servo_v4p1: Add CC DAC functionality

This functionality is available in both RO and RW.

BRANCH=none
BUG=b:146793000
TEST=make -j buildall

Signed-off-by: Sam Hurst <shurst@google.com>
Change-Id: Iace11bd64fe9db2fd7ff14827cb412dae1abcbca
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2216407
Reviewed-by: Wai-Hong Tam <waihong@google.com>
(cherry picked from commit c2981839b8879c43896ac8ba726564ce9fe7cf36)
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2332244

4 files changed, 178 insertions, 0 deletions

diff --git a/board/servo_v4p1/board.c b/board/servo_v4p1/board.c
index 72c95049d1..0ccf596ddd 100644
--- a/board/servo_v4p1/board.c
+++ b/board/servo_v4p1/board.c
@@ -10,6 +10,7 @@
 #include "chg_control.h"
 #include "common.h"
 #include "console.h"
+#include "dacs.h"
 #include "ec_version.h"
 #include "gpio.h"
 #include "hooks.h"
@@ -307,6 +308,7 @@ static void board_init(void)
 	usleep(MSEC);
 
 	init_ioexpanders();
+	init_dacs();
 
 	/* Clear BBRAM, we don't want any PD state carried over on reset. */
 	system_set_bbram(SYSTEM_BBRAM_IDX_PD0, 0);
diff --git a/board/servo_v4p1/build.mk b/board/servo_v4p1/build.mk
index 3d5712ed59..09711e0beb 100644
--- a/board/servo_v4p1/build.mk
+++ b/board/servo_v4p1/build.mk
@@ -16,6 +16,7 @@ test-list-y=
 # These files are compiled into RO and RW
 board-y=board.o tca6416a.o tca6424a.o
 board-y+=ioexpanders.o
+board-y+=dacs.o
 
