[PATCH AUTOSEL 4.19 083/191] net: phy: mdio-bcm-unimac: Allow configuring MDIO clock divider

Sasha Levin
2019-11-10T03:13:10Z

From: Florian Fainelli <f.fainelli@gmail.com>

[ Upstream commit b78ac6ecd1b6b46f8767cbafa95a7b0b51b87ad8 ]

Allow the configuration of the MDIO clock divider when the Device Tree
contains 'clock-frequency' property (similar to I2C and SPI buses).
Because the hardware may have lost its state during suspend/resume,
re-apply the MDIO clock divider upon resumption.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
.../bindings/net/brcm,unimac-mdio.txt | 3 +
drivers/net/phy/mdio-bcm-unimac.c | 83 ++++++++++++++++++-
2 files changed, 84 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/net/brcm,unimac-mdio.txt b/Documentation/devicetree/bindings/net/brcm,unimac-mdio.txt
index 4648948f7c3b8..e15589f477876 100644
--- a/Documentation/devicetree/bindings/net/brcm,unimac-mdio.txt
+++ b/Documentation/devicetree/bindings/net/brcm,unimac-mdio.txt
@@ -19,6 +19,9 @@ Optional properties:
- interrupt-names: must be "mdio_done_error" when there is a share interrupt fed
to this hardware block, or must be "mdio_done" for the first interrupt and
"mdio_error" for the second when there are separate interrupts
+- clocks: A reference to the clock supplying the MDIO bus controller
+- clock-frequency: the MDIO bus clock that must be output by the MDIO bus
+ hardware, if absent, the default hardware values are used

Child nodes of this MDIO bus controller node are standard Ethernet PHY device
nodes as described in Documentation/devicetree/bindings/net/phy.txt
diff --git a/drivers/net/phy/mdio-bcm-unimac.c b/drivers/net/phy/mdio-bcm-unimac.c
index 8d370667fa1b3..80b9583eaa952 100644
--- a/drivers/net/phy/mdio-bcm-unimac.c
+++ b/drivers/net/phy/mdio-bcm-unimac.c
@@ -16,6 +16,7 @@
#include <linux/module.h>
#include <linux/io.h>
#include <linux/delay.h>
+#include <linux/clk.h>

#include <linux/of.h>
#include <linux/of_platform.h>
@@ -45,6 +46,8 @@ struct unimac_mdio_priv {
void __iomem *base;
int (*wait_func) (void *wait_func_data);
void *wait_func_data;
+ struct clk *clk;
+ u32 clk_freq;
};

static inline u32 unimac_mdio_readl(struct unimac_mdio_priv *priv, u32 offset)
@@ -189,6 +192,35 @@ static int unimac_mdio_reset(struct mii_bus *bus)
return 0;
}

+static void unimac_mdio_clk_set(struct unimac_mdio_priv *priv)
+{
+ unsigned long rate;
+ u32 reg, div;
+
+ /* Keep the hardware default values */
+ if (!priv->clk_freq)
+ return;
+
+ if (!priv->clk)
+ rate = 250000000;
+ else
+ rate = clk_get_rate(priv->clk);
+
+ div = (rate / (2 * priv->clk_freq)) - 1;
+ if (div & ~MDIO_CLK_DIV_MASK) {
+ pr_warn("Incorrect MDIO clock frequency, ignoring\n");
+ return;
+ }
+
+ /* The MDIO clock is the reference clock (typicaly 250Mhz) divided by
+ * 2 x (MDIO_CLK_DIV + 1)
+ */
+ reg = unimac_mdio_readl(priv, MDIO_CFG);
+ reg &= ~(MDIO_CLK_DIV_MASK << MDIO_CLK_DIV_SHIFT);
+ reg |= div << MDIO_CLK_DIV_SHIFT;
+ unimac_mdio_writel(priv, reg, MDIO_CFG);
+}
+
static int unimac_mdio_probe(struct platform_device *pdev)
{
struct unimac_mdio_pdata *pdata = pdev->dev.platform_data;
@@ -217,9 +249,26 @@ static int unimac_mdio_probe(struct platform_device *pdev)
return -ENOMEM;
}

+ priv->clk = devm_clk_get(&pdev->dev, NULL);
+ if (PTR_ERR(priv->clk) == -EPROBE_DEFER)
+ return PTR_ERR(priv->clk);
+ else
+ priv->clk = NULL;
+
+ ret = clk_prepare_enable(priv->clk);
+ if (ret)
+ return ret;
+
+ if (of_property_read_u32(np, "clock-frequency", &priv->clk_freq))
+ priv->clk_freq = 0;
+
+ unimac_mdio_clk_set(priv);
+
priv->mii_bus = mdiobus_alloc();
- if (!priv->mii_bus)
- return -ENOMEM;
+ if (!priv->mii_bus) {
+ ret = -ENOMEM;
+ goto out_clk_disable;
+ }

bus = priv->mii_bus;
bus->priv = priv;
@@ -253,6 +302,8 @@ static int unimac_mdio_probe(struct platform_device *pdev)

out_mdio_free:
mdiobus_free(bus);
+out_clk_disable:
+ clk_disable_unprepare(priv->clk);
return ret;
}

@@ -262,10 +313,37 @@ static int unimac_mdio_remove(struct platform_device *pdev)

mdiobus_unregister(priv->mii_bus);
mdiobus_free(priv->mii_bus);
+ clk_disable_unprepare(priv->clk);
+
+ return 0;
+}
+
+static int unimac_mdio_suspend(struct device *d)
+{
+ struct unimac_mdio_priv *priv = dev_get_drvdata(d);
+
+ clk_disable_unprepare(priv->clk);
+
+ return 0;
+}
+
+static int unimac_mdio_resume(struct device *d)
+{
+ struct unimac_mdio_priv *priv = dev_get_drvdata(d);
+ int ret;
+
+ ret = clk_prepare_enable(priv->clk);
+ if (ret)
+ return ret;
+
+ unimac_mdio_clk_set(priv);

return 0;
}

+static SIMPLE_DEV_PM_OPS(unimac_mdio_pm_ops,
+ unimac_mdio_suspend, unimac_mdio_resume);
+
static const struct of_device_id unimac_mdio_ids[] = {
{ .compatible = "brcm,genet-mdio-v5", },
{ .compatible = "brcm,genet-mdio-v4", },
@@ -281,6 +359,7 @@ static struct platform_driver unimac_mdio_driver = {
.driver = {
.name = UNIMAC_MDIO_DRV_NAME,
.of_match_table = unimac_mdio_ids,
+ .pm = &unimac_mdio_pm_ops,
},
.probe = unimac_mdio_probe,
.remove = unimac_mdio_remove,
--
2.20.1