leandrof/linux
1
0
Fork 0
forked from Minki/linux
Code Issues Pull Requests Packages Projects Releases Wiki Activity

usb: typec: fusb302: Fix fusb302_handle_togdone_src Ra handling

Browse Source 
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@redhat.com>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Hans de Goede 2019-03-11 11:48:15 +01:00 committed by Greg Kroah-Hartman
parent 32a155b1a8
commit 702ad49fb8
1 changed files with 98 additions and 53 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

151
drivers/usb/typec/tcpm/fusb302.c
View File

@ -1249,6 +1249,62 @@ 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)
{
@ -1259,71 +1315,62 @@ 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;
/*
* 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 toggling mode off, ret=%d", ret);
return ret;
}
/* 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;
/* 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);
}
/* 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);
if (ret < 0) {
fusb302_log(chip, "cannot set cc polarity %s, ret=%d",
cc_polarity_name[cc_polarity], 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);
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);
}
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);
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)
@ -1509,10 +1556,8 @@ 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);
}
}