On Thu, Mar 07, 2019 at 05:36:00PM +0100, Hans de Goede wrote:
> 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 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.
>
> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> ---
> drivers/usb/typec/tcpm/fusb302.c | 48 +++++++++++---------------------
> 1 file changed, 16 insertions(+), 32 deletions(-)
>
> diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c
> index e9344997329c..d2cce67289d4 100644
> --- 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);
> --
> 2.20.1
>
