/*- * Copyright (C) 2008-2009 Semihalf, Michal Hajduk * Copyright (c) 2012, 2013 The FreeBSD Foundation * Copyright (c) 2015 Ian Lepore * All rights reserved. * * Portions of this software were developed by Oleksandr Rybalko * under sponsorship from the FreeBSD Foundation. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /* * I2C driver for Freescale i.MX hardware. * * Note that the hardware is capable of running as both a master and a slave. * This driver currently implements only master-mode operations. * * This driver supports multi-master i2c busses, by detecting bus arbitration * loss and returning IIC_EBUSBSY status. Notably, it does not do any kind of * retries if some other master jumps onto the bus and interrupts one of our * transfer cycles resulting in arbitration loss in mid-transfer. The caller * must handle retries in a way that makes sense for the slave being addressed. */ #include __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include "iicbus_if.h" #include #include #include #include #define I2C_ADDR_REG 0x00 /* I2C slave address register */ #define I2C_FDR_REG 0x04 /* I2C frequency divider register */ #define I2C_CONTROL_REG 0x08 /* I2C control register */ #define I2C_STATUS_REG 0x0C /* I2C status register */ #define I2C_DATA_REG 0x10 /* I2C data register */ #define I2C_DFSRR_REG 0x14 /* I2C Digital Filter Sampling rate */ #define I2CCR_MEN (1 << 7) /* Module enable */ #define I2CCR_MSTA (1 << 5) /* Master/slave mode */ #define I2CCR_MTX (1 << 4) /* Transmit/receive mode */ #define I2CCR_TXAK (1 << 3) /* Transfer acknowledge */ #define I2CCR_RSTA (1 << 2) /* Repeated START */ #define I2CSR_MCF (1 << 7) /* Data transfer */ #define I2CSR_MASS (1 << 6) /* Addressed as a slave */ #define I2CSR_MBB (1 << 5) /* Bus busy */ #define I2CSR_MAL (1 << 4) /* Arbitration lost */ #define I2CSR_SRW (1 << 2) /* Slave read/write */ #define I2CSR_MIF (1 << 1) /* Module interrupt */ #define I2CSR_RXAK (1 << 0) /* Received acknowledge */ #define I2C_BAUD_RATE_FAST 0x31 #define I2C_BAUD_RATE_DEF 0x3F #define I2C_DFSSR_DIV 0x10 /* * A table of available divisors and the associated coded values to put in the * FDR register to achieve that divisor.. There is no algorithmic relationship I * can see between divisors and the codes that go into the register. The table * begins and ends with entries that handle insane configuration values. */ struct clkdiv { u_int divisor; u_int regcode; }; static struct clkdiv clkdiv_table[] = { { 0, 0x20 }, { 22, 0x20 }, { 24, 0x21 }, { 26, 0x22 }, { 28, 0x23 }, { 30, 0x00 }, { 32, 0x24 }, { 36, 0x25 }, { 40, 0x26 }, { 42, 0x03 }, { 44, 0x27 }, { 48, 0x28 }, { 52, 0x05 }, { 56, 0x29 }, { 60, 0x06 }, { 64, 0x2a }, { 72, 0x2b }, { 80, 0x2c }, { 88, 0x09 }, { 96, 0x2d }, { 104, 0x0a }, { 112, 0x2e }, { 128, 0x2f }, { 144, 0x0c }, { 160, 0x30 }, { 192, 0x31 }, { 224, 0x32 }, { 240, 0x0f }, { 256, 0x33 }, { 288, 0x10 }, { 320, 0x34 }, { 384, 0x35 }, { 448, 0x36 }, { 480, 0x13 }, { 512, 0x37 }, { 576, 0x14 }, { 640, 0x38 }, { 768, 0x39 }, { 896, 0x3a }, { 960, 0x17 }, { 1024, 0x3b }, { 1152, 0x18 }, { 1280, 0x3c }, { 1536, 0x3d }, { 1792, 0x3e }, { 1920, 0x1b }, { 2048, 0x3f }, { 2304, 0x1c }, { 2560, 0x1d }, { 3072, 0x1e }, { 3840, 0x1f }, {UINT_MAX, 0x1f} }; static struct ofw_compat_data compat_data[] = { {"fsl,imx6q-i2c", 1}, {"fsl,imx-i2c", 1}, {NULL, 0} }; struct i2c_softc { device_t dev; device_t iicbus; struct resource *res; int rid; sbintime_t byte_time_sbt; }; static phandle_t i2c_get_node(device_t, device_t); static int i2c_probe(device_t); static int i2c_attach(device_t); static int i2c_repeated_start(device_t, u_char, int); static int i2c_start(device_t, u_char, int); static int i2c_stop(device_t); static int i2c_reset(device_t, u_char, u_char, u_char *); static int i2c_read(device_t, char *, int, int *, int, int); static int i2c_write(device_t, const char *, int, int *, int); static device_method_t i2c_methods[] = { DEVMETHOD(device_probe, i2c_probe), DEVMETHOD(device_attach, i2c_attach), /* OFW methods */ DEVMETHOD(ofw_bus_get_node, i2c_get_node), DEVMETHOD(iicbus_callback, iicbus_null_callback), DEVMETHOD(iicbus_repeated_start, i2c_repeated_start), DEVMETHOD(iicbus_start, i2c_start), DEVMETHOD(iicbus_stop, i2c_stop), DEVMETHOD(iicbus_reset, i2c_reset), DEVMETHOD(iicbus_read, i2c_read), DEVMETHOD(iicbus_write, i2c_write), DEVMETHOD(iicbus_transfer, iicbus_transfer_gen), DEVMETHOD_END }; static driver_t i2c_driver = { "iichb", i2c_methods, sizeof(struct i2c_softc), }; static devclass_t i2c_devclass; DRIVER_MODULE(i2c, simplebus, i2c_driver, i2c_devclass, 0, 0); DRIVER_MODULE(iicbus, i2c, iicbus_driver, iicbus_devclass, 0, 0); static phandle_t i2c_get_node(device_t bus, device_t dev) { /* * Share controller node with iicbus device */ return ofw_bus_get_node(bus); } static __inline void i2c_write_reg(struct i2c_softc *sc, bus_size_t off, uint8_t val) { bus_write_1(sc->res, off, val); } static __inline uint8_t i2c_read_reg(struct i2c_softc *sc, bus_size_t off) { return (bus_read_1(sc->res, off)); } static __inline void i2c_flag_set(struct i2c_softc *sc, bus_size_t off, uint8_t mask) { uint8_t status; status = i2c_read_reg(sc, off); status |= mask; i2c_write_reg(sc, off, status); } /* Wait for bus to become busy or not-busy. */ static int wait_for_busbusy(struct i2c_softc *sc, int wantbusy) { int retry, srb; retry = 1000; while (retry --) { srb = i2c_read_reg(sc, I2C_STATUS_REG) & I2CSR_MBB; if ((srb && wantbusy) || (!srb && !wantbusy)) return (IIC_NOERR); DELAY(1); } return (IIC_ETIMEOUT); } /* Wait for transfer to complete, optionally check RXAK. */ static int wait_for_xfer(struct i2c_softc *sc, int checkack) { int retry, sr; /* * Sleep for about the time it takes to transfer a byte (with precision * set to tolerate 5% oversleep). We calculate the approximate byte * transfer time when we set the bus speed divisor. Slaves are allowed * to do clock-stretching so the actual transfer time can be larger, but * this gets the bulk of the waiting out of the way without tying up the * processor the whole time. */ pause_sbt("imxi2c", sc->byte_time_sbt, sc->byte_time_sbt / 20, 0); retry = 10000; while (retry --) { sr = i2c_read_reg(sc, I2C_STATUS_REG); if (sr & I2CSR_MIF) { if (sr & I2CSR_MAL) return (IIC_EBUSERR); else if (checkack && (sr & I2CSR_RXAK)) return (IIC_ENOACK); else return (IIC_NOERR); } DELAY(1); } return (IIC_ETIMEOUT); } /* * Implement the error handling shown in the state diagram of the imx6 reference * manual. If there was an error, then: * - Clear master mode (MSTA and MTX). * - Wait for the bus to become free or for a timeout to happen. * - Disable the controller. */ static int i2c_error_handler(struct i2c_softc *sc, int error) { if (error != 0) { i2c_write_reg(sc, I2C_STATUS_REG, 0); i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN); wait_for_busbusy(sc, false); i2c_write_reg(sc, I2C_CONTROL_REG, 0); } return (error); } static int i2c_probe(device_t dev) { if (!ofw_bus_status_okay(dev)) return (ENXIO); if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0) return (ENXIO); device_set_desc(dev, "Freescale i.MX I2C"); return (BUS_PROBE_DEFAULT); } static int i2c_attach(device_t dev) { struct i2c_softc *sc; sc = device_get_softc(dev); sc->dev = dev; sc->rid = 0; sc->res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &sc->rid, RF_ACTIVE); if (sc->res == NULL) { device_printf(dev, "could not allocate resources"); return (ENXIO); } sc->iicbus = device_add_child(dev, "iicbus", -1); if (sc->iicbus == NULL) { device_printf(dev, "could not add iicbus child"); return (ENXIO); } bus_generic_attach(dev); return (0); } static int i2c_repeated_start(device_t dev, u_char slave, int timeout) { struct i2c_softc *sc; int error; sc = device_get_softc(dev); if ((i2c_read_reg(sc, I2C_STATUS_REG) & I2CSR_MBB) == 0) { return (IIC_EBUSERR); } /* * Set repeated start condition, delay (per reference manual, min 156nS) * before writing slave address, wait for ack after write. */ i2c_flag_set(sc, I2C_CONTROL_REG, I2CCR_RSTA); DELAY(1); i2c_write_reg(sc, I2C_STATUS_REG, 0x0); i2c_write_reg(sc, I2C_DATA_REG, slave); error = wait_for_xfer(sc, true); return (i2c_error_handler(sc, error)); } static int i2c_start(device_t dev, u_char slave, int timeout) { struct i2c_softc *sc; int error; sc = device_get_softc(dev); i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN); DELAY(10); /* Delay for controller to sample bus state. */ if (i2c_read_reg(sc, I2C_STATUS_REG) & I2CSR_MBB) { return (i2c_error_handler(sc, IIC_EBUSERR)); } i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN | I2CCR_MSTA | I2CCR_MTX); if ((error = wait_for_busbusy(sc, true)) != IIC_NOERR) return (i2c_error_handler(sc, error)); i2c_write_reg(sc, I2C_STATUS_REG, 0); i2c_write_reg(sc, I2C_DATA_REG, slave); error = wait_for_xfer(sc, true); return (i2c_error_handler(sc, error)); } static int i2c_stop(device_t dev) { struct i2c_softc *sc; sc = device_get_softc(dev); i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN); wait_for_busbusy(sc, false); i2c_write_reg(sc, I2C_CONTROL_REG, 0); return (IIC_NOERR); } static int i2c_reset(device_t dev, u_char speed, u_char addr, u_char *oldadr) { struct i2c_softc *sc; u_int busfreq, div, i, ipgfreq; sc = device_get_softc(dev); /* * Look up the divisor that gives the nearest speed that doesn't exceed * the configured value for the bus. */ ipgfreq = imx_ccm_ipg_hz(); busfreq = IICBUS_GET_FREQUENCY(sc->iicbus, speed); div = howmany(ipgfreq, busfreq); for (i = 0; i < nitems(clkdiv_table); i++) { if (clkdiv_table[i].divisor >= div) break; } /* * Calculate roughly how long it will take to transfer a byte (which * requires 9 clock cycles) at the new bus speed. This value is used to * pause() while waiting for transfer-complete. With a 66MHz IPG clock * and the actual i2c bus speeds that leads to, for nominal 100KHz and * 400KHz bus speeds the transfer times are roughly 104uS and 22uS. */ busfreq = ipgfreq / clkdiv_table[i].divisor; sc->byte_time_sbt = SBT_1US * (9000000 / busfreq); /* * Disable the controller (do the reset), and set the new clock divisor. */ i2c_write_reg(sc, I2C_STATUS_REG, 0x0); i2c_write_reg(sc, I2C_CONTROL_REG, 0x0); i2c_write_reg(sc, I2C_FDR_REG, (uint8_t)clkdiv_table[i].regcode); return (IIC_NOERR); } static int i2c_read(device_t dev, char *buf, int len, int *read, int last, int delay) { struct i2c_softc *sc; int error, reg; sc = device_get_softc(dev); *read = 0; if (len) { if (len == 1) i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN | I2CCR_MSTA | I2CCR_TXAK); else i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN | I2CCR_MSTA); /* Dummy read to prime the receiver. */ i2c_write_reg(sc, I2C_STATUS_REG, 0x0); i2c_read_reg(sc, I2C_DATA_REG); } error = 0; *read = 0; while (*read < len) { if ((error = wait_for_xfer(sc, false)) != IIC_NOERR) break; i2c_write_reg(sc, I2C_STATUS_REG, 0x0); if (last) { if (*read == len - 2) { /* NO ACK on last byte */ i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN | I2CCR_MSTA | I2CCR_TXAK); } else if (*read == len - 1) { /* Transfer done, signal stop. */ i2c_write_reg(sc, I2C_CONTROL_REG, I2CCR_MEN | I2CCR_TXAK); wait_for_busbusy(sc, false); } } reg = i2c_read_reg(sc, I2C_DATA_REG); *buf++ = reg; (*read)++; } return (i2c_error_handler(sc, error)); } static int i2c_write(device_t dev, const char *buf, int len, int *sent, int timeout) { struct i2c_softc *sc; int error; sc = device_get_softc(dev); error = 0; *sent = 0; while (*sent < len) { i2c_write_reg(sc, I2C_STATUS_REG, 0x0); i2c_write_reg(sc, I2C_DATA_REG, *buf++); if ((error = wait_for_xfer(sc, true)) != IIC_NOERR) break; (*sent)++; } return (i2c_error_handler(sc, error)); }