fuelgauge: max17042: fix i2c read issue which causes infinity loop.

Issues:
- reading i2c data by passing u16 pointer causes errors in read data.
- max17042 status register fields have not only Power On Reset meaning
  so using proper mask is required.

Changes:
- read i2c data to type u32 instead of u16 - avoids buffer overflow
- compare FG status register using mask not just one bit value
- add checking return value to functions fg read/write
- add model lock and model check count
- add debug msg

Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com>
Cc: Lukasz Majewski <l.majewski@samsung.com>
Cc: Minkyu Kang <mk7.kang@samsung.com>

diff --git a/drivers/power/fuel_gauge/fg_max17042.c b/drivers/power/fuel_gauge/fg_max17042.c
index c285747f3429ab00f7c489ea12d16f5eab6c0461..154ca6a6957ab222ca32662c5eb18b15d1d0963d 100644 (file)
--- a/drivers/power/fuel_gauge/fg_max17042.c
+++ b/drivers/power/fuel_gauge/fg_max17042.c
@@ -20,21 +20,30 @@ static int fg_write_regs(struct pmic *p, u8 addr, u16 *data, int num)
        int ret = 0;
        int i;
 
-       for (i = 0; i < num; i++, addr++)
-               ret |= pmic_reg_write(p, addr, *(data + i));
+       for (i = 0; i < num; i++, addr++) {
+               ret = pmic_reg_write(p, addr, *(data + i));
+               if (ret)
+                       return ret;
+       }
 
-       return ret;
+       return 0;
 }
 
 static int fg_read_regs(struct pmic *p, u8 addr, u16 *data, int num)
 {
+       unsigned int dat;
        int ret = 0;
        int i;
 
-       for (i = 0; i < num; i++, addr++)
-               ret |= pmic_reg_read(p, addr, (u32 *) (data + i));
+       for (i = 0; i < num; i++, addr++) {
+               ret = pmic_reg_read(p, addr, &dat);
+               if (ret)
+                       return ret;
 
-       return ret;
+               *(data + i) = (u16)dat;
+       }
+
+       return 0;
 }
 
 static int fg_write_and_verify(struct pmic *p, u8 addr, u16 data)
@@ -57,9 +66,13 @@ static int fg_write_and_verify(struct pmic *p, u8 addr, u16 data)
 static void por_fuelgauge_init(struct pmic *p)
 {
        u16 r_data0[16], r_data1[16], r_data2[16];
-       u32 rewrite_count = 5, i = 0;
-       unsigned int val;
-       int ret = 0;
+       u32 rewrite_count = 5;
+       u32 check_count;
+       u32 lock_count;
+       u32 i = 0;
+       u32 val;
+       s32 ret = 0;
+       char *status_msg;
 
        /* Delay 500 ms */
        mdelay(500);
@@ -67,29 +80,55 @@ static void por_fuelgauge_init(struct pmic *p)
        pmic_reg_write(p, MAX17042_CONFIG, 0x2310);
 
 rewrite_model:
+       check_count = 5;
+       lock_count = 5;
+
+       if (!rewrite_count--) {
+               status_msg = "init failed!";
+               goto error;
+       }
+
        /* Unlock Model Access */
        pmic_reg_write(p, MAX17042_MLOCKReg1, MODEL_UNLOCK1);
        pmic_reg_write(p, MAX17042_MLOCKReg2, MODEL_UNLOCK2);
 
        /* Write/Read/Verify the Custom Model */
-       ret |= fg_write_regs(p, MAX17042_MODEL1, cell_character0,
+       ret = fg_write_regs(p, MAX17042_MODEL1, cell_character0,
                             ARRAY_SIZE(cell_character0));
-       ret |= fg_write_regs(p, MAX17042_MODEL2, cell_character1,
+       if (ret)
+               goto rewrite_model;
+
+       ret = fg_write_regs(p, MAX17042_MODEL2, cell_character1,
                             ARRAY_SIZE(cell_character1));
-       ret |= fg_write_regs(p, MAX17042_MODEL3, cell_character2,
+       if (ret)
+               goto rewrite_model;
+
+       ret = fg_write_regs(p, MAX17042_MODEL3, cell_character2,
                             ARRAY_SIZE(cell_character2));
+       if (ret)
+               goto rewrite_model;
 
