[PATCH 2/5] max17042: Add POR init procedure from Maxim appnote

From: dirk . brandewie
Date: Tue Jan 24 2012 - 12:28:04 EST

From: Dirk Brandewie <dirk.brandewie@xxxxxxxxx>

Add power on reset (POR) init procedure defined by the maxim
appnote. Using this procedure ensures that the part is
configured/initialized correctly at POR and improves early accuracy of
the fuel gauge and informs the fuel gauge with the battery
characterization parameters. The battery characterization parameters
come from the maxim characterization procedure.

Signed-off-by: Dirk Brandewie <dirk.brandewie@xxxxxxxxx>
---
drivers/power/max17042_battery.c | 389 +++++++++++++++++++++++++++++++-
include/linux/power/max17042_battery.h | 56 +++++
2 files changed, 434 insertions(+), 11 deletions(-)

diff --git a/drivers/power/max17042_battery.c b/drivers/power/max17042_battery.c
index 9f0183c..fce502c 100644
--- a/drivers/power/max17042_battery.c
+++ b/drivers/power/max17042_battery.c
@@ -26,14 +26,40 @@
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/i2c.h>
+#include <linux/delay.h>
#include <linux/mod_devicetable.h>
#include <linux/power_supply.h>
#include <linux/power/max17042_battery.h>

+/* Status register bits */
+#define STATUS_POR_BIT (1 << 1)
+#define STATUS_BST_BIT (1 << 3)
+#define STATUS_VMN_BIT (1 << 8)
+#define STATUS_TMN_BIT (1 << 9)
+#define STATUS_SMN_BIT (1 << 10)
+#define STATUS_BI_BIT (1 << 11)
+#define STATUS_VMX_BIT (1 << 12)
+#define STATUS_TMX_BIT (1 << 13)
+#define STATUS_SMX_BIT (1 << 14)
+#define STATUS_BR_BIT (1 << 15)
+
+#define VFSOC0_LOCK 0x0000
+#define VFSOC0_UNLOCK 0x0080
+#define MODEL_UNLOCK1 0X0059
+#define MODEL_UNLOCK2 0X00C4
+#define MODEL_LOCK1 0X0000
+#define MODEL_LOCK2 0X0000
+
+#define dQ_ACC_DIV 0x4
+#define dP_ACC_100 0x1900
+#define dP_ACC_200 0x3200
+
struct max17042_chip {
struct i2c_client *client;
struct power_supply battery;
struct max17042_platform_data *pdata;
+ struct work_struct work;
+ int init_complete;
};

static int max17042_write_reg(struct i2c_client *client, u8 reg, u16 value)
@@ -86,6 +112,9 @@ static int max17042_get_property(struct power_supply *psy,
struct max17042_chip *chip = container_of(psy,
struct max17042_chip, battery);

+ if (!chip->init_complete)
+ return -EAGAIN;
+
switch (psp) {
case POWER_SUPPLY_PROP_PRESENT:
val->intval = max17042_read_reg(chip->client,
@@ -180,12 +209,343 @@ static int max17042_get_property(struct power_supply *psy,
return 0;
}

