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net/fsl: xgmac_mdio: Support setting the MDC frequency

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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 <tobias@waldekranz.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Tobias Waldekranz 2022-01-26 17:05:42 +01:00 committed by David S. Miller
parent 909bea7348
commit dd8f467eda
1 changed files with 37 additions and 1 deletions
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38
drivers/net/ethernet/freescale/xgmac_mdio.c
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@ -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 @@ irq_restore:
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));