usb: musb: Add musb_set_host and peripheral and use them for omap2430

At least some revisions of musb core need to set devctl session bit
in peripheral mode to force musb to host mode. And we have places
clearing the devctl session bit.

Let's add a generic function to do this, and use it for omap2430.
This should get us a bit closer to completely removing devctl register
tinkering in the SoC glue code.

Before making use of this code for the other glue layers, things need
to be tested carefully as there may be a approximately a 200 ms delay
needed between powering up musb and calling musb_set_host() to avoid.
Otherwise the system hangs at least with omap2430 glue layer.

Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Tony Lindgren <tony@atomide.com>
[b-liu@ti.com: fixed "line over 80 characters" warning]
Signed-off-by: Bin Liu <b-liu@ti.com>
Link: https://lore.kernel.org/r/20200115132547.364-8-b-liu@ti.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 103 insertions, 0 deletions

diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
index 48d95850152db..34090707d1221 100644
--- a/drivers/usb/musb/musb_core.c
+++ b/drivers/usb/musb/musb_core.c
@@ -73,6 +73,7 @@
 #include <linux/prefetch.h>
 #include <linux/platform_device.h>
 #include <linux/io.h>
+#include <linux/iopoll.h>
 #include <linux/dma-mapping.h>
 #include <linux/usb.h>
 #include <linux/usb/of.h>
@@ -414,6 +415,108 @@ void musb_write_fifo(struct musb_hw_ep *hw_ep, u16 len, const u8 *src)
 	return hw_ep->musb->io.write_fifo(hw_ep, len, src);
 }
 
+static u8 musb_read_devctl(struct musb *musb)
+{
+	return musb_readb(musb->mregs, MUSB_DEVCTL);
+}
+
+/**
+ * musb_set_host - set and initialize host mode
+ * @musb: musb controller driver data
+ *
+ * At least some musb revisions need to enable devctl session bit in
+ * peripheral mode to switch to host mode. Initializes things to host
+ * mode and sets A_IDLE. SoC glue needs to advance state further
+ * based on phy provided VBUS state.
+ *
+ * Note that the SoC glue code may need to wait for musb to settle
+ * on enable before calling this to avoid babble.
+ */
+int musb_set_host(struct musb *musb)
+{
+	int error = 0;
+	u8 devctl;
+
+	if (!musb)
+		return -EINVAL;
+
+	devctl = musb_read_devctl(musb);
+	if (!(devctl & MUSB_DEVCTL_BDEVICE)) {
+		dev_info(musb->controller,
+			 "%s: already in host mode: %02x\n",
+			 __func__, devctl);
+		goto init_data;
+	}
+
+	devctl |= MUSB_DEVCTL_SESSION;
+	musb_writeb(musb->mregs, MUSB_DEVCTL, devctl);
+
+	error = readx_poll_timeout(musb_read_devctl, musb, devctl,
+				   !(devctl & MUSB_DEVCTL_BDEVICE), 5000,
+				   1000000);
+	if (error) {
+		dev_err(musb->controller, "%s: could not set host: %02x\n",
+			__func__, devctl);
+
+		return error;
+	}
+
+init_data:
+	musb->is_active = 1;
+	musb->xceiv->otg->state = OTG_STATE_A_IDLE;
+	MUSB_HST_MODE(musb);
+
+	return error;
+}
+EXPORT_SYMBOL_GPL(musb_set_host);
+
+/**
+ * musb_set_peripheral - set and initialize peripheral mode
+ * @musb: musb controller driver data
+ *
+ * Clears devctl session bit and initializes things for peripheral
+ * mode and sets B_IDLE. SoC glue needs to advance state further
+ * based on phy provided VBUS state.
+ */
+int musb_set_peripheral(struct musb *musb)
+{
+	int error = 0;
+	u8 devctl;
+
+	if (!musb)
+		return -EINVAL;
+
+	devctl = musb_read_devctl(musb);
+	if (devctl & MUSB_DEVCTL_BDEVICE) {
+		dev_info(musb->controller,
+			 "%s: already in peripheral mode: %02x\n",
+			 __func__, devctl);
+
+		goto init_data;
+	}
+
+	devctl &= ~MUSB_DEVCTL_SESSION;
+	musb_writeb(musb->mregs, MUSB_DEVCTL, devctl);
+
+	error = readx_poll_timeout(musb_read_devctl, musb, devctl,
+				   devctl & MUSB_DEVCTL_BDEVICE, 5000,
+				   1000000);
+	if (error) {
+		dev_err(musb->controller, "%s: could not set periperal: %02x\n",
+			__func__, devctl);
+
+		return error;
+	}
+
+init_data:
+	musb->is_active = 0;
+	musb->xceiv->otg->state = OTG_STATE_B_IDLE;
+	MUSB_DEV_MODE(musb);
+
+	return error;
+}
+EXPORT_SYMBOL_GPL(musb_set_peripheral);
+
 /*-------------------------------------------------------------------------*/
 
 /* for high speed test mode; see USB 2.0 spec 7.1.20 */