The FUSB302 will stop toggling with a FUSB_REG_STATUS1A_TOGSS_SRC? status,
as soon as it sees either Ra or Rd on a CC pin.
Before this commit fusb302_handle_togdone_src would assume that the toggle-
engine always stopped at the CC pin indicating the polarity, IOW it assumed
that it stopped at the pin connected to Rd. It did check the CC-status of
that pin, but it did not expect to get a CC-status of Ra and therefore
treated this as CC-open. This lead to the following 2 problems:
1) If a powered cable/adapter gets plugged in with Ra on CC1 and Rd on CC2
then 4 of 5 times when plugged in toggling will stop with a togdone_result
of FUSB_REG_STATUS1A_TOGSS_SRC1. 3/5th of the time the toggle-engine is
testing for being connected as a sink and after that it tests 1/5th of the
time for connected as a src through CC1 before finally testing the last
1/5th of the time for being a src connected through CC2.
This was a problem because we would only check the CC pin status for the
pin on which the toggling stopped which in this polarity 4 out of 5
times would be the Ra pin. The code before this commit would treat Ra as
CC-open and then restart toggling. Once toggling is restarted we are
guaranteed to end with FUSB_REG_STATUS1A_TOGSS_SRC1 as CC1 is tested first,
leading to a CC-status of Ra again and an infinite restart toggling loop.
So 4 out of 5 times when plugged in in this polarity a powered adapter
will not work.
2) Even if we happen to have the right polarity or 1/5th of the time in
the polarity with problem 1), we would report the non Rd pin as CC-open
rather then as Ra, resulting in the tcpm.c code not enabling Vconn which
is a problem for some adapters.
This commit fixes this by getting the CC-status of *both* pins and then
determining the polarity based on that, rather then on where the toggling
stopped.
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
Changes in v3
-Keep the delays for measuring Rd / Ra the same as before instead of
multiplying them by a factor 100
---
drivers/usb/typec/tcpm/fusb302.c | 149 ++++++++++++++++++++-----------
1 file changed, 97 insertions(+), 52 deletions(-)
diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c
index a1256855eaa0..a4387ce5ac85 100644
--- a/drivers/usb/typec/tcpm/fusb302.c
+++ b/drivers/usb/typec/tcpm/fusb302.c
@@ -1255,6 +1255,62 @@ static int fusb302_handle_togdone_snk(struct fusb302_chip *chip,
return ret;
}
+/* On error returns < 0, otherwise a typec_cc_status value */
+static int fusb302_get_src_cc_status(struct fusb302_chip *chip,
+ enum typec_cc_polarity cc_polarity,
+ enum typec_cc_status *cc)
+{
+ u8 ra_mda = ra_mda_value[chip->src_current_status];
+ u8 rd_mda = rd_mda_value[chip->src_current_status];
+ u8 switches0_data, status0;
+ int ret;
+
+ /* Step 1: Set switches so that we measure the right CC pin */
+ switches0_data = (cc_polarity == TYPEC_POLARITY_CC1) ?
+ FUSB_REG_SWITCHES0_CC1_PU_EN | FUSB_REG_SWITCHES0_MEAS_CC1 :
+ FUSB_REG_SWITCHES0_CC2_PU_EN | FUSB_REG_SWITCHES0_MEAS_CC2;
+ ret = fusb302_i2c_write(chip, FUSB_REG_SWITCHES0, switches0_data);
+ if (ret < 0)
+ return ret;
+
+ fusb302_i2c_read(chip, FUSB_REG_SWITCHES0, &status0);
+ fusb302_log(chip, "get_src_cc_status switches: 0x%0x", status0);
+
+ /* Step 2: Set compararator volt to differentiate between Open and Rd */
+ ret = fusb302_i2c_write(chip, FUSB_REG_MEASURE, rd_mda);
+ if (ret < 0)
+ return ret;
+
+ usleep_range(50, 100);
+ ret = fusb302_i2c_read(chip, FUSB_REG_STATUS0, &status0);
+ if (ret < 0)
+ return ret;
+
+ fusb302_log(chip, "get_src_cc_status rd_mda status0: 0x%0x", status0);
+ if (status0 & FUSB_REG_STATUS0_COMP) {
+ *cc = TYPEC_CC_OPEN;
+ return 0;
+ }
+
+ /* Step 3: Set compararator input to differentiate between Rd and Ra. */
+ ret = fusb302_i2c_write(chip, FUSB_REG_MEASURE, ra_mda);
+ if (ret < 0)
+ return ret;
+
+ usleep_range(50, 100);
+ ret = fusb302_i2c_read(chip, FUSB_REG_STATUS0, &status0);
+ if (ret < 0)
+ return ret;
+
+ fusb302_log(chip, "get_src_cc_status ra_mda status0: 0x%0x", status0);
+ if (status0 & FUSB_REG_STATUS0_COMP)
+ *cc = TYPEC_CC_RD;
+ else
+ *cc = TYPEC_CC_RA;
+
+ return 0;
+}
+
static int fusb302_handle_togdone_src(struct fusb302_chip *chip,
u8 togdone_result)
{
@@ -1265,71 +1321,62 @@ static int fusb302_handle_togdone_src(struct fusb302_chip *chip,
* - set I_COMP interrupt on
*/
int ret = 0;
- u8 status0;
- u8 ra_mda = ra_mda_value[chip->src_current_status];
u8 rd_mda = rd_mda_value[chip->src_current_status];
- bool ra_comp, rd_comp;
+ enum toggling_mode toggling_mode = chip->toggling_mode;
enum typec_cc_polarity cc_polarity;
- enum typec_cc_status cc_status_active, cc1, cc2;
+ enum typec_cc_status cc1, cc2;
- /* set polarity and pull_up, pull_down */
- cc_polarity = (togdone_result == FUSB_REG_STATUS1A_TOGSS_SRC1) ?