+static int max17042_write_verify_reg(struct i2c_client *client,
+ u8 reg, u16 value)
+{
+ int retries = 8;
+ int ret;
+ u16 read_value;
+
+ do {
+ ret = i2c_smbus_write_word_data(client, reg, value);
+ read_value = max17042_read_reg(client, reg);
+ if (read_value != value) {
+ ret = -EIO;
+ retries--;
+ }
+ } while (retries && read_value != value);
+
+ if (ret < 0)
+ dev_err(&client->dev, "%s: err %d\n", __func__, ret);
+
+ return ret;
+}
+
+static inline void max17042_override_por(
+ struct i2c_client *client, u8 reg, u16 value)
+{
+ if (value)
+ max17042_write_reg(client, reg, value);
+}
+
+static inline void max10742_unlock_model(struct max17042_chip *chip)
+{
+ struct i2c_client *client = chip->client;
+ max17042_write_reg(client, MAX17042_MLOCKReg1, MODEL_UNLOCK1);
+ max17042_write_reg(client, MAX17042_MLOCKReg2, MODEL_UNLOCK2);
+}
+
+static inline void max10742_lock_model(struct max17042_chip *chip)
+{
+ struct i2c_client *client = chip->client;
+ max17042_write_reg(client, MAX17042_MLOCKReg1, MODEL_LOCK1);
+ max17042_write_reg(client, MAX17042_MLOCKReg2, MODEL_LOCK2);
+}
+
+static inline void max17042_write_model_data(struct max17042_chip *chip,
+ u8 addr, int size)
+{
+ struct i2c_client *client = chip->client;
+ int i;
+ for (i = 0; i < size; i++)
+ max17042_write_reg(client, addr + i,
+ chip->pdata->config_data->cell_char_tbl[i]);
+}
+
+static inline void max17042_read_model_data(struct max17042_chip *chip,
+ u8 addr, u16 *data, int size)
+{
+ struct i2c_client *client = chip->client;
+ int i;
+
+ for (i = 0; i < size; i++)
+ data[i] = max17042_read_reg(client, addr + i);
+}
+
+static inline int max17042_model_data_compare(struct max17042_chip *chip,
+ u16 *data1, u16 *data2, int size)
+{
+ int i;
+
+ if (memcmp(data1, data2, size)) {
+ dev_err(&chip->client->dev, "%s compare failed\n", __func__);
+ for (i = 0; i < size; i++)
+ dev_info(&chip->client->dev, "0x%x, 0x%x",
+ data1[i], data2[i]);
+ dev_info(&chip->client->dev, "\n");
+ return -EINVAL;
+ }
+ return 0;
+}
+
+static int max17042_init_model(struct max17042_chip *chip)
+{
+ int ret;
+ int table_size =
+ sizeof(chip->pdata->config_data->cell_char_tbl)/sizeof(u16);
+ u16 *temp_data;
+
+ temp_data = kzalloc(table_size, GFP_KERNEL);
+ if (!temp_data)
+ return -ENOMEM;
+
+ max10742_unlock_model(chip);
+ max17042_write_model_data(chip, MAX17042_MODELChrTbl,
+ table_size);
+ max17042_read_model_data(chip, MAX17042_MODELChrTbl, temp_data,
+ table_size);
+
+ ret = max17042_model_data_compare(
+ chip,
+ chip->pdata->config_data->cell_char_tbl,
+ temp_data,
+ table_size);
+
+ max10742_lock_model(chip);
+ kfree(temp_data);
+
+ return ret;
+}
+
+static int max17042_verify_model_lock(struct max17042_chip *chip)
+{
+ int i;
+ int table_size =
+ sizeof(chip->pdata->config_data->cell_char_tbl);
+ u16 *temp_data;
+ int ret = 0;
+
+ temp_data = kzalloc(table_size, GFP_KERNEL);
+ if (!temp_data)
+ return -ENOMEM;
+
+ max17042_read_model_data(chip, MAX17042_MODELChrTbl, temp_data,
+ table_size);
+ for (i = 0; i < table_size; i++)
+ if (temp_data[i])
+ ret = -EINVAL;
+
+ kfree(temp_data);
+ return ret;
+}
+
+static void max17042_write_config_regs(struct max17042_chip *chip)
+{
+ struct max17042_config_data *config = chip->pdata->config_data;
+
+ max17042_write_reg(chip->client, MAX17042_CONFIG, config->config);
+ max17042_write_reg(chip->client, MAX17042_LearnCFG, config->learn_cfg);
+ max17042_write_reg(chip->client, MAX17042_FilterCFG,
