--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for the Skyworks Si3474 PoE PSE Controller
+ *
+ * Chip Architecture & Terminology:
+ *
+ * The Si3474 is a single-chip PoE PSE controller managing 8 physical power
+ * delivery channels. Internally, it's structured into two logical "Quads".
+ *
+ * Quad 0: Manages physical channels ('ports' in datasheet) 0, 1, 2, 3
+ * Quad 1: Manages physical channels ('ports' in datasheet) 4, 5, 6, 7
+ *
+ * Each Quad is accessed via a separate I2C address. The base address range is
+ * set by hardware pins A1-A4, and the specific address selects Quad 0 (usually
+ * the lower/even address) or Quad 1 (usually the higher/odd address).
+ * See datasheet Table 2.2 for the address mapping.
+ *
+ * While the Quads manage channel-specific operations, the Si3474 package has
+ * several resources shared across the entire chip:
+ * - Single RESETb input pin.
+ * - Single INTb output pin (signals interrupts from *either* Quad).
+ * - Single OSS input pin (Emergency Shutdown).
+ * - Global I2C Address (0x7F) used for firmware updates.
+ * - Global status monitoring (Temperature, VDD/VPWR Undervoltage Lockout).
+ *
+ * Driver Architecture:
+ *
+ * To handle the mix of per-Quad access and shared resources correctly, this
+ * driver treats the entire Si3474 package as one logical device. The driver
+ * instance associated with the primary I2C address (Quad 0) takes ownership.
+ * It discovers and manages the I2C client for the secondary address (Quad 1).
+ * This primary instance handles shared resources like IRQ management and
+ * registers a single PSE controller device representing all logical PIs.
+ * Internal functions route I2C commands to the appropriate Quad's i2c_client
+ * based on the target channel or PI.
+ *
+ * Terminology Mapping:
+ *
+ * - "PI" (Power Interface): Refers to the logical PSE port as defined by
+ * IEEE 802.3 (typically corresponds to an RJ45 connector). This is the
+ * `id` (0-7) used in the pse_controller_ops.
+ * - "Channel": Refers to one of the 8 physical power control paths within
+ * the Si3474 chip itself (hardware channels 0-7). This terminology is
+ * used internally within the driver to avoid confusion with 'ports'.
+ * - "Quad": One of the two internal 4-channel management units within the
+ * Si3474, each accessed via its own I2C address.
+ *
+ * Relationship:
+ * - A 2-Pair PoE PI uses 1 Channel.
+ * - A 4-Pair PoE PI uses 2 Channels.
+ *
+ * ASCII Schematic:
+ *
+ * +-----------------------------------------------------+
+ * | Si3474 Chip |
+ * | |
+ * | +---------------------+ +---------------------+ |
+ * | | Quad 0 | | Quad 1 | |
+ * | | Channels 0, 1, 2, 3 | | Channels 4, 5, 6, 7 | |
+ * | +----------^----------+ +-------^-------------+ |
+ * | I2C Addr 0 | | I2C Addr 1 |
+ * | +------------------------+ |
+ * | (Primary Driver Instance) (Managed by Primary) |
+ * | |
+ * | Shared Resources (affect whole chip): |
+ * | - Single INTb Output -> Handled by Primary |
+ * | - Single RESETb Input |
+ * | - Single OSS Input -> Handled by Primary |
+ * | - Global I2C Addr (0x7F) for Firmware Update |
+ * | - Global Status (Temp, VDD/VPWR UVLO) |
+ * +-----------------------------------------------------+
+ * | | | | | | | |
+ * Ch0 Ch1 Ch2 Ch3 Ch4 Ch5 Ch6 Ch7 (Physical Channels)
+ *
+ * Example Mapping (Logical PI to Physical Channel(s)):
+ * * 2-Pair Mode (8 PIs):
+ * PI 0 -> Ch 0
+ * PI 1 -> Ch 1
+ * ...
