6.17-stable review patch. If anyone has any objections, please let me know.
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From: Bastien Curutchet bastien.curutchet@bootlin.com
[ Upstream commit a0b977a3d19368b235f2a6c06e800fb25452029b ]
At reset, the KSZ8463 uses a strap-based configuration to set SPI as bus interface. SPI is the only bus supported by the driver. If the required pull-ups/pull-downs are missing (by mistake or by design to save power) the pins may float and the configuration can go wrong preventing any communication with the switch.
Introduce a ksz8463_configure_straps_spi() function called during the device reset. It relies on the 'straps-rxd-gpios' OF property and the 'reset' pinmux configuration to enforce SPI as bus interface.
Reviewed-by: Andrew Lunn andrew@lunn.ch Signed-off-by: Bastien Curutchet (Schneider Electric) bastien.curutchet@bootlin.com Link: https://patch.msgid.link/20250918-ksz-strap-pins-v3-3-16662e881728@bootlin.c... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/dsa/microchip/ksz_common.c | 45 ++++++++++++++++++++++++++ 1 file changed, 45 insertions(+)
diff --git a/drivers/net/dsa/microchip/ksz_common.c b/drivers/net/dsa/microchip/ksz_common.c index 9568cc391fe3e..a962055bfdbd8 100644 --- a/drivers/net/dsa/microchip/ksz_common.c +++ b/drivers/net/dsa/microchip/ksz_common.c @@ -23,6 +23,7 @@ #include <linux/of_mdio.h> #include <linux/of_net.h> #include <linux/micrel_phy.h> +#include <linux/pinctrl/consumer.h> #include <net/dsa.h> #include <net/ieee8021q.h> #include <net/pkt_cls.h> @@ -5345,6 +5346,38 @@ static int ksz_parse_drive_strength(struct ksz_device *dev) return 0; }
+static int ksz8463_configure_straps_spi(struct ksz_device *dev) +{ + struct pinctrl *pinctrl; + struct gpio_desc *rxd0; + struct gpio_desc *rxd1; + + rxd0 = devm_gpiod_get_index_optional(dev->dev, "straps-rxd", 0, GPIOD_OUT_LOW); + if (IS_ERR(rxd0)) + return PTR_ERR(rxd0); + + rxd1 = devm_gpiod_get_index_optional(dev->dev, "straps-rxd", 1, GPIOD_OUT_HIGH); + if (IS_ERR(rxd1)) + return PTR_ERR(rxd1); + + if (!rxd0 && !rxd1) + return 0; + + if ((rxd0 && !rxd1) || (rxd1 && !rxd0)) + return -EINVAL; + + pinctrl = devm_pinctrl_get_select(dev->dev, "reset"); + if (IS_ERR(pinctrl)) + return PTR_ERR(pinctrl); + + return 0; +} + +static int ksz8463_release_straps_spi(struct ksz_device *dev) +{ + return pinctrl_select_default_state(dev->dev); +} + int ksz_switch_register(struct ksz_device *dev) { const struct ksz_chip_data *info; @@ -5360,10 +5393,22 @@ int ksz_switch_register(struct ksz_device *dev) return PTR_ERR(dev->reset_gpio);
if (dev->reset_gpio) { + if (of_device_is_compatible(dev->dev->of_node, "microchip,ksz8463")) { + ret = ksz8463_configure_straps_spi(dev); + if (ret) + return ret; + } + gpiod_set_value_cansleep(dev->reset_gpio, 1); usleep_range(10000, 12000); gpiod_set_value_cansleep(dev->reset_gpio, 0); msleep(100); + + if (of_device_is_compatible(dev->dev->of_node, "microchip,ksz8463")) { + ret = ksz8463_release_straps_spi(dev); + if (ret) + return ret; + } }
mutex_init(&dev->dev_mutex);