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net: phy: Add support to configure clock in Broadcom iProc mdio mux 

Add support to configure the internal rate adjust register based on the
core clock supplied through device tree in the Broadcom iProc mdio mux.

The operating frequency of the mdio mux block is 11MHz. This is derrived
by dividing the clock to the mdio mux with the rate adjust register.

In some SoC's the default values of the rate adjust register do not yield
11MHz. These SoC's are required to specify the clock via the device tree
for proper operation.

Signed-off-by: Arun Parameswaran <arun.parameswaran@broadcom.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Arun Parameswaran 2018-08-01 17:53:52 -07:00 committed by David S. Miller
parent 0d5204abe5
commit 56aea577c8
1 changed files with 39 additions and 2 deletions
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41
drivers/net/phy/mdio-mux-bcm-iproc.c
View File

@ -13,7 +13,7 @@
* You should have received a copy of the GNU General Public License
* version 2 (GPLv2) along with this source code.
*/
#include <linux/clk.h>
#include <linux/platform_device.h>
#include <linux/device.h>
#include <linux/of_mdio.h>
@ -22,6 +22,10 @@
#include <linux/mdio-mux.h>
#include <linux/delay.h>
#define MDIO_RATE_ADJ_EXT_OFFSET 0x000
#define MDIO_RATE_ADJ_INT_OFFSET 0x004
#define MDIO_RATE_ADJ_DIVIDENT_SHIFT 16
#define MDIO_SCAN_CTRL_OFFSET 0x008
#define MDIO_SCAN_CTRL_OVRIDE_EXT_MSTR 28
@ -49,21 +53,38 @@
#define MDIO_REG_ADDR_SPACE_SIZE 0x250
#define MDIO_OPERATING_FREQUENCY 11000000
#define MDIO_RATE_ADJ_DIVIDENT 1
struct iproc_mdiomux_desc {
void *mux_handle;
void __iomem *base;
struct device *dev;
struct mii_bus *mii_bus;
struct clk *core_clk;
};
static void mdio_mux_iproc_config(struct iproc_mdiomux_desc *md)
{
u32 divisor;
u32 val;
/* Disable external mdio master access */
val = readl(md->base + MDIO_SCAN_CTRL_OFFSET);
val |= BIT(MDIO_SCAN_CTRL_OVRIDE_EXT_MSTR);
writel(val, md->base + MDIO_SCAN_CTRL_OFFSET);
if (md->core_clk) {
/* use rate adjust regs to derrive the mdio's operating
* frequency from the specified core clock
*/
divisor = clk_get_rate(md->core_clk) / MDIO_OPERATING_FREQUENCY;
divisor = divisor / (MDIO_RATE_ADJ_DIVIDENT + 1);
val = divisor;
val |= MDIO_RATE_ADJ_DIVIDENT << MDIO_RATE_ADJ_DIVIDENT_SHIFT;
writel(val, md->base + MDIO_RATE_ADJ_EXT_OFFSET);
writel(val, md->base + MDIO_RATE_ADJ_INT_OFFSET);
}
}
static int iproc_mdio_wait_for_idle(void __iomem *base, bool result)
@ -204,6 +225,19 @@ static int mdio_mux_iproc_probe(struct platform_device *pdev)
return -ENOMEM;
}
md->core_clk = devm_clk_get(&pdev->dev, NULL);
if (md->core_clk == ERR_PTR(-ENOENT) ||
md->core_clk == ERR_PTR(-EINVAL))
md->core_clk = NULL;
else if (IS_ERR(md->core_clk))
return PTR_ERR(md->core_clk);
rc = clk_prepare_enable(md->core_clk);
if (rc) {
dev_err(&pdev->dev, "failed to enable core clk\n");
return rc;
}
bus = md->mii_bus;
bus->priv = md;
bus->name = "iProc MDIO mux bus";
@ -217,7 +251,7 @@ static int mdio_mux_iproc_probe(struct platform_device *pdev)
rc = mdiobus_register(bus);
if (rc) {
dev_err(&pdev->dev, "mdiomux registration failed\n");
return rc;
goto out_clk;
}
platform_set_drvdata(pdev, md);
@ -236,6 +270,8 @@ static int mdio_mux_iproc_probe(struct platform_device *pdev)
out_register:
mdiobus_unregister(bus);
out_clk:
clk_disable_unprepare(md->core_clk);
return rc;
}
@ -245,6 +281,7 @@ static int mdio_mux_iproc_remove(struct platform_device *pdev)
mdio_mux_uninit(md->mux_handle);
mdiobus_unregister(md->mii_bus);
clk_disable_unprepare(md->core_clk);
return 0;
}