+ * PI 7 -> Ch 7
+ * * 4-Pair Mode (4 PIs):
+ * PI 0 -> Ch 0 + Ch 1 (Managed via Quad 0 Addr)
+ * PI 1 -> Ch 2 + Ch 3 (Managed via Quad 0 Addr)
+ * PI 2 -> Ch 4 + Ch 5 (Managed via Quad 1 Addr)
+ * PI 3 -> Ch 6 + Ch 7 (Managed via Quad 1 Addr)
+ * (Note: Actual mapping depends on Device Tree and PORT_REMAP config)
+ */
+
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pse-pd/pse.h>
+
+#define SI3474_MAX_CHANS 8
+
+#define MANUFACTURER_ID 0x08
+#define IC_ID 0x05
+#define SI3474_DEVICE_ID (MANUFACTURER_ID << 3 | IC_ID)
+
+/* Misc registers */
+#define VENDOR_IC_ID_REG 0x1B
+#define TEMPERATURE_REG 0x2C
+#define FIRMWARE_REVISION_REG 0x41
+#define CHIP_REVISION_REG 0x43
+
+/* Main status registers */
+#define POWER_STATUS_REG 0x10
+#define PORT_MODE_REG 0x12
+#define DETECT_CLASS_ENABLE_REG 0x14
+
+/* PORTn Current */
+#define PORT1_CURRENT_LSB_REG 0x30
+
+/* PORTn Current [mA], return in [nA] */
+/* 1000 * ((PORTn_CURRENT_MSB << 8) + PORTn_CURRENT_LSB) / 16384 */
+#define SI3474_NA_STEP (1000 * 1000 * 1000 / 16384)
+
+/* VPWR Voltage */
+#define VPWR_LSB_REG 0x2E
+#define VPWR_MSB_REG 0x2F
+
+/* PORTn Voltage */
+#define PORT1_VOLTAGE_LSB_REG 0x32
+
+/* VPWR Voltage [V], return in [uV] */
+/* 60 * (( VPWR_MSB << 8) + VPWR_LSB) / 16384 */
+#define SI3474_UV_STEP (1000 * 1000 * 60 / 16384)
+
+/* Helper macros */
+#define CHAN_IDX(chan) ((chan) % 4)
+#define CHAN_BIT(chan) BIT(CHAN_IDX(chan))
+#define CHAN_UPPER_BIT(chan) BIT(CHAN_IDX(chan) + 4)
+
+#define CHAN_MASK(chan) (0x03U << (2 * CHAN_IDX(chan)))
+#define CHAN_REG(base, chan) ((base) + (CHAN_IDX(chan) * 4))
+
+struct si3474_pi_desc {
+ u8 chan[2];
+ bool is_4p;
+};
+
+struct si3474_priv {
+ struct i2c_client *client[2];
+ struct pse_controller_dev pcdev;
+ struct device_node *np;
+ struct si3474_pi_desc pi[SI3474_MAX_CHANS];
+};
+
+static struct si3474_priv *to_si3474_priv(struct pse_controller_dev *pcdev)
+{
+ return container_of(pcdev, struct si3474_priv, pcdev);
+}
+
+static void si3474_get_channels(struct si3474_priv *priv, int id,
+ u8 *chan0, u8 *chan1)
+{
+ *chan0 = priv->pi[id].chan[0];
+ *chan1 = priv->pi[id].chan[1];
+}
+
+static struct i2c_client *si3474_get_chan_client(struct si3474_priv *priv,
+ u8 chan)
+{
+ return (chan < 4) ? priv->client[0] : priv->client[1];
+}
+
+static int si3474_pi_get_admin_state(struct pse_controller_dev *pcdev, int id,
+ struct pse_admin_state *admin_state)
+{
+ struct si3474_priv *priv = to_si3474_priv(pcdev);
+ struct i2c_client *client;
+ bool is_enabled;
+ u8 chan0, chan1;
+ s32 ret;
+
+ si3474_get_channels(priv, id, &chan0, &chan1);
+ client = si3474_get_chan_client(priv, chan0);
+
+ ret = i2c_smbus_read_byte_data(client, PORT_MODE_REG);
+ if (ret < 0) {
+ admin_state->c33_admin_state =
+ ETHTOOL_C33_PSE_ADMIN_STATE_UNKNOWN;
+ return ret;
+ }
+
+ is_enabled = ret & (CHAN_MASK(chan0) | CHAN_MASK(chan1));
+
+ if (is_enabled)
+ admin_state->c33_admin_state =
+ ETHTOOL_C33_PSE_ADMIN_STATE_ENABLED;
+ else
+ admin_state->c33_admin_state =
+ ETHTOOL_C33_PSE_ADMIN_STATE_DISABLED;
+
+ return 0;
+}
+
