From: Andrew Lunn <andrew@lunn.ch>
To: Michael Grzeschik <m.grzeschik@pengutronix.de>
Cc: f.fainelli@gmail.com, netdev@vger.kernel.org,
davem@davemloft.net, kernel@pengutronix.de
Subject: Re: [PATCH] mdio-bitbang: add support for lowlevel mdio read/write
Date: Sat, 21 Dec 2019 17:41:10 +0100 [thread overview]
Message-ID: <20191221164110.GL30801@lunn.ch> (raw)
In-Reply-To: <20191218162919.5293-1-m.grzeschik@pengutronix.de>
Hi Michael
In your V1 patch, you had this diagram.
+/* Serial Management Interface (SMI) uses the following frame format:
+ *
+ * preamble|start|Read/Write| PHY | REG |TA| Data bits | Idle
+ * |frame| OP code |address |address| | |
+ * read | 32x1´s | 01 | 00 | 1xRRR | RRRRR |Z0| 00000000DDDDDDDD | Z
+ * write| 32x1´s | 01 | 00 | 0xRRR | RRRRR |10| xxxxxxxxDDDDDDDD | Z
+ *
+ */
I just compared this to plain MDIO:
+ * preamble|start|Read/Write| PHY | REG |TA| Data bits | Idle
+ * |frame| OP code |address |address| | |
+ * read | 32x1´s | 01 | 10 | AAAA | RRRRR |Z0| DDDDDDDDDDDDDDDD | Z
+ * write| 32x1´s | 01 | 01 | AAAA | RRRRR |10| DDDDDDDDDDDDDDDD | Z
So the only real issue here is the OP code? The rest you can do with a
layer on top of the standard API.
How about something like this. Totally untested, probably does not
even compile.....
Andrew
From 6051479b218fd19942d702e3e051c6355fe2a11f Mon Sep 17 00:00:00 2001
From: Andrew Lunn <andrew@lunn.ch>
Date: Sat, 21 Dec 2019 10:31:19 -0600
Subject: [PATCH] net: phy: Add support for microchip SMI0 MDIO bus.
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 <andrew@lunn.ch>
---
drivers/net/phy/mdio-bitbang.c | 7 +++++--
drivers/net/phy/mdio-gpio.c | 7 +++++++
include/linux/mdio-bitbang.h | 2 ++
3 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/drivers/net/phy/mdio-bitbang.c b/drivers/net/phy/mdio-bitbang.c
index 5136275c8e73..01f620889c78 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);
@@ -216,6 +216,9 @@ struct mii_bus *alloc_mdio_bitbang(struct mdiobb_ctrl *ctrl)
bus->write = mdiobb_write;
bus->priv = ctrl;
+ ctrl->op_c22_read = MDIO_READ;
+ ctrl->op_c22_write = MDIO_WRITE;
+
return bus;
}
EXPORT_SYMBOL(alloc_mdio_bitbang);
diff --git a/drivers/net/phy/mdio-gpio.c b/drivers/net/phy/mdio-gpio.c
index 1b00235d7dc5..282bc38331d7 100644
--- a/drivers/net/phy/mdio-gpio.c
+++ b/drivers/net/phy/mdio-gpio.c
@@ -132,6 +132,12 @@ 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;
+ }
+
dev_set_drvdata(dev, new_bus);
return new_bus;
@@ -196,6 +202,7 @@ 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 5d71e8a8500f..8ae0b3835233 100644
--- a/include/linux/mdio-bitbang.h
+++ b/include/linux/mdio-bitbang.h
@@ -33,6 +33,8 @@ struct mdiobb_ops {
struct mdiobb_ctrl {
const struct mdiobb_ops *ops;
+ u8 op_c22_read;
+ u8 op_c22_write;
};
/* The returned bus is not yet registered with the phy layer. */
--
2.24.0
next prev parent reply other threads:[~2019-12-21 16:41 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-07 11:00 [PATCH v1 0/4] microchip: add support for ksz88x3 driver family Michael Grzeschik
2019-11-07 11:00 ` [PATCH v1 1/4] mdio-bitbang: add SMI0 mode support Michael Grzeschik
2019-11-07 15:42 ` Andrew Lunn
2019-12-18 16:29 ` [PATCH] mdio-bitbang: add support for lowlevel mdio read/write Michael Grzeschik
2019-12-19 20:39 ` Andrew Lunn
2019-12-19 22:01 ` Michael Grzeschik
2019-12-19 22:05 ` Florian Fainelli
2019-12-21 16:41 ` Andrew Lunn [this message]
2020-01-29 15:42 ` Michael Grzeschik
2020-01-29 15:53 ` Andrew Lunn
2020-01-29 21:48 ` Michael Grzeschik
2020-04-21 14:31 ` Michael Grzeschik
2019-11-07 11:00 ` [PATCH v1 2/4] net: tag: ksz: Add KSZ8863 tag code Michael Grzeschik
2019-11-07 15:44 ` Andrew Lunn
2019-11-07 11:00 ` [PATCH v1 3/4] ksz: Add Microchip KSZ8863 SMI-DSA driver Michael Grzeschik
2019-11-07 15:56 ` Andrew Lunn
2019-11-09 8:08 ` kbuild test robot
2019-11-07 11:00 ` [PATCH v1 4/4] dt-bindings: net: dsa: document additional Microchip KSZ8863/8873 switch Michael Grzeschik
2019-11-13 13:34 ` Rob Herring
2019-11-07 15:36 ` [PATCH v1 0/4] microchip: add support for ksz88x3 driver family Michael Grzeschik
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