usb: typec: fusb302: Make fusb302_set_cc_polarity also set pull ups / downs

The 2 callers of fusb302_set_cc_polarity both call fusb302_set_cc_pull
directly before calling fusb302_set_cc_polarity, this is not ideal for
2 reasons:

1) fusb302_set_cc_pull uses the cached polarity when applying the pull-ups,
which maybe changed immediately afterwards, to fix this set_cc_polarity
already does the pull-up setting.

2) Both touch the SWITCHES0 register in a r-w-modify cycle, this leads to
read reg, write reg, read reg, write reg. If we fold the setting of
the pull-downs into fusb302_set_cc_polarity then not only can we avoid
doing the reads / writes twice, at this point we set all bits, so we
can skip the read, turning 4 (slowish) i2c-transfers into 1.

Doing this also avoids the need to cache the pull_up state in
struct fusb302_chip.

Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c
index e934499..d2cce67 100644 (file)
--- a/drivers/usb/typec/tcpm/fusb302.c
+++ b/drivers/usb/typec/tcpm/fusb302.c
@@ -99,7 +99,6 @@ struct fusb302_chip {
        bool intr_comp_chng;
 
        /* port status */
-       bool pull_up;
        bool vconn_on;
        bool vbus_on;
        bool charge_on;
@@ -540,7 +539,6 @@ static int fusb302_set_cc_pull(struct fusb302_chip *chip,
                                     mask, data);
        if (ret < 0)
                return ret;
-       chip->pull_up = pull_up;
 
        return ret;
 }
@@ -1226,38 +1224,36 @@ static const char * const cc_polarity_name[] = {
        [TYPEC_POLARITY_CC2]    = "Polarity_CC2",
 };
 
-static int fusb302_set_cc_polarity(struct fusb302_chip *chip,
-                                  enum typec_cc_polarity cc_polarity)
+static int fusb302_set_cc_polarity_and_pull(struct fusb302_chip *chip,
+                                           enum typec_cc_polarity cc_polarity,
+                                           bool pull_up, bool pull_down)
 {
        int ret = 0;
-       u8 switches0_mask = FUSB_REG_SWITCHES0_CC1_PU_EN |
-                           FUSB_REG_SWITCHES0_CC2_PU_EN |
-                           FUSB_REG_SWITCHES0_VCONN_CC1 |
-                           FUSB_REG_SWITCHES0_VCONN_CC2 |
-                           FUSB_REG_SWITCHES0_MEAS_CC1 |
-                           FUSB_REG_SWITCHES0_MEAS_CC2;
        u8 switches0_data = 0x00;
        u8 switches1_mask = FUSB_REG_SWITCHES1_TXCC1_EN |
                            FUSB_REG_SWITCHES1_TXCC2_EN;
        u8 switches1_data = 0x00;
 
+       if (pull_down)
+               switches0_data |= FUSB_REG_SWITCHES0_CC1_PD_EN |
+                                 FUSB_REG_SWITCHES0_CC2_PD_EN;
+
        if (cc_polarity == TYPEC_POLARITY_CC1) {
-               switches0_data = FUSB_REG_SWITCHES0_MEAS_CC1;
+               switches0_data |= FUSB_REG_SWITCHES0_MEAS_CC1;
                if (chip->vconn_on)
                        switches0_data |= FUSB_REG_SWITCHES0_VCONN_CC2;
-               if (chip->pull_up)
+               if (pull_up)
                        switches0_data |= FUSB_REG_SWITCHES0_CC1_PU_EN;
                switches1_data = FUSB_REG_SWITCHES1_TXCC1_EN;
        } else {
-               switches0_data = FUSB_REG_SWITCHES0_MEAS_CC2;
+               switches0_data |= FUSB_REG_SWITCHES0_MEAS_CC2;
                if (chip->vconn_on)
                        switches0_data |= FUSB_REG_SWITCHES0_VCONN_CC1;
-               if (chip->pull_up)
+               if (pull_up)
                        switches0_data |= FUSB_REG_SWITCHES0_CC2_PU_EN;
                switches1_data = FUSB_REG_SWITCHES1_TXCC2_EN;
        }
-       ret = fusb302_i2c_mask_write(chip, FUSB_REG_SWITCHES0,
-                                    switches0_mask, switches0_data);
+       ret = fusb302_i2c_write(chip, FUSB_REG_SWITCHES0, switches0_data);
        if (ret < 0)
                return ret;
        ret = fusb302_i2c_mask_write(chip, FUSB_REG_SWITCHES1,
@@ -1278,16 +1274,10 @@ static int fusb302_handle_togdone_snk(struct fusb302_chip *chip,
        enum typec_cc_polarity cc_polarity;
        enum typec_cc_status cc_status_active, cc1, cc2;
 
-       /* set pull_up, pull_down */
-       ret = fusb302_set_cc_pull(chip, false, true);
-       if (ret < 0) {
-               fusb302_log(chip, "cannot set cc to pull down, ret=%d", ret);
-               return ret;
-       }
-       /* set polarity */
+       /* set polarity and pull_up, pull_down */
        cc_polarity = (togdone_result == FUSB_REG_STATUS1A_TOGSS_SNK1) ?
                      TYPEC_POLARITY_CC1 : TYPEC_POLARITY_CC2;
-       ret = fusb302_set_cc_polarity(chip, cc_polarity);
+       ret = fusb302_set_cc_polarity_and_pull(chip, cc_polarity, false, true);
        if (ret < 0) {
                fusb302_log(chip, "cannot set cc polarity %s, ret=%d",
                            cc_polarity_name[cc_polarity], ret);
@@ -1354,16 +1344,10 @@ static int fusb302_handle_togdone_src(struct fusb302_chip *chip,
        enum typec_cc_polarity cc_polarity;
        enum typec_cc_status cc_status_active, cc1, cc2;
 
-       /* set pull_up, pull_down */
-       ret = fusb302_set_cc_pull(chip, true, false);
-       if (ret < 0) {
-               fusb302_log(chip, "cannot set cc to pull up, ret=%d", ret);
-               return ret;
-       }
-       /* set polarity */
+       /* 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(chip, cc_polarity);
+       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);