Commit 50675d84 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'dsa-microchip-drive-strength-support' 



Oleksij Rempel says:

====================
net: dsa: microchip: add drive strength support

changes v5:
- rename milliamp to microamp
- do not expect negative error code on snprintf
- set coma after last struct element
- rename found to have_any_prop

changes v4:
- integrate microchip feedback to the ksz9477_drive_strengths comment.
- add Reviewed-by: default avatarRob Herring <robh@kernel.org>

changes v3:
- yaml: use enum instead of min/max
- do not use snprintf() on overlapping buffer.
- unify ksz_drive_strength_to_reg() and ksz_drive_strength_error(). Make
  it usable for KSZ9477 and KSZ8830 variants.
- use ksz_rmw8() in ksz9477_drive_strength_write()
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents b6a7eeb4 d67d7247

Documentation/devicetree/bindings/net/dsa/microchip,ksz.yaml

+20 −0
Original line number Diff line number Diff line
@@ -49,6 +49,26 @@ properties: 
      Set if the output SYNCLKO clock should be disabled. Do not mix with

      microchip,synclko-125.



  microchip,io-drive-strength-microamp:

    description:

      IO Pad Drive Strength

    enum: [8000, 16000]

    default: 16000



  microchip,hi-drive-strength-microamp:

    description:

      High Speed Drive Strength. Controls drive strength of GMII / RGMII /

      MII / RMII (except TX_CLK/REFCLKI, COL and CRS) and CLKO_25_125 lines.

    enum: [2000, 4000, 8000, 12000, 16000, 20000, 24000, 28000]

    default: 24000



  microchip,lo-drive-strength-microamp:

    description:

      Low Speed Drive Strength. Controls drive strength of TX_CLK / REFCLKI,

      COL, CRS, LEDs, PME_N, NTRP_N, SDO and SDI/SDA/MDIO lines.

    enum: [2000, 4000, 8000, 12000, 16000, 20000, 24000, 28000]

    default: 8000



  interrupts:

    maxItems: 1

drivers/net/dsa/microchip/ksz8795_reg.h

+0 −14
Original line number Diff line number Diff line
@@ -442,20 +442,6 @@ 
#define TOS_PRIO_M			KS_PRIO_M

#define TOS_PRIO_S			KS_PRIO_S



#define REG_SW_CTRL_20			0xA3



#define SW_GMII_DRIVE_STRENGTH_S	4

#define SW_DRIVE_STRENGTH_M		0x7

#define SW_DRIVE_STRENGTH_2MA		0

#define SW_DRIVE_STRENGTH_4MA		1

#define SW_DRIVE_STRENGTH_8MA		2

#define SW_DRIVE_STRENGTH_12MA		3

#define SW_DRIVE_STRENGTH_16MA		4

#define SW_DRIVE_STRENGTH_20MA		5

#define SW_DRIVE_STRENGTH_24MA		6

#define SW_DRIVE_STRENGTH_28MA		7

#define SW_MII_DRIVE_STRENGTH_S		0



#define REG_SW_CTRL_21			0xA4



#define SW_IPV6_MLD_OPTION		BIT(3)

drivers/net/dsa/microchip/ksz9477_reg.h

+0 −13
Original line number Diff line number Diff line
@@ -112,19 +112,6 @@ 


#define REG_SW_IBA_SYNC__1		0x010C



#define REG_SW_IO_STRENGTH__1		0x010D

#define SW_DRIVE_STRENGTH_M		0x7

#define SW_DRIVE_STRENGTH_2MA		0

#define SW_DRIVE_STRENGTH_4MA		1

#define SW_DRIVE_STRENGTH_8MA		2

#define SW_DRIVE_STRENGTH_12MA		3

#define SW_DRIVE_STRENGTH_16MA		4

#define SW_DRIVE_STRENGTH_20MA		5

#define SW_DRIVE_STRENGTH_24MA		6

#define SW_DRIVE_STRENGTH_28MA		7

#define SW_HI_SPEED_DRIVE_STRENGTH_S	4

#define SW_LO_SPEED_DRIVE_STRENGTH_S	0



#define REG_SW_IBA_STATUS__4		0x0110



#define SW_IBA_REQ			BIT(31)

drivers/net/dsa/microchip/ksz_common.c

+309 −0
Original line number Diff line number Diff line
@@ -186,6 +186,72 @@ static const struct ksz_mib_names ksz9477_mib_names[] = { 
	{ 0x83, "tx_discards" },

};



struct ksz_driver_strength_prop {

	const char *name;

	int offset;

	int value;

