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DEV-7307: net: phy: sfp: add workaround for missing pull up #32

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Merged
shmuelhazan merged 1 commit into from
May 13, 2025
+12 −1
Merged

DEV-7307: net: phy: sfp: add workaround for missing pull up #32

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13 changes: 12 additions & 1 deletion drivers/net/phy/sfp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -337,6 +337,17 @@ static unsigned int sff_gpio_get_state(struct sfp *sfp)
return sfp_gpio_get_state(sfp) | SFP_F_PRESENT;
}

/**
* simulate_pull_up - simulate a pull-up on a GPIO
* @desc: GPIO descriptor
*
* As a result, the SFP module may not be able to detect the change between
* TX_DISABLE=1 to TX_DISABLE=0, and the other side will be see "link down".
*/
static void simulate_pull_up(struct gpio_desc *desc) {
gpiod_direction_output(desc, 1);
}

static void sfp_gpio_set_state(struct sfp *sfp, unsigned int state)
{
if (state & SFP_F_PRESENT) {
Expand All @@ -350,7 +361,7 @@ static void sfp_gpio_set_state(struct sfp *sfp, unsigned int state)
} else {
/* Otherwise, let them float to the pull-ups */
if (sfp->gpio[GPIO_TX_DISABLE])
gpiod_direction_input(sfp->gpio[GPIO_TX_DISABLE]);
simulate_pull_up(sfp->gpio[GPIO_TX_DISABLE]);
if (state & SFP_F_RATE_SELECT)
gpiod_direction_input(sfp->gpio[GPIO_RATE_SELECT]);
}
Expand Down