hw/sensor: Add lsm303dlhc magnetometer device

This commit adds emulation of the magnetometer on the LSM303DLHC.
It allows the magnetometer's X, Y and Z outputs to be set via the
mag-x, mag-y and mag-z properties, as well as the 12-bit
temperature output via the temperature property. Sensor can be
enabled with 'CONFIG_LSM303DLHC_MAG=y'.

Signed-off-by: Kevin Townsend <kevin.townsend@linaro.org>
Message-id: 20220130095032.35392-1-kevin.townsend@linaro.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

2 files changed, 149 insertions, 0 deletions

diff --git a/tests/qtest/lsm303dlhc-mag-test.c b/tests/qtest/lsm303dlhc-mag-test.c
new file mode 100644
index 0000000000..0f64e7fc67
--- /dev/null
+++ b/tests/qtest/lsm303dlhc-mag-test.c
@@ -0,0 +1,148 @@
+/*
+ * QTest testcase for the LSM303DLHC I2C magnetometer
+ *
+ * Copyright (C) 2021 Linaro Ltd.
+ * Written by Kevin Townsend <kevin.townsend@linaro.org>
+ *
+ * Based on: https://www.st.com/resource/en/datasheet/lsm303dlhc.pdf
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "libqtest-single.h"
+#include "libqos/qgraph.h"
+#include "libqos/i2c.h"
+#include "qapi/qmp/qdict.h"
+
+#define LSM303DLHC_MAG_TEST_ID        "lsm303dlhc_mag-test"
+#define LSM303DLHC_MAG_REG_CRA        0x00
+#define LSM303DLHC_MAG_REG_CRB        0x01
+#define LSM303DLHC_MAG_REG_OUT_X_H    0x03
+#define LSM303DLHC_MAG_REG_OUT_Z_H    0x05
+#define LSM303DLHC_MAG_REG_OUT_Y_H    0x07
+#define LSM303DLHC_MAG_REG_IRC        0x0C
+#define LSM303DLHC_MAG_REG_TEMP_OUT_H 0x31
+
+static int qmp_lsm303dlhc_mag_get_property(const char *id, const char *prop)
+{
+    QDict *response;
+    int ret;
+
+    response = qmp("{ 'execute': 'qom-get', 'arguments': { 'path': %s, "
+                   "'property': %s } }", id, prop);
+    g_assert(qdict_haskey(response, "return"));
+    ret = qdict_get_int(response, "return");
+    qobject_unref(response);
+    return ret;
+}
+
+static void qmp_lsm303dlhc_mag_set_property(const char *id, const char *prop,
+                                            int value)
+{
+    QDict *response;
+
+    response = qmp("{ 'execute': 'qom-set', 'arguments': { 'path': %s, "
+                   "'property': %s, 'value': %d } }", id, prop, value);
+    g_assert(qdict_haskey(response, "return"));
+    qobject_unref(response);
+}
+
+static void send_and_receive(void *obj, void *data, QGuestAllocator *alloc)
+{
+    int64_t value;
+    QI2CDevice *i2cdev = (QI2CDevice *)obj;
+
+    /* Check default value for CRB */
+    g_assert_cmphex(i2c_get8(i2cdev, LSM303DLHC_MAG_REG_CRB), ==, 0x20);
+
+    /* Set x to 1.0 gauss and verify the value */
+    qmp_lsm303dlhc_mag_set_property(LSM303DLHC_MAG_TEST_ID, "mag-x", 100000);
+    value = qmp_lsm303dlhc_mag_get_property(
+        LSM303DLHC_MAG_TEST_ID, "mag-x");
+    g_assert_cmpint(value, ==, 100000);
+
+    /* Set y to 1.5 gauss and verify the value */
+    qmp_lsm303dlhc_mag_set_property(LSM303DLHC_MAG_TEST_ID, "mag-y", 150000);
+    value = qmp_lsm303dlhc_mag_get_property(
+        LSM303DLHC_MAG_TEST_ID, "mag-y");
+    g_assert_cmpint(value, ==, 150000);
+
+    /* Set z to 0.5 gauss and verify the value */
+    qmp_lsm303dlhc_mag_set_property(LSM303DLHC_MAG_TEST_ID, "mag-z", 50000);
+    value = qmp_lsm303dlhc_mag_get_property(
+        LSM303DLHC_MAG_TEST_ID, "mag-z");
