From: Andrew Lunn <and...@lunn.ch>
SMI0 is a mangled version of MDIO. The main low level difference is
the MDIO C22 OP code is always 0, not 0x2 or 0x1 for Read/Write. The
read/write information is instead encoded in the PHY address.
Extend the bit-bang code to allow the op code to be overridden, but
default to normal C22 values. Add an extra compatible to the mdio-gpio
driver, and when this compatible is present, set the op codes to 0.
A higher level driver, sitting on top of the basic MDIO bus driver can
then implement the rest of the microchip SMI0 odderties.
Signed-off-by: Andrew Lunn <and...@lunn.ch>
Signed-off-by: Michael Grzeschik <m.grzesc...@pengutronix.de>
---
v1 -> v2: - patch not present
v2 -> v3: - first patch
v3 -> v4: - added override_c22_op
drivers/net/phy/mdio-bitbang.c | 8 ++++++--
drivers/net/phy/mdio-gpio.c | 9 +++++++++
include/linux/mdio-bitbang.h | 3 +++
3 files changed, 18 insertions(+), 2 deletions(-)
diff --git a/drivers/net/phy/mdio-bitbang.c b/drivers/net/phy/mdio-bitbang.c
index 5136275c8e7399f..528e255d1ffe77f 100644
--- a/drivers/net/phy/mdio-bitbang.c
+++ b/drivers/net/phy/mdio-bitbang.c
@@ -158,7 +158,7 @@ static int mdiobb_read(struct mii_bus *bus, int phy, int
reg)
reg = mdiobb_cmd_addr(ctrl, phy, reg);
mdiobb_cmd(ctrl, MDIO_C45_READ, phy, reg);
} else
- mdiobb_cmd(ctrl, MDIO_READ, phy, reg);
+ mdiobb_cmd(ctrl, ctrl->op_c22_read, phy, reg);
ctrl->ops->set_mdio_dir(ctrl, 0);
@@ -189,7 +189,7 @@ static int mdiobb_write(struct mii_bus *bus, int phy, int
reg, u16 val)
reg = mdiobb_cmd_addr(ctrl, phy, reg);
mdiobb_cmd(ctrl, MDIO_C45_WRITE, phy, reg);
} else
- mdiobb_cmd(ctrl, MDIO_WRITE, phy, reg);
+ mdiobb_cmd(ctrl, ctrl->op_c22_write, phy, reg);
/* send the turnaround (10) */
mdiobb_send_bit(ctrl, 1);
@@ -215,6 +215,10 @@ struct mii_bus *alloc_mdio_bitbang(struct mdiobb_ctrl
*ctrl)
bus->read = mdiobb_read;
bus->write = mdiobb_write;
bus->priv = ctrl;
+ if (!ctrl->override_op_c22) {
+ ctrl->op_c22_read = MDIO_READ;
+ ctrl->op_c22_write = MDIO_WRITE;
+ }
return bus;
}
diff --git a/drivers/net/phy/mdio-gpio.c b/drivers/net/phy/mdio-gpio.c
index 1b00235d7dc5b56..e8d83cee1bc17e1 100644
--- a/drivers/net/phy/mdio-gpio.c
+++ b/drivers/net/phy/mdio-gpio.c
@@ -132,6 +132,14 @@ static struct mii_bus *mdio_gpio_bus_init(struct device
*dev,
new_bus->phy_ignore_ta_mask = pdata->phy_ignore_ta_mask;
}
+ if (dev->of_node &&
+ of_device_is_compatible(dev->of_node, "microchip,mdio-smi0")) {
+ bitbang->ctrl.op_c22_read = 0;
+ bitbang->ctrl.op_c22_write = 0;
+ } else {
+ bitbang->ctrl.override_op_c22 = 1;
+ }
+
dev_set_drvdata(dev, new_bus);
return new_bus;
@@ -196,6 +204,7 @@ static int mdio_gpio_remove(struct platform_device *pdev)
static const struct of_device_id mdio_gpio_of_match[] = {
{ .compatible = "virtual,mdio-gpio", },
+ { .compatible = "microchip,mdio-smi0" },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, mdio_gpio_of_match);
diff --git a/include/linux/mdio-bitbang.h b/include/linux/mdio-bitbang.h
index 5d71e8a8500f5ed..5016e6f60de38af 100644
--- a/include/linux/mdio-bitbang.h
+++ b/include/linux/mdio-bitbang.h
@@ -33,6 +33,9 @@ struct mdiobb_ops {
struct mdiobb_ctrl {
const struct mdiobb_ops *ops;
+ unsigned int override_op_c22;
+ u8 op_c22_read;
+ u8 op_c22_write;
};
/* The returned bus is not yet registered with the phy layer. */
--
2.28.0
