@@ -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)
@@ -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)
@@ -186,6 +186,69 @@ 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
+ * @milliamp: milliamp value
+ */
+struct ksz_drive_strength {
+ u32 reg_val;
+ u32 milliamp;
+};
+
+/* ksz9477_drive_strengths - Drive strength mapping for KSZ9477 variants
+ *
+ * This values are not documented in KSZ9477 variants.
+ * 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,
@@ -3516,6 +3579,245 @@ 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.
+ * @milliamp: The drive strength value in milliamp to be converted.
+ *
+ * This function searches the array of drive strength values for the given
+ * milliamp 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 milliamp)
+{
+ int i;
+
+ for (i = 0; i < array_size; i++) {
+ if (array[i].milliamp == milliamp)
+ 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.
+ * @milliamp: Invalid drive strength value in milliamp
+ *
+ * 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 milliamp)
+{
+ 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].milliamp);
+
+ if (added_len < 0 || 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",
+ milliamp, 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 milliamp;
+ 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);
+ }
+
+ milliamp = props[KSZ_DRIVER_STRENGTH_IO].value;
+ ret = ksz_drive_strength_to_reg(ksz8830_drive_strengths, array_size,
+ milliamp);
+ if (ret < 0) {
+ ksz_drive_strength_error(dev, ksz8830_drive_strengths,
+ array_size, milliamp);
+ 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 found = 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;
+
+ found = true;
+ }
+
+ if (!found)
+ 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;
@@ -3598,6 +3900,10 @@ 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;
@@ -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