path: root/drivers/platform/olpc/olpc-xo175-ec.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * Driver for the OLPC XO-1.75 Embedded Controller.
 *
 * The EC protocol is documented at:
 * http://wiki.laptop.org/go/XO_1.75_HOST_to_EC_Protocol
 *
 * Copyright (C) 2010 One Laptop per Child Foundation.
 * Copyright (C) 2018 Lubomir Rintel <lkundrak@v3.sk>
 */

#include <linux/completion.h>
#include <linux/ctype.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/input.h>
#include <linux/kfifo.h>
#include <linux/module.h>
#include <linux/olpc-ec.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/reboot.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/spi/spi.h>

struct ec_cmd_t {
	u8 cmd;
	u8 bytes_returned;
};

enum ec_chan_t {
	CHAN_NONE = 0,
	CHAN_SWITCH,
	CHAN_CMD_RESP,
	CHAN_KEYBOARD,
	CHAN_TOUCHPAD,
	CHAN_EVENT,
	CHAN_DEBUG,
	CHAN_CMD_ERROR,
};

/*
 * EC events
 */
#define EVENT_AC_CHANGE			1  /* AC plugged/unplugged */
#define EVENT_BATTERY_STATUS		2  /* Battery low/full/error/gone */
#define EVENT_BATTERY_CRITICAL		3  /* Battery critical voltage */
#define EVENT_BATTERY_SOC_CHANGE	4  /* 1% SOC Change */
#define EVENT_BATTERY_ERROR		5  /* Abnormal error, query for cause */
#define EVENT_POWER_PRESSED		6  /* Power button was pressed */
#define EVENT_POWER_PRESS_WAKE		7  /* Woken up with a power button */
#define EVENT_TIMED_HOST_WAKE		8  /* Host wake timer */
#define EVENT_OLS_HIGH_LIMIT		9  /* OLS crossed dark threshold */
#define EVENT_OLS_LOW_LIMIT		10 /* OLS crossed light threshold */

