driver: Add LN9310 switchcap driver

Add LN9310 2:1 and 3:1 switchcap driver. It will be used in Trogdor
projects.

BRANCH=None
BUG=b:163867792
TEST=Defined the CONFIG and built correctly.

Change-Id: I14b55c7cd3be06e3811cc58a182b1694e6ad57ff
Signed-off-by: Wai-Hong Tam <waihong@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2386481
Reviewed-by: Stephen Boyd <swboyd@chromium.org>

1 files changed, 187 insertions, 0 deletions

diff --git a/driver/ln9310.c b/driver/ln9310.c
new file mode 100644
index 0000000000..5a82f3fa28
--- /dev/null
+++ b/driver/ln9310.c
@@ -0,0 +1,187 @@
+/* Copyright 2020 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.
+ *
+ * LION Semiconductor LN-9310 switched capacitor converter.
+ */
+
+#include "common.h"
+#include "console.h"
+#include "ln9310.h"
+#include "hooks.h"
+#include "i2c.h"
+#include "util.h"
+
+#define CPUTS(outstr) cputs(CC_CHIPSET, outstr)
+#define CPRINTF(format, args...) cprintf(CC_CHIPSET, format, ## args)
+#define CPRINTS(format, args...) cprints(CC_CHIPSET, format, ## args)
+
+static int power_good;
+
+int ln9310_power_good(void)
+{
+	return power_good;
+}
+
+static inline int raw_read8(int offset, int *value)
+{
+	return i2c_read8(ln9310_config.i2c_port,
+			 ln9310_config.i2c_addr_flags,
+			 offset,
+			 value);
+}
+
+static inline int field_update8(int offset, int mask, int value)
+{
+	/* Clear mask and then set value in i2c reg value */
+	return i2c_field_update8(ln9310_config.i2c_port,
+				 ln9310_config.i2c_addr_flags,
+				 offset,
+				 mask,
+				 value);
+}
+
+static void ln9310_irq_deferred(void)
+{
+	int status, val, pg_2to1, pg_3to1;
+
+	status = raw_read8(LN9310_REG_INT1, &val);
+	if (status) {
+		CPRINTS("LN9310 reading INT1 failed");
+		return;
+	}
+
+	CPRINTS("LN9310 received interrupt: 0x%x", val);
+	/* Don't care other interrupts except mode change */
+	if (!(val & LN9310_INT1_MODE))
+		return;
+
+	/* Check if the device is active in 2:1 or 3:1 switching mode */
+	status = raw_read8(LN9310_REG_SYS_STS, &val);
+	if (status) {
+		CPRINTS("LN9310 reading SYS_STS failed");
+		return;
+	}
+	CPRINTS("LN9310 system status: 0x%x", val);
+
+	/* Either 2:1 or 3:1 mode active is treated as PGOOD */
+	pg_2to1 = !!(val & LN9310_SYS_SWITCHING21_ACTIVE);
+	pg_3to1 = !!(val & LN9310_SYS_SWITCHING31_ACTIVE);
+	power_good = pg_2to1 || pg_3to1;
+}
+DECLARE_DEFERRED(ln9310_irq_deferred);
+
+void ln9310_interrupt(enum gpio_signal signal)
+{
+	hook_call_deferred(&ln9310_irq_deferred_data, 0);
+}
+
+static int is_battery_3s(void)
+{
+	int status, val, batt3s;
+
+	CPRINTS("LN9310 checking input voltage (2S/3S), threshold=10V");
+	/*
+	 * Turn on INFET_OUT_SWITCH_OK comparator;
+	 * configure INFET_OUT_SWITCH_OK to 10V.
+	 */
+	field_update8(LN9310_REG_TRACK_CTRL,
