2022-01-26 22:12:01

by Tobias Waldekranz

Subject: [PATCH v2 net-next 4/5] net/fsl: xgmac_mdio: Support setting the MDC frequency

Support the standard "clock-frequency" attribute to set the generated
MDC frequency. If not specified, the driver will leave the divisor
bits untouched.

Signed-off-by: Tobias Waldekranz <[email protected]>
---
drivers/net/ethernet/freescale/xgmac_mdio.c | 38 ++++++++++++++++++++-
1 file changed, 37 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/freescale/xgmac_mdio.c b/drivers/net/ethernet/freescale/xgmac_mdio.c
index 18bf2370d45a..d38d0c372585 100644
--- a/drivers/net/ethernet/freescale/xgmac_mdio.c
+++ b/drivers/net/ethernet/freescale/xgmac_mdio.c
@@ -14,6 +14,7 @@

#include <linux/acpi.h>
#include <linux/acpi_mdio.h>
+#include <linux/clk.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/mdio.h>
@@ -36,7 +37,7 @@ struct tgec_mdio_controller {
} __packed;

#define MDIO_STAT_ENC BIT(6)
-#define MDIO_STAT_CLKDIV(x) (((x>>1) & 0xff) << 8)
+#define MDIO_STAT_CLKDIV(x) (((x) & 0x1ff) << 7)
#define MDIO_STAT_BSY BIT(0)
#define MDIO_STAT_RD_ER BIT(1)
#define MDIO_STAT_PRE_DIS BIT(5)
@@ -51,6 +52,8 @@ struct tgec_mdio_controller {

struct mdio_fsl_priv {
struct tgec_mdio_controller __iomem *mdio_base;
+ struct clk *enet_clk;
+ u32 mdc_freq;
bool is_little_endian;
bool has_a009885;
bool has_a011043;
@@ -255,6 +258,35 @@ static int xgmac_mdio_read(struct mii_bus *bus, int phy_id, int regnum)
return ret;
}

+static int xgmac_mdio_set_mdc_freq(struct mii_bus *bus)
+{
+ struct mdio_fsl_priv *priv = (struct mdio_fsl_priv *)bus->priv;
+ struct tgec_mdio_controller __iomem *regs = priv->mdio_base;
+ struct device *dev = bus->parent;
+ u32 mdio_stat, div;
+
+ if (device_property_read_u32(dev, "clock-frequency", &priv->mdc_freq))
+ return 0;
+
+ priv->enet_clk = devm_clk_get(dev, NULL);
+ if (IS_ERR(priv->enet_clk)) {
+ dev_err(dev, "Input clock unknown, not changing MDC frequency");
+ return PTR_ERR(priv->enet_clk);
+ }
+
+ div = ((clk_get_rate(priv->enet_clk) / priv->mdc_freq) - 1) / 2;
+ if (div < 5 || div > 0x1ff) {
+ dev_err(dev, "Requested MDC frequecy is out of range, ignoring");
+ return -EINVAL;
+ }
+
+ mdio_stat = xgmac_read32(&regs->mdio_stat, priv->is_little_endian);
+ mdio_stat &= ~MDIO_STAT_CLKDIV(0x1ff);
+ mdio_stat |= MDIO_STAT_CLKDIV(div);
+ xgmac_write32(mdio_stat, &regs->mdio_stat, priv->is_little_endian);
+ return 0;
+}
+
static void xgmac_mdio_set_suppress_preamble(struct mii_bus *bus)
{
struct mdio_fsl_priv *priv = (struct mdio_fsl_priv *)bus->priv;
@@ -319,6 +351,10 @@ static int xgmac_mdio_probe(struct platform_device *pdev)

xgmac_mdio_set_suppress_preamble(bus);

+ ret = xgmac_mdio_set_mdc_freq(bus);
+ if (ret)
+ return ret;
+
fwnode = pdev->dev.fwnode;
if (is_of_node(fwnode))
ret = of_mdiobus_register(bus, to_of_node(fwnode));
--
2.25.1

2022-01-26 22:18:38

by Andrew Lunn

Subject: Re: [PATCH v2 net-next 4/5] net/fsl: xgmac_mdio: Support setting the MDC frequency

On Wed, Jan 26, 2022 at 05:05:42PM +0100, Tobias Waldekranz wrote:
> Support the standard "clock-frequency" attribute to set the generated
> MDC frequency. If not specified, the driver will leave the divisor
> bits untouched.
>
> Signed-off-by: Tobias Waldekranz <[email protected]>

Reviewed-by: Andrew Lunn <[email protected]>

Andrew