+static int si3474_pi_get_pw_status(struct pse_controller_dev *pcdev, int id,
+ struct pse_pw_status *pw_status)
+{
+ struct si3474_priv *priv = to_si3474_priv(pcdev);
+ struct i2c_client *client;
+ bool delivering;
+ u8 chan0, chan1;
+ s32 ret;
+
+ si3474_get_channels(priv, id, &chan0, &chan1);
+ client = si3474_get_chan_client(priv, chan0);
+
+ ret = i2c_smbus_read_byte_data(client, POWER_STATUS_REG);
+ if (ret < 0) {
+ pw_status->c33_pw_status = ETHTOOL_C33_PSE_PW_D_STATUS_UNKNOWN;
+ return ret;
+ }
+
+ delivering = ret & (CHAN_UPPER_BIT(chan0) | CHAN_UPPER_BIT(chan1));
+
+ if (delivering)
+ pw_status->c33_pw_status =
+ ETHTOOL_C33_PSE_PW_D_STATUS_DELIVERING;
+ else
+ pw_status->c33_pw_status = ETHTOOL_C33_PSE_PW_D_STATUS_DISABLED;
+
+ return 0;
+}
+
+static int si3474_get_of_channels(struct si3474_priv *priv)
+{
+ struct pse_pi *pi;
+ u32 chan_id;
+ u8 pi_no;
+ s32 ret;
+
+ for (pi_no = 0; pi_no < SI3474_MAX_CHANS; pi_no++) {
+ pi = &priv->pcdev.pi[pi_no];
+ bool pairset_found = false;
+ u8 pairset_no;
+
+ for (pairset_no = 0; pairset_no < 2; pairset_no++) {
+ if (!pi->pairset[pairset_no].np)
+ continue;
+
+ pairset_found = true;
+
+ ret = of_property_read_u32(pi->pairset[pairset_no].np,
+ "reg", &chan_id);
+ if (ret) {
+ dev_err(&priv->client[0]->dev,
+ "Failed to read channel reg property\n");
+ return ret;
+ }
+ if (chan_id > SI3474_MAX_CHANS) {
+ dev_err(&priv->client[0]->dev,
+ "Incorrect channel number: %d\n", chan_id);
+ return -EINVAL;
+ }
+
+ priv->pi[pi_no].chan[pairset_no] = chan_id;
+ /* Mark as 4-pair if second pairset is present */
+ priv->pi[pi_no].is_4p = (pairset_no == 1);
+ }
+
+ if (pairset_found && !priv->pi[pi_no].is_4p) {
+ dev_err(&priv->client[0]->dev,
+ "Second pairset is missing for PI %pOF, only 4p configs are supported\n",
+ pi->np);
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+
+static int si3474_setup_pi_matrix(struct pse_controller_dev *pcdev)
+{
+ struct si3474_priv *priv = to_si3474_priv(pcdev);
+ s32 ret;
+
+ ret = si3474_get_of_channels(priv);
+ if (ret < 0)
+ dev_warn(&priv->client[0]->dev,
+ "Unable to parse DT PSE power interface matrix\n");
+
+ return ret;
+}
+
+static int si3474_pi_enable(struct pse_controller_dev *pcdev, int id)
+{
+ struct si3474_priv *priv = to_si3474_priv(pcdev);
+ struct i2c_client *client;
+ u8 chan0, chan1;
+ s32 ret;
+ u8 val;
+
+ si3474_get_channels(priv, id, &chan0, &chan1);
+ client = si3474_get_chan_client(priv, chan0);
+
+ /* Release PI from shutdown */
+ ret = i2c_smbus_read_byte_data(client, PORT_MODE_REG);
+ if (ret < 0)
+ return ret;
+
+ val = (u8)ret;
+ val |= CHAN_MASK(chan0);
+ val |= CHAN_MASK(chan1);
+
+ ret = i2c_smbus_write_byte_data(client, PORT_MODE_REG, val);
+ if (ret)
+ return ret;
+
+ /* DETECT_CLASS_ENABLE must be set when using AUTO mode,
+ * otherwise PI does not power up - datasheet section 2.10.2
+ */
+ val = CHAN_BIT(chan0) | CHAN_UPPER_BIT(chan0) |
+ CHAN_BIT(chan1) | CHAN_UPPER_BIT(chan1);
+
+ ret = i2c_smbus_write_byte_data(client, DETECT_CLASS_ENABLE_REG, val);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static int si3474_pi_disable(struct pse_controller_dev *pcdev, int id)
