board: stm32mp1: Update power supply check via USB TYPE-C

Add 2 new checks:
 - detect when USB TYPE-C cable is not plugged correctly.
   In this case, GND and VBUS pins are connected but not CC1
   and CC2 pins.

 - detect is an USB Type-C charger supplies more than 3 Amps
   which is not compliant with the USB Type-C specification

In these 2 situations, stop the boot process and let red led
blinks forever.

   V cc1      |   V cc2     | power supply | red led | console message
range (Volts) |range (Volts)|   (Amps)     | blinks  |
--------------|-------------|--------------|---------|-----------------------------------
    > 2.15    |   < 0.2     |     > 3      | for ever| USB TYPE-C charger not compliant with specification
[2.15 - 1.23[ |   < 0.2     |     3        |   NO    | NO
[1.23 - 0.66[ |   < 0.2     |     1.5      | 3 times | WARNING 1.5A power supply detected
[0.66 - 0]    |   < 0.2     |     0.5      | 2 times | WARNING 500mA power supply detected
    < 0.2     |   < 0.2     |              | for ever| ERROR USB TYPE-C connection in unattached mode
    > 0.2     |   > 0.2     |              | for ever| ERROR USB TYPE-C connection in unattached mode

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>

diff --git a/board/st/stm32mp1/stm32mp1.c b/board/st/stm32mp1/stm32mp1.c
index af607c5..88bc881 100644 (file)
--- a/board/st/stm32mp1/stm32mp1.c
+++ b/board/st/stm32mp1/stm32mp1.c
@@ -62,9 +62,10 @@
  */
 DECLARE_GLOBAL_DATA_PTR;
 
+#define USB_LOW_THRESHOLD_UV           200000
 #define USB_WARNING_LOW_THRESHOLD_UV   660000
 #define USB_START_LOW_THRESHOLD_UV     1230000
-#define USB_START_HIGH_THRESHOLD_UV    2100000
+#define USB_START_HIGH_THRESHOLD_UV    2150000
 
 int checkboard(void)
 {
@@ -265,9 +266,10 @@ static int board_check_usb_power(void)
        ofnode node;
        unsigned int raw;
        int max_uV = 0;
+       int min_uV = USB_START_HIGH_THRESHOLD_UV;
        int ret, uV, adc_count;
-       u8 i, nb_blink;
-
+       u32 nb_blink;
+       u8 i;
        node = ofnode_path("/config");
        if (!ofnode_valid(node)) {
                debug("%s: no /config node?\n", __func__);
@@ -319,6 +321,8 @@ static int board_check_usb_power(void)
                if (!adc_raw_to_uV(adc, raw, &uV)) {
                        if (uV > max_uV)
                                max_uV = uV;
+                       if (uV < min_uV)
+                               min_uV = uV;
                        pr_debug("%s: %s[%02d] = %u, %d uV\n", __func__,
                                 adc->name, adc_args.args[0], raw, uV);
                } else {
@@ -333,27 +337,66 @@ static int board_check_usb_power(void)
         * continue.
         */
        if (max_uV > USB_START_LOW_THRESHOLD_UV &&
-           max_uV < USB_START_HIGH_THRESHOLD_UV)
+           max_uV <= USB_START_HIGH_THRESHOLD_UV &&
+           min_uV <= USB_LOW_THRESHOLD_UV)
                return 0;
 
-       /* Display warning message and make u-boot,error-led blinking */
-       pr_err("\n*******************************************\n");
+       pr_err("****************************************************\n");
+
+       /*
+        * If highest and lowest value are either both below
+        * USB_LOW_THRESHOLD_UV or both above USB_LOW_THRESHOLD_UV, that
+        * means USB TYPE-C is in unattached mode, this is an issue, make
+        * u-boot,error-led blinking and stop boot process.
+        */
+       if ((max_uV > USB_LOW_THRESHOLD_UV &&
+            min_uV > USB_LOW_THRESHOLD_UV) ||
+            (max_uV <= USB_LOW_THRESHOLD_UV &&
+            min_uV <= USB_LOW_THRESHOLD_UV)) {
+               pr_err("* ERROR USB TYPE-C connection in unattached mode   *\n");
+               pr_err("* Check that USB TYPE-C cable is correctly plugged *\n");
+               /* with 125ms interval, led will blink for 17.02 years ....*/
+               nb_blink = U32_MAX;
+       }
 
-       if (max_uV < USB_WARNING_LOW_THRESHOLD_UV) {
-               pr_err("*   WARNING 500mA power supply detected   *\n");
+       if (max_uV > USB_LOW_THRESHOLD_UV &&
+           max_uV <= USB_WARNING_LOW_THRESHOLD_UV &&
+           min_uV <= USB_LOW_THRESHOLD_UV) {
+               pr_err("*        WARNING 500mA power supply detected       *\n");
                nb_blink = 2;
-       } else {
-               pr_err("* WARNING 1.5A power supply detected      *\n");
+       }
+
+       if (max_uV > USB_WARNING_LOW_THRESHOLD_UV &&
+           max_uV <= USB_START_LOW_THRESHOLD_UV &&
+           min_uV <= USB_LOW_THRESHOLD_UV) {
+               pr_err("*       WARNING 1.5mA power supply detected        *\n");
                nb_blink = 3;
        }
 
-       pr_err("* Current too low, use a 3A power supply! *\n");
-       pr_err("*******************************************\n\n");
+       /*
+        * If highest value is above 2.15 Volts that means that the USB TypeC
+        * supplies more than 3 Amp, this is not compliant with TypeC specification
+        */
+       if (max_uV > USB_START_HIGH_THRESHOLD_UV) {
+               pr_err("*      USB TYPE-C charger not compliant with       *\n");
+               pr_err("*                   specification                  *\n");
+               pr_err("****************************************************\n\n");
+               /* with 125ms interval, led will blink for 17.02 years ....*/
+               nb_blink = U32_MAX;
+       } else {
+               pr_err("*     Current too low, use a 3A power supply!      *\n");
+               pr_err("****************************************************\n\n");
+       }
 
        ret = get_led(&led, "u-boot,error-led");
-       if (ret)
+       if (ret) {
+               /* in unattached case, the boot process must be stopped */
+               if (nb_blink == U32_MAX)
+                       hang();
                return ret;
+       }
 
+       /* make u-boot,error-led blinking */
        for (i = 0; i < nb_blink * 2; i++) {
                led_set_state(led, LEDST_TOGGLE);
                mdelay(125);