- TYPEC_POLARITY_CC1 : TYPEC_POLARITY_CC2;
- ret = fusb302_set_cc_polarity_and_pull(chip, cc_polarity, true, false);
+ /*
+ * The toggle-engine will stop in a src state if it sees either Ra or
+ * Rd. Determine the status for both CC pins, starting with the one
+ * where toggling stopped, as that is where the switches point now.
+ */
+ if (togdone_result == FUSB_REG_STATUS1A_TOGSS_SRC1)
+ ret = fusb302_get_src_cc_status(chip, TYPEC_POLARITY_CC1, &cc1);
+ else
+ ret = fusb302_get_src_cc_status(chip, TYPEC_POLARITY_CC2, &cc2);
+ if (ret < 0)
+ return ret;
+ /* we must turn off toggling before we can measure the other pin */
+ ret = fusb302_set_toggling(chip, TOGGLING_MODE_OFF);
if (ret < 0) {
- fusb302_log(chip, "cannot set cc polarity %s, ret=%d",
- cc_polarity_name[cc_polarity], ret);
+ fusb302_log(chip, "cannot set toggling mode off, ret=%d", ret);
return ret;
}
- /* fusb302_set_cc_polarity() has set the correct measure block */
- ret = fusb302_i2c_write(chip, FUSB_REG_MEASURE, rd_mda);
- if (ret < 0)
- return ret;
- usleep_range(50, 100);
- ret = fusb302_i2c_read(chip, FUSB_REG_STATUS0, &status0);
+ /* get the status of the other pin */
+ if (togdone_result == FUSB_REG_STATUS1A_TOGSS_SRC1)
+ ret = fusb302_get_src_cc_status(chip, TYPEC_POLARITY_CC2, &cc2);
+ else
+ ret = fusb302_get_src_cc_status(chip, TYPEC_POLARITY_CC1, &cc1);
if (ret < 0)
return ret;
- rd_comp = !!(status0 & FUSB_REG_STATUS0_COMP);
- if (!rd_comp) {
- ret = fusb302_i2c_write(chip, FUSB_REG_MEASURE, ra_mda);
- if (ret < 0)
- return ret;
- usleep_range(50, 100);
- ret = fusb302_i2c_read(chip, FUSB_REG_STATUS0, &status0);
- if (ret < 0)
- return ret;
- ra_comp = !!(status0 & FUSB_REG_STATUS0_COMP);
+
+ /* determine polarity based on the status of both pins */
+ if (cc1 == TYPEC_CC_RD &&
+ (cc2 == TYPEC_CC_OPEN || cc2 == TYPEC_CC_RA)) {
+ cc_polarity = TYPEC_POLARITY_CC1;
+ } else if (cc2 == TYPEC_CC_RD &&
+ (cc1 == TYPEC_CC_OPEN || cc1 == TYPEC_CC_RA)) {
+ cc_polarity = TYPEC_POLARITY_CC2;
+ } else {
+ fusb302_log(chip, "unexpected CC status cc1=%s, cc2=%s, restarting toggling",
+ typec_cc_status_name[cc1],
+ typec_cc_status_name[cc2]);
+ return fusb302_set_toggling(chip, toggling_mode);
}
- if (rd_comp)
- cc_status_active = TYPEC_CC_OPEN;
- else if (ra_comp)
- cc_status_active = TYPEC_CC_RD;
- else
- /* Ra is not supported, report as Open */
- cc_status_active = TYPEC_CC_OPEN;
- /* restart toggling if the cc status on the active line is OPEN */
- if (cc_status_active == TYPEC_CC_OPEN) {
- fusb302_log(chip, "restart toggling as CC_OPEN detected");
- ret = fusb302_set_toggling(chip, chip->toggling_mode);
+ /* set polarity and pull_up, pull_down */
+ ret = fusb302_set_cc_polarity_and_pull(chip, cc_polarity, true, false);
+ if (ret < 0) {
+ fusb302_log(chip, "cannot set cc polarity %s, ret=%d",
+ cc_polarity_name[cc_polarity], ret);
return ret;
}
/* update tcpm with the new cc value */
- cc1 = (cc_polarity == TYPEC_POLARITY_CC1) ?
- cc_status_active : TYPEC_CC_OPEN;
- cc2 = (cc_polarity == TYPEC_POLARITY_CC2) ?
- cc_status_active : TYPEC_CC_OPEN;
if ((chip->cc1 != cc1) || (chip->cc2 != cc2)) {
chip->cc1 = cc1;
chip->cc2 = cc2;
tcpm_cc_change(chip->tcpm_port);
}
- /* turn off toggling */
- ret = fusb302_set_toggling(chip, TOGGLING_MODE_OFF);
- if (ret < 0) {
- fusb302_log(chip,
- "cannot set toggling mode off, ret=%d", ret);
- return ret;
- }
/* set MDAC to Rd threshold, and unmask I_COMP for unplug detection */
ret = fusb302_i2c_write(chip, FUSB_REG_MEASURE, rd_mda);
if (ret < 0)
@@ -1515,10 +1562,8 @@ static irqreturn_t fusb302_irq_intn(int irq, void *dev_id)
comp_result ? "true" : "false");
if (comp_result) {
/* cc level > Rd_threashold, detach */
- if (chip->cc_polarity == TYPEC_POLARITY_CC1)
- chip->cc1 = TYPEC_CC_OPEN;
- else
- chip->cc2 = TYPEC_CC_OPEN;
+ chip->cc1 = TYPEC_CC_OPEN;
+ chip->cc2 = TYPEC_CC_OPEN;
tcpm_cc_change(chip->tcpm_port);
}
}
--
2.20.1