+{
+ struct si3474_priv *priv = to_si3474_priv(pcdev);
+ struct i2c_client *client;
+ u8 chan0, chan1;
+ s32 ret;
+ u8 val;
+
+ si3474_get_channels(priv, id, &chan0, &chan1);
+ client = si3474_get_chan_client(priv, chan0);
+
+ /* Set PI in shutdown mode */
+ ret = i2c_smbus_read_byte_data(client, PORT_MODE_REG);
+ if (ret < 0)
+ return ret;
+
+ val = (u8)ret;
+ val &= ~CHAN_MASK(chan0);
+ val &= ~CHAN_MASK(chan1);
+
+ ret = i2c_smbus_write_byte_data(client, PORT_MODE_REG, val);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static int si3474_pi_get_chan_current(struct si3474_priv *priv, u8 chan)
+{
+ struct i2c_client *client;
+ u64 tmp_64;
+ s32 ret;
+ u8 reg;
+
+ client = si3474_get_chan_client(priv, chan);
+
+ /* Registers 0x30 to 0x3d */
+ reg = CHAN_REG(PORT1_CURRENT_LSB_REG, chan);
+
+ ret = i2c_smbus_read_word_data(client, reg);
+ if (ret < 0)
+ return ret;
+
+ tmp_64 = ret * SI3474_NA_STEP;
+
+ /* uA = nA / 1000 */
+ tmp_64 = DIV_ROUND_CLOSEST_ULL(tmp_64, 1000);
+ return (int)tmp_64;
+}
+
+static int si3474_pi_get_chan_voltage(struct si3474_priv *priv, u8 chan)
+{
+ struct i2c_client *client;
+ s32 ret;
+ u32 val;
+ u8 reg;
+
+ client = si3474_get_chan_client(priv, chan);
+
+ /* Registers 0x32 to 0x3f */
+ reg = CHAN_REG(PORT1_VOLTAGE_LSB_REG, chan);
+
+ ret = i2c_smbus_read_word_data(client, reg);
+ if (ret < 0)
+ return ret;
+
+ val = ret * SI3474_UV_STEP;
+
+ return (int)val;
+}
+
+static int si3474_pi_get_voltage(struct pse_controller_dev *pcdev, int id)
+{
+ struct si3474_priv *priv = to_si3474_priv(pcdev);
+ struct i2c_client *client;
+ u8 chan0, chan1;
+ s32 ret;
+
+ si3474_get_channels(priv, id, &chan0, &chan1);
+ client = si3474_get_chan_client(priv, chan0);
+
+ /* Check which channels are enabled*/
+ ret = i2c_smbus_read_byte_data(client, POWER_STATUS_REG);
+ if (ret < 0)
+ return ret;
+
+ /* Take voltage from the first enabled channel */
+ if (ret & CHAN_BIT(chan0))
+ ret = si3474_pi_get_chan_voltage(priv, chan0);
+ else if (ret & CHAN_BIT(chan1))
+ ret = si3474_pi_get_chan_voltage(priv, chan1);
+ else
+ /* 'should' be no voltage in this case */
+ return 0;
+
+ return ret;
+}
+
+static int si3474_pi_get_actual_pw(struct pse_controller_dev *pcdev, int id)
+{
+ struct si3474_priv *priv = to_si3474_priv(pcdev);
+ u8 chan0, chan1;
+ u32 uV, uA;
+ u64 tmp_64;
+ s32 ret;
+
+ ret = si3474_pi_get_voltage(&priv->pcdev, id);
+
+ /* Do not read currents if voltage is 0 */
+ if (ret <= 0)
+ return ret;
+ uV = ret;
+
+ si3474_get_channels(priv, id, &chan0, &chan1);
+
+ ret = si3474_pi_get_chan_current(priv, chan0);
+ if (ret < 0)
+ return ret;
+ uA = ret;
+
+ ret = si3474_pi_get_chan_current(priv, chan1);
+ if (ret < 0)
+ return ret;
+ uA += ret;
+
+ tmp_64 = uV;
+ tmp_64 *= uA;
+ /* mW = uV * uA / 1000000000 */
+ return DIV_ROUND_CLOSEST_ULL(tmp_64, 1000000000);
+}
+
+static const struct pse_controller_ops si3474_ops = {
+ .setup_pi_matrix = si3474_setup_pi_matrix,
+ .pi_enable = si3474_pi_enable,