+    g_assert_cmpint(value, ==, 50000);
+
+    /* Set temperature to 23.6 C and verify the value */
+    qmp_lsm303dlhc_mag_set_property(LSM303DLHC_MAG_TEST_ID,
+        "temperature", 23600);
+    value = qmp_lsm303dlhc_mag_get_property(
+        LSM303DLHC_MAG_TEST_ID, "temperature");
+    /* Should return 23.5 C due to 0.125°C steps. */
+    g_assert_cmpint(value, ==, 23500);
+
+    /* Read raw x axis registers (1 gauss = 1100 at +/-1.3 g gain) */
+    value = i2c_get16(i2cdev, LSM303DLHC_MAG_REG_OUT_X_H);
+    g_assert_cmphex(value, ==, 1100);
+
+    /* Read raw y axis registers (1.5 gauss = 1650 at +/- 1.3 g gain = ) */
+    value = i2c_get16(i2cdev, LSM303DLHC_MAG_REG_OUT_Y_H);
+    g_assert_cmphex(value, ==, 1650);
+
+    /* Read raw z axis registers (0.5 gauss = 490 at +/- 1.3 g gain = ) */
+    value = i2c_get16(i2cdev, LSM303DLHC_MAG_REG_OUT_Z_H);
+    g_assert_cmphex(value, ==, 490);
+
+    /* Read raw temperature registers with temp disabled (CRA = 0x10) */
+    value = i2c_get16(i2cdev, LSM303DLHC_MAG_REG_TEMP_OUT_H);
+    g_assert_cmphex(value, ==, 0);
+
+    /* Enable temperature reads (CRA = 0x90) */
+    i2c_set8(i2cdev, LSM303DLHC_MAG_REG_CRA, 0x90);
+
+    /* Read raw temp registers (23.5 C = 188 at 1 lsb = 0.125 C) */
+    value = i2c_get16(i2cdev, LSM303DLHC_MAG_REG_TEMP_OUT_H);
+    g_assert_cmphex(value, ==, 188);
+}
+
+static void reg_wraparound(void *obj, void *data, QGuestAllocator *alloc)
+{
+    uint8_t value[4];
+    QI2CDevice *i2cdev = (QI2CDevice *)obj;
+
+    /* Set x to 1.0 gauss, and y to 1.5 gauss for known test values */
+    qmp_lsm303dlhc_mag_set_property(LSM303DLHC_MAG_TEST_ID, "mag-x", 100000);
+    qmp_lsm303dlhc_mag_set_property(LSM303DLHC_MAG_TEST_ID, "mag-y", 150000);
+
+    /* Check that requesting 4 bytes starting at Y_H wraps around to X_L */
+    i2c_read_block(i2cdev, LSM303DLHC_MAG_REG_OUT_Y_H, value, 4);
+    /* 1.5 gauss = 1650 lsb = 0x672 */
+    g_assert_cmphex(value[0], ==, 0x06);
+    g_assert_cmphex(value[1], ==, 0x72);
+    /* 1.0 gauss = 1100 lsb = 0x44C */
+    g_assert_cmphex(value[2], ==, 0x04);
+    g_assert_cmphex(value[3], ==, 0x4C);
+
+    /* Check that requesting LSM303DLHC_MAG_REG_IRC wraps around to CRA */
+    i2c_read_block(i2cdev, LSM303DLHC_MAG_REG_IRC, value, 2);
+    /* Default value for IRC = 0x33 */
+    g_assert_cmphex(value[0], ==, 0x33);
+    /* Default value for CRA = 0x10 */
+    g_assert_cmphex(value[1], ==, 0x10);
+}
+
+static void lsm303dlhc_mag_register_nodes(void)
+{
+    QOSGraphEdgeOptions opts = {
+        .extra_device_opts = "id=" LSM303DLHC_MAG_TEST_ID ",address=0x1e"
+    };
+    add_qi2c_address(&opts, &(QI2CAddress) { 0x1E });
+
+    qos_node_create_driver("lsm303dlhc_mag", i2c_device_create);
+    qos_node_consumes("lsm303dlhc_mag", "i2c-bus", &opts);
+
+    qos_add_test("tx-rx", "lsm303dlhc_mag", send_and_receive, NULL);
+    qos_add_test("regwrap", "lsm303dlhc_mag", reg_wraparound, NULL);
+}
+libqos_init(lsm303dlhc_mag_register_nodes);
diff --git a/tests/qtest/meson.build b/tests/qtest/meson.build
index 762f6adcd5..f33d84d19b 100644
--- a/tests/qtest/meson.build
+++ b/tests/qtest/meson.build
@@ -243,6 +243,7 @@ qos_test_ss.add(
   'eepro100-test.c',
   'es1370-test.c',
   'ipoctal232-test.c',
+  'lsm303dlhc-mag-test.c',
   'max34451-test.c',
   'megasas-test.c',
   'ne2000-test.c',