-       if (ret) {
-               printf("%s: Cell parameters write failed!\n", __func__);
-               return;
+check_model:
+       if (!check_count--) {
+               if (rewrite_count)
+                       goto rewrite_model;
+               else
+                       status_msg = "check failed!";
+
+               goto error;
        }
 
-       ret |= fg_read_regs(p, MAX17042_MODEL1, r_data0, ARRAY_SIZE(r_data0));
-       ret |= fg_read_regs(p, MAX17042_MODEL2, r_data1, ARRAY_SIZE(r_data1));
-       ret |= fg_read_regs(p, MAX17042_MODEL3, r_data2, ARRAY_SIZE(r_data2));
+       ret = fg_read_regs(p, MAX17042_MODEL1, r_data0, ARRAY_SIZE(r_data0));
+       if (ret)
+               goto check_model;
+
+       ret = fg_read_regs(p, MAX17042_MODEL2, r_data1, ARRAY_SIZE(r_data1));
+       if (ret)
+               goto check_model;
 
+       ret = fg_read_regs(p, MAX17042_MODEL3, r_data2, ARRAY_SIZE(r_data2));
        if (ret)
-               printf("%s: Cell parameters read failed!\n", __func__);
+               goto check_model;
 
        for (i = 0; i < 16; i++) {
                if ((cell_character0[i] != r_data0[i])
@@ -98,29 +137,37 @@ rewrite_model:
                        goto rewrite_model;
                }
 
+lock_model:
+       if (!lock_count--) {
+               if (rewrite_count)
+                       goto rewrite_model;
+               else
+                       status_msg = "lock failed!";
+
+               goto error;
+       }
+
        /* Lock model access */
        pmic_reg_write(p, MAX17042_MLOCKReg1, MODEL_LOCK1);
        pmic_reg_write(p, MAX17042_MLOCKReg2, MODEL_LOCK2);
 
        /* Verify the model access is locked */
-       ret |= fg_read_regs(p, MAX17042_MODEL1, r_data0, ARRAY_SIZE(r_data0));
-       ret |= fg_read_regs(p, MAX17042_MODEL2, r_data1, ARRAY_SIZE(r_data1));
-       ret |= fg_read_regs(p, MAX17042_MODEL3, r_data2, ARRAY_SIZE(r_data2));
+       ret = fg_read_regs(p, MAX17042_MODEL1, r_data0, ARRAY_SIZE(r_data0));
+       if (ret)
+               goto lock_model;
 
-       if (ret) {
-               printf("%s: Cell parameters read failed!\n", __func__);
-               return;
-       }
+       ret = fg_read_regs(p, MAX17042_MODEL2, r_data1, ARRAY_SIZE(r_data1));
+       if (ret)
+               goto lock_model;
+
+       ret = fg_read_regs(p, MAX17042_MODEL3, r_data2, ARRAY_SIZE(r_data2));
+       if (ret)
+               goto lock_model;
 
        for (i = 0; i < ARRAY_SIZE(r_data0); i++) {
                /* Check if model locked */
-               if (r_data0[i] || r_data1[i] || r_data2[i]) {
-                       /* Rewrite model data - prevent from endless loop */
-                       if (rewrite_count--) {
-                               puts("FG - Lock model access failed!\n");
-                               goto rewrite_model;
-                       }
-               }
+               if (r_data0[i] || r_data1[i] || r_data2[i])
+                       goto lock_model;
        }
 
        /* Write Custom Parameters */
@@ -137,6 +184,11 @@ rewrite_model:
 
        /* Delay at least 350 ms */
        mdelay(350);
+
+       status_msg = "OK!";
+error:
+       debug("%s: model init status: %s\n", p->name, status_msg);
+       return;
 }
 
 static int power_update_battery(struct pmic *p, struct pmic *bat)
@@ -178,7 +230,7 @@ static int power_check_battery(struct pmic *p, struct pmic *bat)
        ret |= pmic_reg_read(p, MAX17042_STATUS, &val);
        debug("fg status: 0x%x\n", val);
 
-       if (val == MAX17042_POR)
+       if (val & MAX17042_POR)
                por_fuelgauge_init(p);
 
        ret |= pmic_reg_read(p, MAX17042_VERSION, &val);