};



enum ksz_driver_strength_type {

	KSZ_DRIVER_STRENGTH_HI,

	KSZ_DRIVER_STRENGTH_LO,

	KSZ_DRIVER_STRENGTH_IO,

};



/**

 * struct ksz_drive_strength - drive strength mapping

 * @reg_val:	register value

 * @microamp:	microamp value

 */

struct ksz_drive_strength {

	u32 reg_val;

	u32 microamp;

};



/* ksz9477_drive_strengths - Drive strength mapping for KSZ9477 variants

 *

 * This values are not documented in KSZ9477 variants but confirmed by

 * Microchip that KSZ9477, KSZ9567, KSZ8567, KSZ9897, KSZ9896, KSZ9563, KSZ9893

 * and KSZ8563 are using same register (drive strength) settings like KSZ8795.

 *

 * Documentation in KSZ8795CLX provides more information with some

 * recommendations:

 * - for high speed signals

 *   1. 4 mA or 8 mA is often used for MII, RMII, and SPI interface with using

 *      2.5V or 3.3V VDDIO.

 *   2. 12 mA or 16 mA is often used for MII, RMII, and SPI interface with

 *      using 1.8V VDDIO.

 *   3. 20 mA or 24 mA is often used for GMII/RGMII interface with using 2.5V

 *      or 3.3V VDDIO.

 *   4. 28 mA is often used for GMII/RGMII interface with using 1.8V VDDIO.

 *   5. In same interface, the heavy loading should use higher one of the

 *      drive current strength.

 * - for low speed signals

 *   1. 3.3V VDDIO, use either 4 mA or 8 mA.

 *   2. 2.5V VDDIO, use either 8 mA or 12 mA.

 *   3. 1.8V VDDIO, use either 12 mA or 16 mA.

 *   4. If it is heavy loading, can use higher drive current strength.

 */

static const struct ksz_drive_strength ksz9477_drive_strengths[] = {

	{ SW_DRIVE_STRENGTH_2MA,  2000 },

	{ SW_DRIVE_STRENGTH_4MA,  4000 },

	{ SW_DRIVE_STRENGTH_8MA,  8000 },

	{ SW_DRIVE_STRENGTH_12MA, 12000 },

	{ SW_DRIVE_STRENGTH_16MA, 16000 },

	{ SW_DRIVE_STRENGTH_20MA, 20000 },

	{ SW_DRIVE_STRENGTH_24MA, 24000 },

	{ SW_DRIVE_STRENGTH_28MA, 28000 },

};



/* ksz8830_drive_strengths - Drive strength mapping for KSZ8830, KSZ8873, ..

 *			     variants.

 * This values are documented in KSZ8873 and KSZ8863 datasheets.

 */

static const struct ksz_drive_strength ksz8830_drive_strengths[] = {

	{ 0,  8000 },

	{ KSZ8873_DRIVE_STRENGTH_16MA, 16000 },

};



static const struct ksz_dev_ops ksz8_dev_ops = {

	.setup = ksz8_setup,

	.get_port_addr = ksz8_get_port_addr,
@@ -3530,6 +3596,245 @@ static void ksz_parse_rgmii_delay(struct ksz_device *dev, int port_num, 
	dev->ports[port_num].rgmii_tx_val = tx_delay;

}



/**

 * ksz_drive_strength_to_reg() - Convert drive strength value to corresponding

 *				 register value.

 * @array:	The array of drive strength values to search.

 * @array_size:	The size of the array.

 * @microamp:	The drive strength value in microamp to be converted.

 *

 * This function searches the array of drive strength values for the given

 * microamp value and returns the corresponding register value for that drive.

 *

 * Returns: If found, the corresponding register value for that drive strength

 * is returned. Otherwise, -EINVAL is returned indicating an invalid value.

 */

static int ksz_drive_strength_to_reg(const struct ksz_drive_strength *array,

				     size_t array_size, int microamp)

{

	int i;



	for (i = 0; i < array_size; i++) {

		if (array[i].microamp == microamp)

			return array[i].reg_val;

	}



	return -EINVAL;

}



/**

 * ksz_drive_strength_error() - Report invalid drive strength value

 * @dev:	ksz device

 * @array:	The array of drive strength values to search.

 * @array_size:	The size of the array.

 * @microamp:	Invalid drive strength value in microamp

 *

 * This function logs an error message when an unsupported drive strength value

 * is detected. It lists out all the supported drive strength values for

 * reference in the error message.

