test: dm: Add tests for regmap managed API and regmap fields

The tests rely on a dummy driver to allocate and initialize the regmaps
and the regmap fields using the managed API. The first test checks if
the regmap config fields like width, reg_offset_shift, range specifiers,
etc work. The second test checks if regmap fields behave properly (mask
and shift are ok) by peeking into the regmap.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/test/dm/regmap.c b/test/dm/regmap.c
index bd21c83..2effef3 100644
--- a/test/dm/regmap.c
+++ b/test/dm/regmap.c
@@ -9,8 +9,10 @@
 #include <mapmem.h>
 #include <regmap.h>
 #include <syscon.h>
+#include <rand.h>
 #include <asm/test.h>
 #include <dm/test.h>
+#include <dm/devres.h>
 #include <linux/err.h>
 #include <test/test.h>
 #include <test/ut.h>
@@ -187,3 +189,199 @@
 }
 
 DM_TEST(dm_test_regmap_poll, UT_TESTF_SCAN_PDATA | UT_TESTF_SCAN_FDT);
+
+struct regmaptest_priv {
+	struct regmap *cfg_regmap; /* For testing regmap_config options. */
+	struct regmap *fld_regmap; /* For testing regmap fields. */
+	struct regmap_field **fields;
+};
+
+static const struct reg_field field_cfgs[] = {
+	{
+		.reg = 0,
+		.lsb = 0,
+		.msb = 6,
+	},
+	{
+		.reg = 2,
+		.lsb = 4,
+		.msb = 12,
+	},
+	{
+		.reg = 2,
+		.lsb = 12,
+		.msb = 15,
+	}
+};
+
+#define REGMAP_TEST_BUF_START 0
+#define REGMAP_TEST_BUF_SZ 5
+
+static int remaptest_probe(struct udevice *dev)
+{
+	struct regmaptest_priv *priv = dev_get_priv(dev);
+	struct regmap *regmap;
+	struct regmap_field *field;
+	struct regmap_config cfg;
+	int i;
+	static const int n = ARRAY_SIZE(field_cfgs);
+
+	/*
+	 * To exercise all the regmap config options, create a regmap that
+	 * points to a custom memory area instead of the one defined in device
+	 * tree. Use 2-byte elements. To allow directly indexing into the
+	 * elements, use an offset shift of 1. So, accessing offset 1 gets the
+	 * element at index 1 at memory location 2.
+	 *
+	 * REGMAP_TEST_BUF_SZ is the number of elements, so we need to multiply
+	 * it by 2 because r_size expects number of bytes.
+	 */
+	cfg.reg_offset_shift = 1;
+	cfg.r_start = REGMAP_TEST_BUF_START;
+	cfg.r_size = REGMAP_TEST_BUF_SZ * 2;
+	cfg.width = REGMAP_SIZE_16;
+
+	regmap = devm_regmap_init(dev, NULL, NULL, &cfg);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+	priv->cfg_regmap = regmap;
+
+	memset(&cfg, 0, sizeof(struct regmap_config));
+	cfg.width = REGMAP_SIZE_16;
+
+	regmap = devm_regmap_init(dev, NULL, NULL, &cfg);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+	priv->fld_regmap = regmap;
+
+	priv->fields = devm_kzalloc(dev, sizeof(struct regmap_field *) * n,
+				    GFP_KERNEL);
+	if (!priv->fields)
+		return -ENOMEM;
+
+	for (i = 0 ; i < n; i++) {
+		field = devm_regmap_field_alloc(dev, priv->fld_regmap,
+						field_cfgs[i]);
+		if (IS_ERR(field))
+			return PTR_ERR(field);
+		priv->fields[i] = field;
+	}
+
+	return 0;
+}
+
+static const struct udevice_id regmaptest_ids[] = {
+	{ .compatible = "sandbox,regmap_test" },
+	{ }
+};
+
+U_BOOT_DRIVER(regmap_test) = {
+	.name	= "regmaptest_drv",
+	.of_match	= regmaptest_ids,
+	.id	= UCLASS_NOP,
+	.probe = remaptest_probe,
+	.priv_auto_alloc_size = sizeof(struct regmaptest_priv),
+};
+
+static int dm_test_devm_regmap(struct unit_test_state *uts)
+{
+	int i = 0;
+	u32 val;
+	u16 pattern[REGMAP_TEST_BUF_SZ];
+	u16 *buffer;
+	struct udevice *dev;
+	struct regmaptest_priv *priv;
+
+	sandbox_set_enable_memio(true);
+
+	/*
+	 * Map the memory area the regmap should point to so we can make sure
+	 * the writes actually go to that location.
