[PATCH v2 2/2] arc_emac: add clock handling

Heiko Stübner
2014-04-25T08:04:14Z

This adds ability for the arc_emac to really handle its supplying clock.
To get the needed clock-frequency either a real clock or the previous
clock-frequency property must be provided.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Max Schwarz <max.schwarz@online.de>
---
changes since v1:
- fix wrong clk error check found by Max Schwarz

Documentation/devicetree/bindings/net/arc_emac.txt | 12 +++++-
drivers/net/ethernet/arc/emac.h | 2 +
drivers/net/ethernet/arc/emac_main.c | 46 ++++++++++++++++------
3 files changed, 47 insertions(+), 13 deletions(-)

diff --git a/Documentation/devicetree/bindings/net/arc_emac.txt b/Documentation/devicetree/bindings/net/arc_emac.txt
index 7fbb027..a1d71eb 100644
--- a/Documentation/devicetree/bindings/net/arc_emac.txt
+++ b/Documentation/devicetree/bindings/net/arc_emac.txt
@@ -4,11 +4,15 @@ Required properties:
- compatible: Should be "snps,arc-emac"
- reg: Address and length of the register set for the device
- interrupts: Should contain the EMAC interrupts
-- clock-frequency: CPU frequency. It is needed to calculate and set polling
-period of EMAC.
- max-speed: see ethernet.txt file in the same directory.
- phy: see ethernet.txt file in the same directory.

+Clock handling:
+The clock frequency is needed to calculate and set polling period of EMAC.
+It must be provided by one of:
+- clock-frequency: CPU frequency.
+- clocks: reference to the clock supplying the EMAC.
+
Child nodes of the driver are the individual PHY devices connected to the
MDIO bus. They must have a "reg" property given the PHY address on the MDIO bus.

@@ -19,7 +23,11 @@ Examples:
reg = <0xc0fc2000 0x3c>;
interrupts = <6>;
mac-address = [ 00 11 22 33 44 55 ];
+
clock-frequency = <80000000>;
+ /* or */
+ clocks = <&emac_clock>;
+
max-speed = <100>;
phy = <&phy0>;

diff --git a/drivers/net/ethernet/arc/emac.h b/drivers/net/ethernet/arc/emac.h
index 928fac6..53f85bf 100644
--- a/drivers/net/ethernet/arc/emac.h
+++ b/drivers/net/ethernet/arc/emac.h
@@ -11,6 +11,7 @@
#include <linux/dma-mapping.h>
#include <linux/netdevice.h>
#include <linux/phy.h>
+#include <linux/clk.h>

/* STATUS and ENABLE Register bit masks */
#define TXINT_MASK (1<<0) /* Transmit interrupt */
@@ -131,6 +132,7 @@ struct arc_emac_priv {
struct mii_bus *bus;

void __iomem *regs;
+ struct clk *clk;

struct napi_struct napi;
struct net_device_stats stats;
diff --git a/drivers/net/ethernet/arc/emac_main.c b/drivers/net/ethernet/arc/emac_main.c
index 9747dda..d647a7d 100644
--- a/drivers/net/ethernet/arc/emac_main.c
+++ b/drivers/net/ethernet/arc/emac_main.c
@@ -649,13 +649,6 @@ static int arc_emac_probe(struct platform_device *pdev)
return -ENODEV;
}

- /* Get CPU clock frequency from device tree */
- if (of_property_read_u32(pdev->dev.of_node, "clock-frequency",
- &clock_frequency)) {
- dev_err(&pdev->dev, "failed to retrieve <clock-frequency> from device tree\n");
- return -EINVAL;
- }
-
/* Get IRQ from device tree */
irq = irq_of_parse_and_map(pdev->dev.of_node, 0);
if (!irq) {
@@ -687,13 +680,32 @@ static int arc_emac_probe(struct platform_device *pdev)
}
dev_dbg(&pdev->dev, "Registers base address is 0x%p\n", priv->regs);

+ priv->clk = of_clk_get(pdev->dev.of_node, 0);
+ if (IS_ERR(priv->clk)) {
+ /* Get CPU clock frequency from device tree */
+ if (of_property_read_u32(pdev->dev.of_node, "clock-frequency",
+ &clock_frequency)) {
+ dev_err(&pdev->dev, "failed to retrieve <clock-frequency> from device tree\n");
+ err = -EINVAL;
+ goto out_netdev;
+ }
+ } else {
+ err = clk_prepare_enable(priv->clk);
+ if (err) {
+ dev_err(&pdev->dev, "failed to enable clock\n");
+ goto out_clkget;
+ }
+
+ clock_frequency = clk_get_rate(priv->clk);
+ }
+
id = arc_reg_get(priv, R_ID);

/* Check for EMAC revision 5 or 7, magic number */
if (!(id == 0x0005fd02 || id == 0x0007fd02)) {
dev_err(&pdev->dev, "ARC EMAC not detected, id=0x%x\n", id);
err = -ENODEV;
- goto out_netdev;
+ goto out_clken;
}
dev_info(&pdev->dev, "ARC EMAC detected with id: 0x%x\n", id);

@@ -708,7 +720,7 @@ static int arc_emac_probe(struct platform_device *pdev)
ndev->name, ndev);
if (err) {
dev_err(&pdev->dev, "could not allocate IRQ\n");
- goto out_netdev;
+ goto out_clken;
}

/* Get MAC address from device tree */
@@ -729,7 +741,7 @@ static int arc_emac_probe(struct platform_device *pdev)
if (!priv->rxbd) {
dev_err(&pdev->dev, "failed to allocate data buffers\n");
err = -ENOMEM;
- goto out_netdev;
+ goto out_clken;
}

priv->txbd = priv->rxbd + RX_BD_NUM;
@@ -741,7 +753,7 @@ static int arc_emac_probe(struct platform_device *pdev)
err = arc_mdio_probe(pdev, priv);
if (err) {
dev_err(&pdev->dev, "failed to probe MII bus\n");
- goto out_netdev;
+ goto out_clken;
}

priv->phy_dev = of_phy_connect(ndev, phy_node, arc_emac_adjust_link, 0,
@@ -771,6 +783,12 @@ out_netif_api:
priv->phy_dev = NULL;
out_mdio:
arc_mdio_remove(priv);
+out_clken:
+ if (!IS_ERR(priv->clk))
+ clk_disable_unprepare(priv->clk);
+out_clkget:
+ if (!IS_ERR(priv->clk))
+ clk_put(priv->clk);
out_netdev:
free_netdev(ndev);
return err;
@@ -786,6 +804,12 @@ static int arc_emac_remove(struct platform_device *pdev)
arc_mdio_remove(priv);
unregister_netdev(ndev);
netif_napi_del(&priv->napi);
+
+ if (!IS_ERR(priv->clk)) {
+ clk_disable_unprepare(priv->clk);
+ clk_put(priv->clk);
+ }
+
free_netdev(ndev);

return 0;
--
1.9.0