mp2964: Add PMIC driver

This adds a driver for the mp2964 IMVP9.1 PMIC. This driver enables
programming control registers within the PMIC.

BRANCH=none
BUG=b:185424011
TEST=buildall passes. functional testing was done with the follow-on
	patch.

Change-Id: I9b2d89007b5f6933ceeb9a1bcd3bbefb819888a3
Signed-off-by: Caveh Jalali <caveh@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2827950
Reviewed-by: Keith Short <keithshort@chromium.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Commit-Queue: Keith Short <keithshort@chromium.org>

1 files changed, 152 insertions, 0 deletions

diff --git a/driver/mp2964.c b/driver/mp2964.c
new file mode 100644
index 0000000000..21a23a8f4c
--- /dev/null
+++ b/driver/mp2964.c
@@ -0,0 +1,152 @@
+/* Copyright 2021 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.
+ */
+
+/* Driver for tuning the MP2964 IMVP8 - IMVP9.1 parameters */
+
+#include "console.h"
+#include "i2c.h"
+#include "mp2964.h"
+#include "timer.h"
+#include "util.h"
+
+#define MP2964_STARTUP_WAIT_US		(50 * MSEC)
+#define MP2964_STORE_WAIT_US		(300 * MSEC)
+#define MP2964_RESTORE_WAIT_US		(2 * MSEC)
+
+enum reg_page {
+	REG_PAGE_0,
+	REG_PAGE_1,
+	REG_PAGE_COUNT
+};
+
+static int mp2964_write8(uint8_t reg, uint8_t value)
+{
+	const uint8_t tx[2] = { reg, value };
+
+	return i2c_xfer_unlocked(I2C_PORT_MP2964, I2C_ADDR_MP2964_FLAGS,
+				 tx, sizeof(tx), NULL, 0, I2C_XFER_SINGLE);
+}
+
+static void mp2964_read16(uint8_t reg, uint16_t *value)
+{
+	const uint8_t tx[1] = { reg };
+	uint8_t rx[2];
+
+	i2c_xfer_unlocked(I2C_PORT_MP2964, I2C_ADDR_MP2964_FLAGS,
+			  tx, sizeof(tx), rx, sizeof(rx), I2C_XFER_SINGLE);
+	*value = (rx[1] << 8) | rx[0];
+}
+
+static void mp2964_write16(uint8_t reg, uint16_t value)
+{
+	const uint8_t tx[3] = { reg, value & 0xff, value >> 8 };
+
+	i2c_xfer_unlocked(I2C_PORT_MP2964, I2C_ADDR_MP2964_FLAGS,
+			  tx, sizeof(tx), NULL, 0, I2C_XFER_SINGLE);
+}
+
+static int mp2964_select_page(enum reg_page page)
+{
+	int status;
+
+	if (page >= REG_PAGE_COUNT)
+		return EC_ERROR_INVAL;
+
+	status = mp2964_write8(MP2964_PAGE, page);
+	if (status != EC_SUCCESS) {
+		ccprintf("%s: could not select page 0x%02x, error %d\n",
+			 __func__, page, status);
+	}
+	return status;
+}
+
+static void mp2964_write_vec16(const struct mp2964_reg_val *init_list,
+			       int count, int *delta)
+{
+	const struct mp2964_reg_val *reg_val;
+	uint16_t outval;
+	int i;
+
+	reg_val = init_list;
+	for (i = 0; i < count; ++i, ++reg_val) {
+		mp2964_read16(reg_val->reg, &outval);
+		if (outval == reg_val->val) {
+			ccprintf("mp2964: reg 0x%02x already 0x%04x\n",
+				 reg_val->reg, outval);
+			continue;
+		}
+		ccprintf("mp2964: tuning reg 0x%02x from 0x%04x to 0x%04x\n",
+			 reg_val->reg, outval, reg_val->val);
+		mp2964_write16(reg_val->reg, reg_val->val);
+		*delta += 1;
+	}
+}
+
+static int mp2964_store_user_all(void)
+{
+	const uint8_t wr = MP2964_STORE_USER_ALL;
+	const uint8_t rd = MP2964_RESTORE_USER_ALL;
+	int status;
+
+	ccprintf("%s: updating persistent settings\n", __func__);
+
+	status = i2c_xfer_unlocked(I2C_PORT_MP2964, I2C_ADDR_MP2964_FLAGS,
+				   &wr, sizeof(wr), NULL, 0, I2C_XFER_SINGLE);
+	if (status != EC_SUCCESS)
+		return status;
+
+	usleep(MP2964_STORE_WAIT_US);
+
+	status = i2c_xfer_unlocked(I2C_PORT_MP2964, I2C_ADDR_MP2964_FLAGS,
+				   &rd, sizeof(rd), NULL, 0, I2C_XFER_SINGLE);
+	if (status != EC_SUCCESS)
+		return status;
+
+	usleep(MP2964_RESTORE_WAIT_US);
+
+	return EC_SUCCESS;
+}
+
+static void mp2964_patch_rail(enum reg_page page,
+			      const struct mp2964_reg_val *page_vals,
+			      int count,
+			      int *delta)
+{
+	if (mp2964_select_page(page) != EC_SUCCESS)
+		return;
+	mp2964_write_vec16(page_vals, count, delta);
+}
+
+int mp2964_tune(const struct mp2964_reg_val *rail_a, int count_a,
+		const struct mp2964_reg_val *rail_b, int count_b)
+{
+	int tries = 2;
+	int delta;
+
+	udelay(MP2964_STARTUP_WAIT_US);
+
+	i2c_lock(I2C_PORT_MP2964, 1);
+
+	do {
+		int status;
+
+		delta = 0;
+		mp2964_patch_rail(REG_PAGE_0, rail_a, count_a, &delta);
+		mp2964_patch_rail(REG_PAGE_1, rail_b, count_b, &delta);
+		if (delta == 0)
+			break;
+
+		status = mp2964_store_user_all();
+		if (status != EC_SUCCESS)
+			ccprintf("%s: STORE_USER_ALL failed\n", __func__);
+	} while (--tries > 0);
+
+	i2c_lock(I2C_PORT_MP2964, 0);
+
+	if (delta)
+		return EC_ERROR_UNKNOWN;
+	else
+		return EC_SUCCESS;
+}