gl3590: Add initial support for USB HUB I2C interface

GL3590 is a USB hub with support for out-of-band transactions via I2C.
Set of additional registers allow to disable/enable ports, query port
status (including power-related information), handle over-current events
and others.

This initial driver implements method for reading and writing from/to
GL3590 registers as well as event handler to parse asynchronous messages
from hub.

BUG:b:150323106,b:169929627
BRANCH:master
TEST:buildall. Functionality can be tested on servo_v4p1 with a
     consecutive commit applied.

Signed-off-by: Jan Dabros <jsd@semihalf.com>
Change-Id: I385ff4790ddc367d07b7e588f4e10aeb83e9f1c0
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2563686
Reviewed-by: Brian Nemec <bnemec@chromium.org>

1 files changed, 144 insertions, 0 deletions

diff --git a/driver/gl3590.c b/driver/gl3590.c
new file mode 100644
index 0000000000..bde2971553
--- /dev/null
+++ b/driver/gl3590.c
@@ -0,0 +1,144 @@
+#include <console.h>
+#include <i2c.h>
+#include <system.h>
+#include <util.h>
+
+#include <gl3590.h>
+
+/* GL3590 is unique in terms of i2c_read, since it doesn't support repeated
+ * start sequence. One need to issue two separate transactions - first is write
+ * with a register offset, then after a delay second transaction is actual read.
+ */
+int gl3590_read(int hub, uint8_t reg, uint8_t *data, int count)
+{
+	int rv;
+	struct uhub_i2c_iface_t *uhub_p = &uhub_config[hub];
+
+	i2c_lock(uhub_p->i2c_host_port, 1);
+	rv = i2c_xfer_unlocked(uhub_p->i2c_host_port,
+			       uhub_p->i2c_addr,
+			       &reg, 1,
+			       NULL, 0,
+			       I2C_XFER_SINGLE);
+	i2c_lock(uhub_p->i2c_host_port, 0);
+
+	if (rv)
+		return rv;
+
+	/* GL3590 requires at least 300us before data is ready */
+	udelay(400);
+
+	i2c_lock(uhub_p->i2c_host_port, 1);
+	rv = i2c_xfer_unlocked(uhub_p->i2c_host_port,
+			       uhub_p->i2c_addr,
+			       NULL, 0,
+			       data, count,
+			       I2C_XFER_SINGLE);
+	i2c_lock(uhub_p->i2c_host_port, 0);
+
+	return rv;
+};
+
+int gl3590_write(int hub, uint8_t reg, uint8_t *data, int count)
+{
+	int rv;
+	uint8_t buf[5];
+	struct uhub_i2c_iface_t *uhub_p = &uhub_config[hub];
+
+	/* GL3590 registers accept 4 bytes at max */
+	if (count > (sizeof(buf) - 1)) {
+		ccprintf("Too many bytes to write");
+		return EC_ERROR_INVAL;
+	}
+
+	buf[0] = reg;
+	memcpy(&buf[1], data, count);
+
+	i2c_lock(uhub_p->i2c_host_port, 1);
+	rv = i2c_xfer_unlocked(uhub_p->i2c_host_port,
+			       uhub_p->i2c_addr,
+			       buf, count + 1,
+			       NULL, 0,
+			       I2C_XFER_SINGLE);
+	i2c_lock(uhub_p->i2c_host_port, 0);
+
+	return rv;
+}
+
+void gl3590_irq_handler(int hub)
+{
+	uint8_t buf = 0;
+	uint8_t res_reg[2];
+
+	/* Verify that irq is pending */
+	if (gl3590_read(hub, GL3590_INT_REG, &buf, sizeof(buf))) {
+		ccprintf("Cannot read from the host hub i2c\n");
+		goto exit;
+	}
+
+	if ((buf & GL3590_INT_PENDING) == 0) {
+		ccprintf("Invalid hub event\n");
+		goto exit;
+	}
+
+	/* Get the hub event reason */
+	if (gl3590_read(hub, GL3590_RESPONSE_REG, res_reg, sizeof(res_reg))) {
+		ccprintf("Cannot read from the host hub i2c\n");
+		goto exit;
+	}
+
+	if ((res_reg[0] & GL3590_RESPONSE_REG_SYNC_MASK) == 0)
+		ccprintf("Host hub response: ");
+	else
+		ccprintf("Host hub event! ");
+
+	switch(res_reg[0]) {
+	case 0x0:
+		ccprintf("No response");
+		break;
+	case 0x1:
+		ccprintf("Successful");
+		break;
+	case 0x2:
+		ccprintf("Invalid command");
+		break;
+	case 0x3:
+		ccprintf("Invalid arguments");
+		break;
+	case 0x4:
+		ccprintf("Invalid port: %d", res_reg[1]);
+		break;
+	case 0x5:
+		ccprintf("Command not completed");
+		break;
+	case 0x80:
+		ccprintf("Reset complete");
+		break;
+	case 0x81:
+		ccprintf("Power operation mode change");
+		break;
+	case 0x82:
+		ccprintf("Connect change");
+		break;
+	case 0x83:
+		ccprintf("Error on the specific port");
+		break;
+	case 0x84:
+		ccprintf("Hub state change");
+		break;
+	case 0x85:
+		ccprintf("SetFeature PORT_POWER failure");
+		break;
+	default:
+		ccprintf("Unknown value: 0x%0x", res_reg[0]);
+	}
+	ccprintf("\n");
+
+	if (res_reg[1])
+		ccprintf("Affected port %d\n", res_reg[1]);
+
+exit:
+	/* Try to clear interrupt */
+	buf = GL3590_INT_CLEAR;
+	gl3590_write(hub, GL3590_INT_REG, &buf, sizeof(buf));
+}