Commit 4f58e6dc authored by Allan W. Nielsen's avatar Allan W. Nielsen Committed by David S. Miller
Browse files

net: phy: Cleanup the Edge-Rate feature in Microsemi PHYs. 



Edge-Rate cleanup include the following:
- Updated device tree bindings documentation for edge-rate
- The edge-rate is now specified as a "slowdown", meaning that it is now
  being specified as positive values instead of negative (both
  documentation and implementation wise).
- Only explicitly documented values for "vsc8531,vddmac" and
  "vsc8531,edge-slowdown" are accepted by the device driver.
- Deleted include/dt-bindings/net/mscc-phy-vsc8531.h as it was not needed.
- Read/validate devicetree settings in probe instead of init

Signed-off-by: default avatarAllan W. Nielsen <allan.nielsen@microsemi.com>
Signed-off-by: default avatarRaju Lakkaraju <raju.lakkaraju@microsemi.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent cf53b1da

Documentation/devicetree/bindings/net/mscc-phy-vsc8531.txt

+28 −23
Original line number Diff line number Diff line
@@ -6,22 +6,27 @@ Required properties: 
		  Documentation/devicetree/bindings/net/phy.txt



Optional properties:

- vsc8531,vddmac	: The vddmac in mV.

- vsc8531,vddmac	: The vddmac in mV. Allowed values is listed

			  in the first row of Table 1 (below).

			  This property is only used in combination

			  with the 'edge-slowdown' property.

			  Default value is 3300.

- vsc8531,edge-slowdown	: % the edge should be slowed down relative to

			  the fastest possible edge time. Native sign

			  need not enter.

			  the fastest possible edge time.

			  Edge rate sets the drive strength of the MAC

			  interface output signals.  Changing the drive

			  strength will affect the edge rate of the output

			  signal.  The goal of this setting is to help

			  reduce electrical emission (EMI) by being able

			  to reprogram drive strength and in effect slow

			  down the edge rate if desired.  Table 1 shows the

			  impact to the edge rate per VDDMAC supply for each

			  drive strength setting.

			  Ref: Table:1 - Edge rate change below.



Note: see dt-bindings/net/mscc-phy-vsc8531.h for applicable values

			  interface output signals.  Changing the

			  drive strength will affect the edge rate of

			  the output signal.  The goal of this setting

			  is to help reduce electrical emission (EMI)

			  by being able to reprogram drive strength

			  and in effect slow down the edge rate if

			  desired.

			  To adjust the edge-slowdown, the 'vddmac'

			  must be specified. Table 1 lists the

			  supported edge-slowdown values for a given

			  'vddmac'.

			  Default value is 0%.

			  Ref: Table:1 - Edge rate change (below).



Table: 1 - Edge rate change

----------------------------------------------------------------|
@@ -29,23 +34,23 @@ Table: 1 - Edge rate change 
|								|

| 3300 mV	2500 mV		1800 mV		1500 mV		|

|---------------------------------------------------------------|

| Default	Deafult		Default		Default		|

| 0%		0%		0%		0%		|

| (Fastest)			(recommended)	(recommended)	|

|---------------------------------------------------------------|

| -2%		-3%		-5%		-6%		|

| 2%		3%		5%		6%		|

|---------------------------------------------------------------|

| -4%		-6%		-9%		-14%		|

| 4%		6%		9%		14%		|

|---------------------------------------------------------------|

| -7%		-10%		-16%		-21%		|

| 7%		10%		16%		21%		|

|(recommended)	(recommended)					|

|---------------------------------------------------------------|

| -10%		-14%		-23%		-29%		|

| 10%		14%		23%		29%		|

|---------------------------------------------------------------|

| -17%		-23%		-35%		-42%		|

| 17%		23%		35%		42%		|

|---------------------------------------------------------------|

| -29%		-37%		-52%		-58%		|

| 29%		37%		52%		58%		|

|---------------------------------------------------------------|

| -53%		-63%		-76%		-77%		|

| 53%		63%		76%		77%		|

| (slowest)							|

|---------------------------------------------------------------|
@@ -54,5 +59,5 @@ Example: 
        vsc8531_0: ethernet-phy@0 {

                compatible = "ethernet-phy-id0007.0570";

                vsc8531,vddmac		= <3300>;

                vsc8531,edge-slowdown	= <21>;

                vsc8531,edge-slowdown	= <7>;

