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board: stm32pm1: update USB-C power detection algorithm on DK boards

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USB-C power supply which are Power Delivery compliant (USB-PD) are able
to provide different voltage/current (for example 5V/3A 9V/3A 12V/2.25A...)

In this case, the power supply need to negotiate the voltage/current to
use with the device using CC1/CC2 USB-C signals.

If this negotiation occurs during ADC measurement (done also on CC1/CC2
USB-C signals) some ADC acquisition can be corrupted which cause wrong
power supply current detection.

To avoid this, the power supply current detection algorithm is updated
as following:
  - perform an ADC measurement, if a 3A current is detected, continue the
    boot process.
  - else, wait 20ms (max tPDDebounce duration) to ensure that USB-PD
    negotiation is done and perform another ADC measurement.

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@st.com>
This commit is contained in:
Patrice Chotard
2020-10-16 09:28:59 +02:00
committed by Patrick Delaunay
parent 8396408e79
commit 42082bc61b
1 changed files with 63 additions and 43 deletions
Download Patch File Download Diff File Expand all files Collapse all files

106
board/st/stm32mp1/stm32mp1.c
View File

@@ -289,41 +289,13 @@ static void __maybe_unused led_error_blink(u32 nb_blink)
hang();
}
static int board_check_usb_power(void)
static int adc_measurement(ofnode node, int adc_count, int *min_uV, int *max_uV)
{
struct ofnode_phandle_args adc_args;
struct udevice *adc;
ofnode node;
unsigned int raw;
int max_uV = 0;
int min_uV = USB_START_HIGH_THRESHOLD_UV;
int ret, uV, adc_count;
u32 nb_blink;
u8 i;
if (!IS_ENABLED(CONFIG_ADC))
return -ENODEV;
node = ofnode_path("/config");
if (!ofnode_valid(node)) {
log_debug("no /config node?\n");
return -ENOENT;
}
/*
* Retrieve the ADC channels devices and get measurement
* for each of them
*/
adc_count = ofnode_count_phandle_with_args(node, "st,adc_usb_pd",
"#io-channel-cells", 0);
if (adc_count < 0) {
if (adc_count == -ENOENT)
return 0;
log_err("can't find adc channel (%d)\n", adc_count);
return adc_count;
}
int ret, uV;
int i;
for (i = 0; i < adc_count; i++) {
if (ofnode_parse_phandle_with_args(node, "st,adc_usb_pd",
@@ -350,10 +322,10 @@ static int board_check_usb_power(void)
}
/* Convert to uV */
if (!adc_raw_to_uV(adc, raw, &uV)) {
if (uV > max_uV)
max_uV = uV;
if (uV < min_uV)
min_uV = uV;
if (uV > *max_uV)
*max_uV = uV;
if (uV < *min_uV)
*min_uV = uV;
log_debug("%s[%02d] = %u, %d uV\n",
adc->name, adc_args.args[0], raw, uV);
} else {
@@ -362,18 +334,66 @@ static int board_check_usb_power(void)
}
}
return 0;
}
static int board_check_usb_power(void)
{
ofnode node;
int max_uV = 0;
int min_uV = USB_START_HIGH_THRESHOLD_UV;
int adc_count, ret;
u32 nb_blink;
u8 i;
node = ofnode_path("/config");
if (!ofnode_valid(node)) {
log_debug("no /config node?\n");
return -ENOENT;
}
/*
* If highest value is inside 1.23 Volts and 2.10 Volts, that means
* board is plugged on an USB-C 3A power supply and boot process can
* continue.
* Retrieve the ADC channels devices and get measurement
* for each of them
*/
if (max_uV > USB_START_LOW_THRESHOLD_UV &&
max_uV <= USB_START_HIGH_THRESHOLD_UV &&
min_uV <= USB_LOW_THRESHOLD_UV)
return 0;
adc_count = ofnode_count_phandle_with_args(node, "st,adc_usb_pd",
"#io-channel-cells", 0);
if (adc_count < 0) {
if (adc_count == -ENOENT)
return 0;
log_err("Can't find adc channel (%d)\n", adc_count);
return adc_count;
}
/* perform maximum of 2 ADC measurements to detect power supply current */
for (i = 0; i < 2; i++) {
if (IS_ENABLED(CONFIG_ADC))
ret = adc_measurement(node, adc_count, &min_uV, &max_uV);
else
ret = -ENODEV;
if (ret)
return ret;
/*
* If highest value is inside 1.23 Volts and 2.10 Volts, that means
* board is plugged on an USB-C 3A power supply and boot process can
* continue.
*/
if (max_uV > USB_START_LOW_THRESHOLD_UV &&
max_uV <= USB_START_HIGH_THRESHOLD_UV &&
min_uV <= USB_LOW_THRESHOLD_UV)
return 0;
if (i == 0) {
log_err("Previous ADC measurements was not the one expected, retry in 20ms\n");
mdelay(20); /* equal to max tPDDebounce duration (min 10ms - max 20ms) */
}
}
log_notice("****************************************************\n");
/*
* If highest and lowest value are either both below
* USB_LOW_THRESHOLD_UV or both above USB_LOW_THRESHOLD_UV, that