+		      LN9310_TRACK_INFET_OUT_SWITCH_OK_EN_MASK |
+				LN9310_TRACK_INFET_OUT_SWITCH_OK_CFG_MASK,
+		      LN9310_TRACK_INFET_OUT_SWITCH_OK_EN_ON |
+				LN9310_TRACK_INFET_OUT_SWITCH_OK_CFG_10V);
+
+	/* Read INFET_OUT_SWITCH_OK comparator */
+	status = raw_read8(LN9310_REG_BC_STS_B, &val);
+	if (status) {
+		CPRINTS("LN9310 reading BC_STS_B failed");
+		return -1;
+	}
+	CPRINTS("LN9310 BC_STS_B: 0x%x", val);
+
+	/*
+	 * If INFET_OUT_SWITCH_OK=0, VIN < 10V --> 2S battery
+	 * If INFET_OUT_SWITCH_OK=1, VIN > 10V --> 3S battery
+	 */
+	batt3s = !!(val & LN9310_BC_STS_B_INFET_OUT_SWITCH_OK);
+	CPRINTS("LN9310 %s battery detected", batt3s ? "3S" : "2S");
+
+	/* Turn off INFET_OUT_SWITCH_OK comparator */
+	field_update8(LN9310_REG_TRACK_CTRL,
+		      LN9310_TRACK_INFET_OUT_SWITCH_OK_EN_MASK,
+		      LN9310_TRACK_INFET_OUT_SWITCH_OK_EN_OFF);
+
+	return batt3s;
+}
+
+static void ln9310_init_3to1(void)
+{
+	CPRINTS("LN9310 init (3:1 operation)");
+
+	/* Enable track protection and SC_OUT configs for 3:1 switching */
+	field_update8(LN9310_REG_MODE_CHANGE_CFG,
+		      LN9310_MODE_TM_TRACK_MASK |
+				LN9310_MODE_TM_SC_OUT_PRECHG_MASK |
+				LN9310_MODE_TM_VIN_OV_CFG_MASK,
+		      LN9310_MODE_TM_TRACK_SWITCH31 |
+				LN9310_MODE_TM_SC_OUT_PRECHG_SWITCH31 |
+				LN9310_MODE_TM_VIN_OV_CFG_3S);
+
+	/* Enable 3:1 operation mode */
+	field_update8(LN9310_REG_PWR_CTRL,
+		      LN9310_PWR_OP_MODE_MASK,
+		      LN9310_PWR_OP_MODE_SWITCH31);
+
+	/* 3S lower bounde delta configurations */
+	field_update8(LN9310_REG_SYS_CTRL,
+		      LN9310_SYS_CTRL_LB_DELTA_MASK,
+		      LN9310_SYS_CTRL_LB_DELTA_3S);
+}
+
+static void ln9310_init_2to1(void)
+{
+	CPRINTS("LN9310 init (2:1 operation)");
+
+	/* Enable track protection and SC_OUT configs for 2:1 switching */
+	field_update8(LN9310_REG_MODE_CHANGE_CFG,
+		      LN9310_MODE_TM_TRACK_MASK |
+				LN9310_MODE_TM_SC_OUT_PRECHG_MASK,
+		      LN9310_MODE_TM_TRACK_SWITCH21 |
+				LN9310_MODE_TM_SC_OUT_PRECHG_SWITCH21);
+
+	/* Enable 2:1 operation mode */
+	field_update8(LN9310_REG_PWR_CTRL,
+		      LN9310_PWR_OP_MODE_MASK,
+		      LN9310_PWR_OP_MODE_SWITCH21);
+
+	/* 2S lower bounde delta configurations */
+	field_update8(LN9310_REG_SYS_CTRL,
+		      LN9310_SYS_CTRL_LB_DELTA_MASK,
+		      LN9310_SYS_CTRL_LB_DELTA_2S);
+}
+
+void ln9310_init(void)
+{
+	int status, val, batt3s;
+
+	batt3s = is_battery_3s();
+	if (batt3s == -1)
+		return;
+	else if (batt3s)
+		ln9310_init_3to1();
+	else
+		ln9310_init_2to1();
+
+	/* Unmask the MODE change interrupt */
+	field_update8(LN9310_REG_INT1_MSK,
+		      LN9310_INT1_MODE,
+		      0);
+
+	/* Dummy clear all interrupts */
+	status = raw_read8(LN9310_REG_INT1, &val);
+	if (status) {
+		CPRINTS("LN9310 reading INT1 failed");
+		return;
+	}
+	CPRINTS("LN9310 cleared interrupts: 0x%x", val);
+}