/*
 * EC commands
 * (from http://dev.laptop.org/git/users/rsmith/ec-1.75/tree/ec_cmd.h)
 */
#define CMD_GET_API_VERSION		0x08 /* out: u8 */
#define CMD_READ_VOLTAGE		0x10 /* out: u16, *9.76/32, mV */
#define CMD_READ_CURRENT		0x11 /* out: s16, *15.625/120, mA */
#define CMD_READ_ACR			0x12 /* out: s16, *6250/15, uAh */
#define CMD_READ_BATT_TEMPERATURE	0x13 /* out: u16, *100/256, deg C */
#define CMD_READ_AMBIENT_TEMPERATURE	0x14 /* unimplemented, no hardware */
#define CMD_READ_BATTERY_STATUS		0x15 /* out: u8, bitmask */
#define CMD_READ_SOC			0x16 /* out: u8, percentage */
#define CMD_READ_GAUGE_ID		0x17 /* out: u8 * 8 */
#define CMD_READ_GAUGE_DATA		0x18 /* in: u8 addr, out: u8 data */
#define CMD_READ_BOARD_ID		0x19 /* out: u16 (platform id) */
#define CMD_READ_BATT_ERR_CODE		0x1f /* out: u8, error bitmask */
#define CMD_SET_DCON_POWER		0x26 /* in: u8 */
#define CMD_RESET_EC			0x28 /* none */
#define CMD_READ_BATTERY_TYPE		0x2c /* out: u8 */
#define CMD_SET_AUTOWAK			0x33 /* out: u8 */
#define CMD_SET_EC_WAKEUP_TIMER		0x36 /* in: u32, out: ? */
#define CMD_READ_EXT_SCI_MASK		0x37 /* ? */
#define CMD_WRITE_EXT_SCI_MASK		0x38 /* ? */
#define CMD_CLEAR_EC_WAKEUP_TIMER	0x39 /* none */
#define CMD_ENABLE_RUNIN_DISCHARGE	0x3B /* none */
#define CMD_DISABLE_RUNIN_DISCHARGE	0x3C /* none */
#define CMD_READ_MPPT_ACTIVE		0x3d /* out: u8 */
#define CMD_READ_MPPT_LIMIT		0x3e /* out: u8 */
#define CMD_SET_MPPT_LIMIT		0x3f /* in: u8 */
#define CMD_DISABLE_MPPT		0x40 /* none */
#define CMD_ENABLE_MPPT			0x41 /* none */
#define CMD_READ_VIN			0x42 /* out: u16 */
#define CMD_EXT_SCI_QUERY		0x43 /* ? */
#define RSP_KEYBOARD_DATA		0x48 /* ? */
#define RSP_TOUCHPAD_DATA		0x49 /* ? */
#define CMD_GET_FW_VERSION		0x4a /* out: u8 * 16 */
#define CMD_POWER_CYCLE			0x4b /* none */
#define CMD_POWER_OFF			0x4c /* none */
#define CMD_RESET_EC_SOFT		0x4d /* none */
#define CMD_READ_GAUGE_U16		0x4e /* ? */
#define CMD_ENABLE_MOUSE		0x4f /* ? */
#define CMD_ECHO			0x52 /* in: u8 * 5, out: u8 * 5 */
#define CMD_GET_FW_DATE			0x53 /* out: u8 * 16 */
#define CMD_GET_FW_USER			0x54 /* out: u8 * 16 */
#define CMD_TURN_OFF_POWER		0x55 /* none (same as 0x4c) */
#define CMD_READ_OLS			0x56 /* out: u16 */
#define CMD_OLS_SMT_LEDON		0x57 /* none */
#define CMD_OLS_SMT_LEDOFF		0x58 /* none */
#define CMD_START_OLS_ASSY		0x59 /* none */
#define CMD_STOP_OLS_ASSY		0x5a /* none */
#define CMD_OLS_SMTTEST_STOP		0x5b /* none */
#define CMD_READ_VIN_SCALED		0x5c /* out: u16 */
#define CMD_READ_BAT_MIN_W		0x5d /* out: u16 */
#define CMD_READ_BAR_MAX_W		0x5e /* out: u16 */
#define CMD_RESET_BAT_MINMAX_W		0x5f /* none */
#define CMD_READ_LOCATION		0x60 /* in: u16 addr, out: u8 data */
#define CMD_WRITE_LOCATION		0x61 /* in: u16 addr, u8 data */
#define CMD_KEYBOARD_CMD		0x62 /* in: u8, out: ? */
#define CMD_TOUCHPAD_CMD		0x63 /* in: u8, out: ? */
#define CMD_GET_FW_HASH			0x64 /* out: u8 * 16 */
#define CMD_SUSPEND_HINT		0x65 /* in: u8 */
#define CMD_ENABLE_WAKE_TIMER		0x66 /* in: u8 */
#define CMD_SET_WAKE_TIMER		0x67 /* in: 32 */
#define CMD_ENABLE_WAKE_AUTORESET	0x68 /* in: u8 */
#define CMD_OLS_SET_LIMITS		0x69 /* in: u16, u16 */
#define CMD_OLS_GET_LIMITS		0x6a /* out: u16, u16 */
#define CMD_OLS_SET_CEILING		0x6b /* in: u16 */
#define CMD_OLS_GET_CEILING		0x6c /* out: u16 */

