driver/ioexpander_it8801: add I/O expander driver for keyboard

IT8801 is an I/O expander with a keyboard matrix controller.

BUG=b:133200075
BRANCH=none
TEST=Press any key on keyboard and the console command
"ksstate on" can print keyboard scan state.

Change-Id: I6903aad1eacfdfb6a7c6c04e6954a14e8c8caaac
Signed-off-by: tim <tim2.lin@ite.corp-partner.google.com>
Signed-off-by: Alexandru M Stan <amstan@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1677976

4 files changed, 279 insertions, 0 deletions

diff --git a/driver/build.mk b/driver/build.mk
index 7bc59eb331..27daf6bb3f 100644
--- a/driver/build.mk
+++ b/driver/build.mk
@@ -79,6 +79,7 @@ driver-$(CONFIG_CHARGER_SY21612)+=charger/sy21612.o
 include $(_driver_cur_dir)fingerprint/build.mk
 
 # I/O expander
+driver-$(CONFIG_IO_EXPANDER_IT8801)+=ioexpander_it8801.o
 driver-$(CONFIG_IO_EXPANDER_PCA9534)+=ioexpander_pca9534.o
 driver-$(CONFIG_IO_EXPANDER_NCT38XX)+=ioexpander_nct38xx.o
 
diff --git a/driver/ioexpander_it8801.c b/driver/ioexpander_it8801.c
new file mode 100644
index 0000000000..64ef3628ed
--- /dev/null
+++ b/driver/ioexpander_it8801.c
@@ -0,0 +1,227 @@
+/* Copyright 2019 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "common.h"
+#include "console.h"
+#include "driver/ioexpander_it8801.h"
+#include "gpio.h"
+#include "hooks.h"
+#include "i2c.h"
+#include "keyboard_raw.h"
+#include "keyboard_scan.h"
+#include "registers.h"
+#include "task.h"
+
+#define CPRINTS(format, args...) cprints(CC_KEYSCAN, format, ## args)
+
+static int it8801_read(int reg, int *data)
+{
+	return i2c_read8(I2C_PORT_IO_EXPANDER_IT8801, IT8801_I2C_ADDR,
+		reg, data);
+}
+
+static int it8801_write(int reg, int data)
+{
+	return i2c_write8(I2C_PORT_IO_EXPANDER_IT8801, IT8801_I2C_ADDR,
+		reg, data);
+}
+
+struct it8801_vendor_id_t {
+	uint8_t chip_id;
+	uint8_t reg;
+};
+
+static const struct it8801_vendor_id_t it8801_vendor_id_verify[] = {
+	{ 0x12, IT8801_REG_HBVIDR},
+	{ 0x83, IT8801_REG_LBVIDR},
+};
+
+static int it8801_check_vendor_id(void)
+{
+	int i, ret, val;
+
+	/*  Verify vendor ID registers(16-bits). */
+	for (i = 0; i < ARRAY_SIZE(it8801_vendor_id_verify); i++) {
+		ret = it8801_read(it8801_vendor_id_verify[i].reg, &val);
+
+		if (ret != EC_SUCCESS)
+			return ret;
+
+		if (val != it8801_vendor_id_verify[i].chip_id)
+			return EC_ERROR_UNKNOWN;
+	}
+
+	return EC_SUCCESS;
+}
+
+void keyboard_raw_init(void)
+{
+	int ret, val;
+
+	/*  Verify Vendor ID registers. */
+	ret = it8801_check_vendor_id();
+	if (ret) {
+		CPRINTS("Failed to read IT8801 vendor id %x", ret);
+		return;
+	}
+
+	/* KSO alternate function switching(KSO[21:20, 18]). */
+	it8801_write(IT8801_REG_GPIO01_KSO18, IT8801_REG_MASK_GPIOAFS_FUNC2);
+	it8801_write(IT8801_REG_GPIO22_KSO21, IT8801_REG_MASK_GPIOAFS_FUNC2);
+	it8801_write(IT8801_REG_GPIO23_KSO20, IT8801_REG_MASK_GPIOAFS_FUNC2);
+
+	/* Start with KEYBOARD_COLUMN_ALL, KSO[22:11, 6:0] output low. */
+	it8801_write(IT8801_REG_KSOMCR, IT8801_REG_MASK_AKSOSC);
+
+	if (IS_ENABLED(CONFIG_KEYBOARD_COL2_INVERTED)) {
+		/*
+		 * Since most of the KSO pins can't drive up, we'll must use
+		 * a pin capable of being a GPIO instead and use the GPIO
