ohci_at91->caps->suspend_ctrl)
> + ohci_at91_port_suspend(ohci_at91->sfr_regmap);
> +
> /* flush the writes */
> (void) ohci_readl (ohci, &ohci->regs->control);
> at91_stop_clock(ohci_at91);
> @@ -637,6 +712,9 @@ ohci_hcd_at91_drv_resume(struct device *dev)
>
> at91_start_clock(ohci_at91);
>
> + if (ohci_at91->caps->suspend_ctrl)
> + ohci_at91_port_resume(ohci_at91->sfr_regmap);
> +
> ohci_resume(hcd, false);
> return 0;
> }
> diff --git a/include/soc/at91/at91_sfr.h b/include/soc/at91/at91_sfr.h
> new file mode 100644
> index 0000000..04a3a1e
> --- /dev/null
> +++ b/include/soc/at91/at91_sfr.h
> @@ -0,0 +1,29 @@
> +/*
> + * Header file for the Atmel DDR/SDR SDRAM Controller
> + *
> + * Copyright (C) 2016 Atmel Corporation
> + *
> + * Author: Wenyou Yang <wenyou.yang@atmel.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + */
> +#ifndef __AT91_SFR_H__
> +#define __AT91_SFR_H__
> +
> +#define SFR_DDRCFG 0x04 /* DDR Configuration Register */
> +/* 0x08 ~ 0x0c: Reserved */
> +#define SFR_OHCIICR 0x10 /* OHCI Interrupt Configuration Register */
> +#define SFR_OHCIISR 0x14 /* OHCI Interrupt Status Register */
> +
> +#define SFR_OHCIICR_SUSPEND_A BIT(8)
> +#define SFR_OHCIICR_SUSPEND_B BIT(9)
> +#define SFR_OHCIICR_SUSPEND_C BIT(10)
> +
> +#define SFR_OHCIICR_USB_SUSPEND (SFR_OHCIICR_SUSPEND_A | \
> + SFR_OHCIICR_SUSPEND_B | \
> + SFR_OHCIICR_SUSPEND_C)
> +
> +#endif
> --
> 2.7.4
>