[v3] power: supply: max1720x: add read support for nvmem

diff --git a/drivers/power/supply/max1720x_battery.c b/drivers/power/supply/max1720x_battery.c
index edc262f0a62f..3e84e70340e4 100644
--- a/drivers/power/supply/max1720x_battery.c
+++ b/drivers/power/supply/max1720x_battery.c
@@ -10,13 +10,16 @@ 
 #include <linux/bitfield.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
+#include <linux/nvmem-provider.h>
 #include <linux/power_supply.h>
 #include <linux/regmap.h>
 
 #include <asm/unaligned.h>
 
 /* Nonvolatile registers */
+#define MAX1720X_NXTABLE0		0x80
 #define MAX1720X_NRSENSE		0xCF	/* RSense in 10^-5 Ohm */
+#define MAX1720X_NDEVICE_NAME4		0xDF
 
 /* ModelGauge m5 */
 #define MAX172XX_STATUS			0x00	/* Status */
@@ -46,6 +49,8 @@  static const char *const max17205_model = "MAX17205";
 
 struct max1720x_device_info {
 	struct regmap *regmap;
+	struct regmap *regmap_nv;
+	struct i2c_client *ancillary;
 	int rsense;
 };
 
@@ -106,6 +111,134 @@  static const struct regmap_config max1720x_regmap_cfg = {
 	.cache_type = REGCACHE_RBTREE,
 };
 