        };

drivers/net/phy/mscc.c

+62 −73
Original line number Diff line number Diff line
@@ -12,7 +12,6 @@ 
#include <linux/mii.h>

#include <linux/phy.h>

#include <linux/of.h>

#include <dt-bindings/net/mscc-phy-vsc8531.h>

#include <linux/netdevice.h>



enum rgmii_rx_clock_delay {
@@ -69,22 +68,28 @@ enum rgmii_rx_clock_delay { 
#define PHY_ID_VSC8531			  0x00070570

#define PHY_ID_VSC8541			  0x00070770



struct edge_rate_table {

	u16 vddmac;

	int slowdown[MSCC_SLOWDOWN_MAX];

};

#define MSCC_VDDMAC_1500		  1500

#define MSCC_VDDMAC_1800		  1800

#define MSCC_VDDMAC_2500		  2500

#define MSCC_VDDMAC_3300		  3300



struct edge_rate_table edge_table[MSCC_VDDMAC_MAX] = {

	{3300, { 0, -2, -4,  -7,  -10, -17, -29, -53} },

	{2500, { 0, -3, -6,  -10, -14, -23, -37, -63} },

	{1800, { 0, -5, -9,  -16, -23, -35, -52, -76} },

	{1500, { 0, -6, -14, -21, -29, -42, -58, -77} },

struct vsc8531_private {

	int rate_magic;

};



struct vsc8531_private {

	u8 edge_slowdown;

#ifdef CONFIG_OF_MDIO

struct vsc8531_edge_rate_table {

	u16 vddmac;

	u8 slowdown[8];

};



static const struct vsc8531_edge_rate_table edge_table[] = {

	{MSCC_VDDMAC_3300, { 0, 2,  4,  7, 10, 17, 29, 53} },

	{MSCC_VDDMAC_2500, { 0, 3,  6, 10, 14, 23, 37, 63} },

	{MSCC_VDDMAC_1800, { 0, 5,  9, 16, 23, 35, 52, 76} },

	{MSCC_VDDMAC_1500, { 0, 6, 14, 21, 29, 42, 58, 77} },

};

#endif /* CONFIG_OF_MDIO */



static int vsc85xx_phy_page_set(struct phy_device *phydev, u8 page)

{
@@ -205,29 +210,43 @@ out_unlock: 
	mutex_unlock(&phydev->lock);

}



static u8 edge_rate_magic_get(u16 vddmac,

			      int slowdown)

#ifdef CONFIG_OF_MDIO

static int vsc85xx_edge_rate_magic_get(struct phy_device *phydev)

{

	int rc = (MSCC_SLOWDOWN_MAX - 1);

	u8 vdd;

	u8 sd;

	u16 vdd;

	int rc, i, j;

	struct device *dev = &phydev->mdio.dev;

	struct device_node *of_node = dev->of_node;

	u8 sd_array_size = ARRAY_SIZE(edge_table[0].slowdown);



	for (vdd = 0; vdd < MSCC_VDDMAC_MAX; vdd++) {

		if (edge_table[vdd].vddmac == vddmac) {

			for (sd = 0; sd < MSCC_SLOWDOWN_MAX; sd++) {

				if (edge_table[vdd].slowdown[sd] <= slowdown) {

					rc = (MSCC_SLOWDOWN_MAX - sd - 1);

					break;

				}

			}

		}

	}

	if (!of_node)

		return -ENODEV;



	return rc;

	rc = of_property_read_u16(of_node, "vsc8531,vddmac", &vdd);

	if (rc != 0)

		vdd = MSCC_VDDMAC_3300;



	rc = of_property_read_u8(of_node, "vsc8531,edge-slowdown", &sd);

	if (rc != 0)

		sd = 0;



	for (i = 0; i < ARRAY_SIZE(edge_table); i++)

		if (edge_table[i].vddmac == vdd)

			for (j = 0; j < sd_array_size; j++)

				if (edge_table[i].slowdown[j] == sd)

					return (sd_array_size - j - 1);



	return -EINVAL;