+	 */
+	buffer = map_physmem(REGMAP_TEST_BUF_START,
+			     REGMAP_TEST_BUF_SZ * 2, MAP_NOCACHE);
+
+	ut_assertok(uclass_get_device_by_name(UCLASS_NOP, "regmap-test_0",
+					      &dev));
+	priv = dev_get_priv(dev);
+
+	srand(get_ticks() + rand());
+	for (i = 0; i < REGMAP_TEST_BUF_SZ; i++) {
+		pattern[i] = rand();
+		ut_assertok(regmap_write(priv->cfg_regmap, i, pattern[i]));
+	}
+	for (i = 0; i < REGMAP_TEST_BUF_SZ; i++) {
+		ut_assertok(regmap_read(priv->cfg_regmap, i, &val));
+		ut_asserteq(val, buffer[i]);
+		ut_asserteq(val, pattern[i]);
+	}
+
+	ut_asserteq(-ERANGE, regmap_write(priv->cfg_regmap, REGMAP_TEST_BUF_SZ,
+					  val));
+	ut_asserteq(-ERANGE, regmap_read(priv->cfg_regmap, REGMAP_TEST_BUF_SZ,
+					 &val));
+	ut_asserteq(-ERANGE, regmap_write(priv->cfg_regmap, -1, val));
+	ut_asserteq(-ERANGE, regmap_read(priv->cfg_regmap, -1, &val));
+
+	return 0;
+}
+DM_TEST(dm_test_devm_regmap, UT_TESTF_SCAN_PDATA | UT_TESTF_SCAN_FDT);
+
+static int test_one_field(struct unit_test_state *uts,
+			  struct regmap *regmap,
+			  struct regmap_field *field,
+			  struct reg_field field_cfg)
+{
+	int j;
+	unsigned int val;
+	int mask = (1 << (field_cfg.msb - field_cfg.lsb + 1)) - 1;
+	int shift = field_cfg.lsb;
+
+	ut_assertok(regmap_write(regmap, field_cfg.reg, 0));
+	ut_assertok(regmap_read(regmap, field_cfg.reg, &val));
+	ut_asserteq(0, val);
+
+	for (j = 0; j <= mask; j++) {
+		ut_assertok(regmap_field_write(field, j));
+		ut_assertok(regmap_field_read(field, &val));
+		ut_asserteq(j, val);
+		ut_assertok(regmap_read(regmap, field_cfg.reg, &val));
+		ut_asserteq(j << shift, val);
+	}
+
+	ut_assertok(regmap_field_write(field, mask + 1));
+	ut_assertok(regmap_read(regmap, field_cfg.reg, &val));
+	ut_asserteq(0, val);
+
+	ut_assertok(regmap_field_write(field, 0xFFFF));
+	ut_assertok(regmap_read(regmap, field_cfg.reg, &val));
+	ut_asserteq(mask << shift, val);
+
+	ut_assertok(regmap_write(regmap, field_cfg.reg, 0xFFFF));
+	ut_assertok(regmap_field_write(field, 0));
+	ut_assertok(regmap_read(regmap, field_cfg.reg, &val));
+	ut_asserteq(0xFFFF & ~(mask << shift), val);
+	return 0;
+}
+
+static int dm_test_devm_regmap_field(struct unit_test_state *uts)
+{
+	int i, rc;
+	struct udevice *dev;
+	struct regmaptest_priv *priv;
+
+	ut_assertok(uclass_get_device_by_name(UCLASS_NOP, "regmap-test_0",
+					      &dev));
+	priv = dev_get_priv(dev);
+
+	sandbox_set_enable_memio(true);
+	for (i = 0 ; i < ARRAY_SIZE(field_cfgs); i++) {
+		rc = test_one_field(uts, priv->fld_regmap, priv->fields[i],
+				    field_cfgs[i]);
+		if (rc)
+			break;
+	}
+
+	return 0;
+}
+DM_TEST(dm_test_devm_regmap_field, UT_TESTF_SCAN_PDATA | UT_TESTF_SCAN_FDT);