/* * Driver for the Renesas RCar I2C unit * * Copyright (C) 2014 Wolfram Sang <wsa@sang-engineering.com> * * Copyright (C) 2012-14 Renesas Solutions Corp. * Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> * * This file is based on the drivers/i2c/busses/i2c-sh7760.c * (c) 2005-2008 MSC Vertriebsges.m.b.H, Manuel Lauss <mlau@msc-ge.com> * * This file used out-of-tree driver i2c-rcar.c * Copyright (C) 2011-2012 Renesas Electronics Corporation * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; version 2 of the License. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #include <linux/clk.h> #include <linux/delay.h> #include <linux/err.h> #include <linux/interrupt.h> #include <linux/io.h> #include <linux/i2c.h> #include <linux/i2c/i2c-rcar.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/of_device.h> #include <linux/platform_device.h> #include <linux/pm_runtime.h> #include <linux/slab.h> #include <linux/spinlock.h> /* register offsets */ #define ICSCR 0x00 /* slave ctrl */ #define ICMCR 0x04 /* master ctrl */ #define ICSSR 0x08 /* slave status */ #define ICMSR 0x0C /* master status */ #define ICSIER 0x10 /* slave irq enable */ #define ICMIER 0x14 /* master irq enable */ #define ICCCR 0x18 /* clock dividers */ #define ICSAR 0x1C /* slave address */ #define ICMAR 0x20 /* master address */ #define ICRXTX 0x24 /* data port */ /* ICSCR */ #define SDBS (1 << 3) /* slave data buffer select */ #define SIE (1 << 2) /* slave interface enable */ #define GCAE (1 << 1) /* general call address enable */ #define FNA (1 << 0) /* forced non acknowledgment */ /* ICMCR */ #define MDBS (1 << 7) /* non-fifo mode switch */ #define FSCL (1 << 6) /* override SCL pin */ #define FSDA (1 << 5) /* override SDA pin */ #define OBPC (1 << 4) /* override pins */ #define MIE (1 << 3) /* master if enable */ #define TSBE (1 << 2) #define FSB (1 << 1) /* force stop bit */ #define ESG (1 << 0) /* en startbit gen */ /* ICSSR (also for ICSIER) */ #define GCAR (1 << 6) /* general call received */ #define STM (1 << 5) /* slave transmit mode */ #define SSR (1 << 4) /* stop received */ #define SDE (1 << 3) /* slave data empty */ #define SDT (1 << 2) /* slave data transmitted */ #define SDR (1 << 1) /* slave data received */ #define SAR (1 << 0) /* slave addr received */ /* ICMSR (also for ICMIE) */ #define MNR (1 << 6) /* nack received */ #define MAL (1 << 5) /* arbitration lost */ #define MST (1 << 4) /* sent a stop */ #define MDE (1 << 3) #define MDT (1 << 2) #define MDR (1 << 1) #define MAT (1 << 0) /* slave addr xfer done */ #define RCAR_BUS_PHASE_START (MDBS | MIE | ESG) #define RCAR_BUS_PHASE_DATA (MDBS | MIE) #define RCAR_BUS_PHASE_STOP (MDBS | MIE | FSB) #define RCAR_IRQ_SEND (MNR | MAL | MST | MAT | MDE) #define RCAR_IRQ_RECV (MNR | MAL | MST | MAT | MDR) #define RCAR_IRQ_STOP (MST) #define RCAR_IRQ_ACK_SEND (~(MAT | MDE) & 0xFF) #define RCAR_IRQ_ACK_RECV (~(MAT | MDR) & 0xFF) #define ID_LAST_MSG (1 << 0) #define ID_IOERROR (1 << 1) #define ID_DONE (1 << 2) #define ID_ARBLOST (1 << 3) #define ID_NACK (1 << 4) enum rcar_i2c_type { I2C_RCAR_GEN1, I2C_RCAR_GEN2, }; struct rcar_i2c_priv { void __iomem *io; struct i2c_adapter adap; struct i2c_msg *msg; struct clk *clk; spinlock_t lock; wait_queue_head_t wait; int pos; u32 icccr; u32 flags; enum rcar_i2c_type devtype; struct i2c_client *slave; }; #define rcar_i2c_priv_to_dev(p) ((p)->adap.dev.parent) #define