+		 * feature to do the required inverted push pull.
+		 */
+		it8801_write(IT8801_REG_GPIO23_KSO20, IT8801_REG_MASK_GPIODIR);
+
+		/* Start with KEYBOARD_COLUMN_ALL, output high(so selected). */
+		it8801_read(IT8801_REG_GPIOG2SOVR, &val);
+		it8801_write(IT8801_REG_GPIOG2SOVR, val | IT8801_REG_GPIO23SOV);
+	}
+
+	/* Keyboard scan in interrupt enable register */
+	it8801_write(IT8801_REG_KSIIER, 0xff);
+	/* Gather KSI interrupt enable */
+	it8801_write(IT8801_REG_GIECR, IT8801_REG_MASK_GKSIIE);
+	/* Alert response enable */
+	it8801_write(IT8801_REG_SMBCR, IT8801_REG_MASK_ARE);
+
+	keyboard_raw_enable_interrupt(0);
+}
+
+void keyboard_raw_task_start(void)
+{
+	keyboard_raw_enable_interrupt(1);
+}
+
+static const uint8_t kso_mapping[] = {
+	0, 1, 20, 3, 4, 5, 6, 17, 18, 16, 15, 11, 12,
+#ifdef CONFIG_KEYBOARD_KEYPAD
+	13, 14
+#endif
+};
+BUILD_ASSERT(ARRAY_SIZE(kso_mapping) == KEYBOARD_COLS_MAX);
+
+test_mockable void keyboard_raw_drive_column(int col)
+{
+	int kso_val, val;
+
+	/* Tri-state all outputs */
+	if (col == KEYBOARD_COLUMN_NONE) {
+		/* KSO[22:11, 6:0] output high */
+		kso_val = IT8801_REG_MASK_KSOSDIC | IT8801_REG_MASK_AKSOSC;
+
+		if (IS_ENABLED(CONFIG_KEYBOARD_COL2_INVERTED)) {
+			/* Output low(so not selected). */
+			it8801_read(IT8801_REG_GPIOG2SOVR, &val);
+			it8801_write(IT8801_REG_GPIOG2SOVR, val &
+				~IT8801_REG_GPIO23SOV);
+		}
+	}
+	/* Assert all outputs */
+	else if (col == KEYBOARD_COLUMN_ALL) {
+		/* KSO[22:11, 6:0] output low */
+		kso_val = IT8801_REG_MASK_AKSOSC;
+
+		if (IS_ENABLED(CONFIG_KEYBOARD_COL2_INVERTED)) {
+			/* Output high(so selected). */
+			it8801_read(IT8801_REG_GPIOG2SOVR, &val);
+			it8801_write(IT8801_REG_GPIOG2SOVR, val |
+				IT8801_REG_GPIO23SOV);
+		}
+	} else {
+		/* To check if column is valid or not. */
+		if (col >= KEYBOARD_COLS_MAX)
+			return;
+		/*
+		 * Selected KSO[20, 18:11, 6:3, 1:0] output low,
+		 * all others KSO output high.
+		 */
+		kso_val = kso_mapping[col];
+
+		if (IS_ENABLED(CONFIG_KEYBOARD_COL2_INVERTED)) {
+			/* GPIO23 is inverted. */
+			if (col == IT8801_REG_MASK_SELKSO2) {
+				/* Output high(so selected). */
+				it8801_read(IT8801_REG_GPIOG2SOVR, &val);
+				it8801_write(IT8801_REG_GPIOG2SOVR, val |
+					IT8801_REG_GPIO23SOV);
+			} else {
+				/* Output low(so not selected). */
+				it8801_read(IT8801_REG_GPIOG2SOVR, &val);
+				it8801_write(IT8801_REG_GPIOG2SOVR, val &
+					~IT8801_REG_GPIO23SOV);
+			}
+		}
+	}
+
+	it8801_write(IT8801_REG_KSOMCR, kso_val);
+}
+
+test_mockable int keyboard_raw_read_rows(void)
+{
+	int data = 0;
+	int ksieer = 0;
+
+	it8801_read(IT8801_REG_KSIDR, &data);
+
+	/* This register needs to write clear after reading data */
+	it8801_read(IT8801_REG_KSIEER, &ksieer);
+	it8801_write(IT8801_REG_KSIEER, ksieer);
+
+	/* Bits are active-low, so invert returned levels */
+	return (~data) & 0xff;
+}
+
+void keyboard_raw_enable_interrupt(int enable)
+{
+	if (enable) {
+		it8801_write(IT8801_REG_KSIEER, 0xff);
+		gpio_clear_pending_interrupt(GPIO_IT8801_SMB_INT);
+		gpio_enable_interrupt(GPIO_IT8801_SMB_INT);
+	} else {
+		gpio_disable_interrupt(GPIO_IT8801_SMB_INT);
+	}
+}
+