+static const struct regmap_range max1720x_nvmem_allow[] = {
+	regmap_reg_range(MAX1720X_NXTABLE0, MAX1720X_NDEVICE_NAME4),
+};
+
+static const struct regmap_range max1720x_nvmem_deny[] = {
+	regmap_reg_range(0x00, 0x7F),
+	regmap_reg_range(0xE0, 0xFF),
+};
+
+static const struct regmap_access_table max1720x_nvmem_regs = {
+	.yes_ranges	= max1720x_nvmem_allow,
+	.n_yes_ranges	= ARRAY_SIZE(max1720x_nvmem_allow),
+	.no_ranges	= max1720x_nvmem_deny,
+	.n_no_ranges	= ARRAY_SIZE(max1720x_nvmem_deny),
+};
+
+static const struct regmap_config max1720x_nvmem_regmap_cfg = {
+	.reg_bits = 8,
+	.val_bits = 16,
+	.max_register = MAX1720X_NDEVICE_NAME4,
+	.val_format_endian = REGMAP_ENDIAN_LITTLE,
+	.rd_table = &max1720x_nvmem_regs,
+};
+
+static const struct nvmem_cell_info max1720x_nvmem_cells[] = {
+	{ .name = "nXTable0",  .offset = 0,  .bytes = 2, },
+	{ .name = "nXTable1",  .offset = 2,  .bytes = 2, },
+	{ .name = "nXTable2",  .offset = 4,  .bytes = 2, },
+	{ .name = "nXTable3",  .offset = 6,  .bytes = 2, },
+	{ .name = "nXTable4",  .offset = 8,  .bytes = 2, },
+	{ .name = "nXTable5",  .offset = 10, .bytes = 2, },
+	{ .name = "nXTable6",  .offset = 12, .bytes = 2, },
+	{ .name = "nXTable7",  .offset = 14, .bytes = 2, },
+	{ .name = "nXTable8",  .offset = 16, .bytes = 2, },
+	{ .name = "nXTable9",  .offset = 18, .bytes = 2, },
+	{ .name = "nXTable10", .offset = 20, .bytes = 2, },
+	{ .name = "nXTable11", .offset = 22, .bytes = 2, },
+	{ .name = "nUser18C",  .offset = 24, .bytes = 2, },
+	{ .name = "nUser18D",  .offset = 26, .bytes = 2, },
+	{ .name = "nODSCTh",   .offset = 28, .bytes = 2, },
+	{ .name = "nODSCCfg",  .offset = 30, .bytes = 2, },
+
+	{ .name = "nOCVTable0",  .offset = 32, .bytes = 2, },
+	{ .name = "nOCVTable1",  .offset = 34, .bytes = 2, },
+	{ .name = "nOCVTable2",  .offset = 36, .bytes = 2, },
+	{ .name = "nOCVTable3",  .offset = 38, .bytes = 2, },
+	{ .name = "nOCVTable4",  .offset = 40, .bytes = 2, },
+	{ .name = "nOCVTable5",  .offset = 42, .bytes = 2, },
+	{ .name = "nOCVTable6",  .offset = 44, .bytes = 2, },
+	{ .name = "nOCVTable7",  .offset = 46, .bytes = 2, },
+	{ .name = "nOCVTable8",  .offset = 48, .bytes = 2, },
+	{ .name = "nOCVTable9",  .offset = 50, .bytes = 2, },
+	{ .name = "nOCVTable10", .offset = 52, .bytes = 2, },
+	{ .name = "nOCVTable11", .offset = 54, .bytes = 2, },
+	{ .name = "nIChgTerm",   .offset = 56, .bytes = 2, },
+	{ .name = "nFilterCfg",  .offset = 58, .bytes = 2, },
+	{ .name = "nVEmpty",     .offset = 60, .bytes = 2, },
+	{ .name = "nLearnCfg",   .offset = 62, .bytes = 2, },
+
+	{ .name = "nQRTable00",  .offset = 64, .bytes = 2, },
+	{ .name = "nQRTable10",  .offset = 66, .bytes = 2, },
+	{ .name = "nQRTable20",  .offset = 68, .bytes = 2, },
+	{ .name = "nQRTable30",  .offset = 70, .bytes = 2, },
+	{ .name = "nCycles",     .offset = 72, .bytes = 2, },
+	{ .name = "nFullCapNom", .offset = 74, .bytes = 2, },
+	{ .name = "nRComp0",     .offset = 76, .bytes = 2, },
+	{ .name = "nTempCo",     .offset = 78, .bytes = 2, },
+	{ .name = "nIAvgEmpty",  .offset = 80, .bytes = 2, },
+	{ .name = "nFullCapRep", .offset = 82, .bytes = 2, },
+	{ .name = "nVoltTemp",   .offset = 84, .bytes = 2, },
+	{ .name = "nMaxMinCurr", .offset = 86, .bytes = 2, },
+	{ .name = "nMaxMinVolt", .offset = 88, .bytes = 2, },
+	{ .name = "nMaxMinTemp", .offset = 90, .bytes = 2, },
+	{ .name = "nSOC",        .offset = 92, .bytes = 2, },
+	{ .name = "nTimerH",     .offset = 94, .bytes = 2, },
+
+	{ .name = "nConfig",    .offset = 96,  .bytes = 2, },
+	{ .name = "nRippleCfg", .offset = 98,  .bytes = 2, },
+	{ .name = "nMiscCfg",   .offset = 100, .bytes = 2, },
+	{ .name = "nDesignCap", .offset = 102, .bytes = 2, },
+	{ .name = "nHibCfg",    .offset = 104, .bytes = 2, },
+	{ .name = "nPackCfg",   .offset = 106, .bytes = 2, },
+	{ .name = "nRelaxCfg",  .offset = 108, .bytes = 2, },
+	{ .name = "nConvgCfg",  .offset = 110, .bytes = 2, },
+	{ .name = "nNVCfg0",    .offset = 112, .bytes = 2, },
+	{ .name = "nNVCfg1",    .offset = 114, .bytes = 2, },
+	{ .name = "nNVCfg2",    .offset = 116, .bytes = 2, },
+	{ .name = "nSBSCfg",    .offset = 118, .bytes = 2, },
+	{ .name = "nROMID0",    .offset = 120, .bytes = 2, },
+	{ .name = "nROMID1",    .offset = 122, .bytes = 2, },
+	{ .name = "nROMID2",    .offset = 124, .bytes = 2, },
+	{ .name = "nROMID3",    .offset = 126, .bytes = 2, },
+
+	{ .name = "nVAlrtTh",      .offset = 128, .bytes = 2, },
+	{ .name = "nTAlrtTh",      .offset = 130, .bytes = 2, },
+	{ .name = "nSAlrtTh",      .offset = 132, .bytes = 2, },
+	{ .name = "nIAlrtTh",      .offset = 134, .bytes = 2, },
+	{ .name = "nUser1C4",      .offset = 136, .bytes = 2, },
+	{ .name = "nUser1C5",      .offset = 138, .bytes = 2, },
+	{ .name = "nFullSOCThr",   .offset = 140, .bytes = 2, },
+	{ .name = "nTTFCfg",       .offset = 142, .bytes = 2, },
+	{ .name = "nCGain",        .offset = 144, .bytes = 2, },
+	{ .name = "nTCurve",       .offset = 146, .bytes = 2, },
+	{ .name = "nTGain",        .offset = 148, .bytes = 2, },
+	{ .name = "nTOff",         .offset = 150, .bytes = 2, },
+	{ .name = "nManfctrName0", .offset = 152, .bytes = 2, },
+	{ .name = "nManfctrName1", .offset = 154, .bytes = 2, },
+	{ .name = "nManfctrName2", .offset = 156, .bytes = 2, },
+	{ .name = "nRSense",       .offset = 158, .bytes = 2, },
+
+	{ .name = "nUser1D0",       .offset = 160, .bytes = 2, },
+	{ .name = "nUser1D1",       .offset = 162, .bytes = 2, },
+	{ .name = "nAgeFcCfg",      .offset = 164, .bytes = 2, },
+	{ .name = "nDesignVoltage", .offset = 166, .bytes = 2, },
+	{ .name = "nUser1D4",       .offset = 168, .bytes = 2, },
+	{ .name = "nRFastVShdn",    .offset = 170, .bytes = 2, },
+	{ .name = "nManfctrDate",   .offset = 172, .bytes = 2, },
+	{ .name = "nFirstUsed",     .offset = 174, .bytes = 2, },
+	{ .name = "nSerialNumber0", .offset = 176, .bytes = 2, },
+	{ .name = "nSerialNumber1", .offset = 178, .bytes = 2, },
+	{ .name = "nSerialNumber2", .offset = 180, .bytes = 2, },
+	{ .name = "nDeviceName0",   .offset = 182, .bytes = 2, },
+	{ .name = "nDeviceName1",   .offset = 184, .bytes = 2, },
+	{ .name = "nDeviceName2",   .offset = 186, .bytes = 2, },
+	{ .name = "nDeviceName3",   .offset = 188, .bytes = 2, },
+	{ .name = "nDeviceName4",   .offset = 190, .bytes = 2, },
+};
+
 static const enum power_supply_property max1720x_battery_props[] = {
 	POWER_SUPPLY_PROP_PRESENT,
 	POWER_SUPPLY_PROP_CAPACITY,
@@ -249,30 +382,81 @@  static int max1720x_battery_get_property(struct power_supply *psy,
 	return ret;
 }
 
