[PATCH] usb: ohci-at91: Suspend the ports while USB suspending

From: Wenyou Yang
Date: Wed May 11 2016 - 21:13:29 EST


In order to get lower consumption, as a workaround, suspend
the USB PORTA/B/C via set the SUSPEND_A/B/C bits of OHCI Interrupt
Configuration Register while OHCI USB suspending.

This suspend operation must be done before stopping the USB clock,
resume after the USB clock enabled.

Signed-off-by: Wenyou Yang <wenyou.yang@xxxxxxxxx>
---

drivers/usb/host/ohci-at91.c | 63 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 63 insertions(+)

diff --git a/drivers/usb/host/ohci-at91.c b/drivers/usb/host/ohci-at91.c
index d177372..ce898e0 100644
--- a/drivers/usb/host/ohci-at91.c
+++ b/drivers/usb/host/ohci-at91.c
@@ -21,6 +21,8 @@
#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>

@@ -51,6 +53,7 @@ struct ohci_at91_priv {
struct clk *hclk;
bool clocked;
bool wakeup; /* Saved wake-up state for resume */
+ struct regmap *sfr_regmap;
};
/* interface and function clocks; sometimes also an AHB clock */

@@ -132,6 +135,17 @@ 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))
+ return 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 +211,8 @@ static int usb_hcd_at91_probe(const struct hc_driver *driver,
goto err;
}

+ ohci_at91->sfr_regmap = at91_dt_syscon_sfr();
+
board = hcd->self.controller->platform_data;
ohci = hcd_to_ohci(hcd);
ohci->num_ports = board->ports;
@@ -581,6 +597,49 @@ static int ohci_hcd_at91_drv_remove(struct platform_device *pdev)
return 0;
}

+#define SFR_OHCIICR 0x10
+#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)
+
+static int ohci_at91_port_ctrl(struct regmap *regmap, bool enable)
+{
+ u32 regval;
+ int ret;
+
+ if (IS_ERR(regmap))
+ return PTR_ERR(regmap);
+
+ 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);
+
+ regmap_read(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 +677,8 @@ ohci_hcd_at91_drv_suspend(struct device *dev)
ohci_writel(ohci, ohci->hc_control, &ohci->regs->control);
ohci->rh_state = OHCI_RH_HALTED;

+ 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 +698,8 @@ ohci_hcd_at91_drv_resume(struct device *dev)

at91_start_clock(ohci_at91);

+ ohci_at91_port_resume(ohci_at91->sfr_regmap);
+
ohci_resume(hcd, false);
return 0;
}
--
2.7.4