 */

static void ksz_drive_strength_error(struct ksz_device *dev,

				     const struct ksz_drive_strength *array,

				     size_t array_size, int microamp)

{

	char supported_values[100];

	size_t remaining_size;

	int added_len;

	char *ptr;

	int i;



	remaining_size = sizeof(supported_values);

	ptr = supported_values;



	for (i = 0; i < array_size; i++) {

		added_len = snprintf(ptr, remaining_size,

				     i == 0 ? "%d" : ", %d", array[i].microamp);



		if (added_len >= remaining_size)

			break;



		ptr += added_len;

		remaining_size -= added_len;

	}



	dev_err(dev->dev, "Invalid drive strength %d, supported values are %s\n",

		microamp, supported_values);

}



/**

 * ksz9477_drive_strength_write() - Set the drive strength for specific KSZ9477

 *				    chip variants.

 * @dev:       ksz device

 * @props:     Array of drive strength properties to be applied

 * @num_props: Number of properties in the array

 *

 * This function configures the drive strength for various KSZ9477 chip variants

 * based on the provided properties. It handles chip-specific nuances and

 * ensures only valid drive strengths are written to the respective chip.

 *

 * Return: 0 on successful configuration, a negative error code on failure.

 */

static int ksz9477_drive_strength_write(struct ksz_device *dev,

					struct ksz_driver_strength_prop *props,

					int num_props)

{

	size_t array_size = ARRAY_SIZE(ksz9477_drive_strengths);

	int i, ret, reg;

	u8 mask = 0;

	u8 val = 0;



	if (props[KSZ_DRIVER_STRENGTH_IO].value != -1)

		dev_warn(dev->dev, "%s is not supported by this chip variant\n",

			 props[KSZ_DRIVER_STRENGTH_IO].name);



	if (dev->chip_id == KSZ8795_CHIP_ID ||

	    dev->chip_id == KSZ8794_CHIP_ID ||

	    dev->chip_id == KSZ8765_CHIP_ID)

		reg = KSZ8795_REG_SW_CTRL_20;

	else

		reg = KSZ9477_REG_SW_IO_STRENGTH;



	for (i = 0; i < num_props; i++) {

		if (props[i].value == -1)

			continue;



		ret = ksz_drive_strength_to_reg(ksz9477_drive_strengths,

						array_size, props[i].value);

		if (ret < 0) {

			ksz_drive_strength_error(dev, ksz9477_drive_strengths,

						 array_size, props[i].value);

			return ret;

		}



		mask |= SW_DRIVE_STRENGTH_M << props[i].offset;

		val |= ret << props[i].offset;

	}



	return ksz_rmw8(dev, reg, mask, val);

}



/**

 * ksz8830_drive_strength_write() - Set the drive strength configuration for

 *				    KSZ8830 compatible chip variants.

 * @dev:       ksz device

 * @props:     Array of drive strength properties to be set

 * @num_props: Number of properties in the array

 *

 * This function applies the specified drive strength settings to KSZ8830 chip

 * variants (KSZ8873, KSZ8863).

 * It ensures the configurations align with what the chip variant supports and

 * warns or errors out on unsupported settings.

 *

 * Return: 0 on success, error code otherwise

 */

static int ksz8830_drive_strength_write(struct ksz_device *dev,

					struct ksz_driver_strength_prop *props,

					int num_props)

{

	size_t array_size = ARRAY_SIZE(ksz8830_drive_strengths);

	int microamp;

	int i, ret;



	for (i = 0; i < num_props; i++) {

		if (props[i].value == -1 || i == KSZ_DRIVER_STRENGTH_IO)

			continue;



		dev_warn(dev->dev, "%s is not supported by this chip variant\n",

			 props[i].name);

	}



	microamp = props[KSZ_DRIVER_STRENGTH_IO].value;

	ret = ksz_drive_strength_to_reg(ksz8830_drive_strengths, array_size,

					microamp);

	if (ret < 0) {

		ksz_drive_strength_error(dev, ksz8830_drive_strengths,

					 array_size, microamp);

		return ret;

	}



	return ksz_rmw8(dev, KSZ8873_REG_GLOBAL_CTRL_12,

			KSZ8873_DRIVE_STRENGTH_16MA, ret);

}



/**

 * ksz_parse_drive_strength() - Extract and apply drive strength configurations

 *				from device tree properties.

 * @dev:	ksz device

 *

 * This function reads the specified drive strength properties from the

 * device tree, validates against the supported chip variants, and sets

 * them accordingly. An error should be critical here, as the drive strength

 * settings are crucial for EMI compliance.