 # These files are compiled into RO only
 board-ro+=ccd_measure_sbu.o
diff --git a/board/servo_v4p1/dacs.c b/board/servo_v4p1/dacs.c
new file mode 100644
index 0000000000..b5c62bb438
--- /dev/null
+++ b/board/servo_v4p1/dacs.c
@@ -0,0 +1,138 @@
+/* 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.
+ */
+
+#include "dacs.h"
+#include "i2c.h"
+#include "ioexpanders.h"
+#include "util.h"
+
+#define MAX_MV 5000
+
+#define CC1_DAC_ADDR 0x48
+#define CC2_DAC_ADDR 0x49
+
+#define REG_NOOP    0
+#define REG_DEVID   1
+#define REG_SYNC    2
+#define REG_CONFIG  3
+#define REG_GAIN    4
+#define REG_TRIGGER 5
+#define REG_STATUS  7
+#define REG_DAC     8
+
+#define DAC1	BIT(0)
+#define DAC2	BIT(1)
+
+static uint8_t dac_enabled;
+
+void init_dacs(void)
+{
+	/* Disable both DACS by default */
+	enable_dac(CC1_DAC, 0);
+	enable_dac(CC2_DAC, 0);
+	dac_enabled = 0;
+}
+
+void enable_dac(enum dac_t dac, uint8_t en)
+{
+	switch (dac) {
+	case CC1_DAC:
+		if (en) {
+			fault_clear_cc(1);
+			fault_clear_cc(0);
+			en_vout_buf_cc1(1);
+			/* Power ON DAC */
+			i2c_write8(1, CC1_DAC_ADDR, REG_CONFIG, 0);
+			dac_enabled |= DAC1;
+		} else {
+			en_vout_buf_cc1(0);
+			/* Power OFF DAC */
+			i2c_write8(1, CC1_DAC_ADDR, REG_CONFIG, 1);
+			dac_enabled &= ~DAC1;
+		}
+		break;
+	case CC2_DAC:
+		if (en) {
+			fault_clear_cc(1);
+			fault_clear_cc(0);
+			en_vout_buf_cc2(1);
+			i2c_write8(1, CC2_DAC_ADDR, REG_CONFIG, 0);
+			dac_enabled |= DAC2;
+		} else {
+			en_vout_buf_cc2(0);
+			/* Power down DAC */
+			i2c_write8(1, CC2_DAC_ADDR, REG_CONFIG, 1);
+			dac_enabled &= ~DAC2;
+		}
+		break;
+	}
+}
+
+int write_dac(enum dac_t dac, uint16_t value)
+{
+	uint16_t tmp;
+
+	/*
+	 * Data are MSB aligned in straight binary format, and
+	 * use the following format: DATA[13:0], 0, 0
+	 */
+	tmp = (value << 8) & 0xff00;
+	tmp |= (value >> 8) & 0xff;
+	tmp <<= 2;
+
+	switch (dac) {
+	case CC1_DAC:
+		if (!(dac_enabled & DAC1)) {
+			ccprintf("CC1_DAC is disabled\n");
+			return EC_ERROR_ACCESS_DENIED;
+		}
+		i2c_write16(1, CC1_DAC_ADDR, REG_DAC, tmp);
+		break;
+	case CC2_DAC:
+		if (!(dac_enabled & DAC2)) {
+			ccprintf("CC2_DAC is disabled\n");
+			return EC_ERROR_ACCESS_DENIED;
+		}
+		i2c_write16(1, CC2_DAC_ADDR, REG_DAC, tmp);
+		break;
+	}
+	return EC_SUCCESS;
+}
+
+static int cmd_cc_dac(int argc, char *argv[])
+{
+	uint8_t dac;
+	uint64_t mv;
+	uint64_t round_up;
+	char *e;
+
+	if (argc < 3)
+		return EC_ERROR_PARAM_COUNT;
+
+	dac = strtoi(argv[1], &e, 10);
+	if (*e || (dac != CC1_DAC && dac != CC2_DAC))
+		return EC_ERROR_PARAM2;
+
+	if (!strcasecmp(argv[2], "on")) {
+		enable_dac(dac, 1);
+	} else if (!strcasecmp(argv[2], "off")) {
+		enable_dac(dac, 0);
+	} else {
+		/* get value in mV */
+		mv = strtoi(argv[2], &e, 10);
+		/* 5000 mV max */
+		if (*e || mv > MAX_MV)
+			return EC_ERROR_PARAM3;
+		/* 305176 = (5V / 2^14) * 1000000 */
+		/* 152588 = 305176 / 2 : used for round up after division */
+		round_up = (((mv * 1000000) + 152588) / 305176);
+		if (!write_dac(dac, (uint16_t)round_up))
+			ccprintf("Setting DAC to %lld counts\n", round_up);
+	}
+	return EC_SUCCESS;
+}
+DECLARE_CONSOLE_COMMAND(cc_dac, cmd_cc_dac,
+			"dac <\"on\"|\"off\"|mv>",
+			"Set Servo v4.1 CC dacs");
diff --git a/board/servo_v4p1/dacs.h b/board/servo_v4p1/dacs.h
new file mode 100644
index 0000000000..bd0ecd67da
--- /dev/null
+++ b/board/servo_v4p1/dacs.h
@@ -0,0 +1,37 @@
+/* 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.
+ */
+#ifndef __CROS_EC_DACS_H
+#define __CROS_EC_DACS_H
+
+#include <stdint.h>
+
+enum dac_t {
+	CC1_DAC = 1,
+	CC2_DAC,
+};
+
+/*
+ * Initialize the DACs
+ */
+void init_dacs(void);
+
+/*
+ * Enable/Disable one of the DACs
+ *
+ * @param dac DAC to enable or disable
+ * @param en 0 to disable or 1 to enable
+ */
+void enable_dac(enum dac_t dac, uint8_t en);
+
+/*
+ * Write a value to the DAC
+ *
+ * @param dac DAC to write to
+ * @param value to write to the DAC in mV. (0 to 5000mV)
+ * @return EC_SUCCESS or EC_ERROR_ACCESS_DENIED on failure
+ */
+int write_dac(enum dac_t dac, uint16_t value);
+
+#endif /* __CROS_EC_DACS_H */