+void io_expander_it8801_interrupt(enum gpio_signal signal)
+{
+	/* Wake the scan task */
+	task_wake(TASK_ID_KEYSCAN);
+}
+
+static void dump_register(int reg)
+{
+	int rv;
+	int data;
+
+	ccprintf("[%Xh] = ", reg);
+
+	rv = it8801_read(reg, &data);
+
+	if (!rv)
+		ccprintf("0x%02x\n", data);
+	else
+		ccprintf("ERR (%d)\n", rv);
+}
+
+static int it8801_dump(int argc, char **argv)
+{
+	dump_register(IT8801_REG_KSIIER);
+	dump_register(IT8801_REG_KSIEER);
+	dump_register(IT8801_REG_KSIDR);
+	dump_register(IT8801_REG_KSOMCR);
+
+	return EC_SUCCESS;
+}
+DECLARE_CONSOLE_COMMAND(it8801_dump, it8801_dump, "NULL",
+			"Dumps IT8801 registers");
diff --git a/driver/ioexpander_it8801.h b/driver/ioexpander_it8801.h
new file mode 100644
index 0000000000..9b84adf764
--- /dev/null
+++ b/driver/ioexpander_it8801.h
@@ -0,0 +1,46 @@
+/* Copyright 2019 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * IT8801 is an I/O expander with the keyboard matrix controller.
+ *
+ */
+
+#ifndef __CROS_EC_IO_EXPANDER_IT8801_H
+#define __CROS_EC_IO_EXPANDER_IT8801_H
+
+/* I2C slave address(7-bit without R/W) */
+#define IT8801_I2C_ADDR 0x38
+
+/* Keyboard Matrix Scan control (KBS) */
+#define IT8801_REG_KSOMCR               0x40
+#define IT8801_REG_MASK_KSOSDIC         BIT(7)
+#define IT8801_REG_MASK_KSE             BIT(6)
+#define IT8801_REG_MASK_AKSOSC          BIT(5)
+#define IT8801_REG_KSIDR                0x41
+#define IT8801_REG_KSIEER               0x42
+#define IT8801_REG_KSIIER               0x43
+#define IT8801_REG_SMBCR                0xfa
+#define IT8801_REG_MASK_ARE             BIT(4)
+#define IT8801_REG_GIECR                0xfb
+#define IT8801_REG_MASK_GKSIIE          BIT(3)
+#define IT8801_REG_GPIO10               0x12
+#define IT8801_REG_GPIO00_KSO19         0x0a
+#define IT8801_REG_GPIO01_KSO18         0x0b
+#define IT8801_REG_GPIO22_KSO21         0x1c
+#define IT8801_REG_GPIO23_KSO20         0x1d
+#define IT8801_REG_MASK_GPIOAFS_PULLUP  BIT(7)
+#define IT8801_REG_MASK_GPIOAFS_FUNC2   BIT(6)
+#define IT8801_REG_MASK_GPIODIR         BIT(5)
+#define IT8801_REG_MASK_GPIOPUE         BIT(0)
+#define IT8801_REG_GPIOG2SOVR           0x07
+#define IT8801_REG_GPIO23SOV            BIT(3)
+#define IT8801_REG_MASK_SELKSO2         0x02
+#define IT8801_REG_LBVIDR               0xFE
+#define IT8801_REG_HBVIDR               0xFF
+#define IT8801_KSO_COUNT                18
+
+/* ISR for IT8801's SMB_INT# */
+void io_expander_it8801_interrupt(enum gpio_signal signal);
+
+#endif /* __CROS_EC_KBEXPANDER_IT8801_H */
diff --git a/include/config.h b/include/config.h
index ebf3f09c49..e09a13bf39 100644
--- a/include/config.h
+++ b/include/config.h
@@ -2344,6 +2344,9 @@
 
 /******************************************************************************/
 
+/* Support IT8801 I/O expander. */
+#undef CONFIG_IO_EXPANDER_IT8801
+
 /* Support Nuvoton NCT38xx I/O expander. */
 #undef CONFIG_IO_EXPANDER_NCT38XX
 
@@ -2517,6 +2520,8 @@
 
 /*****************************************************************************/
 
+/*****************************************************************************/
+
 /* Support common LED interface */
 #undef CONFIG_LED_COMMON