+ .pi_disable = si3474_pi_disable,
+ .pi_get_actual_pw = si3474_pi_get_actual_pw,
+ .pi_get_voltage = si3474_pi_get_voltage,
+ .pi_get_admin_state = si3474_pi_get_admin_state,
+ .pi_get_pw_status = si3474_pi_get_pw_status,
+};
+
+static void si3474_ancillary_i2c_remove(void *data)
+{
+ struct i2c_client *client = data;
+
+ i2c_unregister_device(client);
+}
+
+static int si3474_i2c_probe(struct i2c_client *client)
+{
+ struct device *dev = &client->dev;
+ struct si3474_priv *priv;
+ u8 fw_version;
+ s32 ret;
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+ dev_err(dev, "i2c check functionality failed\n");
+ return -ENXIO;
+ }
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ ret = i2c_smbus_read_byte_data(client, VENDOR_IC_ID_REG);
+ if (ret < 0)
+ return ret;
+
+ if (ret != SI3474_DEVICE_ID) {
+ dev_err(dev, "Wrong device ID: 0x%x\n", ret);
+ return -ENXIO;
+ }
+
+ ret = i2c_smbus_read_byte_data(client, FIRMWARE_REVISION_REG);
+ if (ret < 0)
+ return ret;
+ fw_version = ret;
+
+ ret = i2c_smbus_read_byte_data(client, CHIP_REVISION_REG);
+ if (ret < 0)
+ return ret;
+
+ dev_dbg(dev, "Chip revision: 0x%x, firmware version: 0x%x\n",
+ ret, fw_version);
+
+ priv->client[0] = client;
+ i2c_set_clientdata(client, priv);
+
+ priv->client[1] = i2c_new_ancillary_device(priv->client[0], "secondary",
+ priv->client[0]->addr + 1);
+ if (IS_ERR(priv->client[1]))
+ return PTR_ERR(priv->client[1]);
+
+ ret = devm_add_action_or_reset(dev, si3474_ancillary_i2c_remove, priv->client[1]);
+ if (ret < 0) {
+ dev_err(&priv->client[1]->dev, "Cannot register remove callback\n");
+ return ret;
+ }
+
+ ret = i2c_smbus_read_byte_data(priv->client[1], VENDOR_IC_ID_REG);
+ if (ret < 0) {
+ dev_err(&priv->client[1]->dev, "Cannot access secondary PSE controller\n");
+ return ret;
+ }
+
+ if (ret != SI3474_DEVICE_ID) {
+ dev_err(&priv->client[1]->dev,
+ "Wrong device ID for secondary PSE controller: 0x%x\n", ret);
+ return -ENXIO;
+ }
+
+ priv->np = dev->of_node;
+ priv->pcdev.owner = THIS_MODULE;
+ priv->pcdev.ops = &si3474_ops;
+ priv->pcdev.dev = dev;
+ priv->pcdev.types = ETHTOOL_PSE_C33;
+ priv->pcdev.nr_lines = SI3474_MAX_CHANS;
+
+ ret = devm_pse_controller_register(dev, &priv->pcdev);
+ if (ret) {
+ dev_err(dev, "Failed to register PSE controller: 0x%x\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static const struct i2c_device_id si3474_id[] = {
+ { "si3474" },
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, si3474_id);
+
+static const struct of_device_id si3474_of_match[] = {
+ {
+ .compatible = "skyworks,si3474",
+ },
+ {},
+};
+MODULE_DEVICE_TABLE(of, si3474_of_match);
+
+static struct i2c_driver si3474_driver = {
+ .probe = si3474_i2c_probe,
+ .id_table = si3474_id,
+ .driver = {
+ .name = "si3474",
+ .of_match_table = si3474_of_match,
+ },
+};
+module_i2c_driver(si3474_driver);
+
+MODULE_AUTHOR("Piotr Kubik <piotr.kubik@adtran.com>");
+MODULE_DESCRIPTION("Skyworks Si3474 PoE PSE Controller driver");
+MODULE_LICENSE("GPL");
projects / thirdparty / kernel / stable.git / commitdiff
