@@ -8,6 +8,7 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/errno.h>
@@ -67,6 +68,19 @@ static int mdiobus_register_reset(struct mdio_device *mdiodev)
return 0;
}
+static int mdiobus_register_clock(struct mdio_device *mdiodev)
+{
+ struct clk *clk;
+
+ clk = devm_clk_get_optional(&mdiodev->dev, NULL);
+ if (IS_ERR(clk))
+ return PTR_ERR(clk);
+
+ mdiodev->clk = clk;
+
+ return 0;
+}
+
int mdiobus_register_device(struct mdio_device *mdiodev)
{
int err;
@@ -83,6 +97,10 @@ int mdiobus_register_device(struct mdio_device *mdiodev)
if (err)
return err;
+ err = mdiobus_register_clock(mdiodev);
+ if (err)
+ return err;
+
/* Assert the reset signal */
mdio_device_reset(mdiodev, 1);
}
@@ -6,6 +6,7 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/gpio.h>
@@ -136,6 +137,14 @@ void mdio_device_reset(struct mdio_device *mdiodev, int value)
}
EXPORT_SYMBOL(mdio_device_reset);
+static void mdio_device_toggle_clock(struct mdio_device *mdiodev, int value)
+{
+ if (value)
+ clk_prepare_enable(mdiodev->clk);
+ else
+ clk_disable_unprepare(mdiodev->clk);
+}
+
/**
* mdio_probe - probe an MDIO device
* @dev: device to probe
@@ -152,11 +161,13 @@ static int mdio_probe(struct device *dev)
/* Deassert the reset signal */
mdio_device_reset(mdiodev, 0);
+ mdio_device_toggle_clock(mdiodev, 1);
if (mdiodrv->probe) {
err = mdiodrv->probe(mdiodev);
if (err) {
/* Assert the reset signal */
+ mdio_device_toggle_clock(mdiodev, 0);
mdio_device_reset(mdiodev, 1);
}
}
@@ -174,6 +185,7 @@ static int mdio_remove(struct device *dev)
mdiodrv->remove(mdiodev);
/* Assert the reset signal */
+ mdio_device_toggle_clock(mdiodev, 0);
mdio_device_reset(mdiodev, 1);
return 0;
@@ -50,6 +50,7 @@ struct mdio_device {
struct reset_control *reset_ctrl;
unsigned int reset_assert_delay;
unsigned int reset_deassert_delay;
+ struct clk *clk;
};
static inline struct mdio_device *to_mdio_device(const struct device *dev)
So far the generic Ethernet PHY subsystem supports PHYs having a reset line, which needs to be de-asserted before the PHY can be used. This corresponds to an "RST" pin on most external PHY chips. But most PHY chips also need an external clock signal, which may feed some internal PLL, and/or is used to drive the internal logic. In many systems this clock signal is provided by a fixed crystal oscillator, so is of no particular interest to software. However some systems use a more complex clock source, or try to save a few pennies by avoiding the crystal. The X-Powers AC200 mixed signal PHY chip, for instance, uses a software-controlled clock gate, and the Lindenis V5 development board drives its RTL8211 PHY via a clock pin on the SoC. On those systems the clock source needs to be actively enabled by software, before the PHY can be used. To support those machines, add a struct clk, populate it from firmware tables, and enable or disable it when needed, similar to toggling the reset line. In contrast to exclusive reset lines, calls to clock_disable() need to be balanced with calls to clock_enable() before, also the gate is supposed to be initially disabled. This means we cannot treat it exactly the same as the reset line, but have to skip the initial handling, and just enable or disable the gate in the probe and remove handlers. Signed-off-by: Andre Przywara <andre.przywara@arm.com> --- drivers/net/phy/mdio_bus.c | 18 ++++++++++++++++++ drivers/net/phy/mdio_device.c | 12 ++++++++++++ include/linux/mdio.h | 1 + 3 files changed, 31 insertions(+)