/*
 * Accepted EC commands, and how many bytes they return. There are plenty
 * of EC commands that are no longer implemented, or are implemented only on
 * certain older boards.
 */
static const struct ec_cmd_t olpc_xo175_ec_cmds[] = {
	{ CMD_GET_API_VERSION, 1 },
	{ CMD_READ_VOLTAGE, 2 },
	{ CMD_READ_CURRENT, 2 },
	{ CMD_READ_ACR, 2 },
	{ CMD_READ_BATT_TEMPERATURE, 2 },
	{ CMD_READ_BATTERY_STATUS, 1 },
	{ CMD_READ_SOC, 1 },
	{ CMD_READ_GAUGE_ID, 8 },
	{ CMD_READ_GAUGE_DATA, 1 },
	{ CMD_READ_BOARD_ID, 2 },
	{ CMD_READ_BATT_ERR_CODE, 1 },
	{ CMD_SET_DCON_POWER, 0 },
	{ CMD_RESET_EC, 0 },
	{ CMD_READ_BATTERY_TYPE, 1 },
	{ CMD_ENABLE_RUNIN_DISCHARGE, 0 },
	{ CMD_DISABLE_RUNIN_DISCHARGE, 0 },
	{ CMD_READ_MPPT_ACTIVE, 1 },
	{ CMD_READ_MPPT_LIMIT, 1 },
	{ CMD_SET_MPPT_LIMIT, 0 },
	{ CMD_DISABLE_MPPT, 0 },
	{ CMD_ENABLE_MPPT, 0 },
	{ CMD_READ_VIN, 2 },
	{ CMD_GET_FW_VERSION, 16 },
	{ CMD_POWER_CYCLE, 0 },
	{ CMD_POWER_OFF, 0 },
	{ CMD_RESET_EC_SOFT, 0 },
	{ CMD_ECHO, 5 },
	{ CMD_GET_FW_DATE, 16 },
	{ CMD_GET_FW_USER, 16 },
	{ CMD_TURN_OFF_POWER, 0 },
	{ CMD_READ_OLS, 2 },
	{ CMD_OLS_SMT_LEDON, 0 },
	{ CMD_OLS_SMT_LEDOFF, 0 },
	{ CMD_START_OLS_ASSY, 0 },
	{ CMD_STOP_OLS_ASSY, 0 },
	{ CMD_OLS_SMTTEST_STOP, 0 },
	{ CMD_READ_VIN_SCALED, 2 },
	{ CMD_READ_BAT_MIN_W, 2 },
	{ CMD_READ_BAR_MAX_W, 2 },
	{ CMD_RESET_BAT_MINMAX_W, 0 },
	{ CMD_READ_LOCATION, 1 },
	{ CMD_WRITE_LOCATION, 0 },
	{ CMD_GET_FW_HASH, 16 },
	{ CMD_SUSPEND_HINT, 0 },
	{ CMD_ENABLE_WAKE_TIMER, 0 },
	{ CMD_SET_WAKE_TIMER, 0 },
	{ CMD_ENABLE_WAKE_AUTORESET, 0 },
	{ CMD_OLS_SET_LIMITS, 0 },
	{ CMD_OLS_GET_LIMITS, 4 },
	{ CMD_OLS_SET_CEILING, 0 },
	{ CMD_OLS_GET_CEILING, 2 },
	{ CMD_READ_EXT_SCI_MASK, 2 },
	{ CMD_WRITE_EXT_SCI_MASK, 0 },

	{ }
};

#define EC_MAX_CMD_DATA_LEN	5
#define EC_MAX_RESP_LEN		16

#define LOG_BUF_SIZE		128

#define PM_WAKEUP_TIME		1000

#define EC_ALL_EVENTS		GENMASK(15, 0)

enum ec_state_t {
	CMD_STATE_IDLE = 0,
	CMD_STATE_WAITING_FOR_SWITCH,
	CMD_STATE_CMD_IN_TX_FIFO,
	CMD_STATE_CMD_SENT,
	CMD_STATE_RESP_RECEIVED,
	CMD_STATE_ERROR_RECEIVED,
};

struct olpc_xo175_ec_cmd {
	u8 command;
	u8 nr_args;
	u8 data_len;
	u8 args[EC_MAX_CMD_DATA_LEN];
};

struct olpc_xo175_ec_resp {
	u8 channel;
	u8 byte;
};

struct olpc_xo175_ec {
	bool suspended;

	/* SPI related stuff. */
	struct spi_device *spi;
	struct spi_transfer xfer;
	struct spi_message msg;
	union {
		struct olpc_xo175_ec_cmd cmd;
		struct olpc_xo175_ec_resp resp;
	} tx_buf, rx_buf;

	/* GPIO for the CMD signals. */
	struct gpio_desc *gpio_cmd;

	/* Command handling related state. */
	spinlock_t cmd_state_lock;
	int cmd_state;
	bool cmd_running;
	struct completion cmd_done;
	struct olpc_xo175_ec_cmd cmd;
	u8 resp_data[EC_MAX_RESP_LEN];
	int expected_resp_len;
	int resp_len;

	/* Power button. */
	struct input_dev *pwrbtn;

	/* Debug handling. */
	char logbuf[LOG_BUF_SIZE];
	int logbuf_len;
};

static struct platform_device *olpc_ec;

static int olpc_xo175_ec_resp_len