rcar_i2c_is_recv(p) ((p)->msg->flags & I2C_M_RD) #define rcar_i2c_flags_set(p, f) ((p)->flags |= (f)) #define rcar_i2c_flags_has(p, f) ((p)->flags & (f)) #define LOOP_TIMEOUT 1024 static void rcar_i2c_write(struct rcar_i2c_priv *priv, int reg, u32 val) { writel(val, priv->io + reg); } static u32 rcar_i2c_read(struct rcar_i2c_priv *priv, int reg) { return readl(priv->io + reg); } static void rcar_i2c_init(struct rcar_i2c_priv *priv) { /* reset master mode */ rcar_i2c_write(priv, ICMIER, 0); rcar_i2c_write(priv, ICMCR, 0); rcar_i2c_write(priv, ICMSR, 0); rcar_i2c_write(priv, ICMAR, 0); } static int rcar_i2c_bus_barrier(struct rcar_i2c_priv *priv) { int i; for (i = 0; i < LOOP_TIMEOUT; i++) { /* make sure that bus is not busy */ if (!(rcar_i2c_read(priv, ICMCR) & FSDA)) return 0; udelay(1); } return -EBUSY; } static int rcar_i2c_clock_calculate(struct rcar_i2c_priv *priv, u32 bus_speed, struct device *dev) { u32 scgd, cdf; u32 round, ick; u32 scl; u32 cdf_width; unsigned long rate; switch (priv->devtype) { case I2C_RCAR_GEN1: cdf_width = 2; break; case I2C_RCAR_GEN2: cdf_width = 3; break; default: dev_err(dev, "device type error\n"); return -EIO; } /* * calculate SCL clock * see * ICCCR * * ick = clkp / (1 + CDF) * SCL = ick / (20 + SCGD * 8 + F[(ticf + tr + intd) * ick]) * * ick : I2C internal clock < 20 MHz * ticf : I2C SCL falling time = 35 ns here * tr : I2C SCL rising time = 200 ns here * intd : LSI internal delay = 50 ns here * clkp : peripheral_clk * F[] : integer up-valuation */ rate = clk_get_rate(priv->clk); cdf = rate / 20000000; if (cdf >= 1U << cdf_width) { dev_err(dev, "Input clock %lu too high\n", rate); return -EIO; } ick = rate / (cdf + 1); /* * it is impossible to calculate large scale * number on u32. separate it * * F[(ticf + tr + intd) * ick] * = F[(35 + 200 + 50)ns * ick] * = F[285 * ick / 1000000000] * = F[(ick / 1000000) * 285 / 1000] */ round = (ick + 500000) / 1000000 * 285; round = (round + 500) / 1000; /* * SCL = ick / (20 + SCGD * 8 + F[(ticf + tr + intd) * ick]) * * Calculation result (= SCL) should be less than * bus_speed for hardware safety * * We could use something along the lines of * div = ick / (bus_speed + 1) + 1; * scgd = (div - 20 - round + 7) / 8; * scl = ick / (20 + (scgd * 8) + round); * (not fully verified) but that would get pretty involved */ for (scgd = 0; scgd < 0x40; scgd++) { scl = ick / (20 + (scgd * 8) + round); if (scl <= bus_speed) goto scgd_find; } dev_err(dev, "it is impossible to calculate best SCL\n"); return -EIO; scgd_find: dev_dbg(dev, "clk %d/%d(%lu), round %u, CDF:0x%x, SCGD: 0x%x\n", scl, bus_speed, clk_get_rate(priv->clk), round, cdf, scgd); /* * keep icccr value */ priv->icccr = scgd << cdf_width | cdf; return 0; } static void rcar_i2c_prepare_msg(struct rcar_i2c_priv *priv) { int read = !!rcar_i2c_is_recv(priv); rcar_i2c_write(priv, ICMAR, (priv->msg->addr << 1) | read); rcar_i2c_write(priv, ICMSR, 0); rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_START); rcar_i2c_write(priv, ICMIER, read ? RCAR_IRQ_RECV : RCAR_IRQ_SEND); } /* * interrupt functions */ static int rcar_i2c_irq_send(struct rcar_i2c_priv *priv, u32 msr) { struct i2c_msg *msg = priv->msg; /* * FIXME * sometimes, unknown interrupt happened. * Do nothing */ if (!