+ config->filter_cfg);
+ max17042_write_reg(chip->client, MAX17042_RelaxCFG, config->relax_cfg);
+}
+
+static void max17042_write_custom_regs(struct max17042_chip *chip)
+{
+ struct max17042_config_data *config = chip->pdata->config_data;
+
+ max17042_write_verify_reg(chip->client, MAX17042_RCOMP0,
+ config->rcomp0);
+ max17042_write_verify_reg(chip->client, MAX17042_TempCo,
+ config->tcompc0);
+ max17042_write_reg(chip->client, MAX17042_EmptyTempCo,
+ config->empty_tempco);
+ max17042_write_verify_reg(chip->client, MAX17042_K_empty0,
+ config->kempty0);
+ max17042_write_verify_reg(chip->client, MAX17042_ICHGTerm,
+ config->ichgt_term);
+}
+
+static void max17042_update_capacity_regs(struct max17042_chip *chip)
+{
+ struct max17042_config_data *config = chip->pdata->config_data;
+
+ max17042_write_verify_reg(chip->client, MAX17042_FullCAP,
+ config->fullcap);
+ max17042_write_reg(chip->client, MAX17042_DesignCap,
+ config->design_cap);
+ max17042_write_verify_reg(chip->client, MAX17042_FullCAPNom,
+ config->fullcapnom);
+}
+
+static void max17042_reset_vfsoc0_reg(struct max17042_chip *chip)
+{
+ u16 vfSoc;
+
+ vfSoc = max17042_read_reg(chip->client, MAX17042_VFSOC);
+ max17042_write_reg(chip->client, MAX17042_VFSOC0Enable, VFSOC0_UNLOCK);
+ max17042_write_verify_reg(chip->client, MAX17042_VFSOC0, vfSoc);
+ max17042_write_reg(chip->client, MAX17042_VFSOC0Enable, VFSOC0_LOCK);
+}
+
+static void max17042_load_new_capacity_params(struct max17042_chip *chip)
+{
+ u16 full_cap0, rep_cap, dq_acc, vfSoc;
+ u32 rem_cap;
+
+ struct max17042_config_data *config = chip->pdata->config_data;
+
+ full_cap0 = max17042_read_reg(chip->client, MAX17042_FullCAP0);
+ vfSoc = max17042_read_reg(chip->client, MAX17042_VFSOC);
+
+ /* fg_vfSoc needs to shifted by 8 bits to get the
+ * perc in 1% accuracy, to get the right rem_cap multiply
+ * full_cap0, fg_vfSoc and devide by 100
+ */
+ rem_cap = ((vfSoc >> 8) * full_cap0) / 100;
+ max17042_write_verify_reg(chip->client, MAX17042_RemCap, (u16)rem_cap);
+
+ rep_cap = (u16)rem_cap;
+ max17042_write_verify_reg(chip->client, MAX17042_RepCap, rep_cap);
+
+ /* Write dQ_acc to 200% of Capacity and dP_acc to 200% */
+ dq_acc = config->fullcap / dQ_ACC_DIV;
+ max17042_write_verify_reg(chip->client, MAX17042_dQacc, dq_acc);
+ max17042_write_verify_reg(chip->client, MAX17042_dPacc, dP_ACC_200);
+
+ max17042_write_verify_reg(chip->client, MAX17042_FullCAP,
+ config->fullcap);
+ max17042_write_reg(chip->client, MAX17042_DesignCap,
+ config->design_cap);
+ max17042_write_verify_reg(chip->client, MAX17042_FullCAPNom,
+ config->fullcapnom);
+}
+
+/*
+ * Block write all the override values coming from platform data.
+ * This function MUST be called before the POR initialization proceedure
+ * specified by maxim.
+ */
+static inline void max17042_override_por_values(struct max17042_chip *chip)
+{
+ struct i2c_client *client = chip->client;
+ struct max17042_config_data *config = chip->pdata->config_data;
+
+ max17042_override_por(client, MAX17042_TGAIN, config->tgain);
+ max17042_override_por(client, MAx17042_TOFF, config->toff);
+ max17042_override_por(client, MAX17042_CGAIN, config->cgain);
+ max17042_override_por(client, MAX17042_COFF, config->coff);
+
+ max17042_override_por(client, MAX17042_VALRT_Th, config->valrt_thresh);
+ max17042_override_por(client, MAX17042_TALRT_Th, config->talrt_thresh);
+ max17042_override_por(client, MAX17042_SALRT_Th,
+ config->soc_alrt_thresh);
