// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright 2022 Google LLC
 *
 * This driver provides the ability to configure Type-C muxes and retimers which are controlled by
 * the ChromeOS EC.
 */

#include <linux/acpi.h>
#include <linux/delay.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/platform_data/cros_ec_commands.h>
#include <linux/platform_data/cros_ec_proto.h>
#include <linux/platform_device.h>
#include <linux/usb/typec_altmode.h>
#include <linux/usb/typec_dp.h>
#include <linux/usb/typec_mux.h>
#include <linux/usb/typec_retimer.h>

/* Handles and other relevant data required for each port's switches. */
struct cros_typec_port {
        int port_num;
        struct typec_mux_dev *mode_switch;
        struct typec_retimer *retimer;
        struct cros_typec_switch_data *sdata;
};

/* Driver-specific data. */
struct cros_typec_switch_data {
        struct device *dev;
        struct cros_ec_device *ec;
        struct cros_typec_port *ports[EC_USB_PD_MAX_PORTS];
};

static int cros_typec_cmd_mux_set(struct cros_typec_switch_data *sdata, int port_num, u8 index,
                                  u8 state)
{
        struct ec_params_typec_control req = {
                .port = port_num,
                .command = TYPEC_CONTROL_COMMAND_USB_MUX_SET,
                .mux_params = {
                        .mux_index = index,
                        .mux_flags = state,
                },
        };

        return cros_ec_cmd(sdata->ec, 0, EC_CMD_TYPEC_CONTROL, &req, sizeof(req), NULL, 0);
}

static int cros_typec_get_mux_state(unsigned long mode, struct typec_altmode *alt)
{
        int ret = -EOPNOTSUPP;
        u8 pin_assign;

        if (mode == TYPEC_STATE_SAFE) {
                ret = USB_PD_MUX_SAFE_MODE;
        } else if (mode == TYPEC_STATE_USB) {
                ret = USB_PD_MUX_USB_ENABLED;
        } else if (alt && alt->svid == USB_TYPEC_DP_SID) {
                ret = USB_PD_MUX_DP_ENABLED;
                pin_assign = mode - TYPEC_STATE_MODAL;
                if (pin_assign & DP_PIN_ASSIGN_D)
                        ret |= USB_PD_MUX_USB_ENABLED;
        }

        return ret;
}

static int cros_typec_send_clear_event(struct cros_typec_switch_data *sdata, int port_num,
                                       u32 events_mask)
{
        struct ec_params_typec_control req = {
                .port = port_num,
                .command = TYPEC_CONTROL_COMMAND_CLEAR_EVENTS,
                .clear_events_mask = events_mask,
        };

        return cros_ec_cmd(sdata->ec, 0, EC_CMD_TYPEC_CONTROL, &req, sizeof(req), NULL, 0);
}

static bool cros_typec_check_event(struct cros_typec_switch_data *sdata, int port_num, u32 mask)
{
        struct ec_response_typec_status resp;
        struct ec_params_typec_status req = {
                .port = port_num,
        };
        int ret;

        ret = cros_ec_cmd(sdata->ec, 0, EC_CMD_TYPEC_STATUS, &req, sizeof(req),
                          &resp, sizeof(resp));
        if (ret < 0) {
                dev_warn(sdata->dev, "EC_CMD_TYPEC_STATUS failed for port: %d\n", port_num);
                return false;
        }

        if (resp.events & mask)
                return true;

        return false;
}

/*
 * The ChromeOS EC treats both mode-switches and retimers as "muxes" for the purposes of the
 * host command API. This common function configures and verifies the retimer/mode-switch
 * according to the provided setting.
 */
static int cros_typec_configure_mux(struct cros_typec_switch_data *sdata, int port_num, int index,
                                    unsigned long mode, struct typec_altmode *alt)
{
        unsigned long end;
        u32 event_mask;
        u8 mux_state;
        int ret;

        ret = cros_typec_get_mux_state(mode, alt);
        if (ret < 0)
                return ret;
        mux_state = (u8)ret;

        /* Clear any old mux set done event. */
        if (index == 0)
                event_mask = PD_STATUS_EVENT_MUX_0_SET_DONE;
        else
                event_mask = PD_STATUS_EVENT_MUX_1_SET_DONE;

        ret = cros_typec_send_clear_event(sdata, port_num, event_mask);
        if (ret < 0)
                return ret;

        /* Send the set command. */
        ret = cros_typec_cmd_mux_set(sdata, port_num, index, mux_state);
        if (ret < 0)
                return ret;

        /* Check for the mux set done event. */
        end = jiffies + msecs_to_jiffies(1000);
        do {
                if (cros_typec_check_event(sdata, port_num, event_mask))
                        return 0;

                usleep_range(500, 1000);
        } while (time_before(jiffies, end));

        dev_err(sdata->dev, "Timed out waiting for mux set done on index: %d, state: %d\n",
                index, mux_state);

        return -ETIMEDOUT;
}

static int cros_typec_mode_switch_set(struct typec_mux_dev *mode_switch,
                                      struct typec_mux_state *state)
{
        struct cros_typec_port *port = typec_mux_get_drvdata(mode_switch);