}

#else

static int vsc85xx_edge_rate_magic_get(struct phy_device *phydev)

{

	return 0;

}

#endif /* CONFIG_OF_MDIO */



static int vsc85xx_edge_rate_cntl_set(struct phy_device *phydev,

				      u8 edge_rate)

static int vsc85xx_edge_rate_cntl_set(struct phy_device *phydev, u8 edge_rate)

{

	int rc;

	u16 reg_val;
@@ -308,45 +327,10 @@ out_unlock: 
	return rc;

}



#ifdef CONFIG_OF_MDIO

static int vsc8531_of_init(struct phy_device *phydev)

{

	int rc;

	struct vsc8531_private *vsc8531 = phydev->priv;

	struct device *dev = &phydev->mdio.dev;

	struct device_node *of_node = dev->of_node;



	if (!of_node)

		return -ENODEV;



	rc = of_property_read_u16(of_node, "vsc8531,vddmac",

				  &vsc8531->vddmac);

	if (rc == -EINVAL)

		vsc8531->vddmac = MSCC_VDDMAC_3300;

	rc = of_property_read_u8(of_node, "vsc8531,edge-slowdown",

				 &vsc8531->edge_slowdown);

	if (rc == -EINVAL)

		vsc8531->edge_slowdown = 0;



	rc = 0;

	return rc;

}

#else

static int vsc8531_of_init(struct phy_device *phydev)

{

	return 0;

}

#endif /* CONFIG_OF_MDIO */



static int vsc85xx_config_init(struct phy_device *phydev)

{

	int rc;

	struct vsc8531_private *vsc8531 = phydev->priv;

	u8 edge_rate;



	rc = vsc8531_of_init(phydev);

	if (rc)

		return rc;



	rc = vsc85xx_default_config(phydev);

	if (rc)
@@ -356,9 +340,7 @@ static int vsc85xx_config_init(struct phy_device *phydev) 
	if (rc)

		return rc;



	edge_rate = edge_rate_magic_get(vsc8531->vddmac,

					-(int)vsc8531->edge_slowdown);

	rc = vsc85xx_edge_rate_cntl_set(phydev, edge_rate);

	rc = vsc85xx_edge_rate_cntl_set(phydev, vsc8531->rate_magic);

	if (rc)

		return rc;
@@ -396,14 +378,21 @@ static int vsc85xx_config_intr(struct phy_device *phydev) 


static int vsc85xx_probe(struct phy_device *phydev)

{

	int rate_magic;

	struct vsc8531_private *vsc8531;



	rate_magic = vsc85xx_edge_rate_magic_get(phydev);

	if (rate_magic < 0)

		return rate_magic;



	vsc8531 = devm_kzalloc(&phydev->mdio.dev, sizeof(*vsc8531), GFP_KERNEL);

	if (!vsc8531)

		return -ENOMEM;



	phydev->priv = vsc8531;



	vsc8531->rate_magic = rate_magic;



	return 0;

}

include/dt-bindings/net/mscc-phy-vsc8531.h

deleted100644 → 0
+0 −21
Original line number Diff line number Diff line 
/*

 * Device Tree constants for Microsemi VSC8531 PHY

 *

 * Author: Nagaraju Lakkaraju

 *

 * License: Dual MIT/GPL

 * Copyright (c) 2016 Microsemi Corporation

 */



#ifndef _DT_BINDINGS_MSCC_VSC8531_H

#define _DT_BINDINGS_MSCC_VSC8531_H



/* MAC interface Edge rate control VDDMAC in milli Volts */

#define MSCC_VDDMAC_3300		 3300

#define MSCC_VDDMAC_2500		 2500

#define MSCC_VDDMAC_1800		 1800

#define MSCC_VDDMAC_1500		 1500

#define MSCC_VDDMAC_MAX			 4

#define MSCC_SLOWDOWN_MAX		 8



#endif

CRA Git | Maintained and supported by SUSTech CRA and CCSE