+ max17042_override_por(client, MAX17042_CONFIG, config->config);
+ max17042_override_por(client, MAX17042_SHDNTIMER, config->shdntimer);
+
+ max17042_override_por(client, MAX17042_DesignCap, config->design_cap);
+ max17042_override_por(client, MAX17042_ICHGTerm, config->ichgt_term);
+
+ max17042_override_por(client, MAX17042_AtRate, config->at_rate);
+ max17042_override_por(client, MAX17042_LearnCFG, config->learn_cfg);
+ max17042_override_por(client, MAX17042_FilterCFG, config->filter_cfg);
+ max17042_override_por(client, MAX17042_RelaxCFG, config->relax_cfg);
+ max17042_override_por(client, MAX17042_MiscCFG, config->misc_cfg);
+ max17042_override_por(client, MAX17042_MaskSOC, config->masksoc);
+
+ max17042_override_por(client, MAX17042_FullCAP, config->fullcap);
+ max17042_override_por(client, MAX17042_FullCAPNom, config->fullcapnom);
+ max17042_override_por(client, MAX17042_SOC_empty, config->socempty);
+ max17042_override_por(client, MAX17042_LAvg_empty, config->lavg_empty);
+ max17042_override_por(client, MAX17042_dQacc, config->dqacc);
+ max17042_override_por(client, MAX17042_dPacc, config->dpacc);
+
+ max17042_override_por(client, MAX17042_V_empty, config->vempty);
+ max17042_override_por(client, MAX17042_TempNom, config->temp_nom);
+ max17042_override_por(client, MAX17042_TempLim, config->temp_lim);
+ max17042_override_por(client, MAX17042_FCTC, config->fctc);
+ max17042_override_por(client, MAX17042_RCOMP0, config->rcomp0);
+ max17042_override_por(client, MAX17042_TempCo, config->tcompc0);
+ max17042_override_por(client, MAX17042_EmptyTempCo,
+ config->empty_tempco);
+ max17042_override_por(client, MAX17042_K_empty0, config->kempty0);
+}
+
+static int max17042_init_chip(struct max17042_chip *chip)
+{
+ int ret;
+ int val;
+
+ max17042_override_por_values(chip);
+ /* After Power up, the MAX17042 requires 500mS in order
+ * to perform signal debouncing and initial SOC reporting
+ */
+ msleep(500);
+
+ /* Initialize configaration */
+ max17042_write_config_regs(chip);
+
+ /* write cell characterization data */
+ ret = max17042_init_model(chip);
+ if (ret) {
+ dev_err(&chip->client->dev, "%s init failed\n",
+ __func__);
+ return -EIO;
+ }
+ max17042_verify_model_lock(chip);
+ if (ret) {
+ dev_err(&chip->client->dev, "%s lock verify failed\n",
+ __func__);
+ return -EIO;
+ }
+ /* write custom parameters */
+ max17042_write_custom_regs(chip);
+
+ /* update capacity params */
+ max17042_update_capacity_regs(chip);
+
+ /* delay must be atleast 350mS to allow VFSOC
+ * to be calculated from the new configuration
+ */
+ msleep(350);
+
+ /* reset vfsoc0 reg */
+ max17042_reset_vfsoc0_reg(chip);
+
+ /* load new capacity params */
+ max17042_load_new_capacity_params(chip);
+
+ /* Init complete, Clear the POR bit */
+ val = max17042_read_reg(chip->client, MAX17042_STATUS);
+ max17042_write_reg(chip->client, MAX17042_STATUS,
+ val & (~STATUS_POR_BIT));
+ return 0;
+}
+
+
+static void max17042_init_worker(struct work_struct *work)
+{
+ struct max17042_chip *chip = container_of(work,
+ struct max17042_chip, work);
+ int ret;
+
+ /* Initialize registers according to values from the platform data */
+ if (chip->pdata->enable_por_init && chip->pdata->config_data) {
+ ret = max17042_init_chip(chip);
+ if (ret)
+ return;
+ }
+
+ chip->init_complete = 1;
+}
+
static int __devinit max17042_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
struct max17042_chip *chip;
int ret;
+ int reg;