 *

 * Return: 0 on success, error code otherwise

 */

static int ksz_parse_drive_strength(struct ksz_device *dev)

{

	struct ksz_driver_strength_prop of_props[] = {

		[KSZ_DRIVER_STRENGTH_HI] = {

			.name = "microchip,hi-drive-strength-microamp",

			.offset = SW_HI_SPEED_DRIVE_STRENGTH_S,

			.value = -1,

		},

		[KSZ_DRIVER_STRENGTH_LO] = {

			.name = "microchip,lo-drive-strength-microamp",

			.offset = SW_LO_SPEED_DRIVE_STRENGTH_S,

			.value = -1,

		},

		[KSZ_DRIVER_STRENGTH_IO] = {

			.name = "microchip,io-drive-strength-microamp",

			.offset = 0, /* don't care */

			.value = -1,

		},

	};

	struct device_node *np = dev->dev->of_node;

	bool have_any_prop = false;

	int i, ret;



	for (i = 0; i < ARRAY_SIZE(of_props); i++) {

		ret = of_property_read_u32(np, of_props[i].name,

					   &of_props[i].value);

		if (ret && ret != -EINVAL)

			dev_warn(dev->dev, "Failed to read %s\n",

				 of_props[i].name);

		if (ret)

			continue;



		have_any_prop = true;

	}



	if (!have_any_prop)

		return 0;



	switch (dev->chip_id) {

	case KSZ8830_CHIP_ID:

		return ksz8830_drive_strength_write(dev, of_props,

						    ARRAY_SIZE(of_props));

	case KSZ8795_CHIP_ID:

	case KSZ8794_CHIP_ID:

	case KSZ8765_CHIP_ID:

	case KSZ8563_CHIP_ID:

	case KSZ9477_CHIP_ID:

	case KSZ9563_CHIP_ID:

	case KSZ9567_CHIP_ID:

	case KSZ9893_CHIP_ID:

	case KSZ9896_CHIP_ID:

	case KSZ9897_CHIP_ID:

		return ksz9477_drive_strength_write(dev, of_props,

						    ARRAY_SIZE(of_props));

	default:

		for (i = 0; i < ARRAY_SIZE(of_props); i++) {

			if (of_props[i].value == -1)

				continue;



			dev_warn(dev->dev, "%s is not supported by this chip variant\n",

				 of_props[i].name);

		}

	}



	return 0;

}



int ksz_switch_register(struct ksz_device *dev)

{

	const struct ksz_chip_data *info;
@@ -3612,6 +3917,10 @@ int ksz_switch_register(struct ksz_device *dev) 
	for (port_num = 0; port_num < dev->info->port_cnt; ++port_num)

		dev->ports[port_num].interface = PHY_INTERFACE_MODE_NA;

	if (dev->dev->of_node) {

		ret = ksz_parse_drive_strength(dev);

		if (ret)

			return ret;



		ret = of_get_phy_mode(dev->dev->of_node, &interface);

		if (ret == 0)

			dev->compat_interface = interface;

drivers/net/dsa/microchip/ksz_common.h

+20 −0
Original line number Diff line number Diff line
@@ -689,6 +689,26 @@ static inline int is_lan937x(struct ksz_device *dev) 
#define KSZ8_LEGAL_PACKET_SIZE		1518

#define KSZ9477_MAX_FRAME_SIZE		9000



#define KSZ8873_REG_GLOBAL_CTRL_12	0x0e

/* Drive Strength of I/O Pad

 * 0: 8mA, 1: 16mA

 */

#define KSZ8873_DRIVE_STRENGTH_16MA	BIT(6)



#define KSZ8795_REG_SW_CTRL_20		0xa3

#define KSZ9477_REG_SW_IO_STRENGTH	0x010d

#define SW_DRIVE_STRENGTH_M		0x7

#define SW_DRIVE_STRENGTH_2MA		0

#define SW_DRIVE_STRENGTH_4MA		1

#define SW_DRIVE_STRENGTH_8MA		2

#define SW_DRIVE_STRENGTH_12MA		3

#define SW_DRIVE_STRENGTH_16MA		4

#define SW_DRIVE_STRENGTH_20MA		5

#define SW_DRIVE_STRENGTH_24MA		6

#define SW_DRIVE_STRENGTH_28MA		7

#define SW_HI_SPEED_DRIVE_STRENGTH_S	4

#define SW_LO_SPEED_DRIVE_STRENGTH_S	0



#define KSZ9477_REG_PORT_OUT_RATE_0	0x0420

#define KSZ9477_OUT_RATE_NO_LIMIT	0