(msr & MDE)) return 0; /* * If address transfer phase finished, * goto data phase. */ if (msr & MAT) rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_DATA); if (priv->pos < msg->len) { /* * Prepare next data to ICRXTX register. * This data will go to _SHIFT_ register. * * * * [ICRXTX] -> [SHIFT] -> [I2C bus] */ rcar_i2c_write(priv, ICRXTX, msg->buf[priv->pos]); priv->pos++; } else { /* * The last data was pushed to ICRXTX on _PREV_ empty irq. * It is on _SHIFT_ register, and will sent to I2C bus. * * * * [ICRXTX] -> [SHIFT] -> [I2C bus] */ if (priv->flags & ID_LAST_MSG) /* * If current msg is the _LAST_ msg, * prepare stop condition here. * ID_DONE will be set on STOP irq. */ rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_STOP); else /* * If current msg is _NOT_ last msg, * it doesn't call stop phase. * thus, there is no STOP irq. * return ID_DONE here. */ return ID_DONE; } rcar_i2c_write(priv, ICMSR, RCAR_IRQ_ACK_SEND); return 0; } static int rcar_i2c_irq_recv(struct rcar_i2c_priv *priv, u32 msr) { struct i2c_msg *msg = priv->msg; /* * FIXME * sometimes, unknown interrupt happened. * Do nothing */ if (!(msr & MDR)) return 0; if (msr & MAT) { /* * Address transfer phase finished, * but, there is no data at this point. * Do nothing. */ } else if (priv->pos < msg->len) { /* * get received data */ msg->buf[priv->pos] = rcar_i2c_read(priv, ICRXTX); priv->pos++; } /* * If next received data is the _LAST_, * go to STOP phase, * otherwise, go to DATA phase. */ if (priv->pos + 1 >= msg->len) rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_STOP); else rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_DATA); rcar_i2c_write(priv, ICMSR, RCAR_IRQ_ACK_RECV); return 0; } static bool rcar_i2c_slave_irq(struct rcar_i2c_priv *priv) { u32 ssr_raw, ssr_filtered; u8 value; ssr_raw = rcar_i2c_read(priv, ICSSR) & 0xff; ssr_filtered = ssr_raw & rcar_i2c_read(priv, ICSIER); if (!ssr_filtered) return false; /* address detected */ if (ssr_filtered & SAR) { /* read or write request */ if (ssr_raw & STM) { i2c_slave_event(priv->slave, I2C_SLAVE_READ_REQUESTED, &value); rcar_i2c_write(priv, ICRXTX, value); rcar_i2c_write(priv, ICSIER, SDE | SSR | SAR); } else { i2c_slave_event(priv->slave, I2C_SLAVE_WRITE_REQUESTED, &value); rcar_i2c_read(priv, ICRXTX); /* dummy read */ rcar_i2c_write(priv, ICSIER, SDR | SSR | SAR); } rcar_i2c_write(priv, ICSSR, ~SAR & 0xff); } /* master sent stop */ if (ssr_filtered & SSR) { i2c_slave_event(priv->slave, I2C_SLAVE_STOP, &value); rcar_i2c_write(priv, ICSIER, SAR | SSR); rcar_i2c_write(priv, ICSSR, ~SSR & 0xff); } /* master wants to write to us */ if (ssr_filtered & SDR) { int ret; value = rcar_i2c_read(priv, ICRXTX); ret = i2c_slave_event(priv->slave, I2C_SLAVE_WRITE_RECEIVED, &value); /* Send NACK in case of error */ rcar_i2c_write(priv, ICSCR, SIE | SDBS | (ret < 0 ? FNA : 0)); rcar_i2c_write(priv, ICSSR, ~SDR & 0xff); } /* master wants to read from us */ if (ssr_filtered & SDE) { i2c_slave_event(priv->slave, I2C_SLAVE_READ_PROCESSED, &value); rcar_i2c_write(priv, ICRXTX, value); rcar_i2c_write(priv, ICSSR, ~SDE & 0xff); } return true; } static irqreturn_t rcar_i2c_irq(int irq, void *ptr) { struct rcar_i2c_priv *priv = ptr; irqreturn_t result = IRQ_HANDLED; u32 msr; /*-------------- spin lock -----------------*/ spin_lock(&priv->lock); if (rcar_i2c_slave_irq(priv)) goto exit; msr = rcar_i2c_read(priv, ICMSR); /* Only handle interrupts that are currently enabled */ msr &= rcar_i2c_read(priv, ICMIER); if (!msr) { result = IRQ_NONE; goto exit; } /* Arbitration lost */ if (msr & MAL) { rcar_i2c_flags_set(priv, (ID_DONE | ID_ARBLOST)); goto out; } /* Nack */ if (msr & MNR) { /* go to stop phase */ rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_STOP); rcar_i2c_write(priv, ICMIER, RCAR_IRQ_STOP); rcar_i2c_flags_set(priv, ID_NACK); goto out; } /* Stop */ if (msr & MST) { rcar_i2c_flags_set(priv, ID_DONE); goto out; } if (rcar_i2c_is_recv(priv)) rcar_i2c_flags_set(priv, rcar_i2c_irq_recv(priv, msr)); else rcar_i2c_flags_set(priv, rcar_i2c_irq_send(priv, msr)); out: if (rcar_i2c_flags_has(priv, ID_DONE)) { rcar_i2c_write(priv, ICMIER, 0); rcar_i2c_write(priv, ICMSR, 0); wake_up(&priv->wait); } exit: spin_unlock(&priv->lock); /*-------------- spin unlock -----------------*/ return result; } static int rcar_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) { struct rcar_i2c_priv *priv = i2c_get_adapdata(adap); struct device *dev = rcar_i2c_priv_to_dev(priv); unsigned long flags; int i, ret, timeout; pm_runtime_get_sync(dev); /*-------------- spin lock -----------------*/ spin_lock_irqsave(&priv->lock, flags); rcar_i2c_init(priv); /* start clock */ rcar_i2c_write(priv, ICCCR, priv->icccr); spin_unlock_irqrestore(&priv->lock, flags); /*-------------- spin unlock -----------------*/ ret = rcar_i2c_bus_barrier(priv); if (ret < 0) goto out; for (i = 0; i < num; i++) { /* This HW can't send STOP after address phase */ if (msgs[i].len == 0) { ret = -EOPNOTSUPP; break; } /*-------------- spin lock -----------------*/ spin_lock_irqsave(&priv->lock, flags); /* init each data */ priv->msg = &msgs[i]; priv->pos = 0; priv->flags = 0; if (i == num - 1) rcar_i2c_flags_set(priv, ID_LAST_MSG); rcar_i2c_prepare_msg(priv); spin_unlock_irqrestore(&priv->lock, flags); /*-------------- spin unlock -----------------*/ timeout = wait_event_timeout(priv->wait, rcar_i2c_flags_has(priv, ID_DONE), 5 * HZ); if (!timeout) { ret = -ETIMEDOUT; break; } if (rcar_i2c_flags_has(priv, ID_NACK)) { ret = -ENXIO; break; } if (rcar_i2c_flags_has(priv, ID_ARBLOST)) { ret = -EAGAIN; break; } if (rcar_i2c_flags_has(priv, ID_IOERROR)) { ret = -EIO; break; } ret = i + 1; /* The number of transfer */ } out: pm_runtime_put(dev); if (ret < 0 && ret != -ENXIO) dev_err(dev, "error %d : %x\n", ret, priv->flags); return ret; } static int rcar_reg_slave(struct i2c_client *slave) { struct rcar_i2c_priv *priv = i2c_get_adapdata(slave->adapter); if (priv->slave) return -EBUSY; if (slave->flags & I2C_CLIENT_TEN) return -EAFNOSUPPORT; pm_runtime_forbid(rcar_i2c_priv_to_dev(priv)); priv->slave = slave; rcar_i2c_write(priv, ICSAR, slave->addr); rcar_i2c_write(priv, ICSSR, 0); rcar_i2c_write(priv, ICSIER, SAR | SSR); rcar_i2c_write(priv, ICSCR, SIE | SDBS); return 0; } static int rcar_unreg_slave(struct i2c_client *slave) { struct rcar_i2c_priv *priv = i2c_get_adapdata(slave->adapter); WARN_ON(!priv->slave); rcar_i2c_write(priv, ICSIER, 0); rcar_i2c_write(priv, ICSCR, 0); priv->slave = NULL; pm_runtime_allow(rcar_i2c_priv_to_dev(priv)); return 0; } static u32 rcar_i2c_func(struct i2c_adapter *adap) { /* This HW can't do SMBUS_QUICK and NOSTART */ return I2C_FUNC_I2C | I2C_FUNC_SLAVE | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK); } static const struct i2c_algorithm rcar_i2c_algo = { .master_xfer = rcar_i2c_master_xfer, .functionality = rcar_i2c_func, .reg_slave = rcar_reg_slave, .unreg_slave = rcar_unreg_slave, }; static const struct of_device_id rcar_i2c_dt_ids[] = { { .compatible = "renesas,i2c-rcar", .data = (void *)I2C_RCAR_GEN1 }, { .compatible = "renesas,i2c-r8a7778", .data = (void *)I2C_RCAR_GEN1 }, { .compatible = "renesas,i2c-r8a7779", .data = (void *)I2C_RCAR_GEN1 }, { .compatible = "renesas,i2c-r8a7790", .data = (void *)I2C_RCAR_GEN2 }, { .compatible = "renesas,i2c-r8a7791", .data = (void *)I2C_RCAR_GEN2 }, { .compatible = "renesas,i2c-r8a7792", .data = (void *)I2C_RCAR_GEN2 }, { .compatible = "renesas,i2c-r8a7793", .data = (void *)I2C_RCAR_GEN2 }, { .compatible = "renesas,i2c-r8a7794", .data = (void *)I2C_RCAR_GEN2 }, {}, }; MODULE_DEVICE_TABLE(of, rcar_i2c_dt_ids); static int rcar_i2c_probe(struct platform_device *pdev) { struct i2c_rcar_platform_data *pdata = dev_get_platdata(&pdev->dev); struct rcar_i2c_priv *priv; struct i2c_adapter *adap; struct resource *res; struct device *dev = &pdev->dev; u32 bus_speed; int irq, ret; priv = devm_kzalloc(dev, sizeof(struct rcar_i2c_priv), GFP_KERNEL); if (!priv) return -ENOMEM; priv->clk = devm_clk_get(dev, NULL); if (IS_ERR(priv->clk)) { dev_err(dev, "cannot get clock\n"); return PTR_ERR(priv->clk); } bus_speed = 100000; /* default 100 kHz */ ret = of_property_read_u32(dev->of_node, "clock-frequency", &bus_speed); if (ret < 0 && pdata && pdata->bus_speed) bus_speed = pdata->bus_speed; if (pdev->dev.of_node) priv->devtype = (long)of_match_device(rcar_i2c_dt_ids, dev)->data; else priv->devtype = platform_get_device_id(pdev)->driver_data; ret = rcar_i2c_clock_calculate(priv, bus_speed, dev); if (ret < 0) return ret; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); priv->io = devm_ioremap_resource(dev, res); if (IS_ERR(priv->io)) return PTR_ERR(priv->io); irq = platform_get_irq(pdev, 0); init_waitqueue_head(&priv->wait); spin_lock_init(&priv->lock); adap = &priv->adap; adap->nr = pdev->id; adap->algo = &rcar_i2c_algo; adap->class = I2C_CLASS_DEPRECATED; adap->retries = 3; adap->dev.parent = dev; adap->dev.of_node = dev->of_node; i2c_set_adapdata(adap, priv); strlcpy(adap->name, pdev->name, sizeof(adap->name)); ret = devm_request_irq(dev, irq, rcar_i2c_irq, 0, dev_name(dev), priv); if (ret < 0) { dev_err(dev, "cannot get irq %d\n", irq); return ret; } ret = i2c_add_numbered_adapter(adap); if (ret < 0) { dev_err(dev, "reg adap failed: %d\n", ret); return ret; } pm_runtime_enable(dev); platform_set_drvdata(pdev, priv); dev_info(dev, "probed\n"); return 0; } static int rcar_i2c_remove(struct platform_device *pdev) { struct rcar_i2c_priv *priv = platform_get_drvdata(pdev); struct device *dev = &pdev->dev; i2c_del_adapter(&priv->adap); pm_runtime_disable(dev); return 0; } static const struct platform_device_id rcar_i2c_id_table[] = { { "i2c-rcar", I2C_RCAR_GEN1 }, { "i2c-rcar_gen1", I2C_RCAR_GEN1 }, { "i2c-rcar_gen2", I2C_RCAR_GEN2 }, {}, }; MODULE_DEVICE_TABLE(platform, rcar_i2c_id_table); static struct platform_driver rcar_i2c_driver = { .driver = { .name = "i2c-rcar", .of_match_table = rcar_i2c_dt_ids, }, .probe = rcar_i2c_probe, .remove = rcar_i2c_remove, .id_table = rcar_i2c_id_table, }; module_platform_driver(rcar_i2c_driver); MODULE_LICENSE("GPL v2"); MODULE_DESCRIPTION("Renesas R-Car I2C bus driver"); MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>");