if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
return -EIO;
@@ -210,17 +570,9 @@ static int __devinit max17042_probe(struct i2c_client *client,
if (!chip->pdata->enable_current_sense)
chip->battery.num_properties -= 2;

- ret = power_supply_register(&client->dev, &chip->battery);
- if (ret) {
- dev_err(&client->dev, "failed: power supply register\n");
- kfree(chip);
- return ret;
- }
-
- /* Initialize registers according to values from the platform data */
if (chip->pdata->init_data)
max17042_set_reg(client, chip->pdata->init_data,
- chip->pdata->num_init_data);
+ chip->pdata->num_init_data);

if (!chip->pdata->enable_current_sense) {
max17042_write_reg(client, MAX17042_CGAIN, 0x0000);
@@ -228,10 +580,25 @@ static int __devinit max17042_probe(struct i2c_client *client,
max17042_write_reg(client, MAX17042_LearnCFG, 0x0007);
} else {
if (chip->pdata->r_sns == 0)
- chip->pdata->r_sns = MAX17042_DEFAULT_SNS_RESISTOR;
+ chip->pdata->r_sns =
+ MAX17042_DEFAULT_SNS_RESISTOR;
}

- return 0;
+ reg = max17042_read_reg(chip->client, MAX17042_STATUS);
+
+ if (reg & STATUS_POR_BIT) {
+ INIT_WORK(&chip->work, max17042_init_worker);
+ schedule_work(&chip->work);
+ } else {
+ chip->init_complete = 1;
+ }
+
+ ret = power_supply_register(&client->dev, &chip->battery);
+ if (ret) {
+ dev_err(&client->dev, "failed: power supply register\n");
+ kfree(chip);
+ }
+ return ret;
}

static int __devexit max17042_remove(struct i2c_client *client)
diff --git a/include/linux/power/max17042_battery.h b/include/linux/power/max17042_battery.h
index 67eeada..e01b167 100644
--- a/include/linux/power/max17042_battery.h
+++ b/include/linux/power/max17042_battery.h
@@ -27,6 +27,8 @@
#define MAX17042_BATTERY_FULL (100)
#define MAX17042_DEFAULT_SNS_RESISTOR (10000)

+#define MAX17042_CHARACTERIZATION_DATA_SIZE 48
+
enum max17042_register {
MAX17042_STATUS = 0x00,
MAX17042_VALRT_Th = 0x01,
@@ -124,10 +126,64 @@ struct max17042_reg_data {
u16 data;
};

+struct max17042_config_data {
+ /* External current sense resistor value in milli-ohms */
+ u32 cur_sense_val;
+
+ /* A/D measurement */
+ u16 tgain; /* 0x2C */
+ u16 toff; /* 0x2D */
+ u16 cgain; /* 0x2E */
+ u16 coff; /* 0x2F */
+
+ /* Alert / Status */
+ u16 valrt_thresh; /* 0x01 */
+ u16 talrt_thresh; /* 0x02 */
+ u16 soc_alrt_thresh; /* 0x03 */
+ u16 config; /* 0x01D */
+ u16 shdntimer; /* 0x03F */
+
+ /* App data */
+ u16 design_cap; /* 0x18 */
+ u16 ichgt_term; /* 0x1E */
+
+ /* MG3 config */
+ u16 at_rate; /* 0x04 */
+ u16 learn_cfg; /* 0x28 */
+ u16 filter_cfg; /* 0x29 */
+ u16 relax_cfg; /* 0x2A */
+ u16 misc_cfg; /* 0x2B */
+ u16 masksoc; /* 0x32 */
+
+ /* MG3 save and restore */
+ u16 fullcap; /* 0x10 */
+ u16 fullcapnom; /* 0x23 */
+ u16 socempty; /* 0x33 */
+ u16 lavg_empty; /* 0x36 */
+ u16 dqacc; /* 0x45 */
+ u16 dpacc; /* 0x46 */
+
+ /* Cell technology from power_supply.h */
+ u16 cell_technology;
+
+ /* Cell Data */
+ u16 vempty; /* 0x12 */
+ u16 temp_nom; /* 0x24 */
+ u16 temp_lim; /* 0x25 */
+ u16 fctc; /* 0x37 */
+ u16 rcomp0; /* 0x38 */
+ u16 tcompc0; /* 0x39 */
+ u16 empty_tempco; /* 0x3A */
+ u16 kempty0; /* 0x3B */
+ u16 cell_char_tbl[MAX17042_CHARACTERIZATION_DATA_SIZE];
+} __packed;
+
struct max17042_platform_data {
struct max17042_reg_data *init_data;
+ struct max17042_config_data *config_data;
int num_init_data; /* Number of enties in init_data array */
bool enable_current_sense;
+ bool enable_por_init; /* Use POR init from Maxim appnote */

/*
* R_sns in micro-ohms.
--
1.7.7.5

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