board: common: vid: Add support for LTC3882 voltage regulator chip

[people/ms/u-boot.git] / board / freescale / common / vid.c

diff --git a/board/freescale/common/vid.c b/board/freescale/common/vid.c
index f68068eaf896b601bc71e942c141fab95ec16a81..a9451c5c6ee5de5383c530a7f78038324f4ff86c 100644 (file)
--- a/board/freescale/common/vid.c
+++ b/board/freescale/common/vid.c
@@ -174,6 +174,36 @@ static int read_voltage_from_IR(int i2caddress)
 }
 #endif
 
+#ifdef CONFIG_VOL_MONITOR_LTC3882_READ
+/* read the current value of the LTC Regulator Voltage */
+static int read_voltage_from_LTC(int i2caddress)
+{
+       int  ret, vcode = 0;
+       u8 chan = PWM_CHANNEL0;
+
+       /* select the PAGE 0 using PMBus commands PAGE for VDD*/
+       ret = i2c_write(I2C_VOL_MONITOR_ADDR,
+                       PMBUS_CMD_PAGE, 1, &chan, 1);
+       if (ret) {
+               printf("VID: failed to select VDD Page 0\n");
+               return ret;
+       }
+
+       /*read the output voltage using PMBus command READ_VOUT*/
+       ret = i2c_read(I2C_VOL_MONITOR_ADDR,
+                      PMBUS_CMD_READ_VOUT, 1, (void *)&vcode, 2);
+       if (ret) {
+               printf("VID: failed to read the volatge\n");
+               return ret;
+       }
+
+       /* Scale down to the real mV as LTC resolution is 1/4096V,rounding up */
+       vcode = DIV_ROUND_UP(vcode * 1000, 4096);
+
+       return vcode;
+}
+#endif
+
 static int read_voltage(int i2caddress)
 {
        int voltage_read;
@@ -181,6 +211,8 @@ static int read_voltage(int i2caddress)
        voltage_read = read_voltage_from_INA220(i2caddress);
 #elif defined CONFIG_VOL_MONITOR_IR36021_READ
        voltage_read = read_voltage_from_IR(i2caddress);
+#elif defined CONFIG_VOL_MONITOR_LTC3882_READ
+       voltage_read = read_voltage_from_LTC(i2caddress);
 #else
        return -1;
 #endif
@@ -281,6 +313,43 @@ static int set_voltage_to_IR(int i2caddress, int vdd)
        debug("VID: Current voltage is %d mV\n", vdd_last);
        return vdd_last;
 }
+
+#endif
+
+#ifdef CONFIG_VOL_MONITOR_LTC3882_SET
+/* this function sets the VDD and returns the value set */
+static int set_voltage_to_LTC(int i2caddress, int vdd)
+{
+       int ret, vdd_last, vdd_target = vdd;
+
+       /* Scale up to the LTC resolution is 1/4096V */
+       vdd = (vdd * 4096) / 1000;
+
+       /* 5-byte buffer which needs to be sent following the
+        * PMBus command PAGE_PLUS_WRITE.
+        */
+       u8 buff[5] = {0x04, PWM_CHANNEL0, PMBUS_CMD_VOUT_COMMAND,
+                       vdd & 0xFF, (vdd & 0xFF00) >> 8};
+
+       /* Write the desired voltage code to the regulator */
+       ret = i2c_write(I2C_VOL_MONITOR_ADDR,
+                       PMBUS_CMD_PAGE_PLUS_WRITE, 1, (void *)&buff, 5);
+       if (ret) {
+               printf("VID: I2C failed to write to the volatge regulator\n");
+               return -1;
+       }
+
+       /* Wait for the volatge to get to the desired value */
+       do {
+               vdd_last = read_voltage_from_LTC(i2caddress);
+               if (vdd_last < 0) {
+                       printf("VID: Couldn't read sensor abort VID adjust\n");
+                       return -1;
+               }
+       } while (vdd_last != vdd_target);
+
+       return vdd_last;
+}
 #endif
 
 static int set_voltage(int i2caddress, int vdd)
@@ -289,6 +358,8 @@ static int set_voltage(int i2caddress, int vdd)
 
 #ifdef CONFIG_VOL_MONITOR_IR36021_SET
        vdd_last = set_voltage_to_IR(i2caddress, vdd);
+#elif defined CONFIG_VOL_MONITOR_LTC3882_SET
+       vdd_last = set_voltage_to_LTC(i2caddress, vdd);
 #else
        #error Specific voltage monitor must be defined
 #endif
@@ -472,6 +543,11 @@ int adjust_vdd(ulong vdd_override)
        }
        vdd_current = vdd_last;
        debug("VID: Core voltage is currently at %d mV\n", vdd_last);
+
+#ifdef CONFIG_VOL_MONITOR_LTC3882_SET
+       /* Set the target voltage */
+       vdd_last = vdd_current = set_voltage(i2caddress, vdd_target);
+#else
        /*
          * Adjust voltage to at or one step above target.
          * As measurements are less precise than setting the values
@@ -489,6 +565,7 @@ int adjust_vdd(ulong vdd_override)
                vdd_last = set_voltage(i2caddress, vdd_current);
        }
 
+#endif
        if (board_adjust_vdd(vdd_target) < 0) {
                ret = -1;
                goto exit;