        /* Mode switches have index 0. */
        return cros_typec_configure_mux(port->sdata, port->port_num, 0, state->mode, state->alt);
}

static int cros_typec_retimer_set(struct typec_retimer *retimer, struct typec_retimer_state *state)
{
        struct cros_typec_port *port = typec_retimer_get_drvdata(retimer);

        /* Retimers have index 1. */
        return cros_typec_configure_mux(port->sdata, port->port_num, 1, state->mode, state->alt);
}

static void cros_typec_unregister_switches(struct cros_typec_switch_data *sdata)
{
        int i;

        for (i = 0; i < EC_USB_PD_MAX_PORTS; i++) {
                if (!sdata->ports[i])
                        continue;
                typec_retimer_unregister(sdata->ports[i]->retimer);
                typec_mux_unregister(sdata->ports[i]->mode_switch);
        }
}

static int cros_typec_register_mode_switch(struct cros_typec_port *port,
                                           struct fwnode_handle *fwnode)
{
        struct typec_mux_desc mode_switch_desc = {
                .fwnode = fwnode,
                .drvdata = port,
                .name = fwnode_get_name(fwnode),
                .set = cros_typec_mode_switch_set,
        };

        port->mode_switch = typec_mux_register(port->sdata->dev, &mode_switch_desc);

        return PTR_ERR_OR_ZERO(port->mode_switch);
}

static int cros_typec_register_retimer(struct cros_typec_port *port, struct fwnode_handle *fwnode)
{
        struct typec_retimer_desc retimer_desc = {
                .fwnode = fwnode,
                .drvdata = port,
                .name = fwnode_get_name(fwnode),
                .set = cros_typec_retimer_set,
        };

        port->retimer = typec_retimer_register(port->sdata->dev, &retimer_desc);

        return PTR_ERR_OR_ZERO(port->retimer);
}

static int cros_typec_register_switches(struct cros_typec_switch_data *sdata)
{
        struct cros_typec_port *port;
        struct device *dev = sdata->dev;
        struct fwnode_handle *fwnode;
        int nports, ret;
        u64 index;

        nports = device_get_child_node_count(dev);
        if (nports == 0) {
                dev_err(dev, "No switch devices found.\n");
                return -ENODEV;
        }

        device_for_each_child_node(dev, fwnode) {
                port = devm_kzalloc(dev, sizeof(*port), GFP_KERNEL);
                if (!port) {
                        ret = -ENOMEM;
                        goto err_switch;
                }

                ret = acpi_get_local_u64_address(ACPI_HANDLE_FWNODE(fwnode), &index);
                if (ret) {
                        dev_err(dev, "_ADR wasn't evaluated for %pfwP\n", fwnode);
                        goto err_switch;
                }

                if (index >= EC_USB_PD_MAX_PORTS) {
                        dev_err(dev, "%pfwP: Invalid port index number: %llu\n", fwnode, index);
                        ret = -EINVAL;
                        goto err_switch;
                }
                port->sdata = sdata;
                port->port_num = index;
                sdata->ports[index] = port;

                if (fwnode_property_present(fwnode, "retimer-switch")) {
                        ret = cros_typec_register_retimer(port, fwnode);
                        if (ret) {
                                dev_err(dev, "Retimer switch register failed\n");
                                goto err_switch;
                        }

                        dev_dbg(dev, "Retimer switch registered for index %llu\n", index);
                }

                if (!fwnode_property_present(fwnode, "mode-switch"))
                        continue;

                ret = cros_typec_register_mode_switch(port, fwnode);
                if (ret) {
                        dev_err(dev, "Mode switch register failed\n");
                        goto err_switch;
                }

                dev_dbg(dev, "Mode switch registered for index %llu\n", index);
        }

        return 0;
err_switch:
        fwnode_handle_put(fwnode);
        cros_typec_unregister_switches(sdata);
        return ret;
}

static int cros_typec_switch_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct cros_typec_switch_data *sdata;

        sdata = devm_kzalloc(dev, sizeof(*sdata), GFP_KERNEL);
        if (!sdata)
                return -ENOMEM;

        sdata->dev = dev;
        sdata->ec = dev_get_drvdata(pdev->dev.parent);

        platform_set_drvdata(pdev, sdata);

        return cros_typec_register_switches(sdata);
}

static void cros_typec_switch_remove(struct platform_device *pdev)
{
        struct cros_typec_switch_data *sdata = platform_get_drvdata(pdev);

        cros_typec_unregister_switches(sdata);
}

#ifdef CONFIG_ACPI
static const struct acpi_device_id cros_typec_switch_acpi_id[] = {
        { "GOOG001A", 0 },
        {}
};
MODULE_DEVICE_TABLE(acpi, cros_typec_switch_acpi_id);
#endif

static struct platform_driver cros_typec_switch_driver = {
        .driver = {
                .name = "cros-typec-switch",
                .acpi_match_table = ACPI_PTR(cros_typec_switch_acpi_id),
        },
        .probe = cros_typec_switch_probe,
        .remove = cros_typec_switch_remove,
};

module_platform_driver(cros_typec_switch_driver);

MODULE_AUTHOR("Prashant Malani <pmalani@chromium.org>");
MODULE_DESCRIPTION("ChromeOS EC Type-C Switch control");
MODULE_LICENSE("GPL");