-static int max1720x_probe_sense_resistor(struct i2c_client *client,
-					 struct max1720x_device_info *info)
+static
+int max1720x_nvmem_reg_read(void *priv, unsigned int off, void *val, size_t len)
+{
+	struct max1720x_device_info *info = priv;
+	unsigned int reg = MAX1720X_NXTABLE0 + (off / 2);
+
+	return regmap_bulk_read(info->regmap_nv, reg, val, len / 2);
+}
+
+static void max1720x_unregister_ancillary(void *data)
+{
+	struct max1720x_device_info *info = data;
+
+	i2c_unregister_device(info->ancillary);
+}
+
+static int max1720x_probe_nvmem(struct i2c_client *client,
+				struct max1720x_device_info *info)
 {
 	struct device *dev = &client->dev;
-	struct i2c_client *ancillary;
+	struct nvmem_config nvmem_config = {
+		.dev = dev,
+		.name = "max1720x_nvmem",
+		.cells = max1720x_nvmem_cells,
+		.ncells = ARRAY_SIZE(max1720x_nvmem_cells),
+		.read_only = true,
+		.root_only = true,
+		.reg_read = max1720x_nvmem_reg_read,
+		.size = ARRAY_SIZE(max1720x_nvmem_cells) * 2,
+		.word_size = 2,
+		.stride = 2,
+		.priv = info,
+	};
+	struct nvmem_device *nvmem;
+	unsigned int val;
 	int ret;
 
-	ancillary = i2c_new_ancillary_device(client, "nvmem", 0xb);
-	if (IS_ERR(ancillary)) {
+	info->ancillary = i2c_new_ancillary_device(client, "nvmem", 0xb);
+	if (IS_ERR(info->ancillary)) {
 		dev_err(dev, "Failed to initialize ancillary i2c device\n");
-		return PTR_ERR(ancillary);
+		return PTR_ERR(info->ancillary);
 	}
 
-	ret = i2c_smbus_read_word_data(ancillary, MAX1720X_NRSENSE);
-	i2c_unregister_device(ancillary);
-	if (ret < 0)
+	ret = devm_add_action_or_reset(dev, max1720x_unregister_ancillary, info);
+	if (ret) {
+		i2c_unregister_device(info->ancillary);
+		dev_err(dev, "Failed to add unregister callback\n");
 		return ret;
+	}
+
+	info->regmap_nv = devm_regmap_init_i2c(info->ancillary,
+					       &max1720x_nvmem_regmap_cfg);
+	if (IS_ERR(info->regmap_nv)) {
+		dev_err(dev, "regmap initialization of nvmem failed\n");
+		return PTR_ERR(info->regmap_nv);
+	}
+
+	ret = regmap_read(info->regmap_nv, MAX1720X_NRSENSE, &val);
+	if (ret < 0) {
+		dev_err(dev, "Failed to read sense resistor value\n");
+		return ret;
+	}
 
-	info->rsense = ret;
+	info->rsense = val;
 	if (!info->rsense) {
 		dev_warn(dev, "RSense not calibrated, set 10 mOhms!\n");
 		info->rsense = 1000; /* in regs in 10^-5 */
 	}
 
+	nvmem = devm_nvmem_register(dev, &nvmem_config);
+	if (IS_ERR(nvmem)) {
+		dev_err(dev, "Could not register nvmem!");
+		return PTR_ERR(nvmem);
+	}
+
 	return 0;
 }
 
@@ -299,15 +483,15 @@  static int max1720x_probe(struct i2c_client *client)
 
 	psy_cfg.drv_data = info;
 	psy_cfg.fwnode = dev_fwnode(dev);
+	i2c_set_clientdata(client, info);
 	info->regmap = devm_regmap_init_i2c(client, &max1720x_regmap_cfg);
 	if (IS_ERR(info->regmap))
 		return dev_err_probe(dev, PTR_ERR(info->regmap),
 				     "regmap initialization failed\n");
 
-	ret = max1720x_probe_sense_resistor(client, info);
+	ret = max1720x_probe_nvmem(client, info);
 	if (ret)
-		return dev_err_probe(dev, ret,
-				     "Failed to read sense resistor value\n");
+		return dev_err_probe(dev, ret, "Failed to probe nvmem\n");
 
 	bat = devm_power_supply_register(dev, &max1720x_bat_desc, &psy_cfg);
 	if (IS_ERR(bat))