karo: tx6: setup PMIC to use BURST mode for better efficiency

diff --git a/board/karo/tx6/tx6qdl.c b/board/karo/tx6/tx6qdl.c
index 59e0e023b4ce1d5318fa2a4a6dd739f5534cf09c..c41f0d46d3effd0e956b6380dbfd8dd6ea364ef4 100644 (file)
--- a/board/karo/tx6/tx6qdl.c
+++ b/board/karo/tx6/tx6qdl.c
@@ -225,23 +225,54 @@ static void tx6qdl_print_cpuinfo(void)
        check_cpu_temperature(1);
 }
 
+#define LTC3676_BUCK1          0x01
+#define LTC3676_BUCK2          0x02
+#define LTC3676_BUCK3          0x03
+#define LTC3676_BUCK4          0x04
 #define LTC3676_DVB2A          0x0C
 #define LTC3676_DVB2B          0x0D
 #define LTC3676_DVB4A          0x10
 #define LTC3676_DVB4B          0x11
+#define LTC3676_CLIRQ          0x1f
 
 #define VDD_SOC_mV             (1375 + 50)
 #define VDD_CORE_mV            (1375 + 50)
 
+#define LTC3676_BUCK_DVDT_FAST (1 << 0)
+#define LTC3676_BUCK_KEEP_ALIVE        (1 << 1)
+#define LTC3676_BUCK_CLK_RATE_LOW      (1 << 2)
+#define LTC3676_BUCK_PHASE_SEL (1 << 3)
+#define LTC3676_BUCK_ENABLE_300        (1 << 4)
+#define LTC3676_BUCK_PULSE_SKIP        (0 << 5)
+#define LTC3676_BUCK_BURST_MODE        (1 << 5)
+#define LTC3676_BUCK_CONTINUOUS        (2 << 5)
+#define LTC3676_BUCK_ENABLE    (1 << 7)
+
+#define LTC3676_PGOOD_MASK     (1 << 5)
+
 #define mV_to_regval(mV)       (((mV) * 360 / 330 - 825 + 1) / 25)
 #define regval_to_mV(v)                (((v) * 25 + 825) * 330 / 360)
 
+static struct pmic_regs {
+       u8 addr;
+       u8 val;
+} ltc3676_regs[] = {
+       { LTC3676_DVB2B, mV_to_regval(900) | LTC3676_PGOOD_MASK, },
+       { LTC3676_DVB4B, mV_to_regval(900) | LTC3676_PGOOD_MASK, },
+       { LTC3676_DVB2A, mV_to_regval(VDD_SOC_mV), },
+       { LTC3676_DVB4A, mV_to_regval(VDD_CORE_mV), },
+       { LTC3676_BUCK1, LTC3676_BUCK_BURST_MODE | LTC3676_BUCK_CLK_RATE_LOW, },
+       { LTC3676_BUCK2, LTC3676_BUCK_BURST_MODE | LTC3676_BUCK_CLK_RATE_LOW, },
+       { LTC3676_BUCK3, LTC3676_BUCK_BURST_MODE | LTC3676_BUCK_CLK_RATE_LOW, },
+       { LTC3676_BUCK4, LTC3676_BUCK_BURST_MODE | LTC3676_BUCK_CLK_RATE_LOW, },
+       { LTC3676_CLIRQ, 0, }, /* clear interrupt status */
+};
+
 static int setup_pmic_voltages(void)
 {
        int ret;
        unsigned char value;
-
-       i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
+       int i;
 
        ret = i2c_probe(CONFIG_SYS_I2C_SLAVE);
        if (ret != 0) {
@@ -255,41 +286,17 @@ static int setup_pmic_voltages(void)
                return ret;
        }
 
-       /* VDDCORE/VDDSOC default 1.375V is not enough, considering
-          pfuze tolerance and IR drop and ripple, need increase
-          to 1.425V for SabreSD */
-
-       value = 0x39; /* VB default value & PGOOD not forced when slewing */
-       ret = i2c_write(CONFIG_SYS_I2C_SLAVE, LTC3676_DVB2B, 1, &value, 1);
-       if (ret) {
-               printf("%s: failed to write PMIC DVB2B register: %d\n",
-                       __func__, ret);
-               return ret;
-       }
-       ret = i2c_write(CONFIG_SYS_I2C_SLAVE, LTC3676_DVB4B, 1, &value, 1);
-       if (ret) {
-               printf("%s: failed to write PMIC DVB4B register: %d\n",
-                       __func__, ret);
-               return ret;
-       }
-
-       value = mV_to_regval(VDD_SOC_mV);
-       ret = i2c_write(CONFIG_SYS_I2C_SLAVE, LTC3676_DVB2A, 1, &value, 1);
-       if (ret) {
-               printf("%s: failed to write PMIC DVB2A register: %d\n",
-                       __func__, ret);
-               return ret;
-       }
-       printf("VDDSOC  set to %dmV\n", regval_to_mV(value));
-
-       value = mV_to_regval(VDD_CORE_mV);
-       ret = i2c_write(CONFIG_SYS_I2C_SLAVE, LTC3676_DVB4A, 1, &value, 1);
-       if (ret) {
-               printf("%s: failed to write PMIC DVB4A register: %d\n",
-                       __func__, ret);
-               return ret;
+       for (i = 0; i < ARRAY_SIZE(ltc3676_regs); i++) {
+               ret = i2c_write(CONFIG_SYS_I2C_SLAVE, ltc3676_regs[i].addr, 1,
+                               &ltc3676_regs[i].val, 1);
+               if (ret) {
+                       printf("%s: failed to write PMIC register %02x: %d\n",
+                               __func__, ltc3676_regs[i].addr, ret);
+                       return ret;
+               }
        }
-       printf("VDDCORE set to %dmV\n", regval_to_mV(value));
+       printf("VDDCORE set to %dmV\n", VDD_CORE_mV);
+       printf("VDDSOC  set to %dmV\n", VDD_SOC_mV);
        return 0;
 }