From 702ad49fb8d2d5c8f3ddd22e4119d9e507e5c1a2 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Mon, 11 Mar 2019 11:48:15 +0100 Subject: [PATCH] usb: typec: fusb302: Fix fusb302_handle_togdone_src Ra handling 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 Acked-by: Heikki Krogerus Reviewed-by: Guenter Roeck Signed-off-by: Greg Kroah-Hartman --- drivers/usb/typec/tcpm/fusb302.c | 151 ++++++++++++++++++++----------- 1 file changed, 98 insertions(+), 53 deletions(-) diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c index 416b2dd64eae..fa04d4a9bfcb 100644 --- a/drivers/usb/typec/tcpm/fusb302.c +++ b/drivers/usb/typec/tcpm/fusb302.c @@ -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); } }