/* * SuperH Mobile I2C Controller * * Copyright (C) 2008 Magnus Damm * * Portions of the code based on out-of-tree driver i2c-sh7343.c * Copyright (c) 2006 Carlos Munoz * * 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; either 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. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include #include #include #include #include #include #include #include #include #include #include #include #include /* Transmit operation: */ /* */ /* 0 byte transmit */ /* BUS: S A8 ACK P(*) */ /* IRQ: DTE WAIT */ /* ICIC: */ /* ICCR: 0x94 0x90 */ /* ICDR: A8 */ /* */ /* 1 byte transmit */ /* BUS: S A8 ACK D8(1) ACK P(*) */ /* IRQ: DTE WAIT WAIT */ /* ICIC: -DTE */ /* ICCR: 0x94 0x90 */ /* ICDR: A8 D8(1) */ /* */ /* 2 byte transmit */ /* BUS: S A8 ACK D8(1) ACK D8(2) ACK P(*) */ /* IRQ: DTE WAIT WAIT WAIT */ /* ICIC: -DTE */ /* ICCR: 0x94 0x90 */ /* ICDR: A8 D8(1) D8(2) */ /* */ /* 3 bytes or more, +---------+ gets repeated */ /* */ /* */ /* Receive operation: */ /* */ /* 0 byte receive - not supported since slave may hold SDA low */ /* */ /* 1 byte receive [TX] | [RX] */ /* BUS: S A8 ACK | D8(1) ACK P(*) */ /* IRQ: DTE WAIT | WAIT DTE */ /* ICIC: -DTE | +DTE */ /* ICCR: 0x94 0x81 | 0xc0 */ /* ICDR: A8 | D8(1) */ /* */ /* 2 byte receive [TX]| [RX] */ /* BUS: S A8 ACK | D8(1) ACK D8(2) ACK P(*) */ /* IRQ: DTE WAIT | WAIT WAIT DTE */ /* ICIC: -DTE | +DTE */ /* ICCR: 0x94 0x81 | 0xc0 */ /* ICDR: A8 | D8(1) D8(2) */ /* */ /* 3 byte receive [TX] | [RX] (*) */ /* BUS: S A8 ACK | D8(1) ACK D8(2) ACK D8(3) ACK P */ /* IRQ: DTE WAIT | WAIT WAIT WAIT DTE */ /* ICIC: -DTE | +DTE */ /* ICCR: 0x94 0x81 | 0xc0 */ /* ICDR: A8 | D8(1) D8(2) D8(3) */ /* */ /* 4 bytes or more, this part is repeated +---------+ */ /* */ /* */ /* Interrupt order and BUSY flag */ /* ___ _ */ /* SDA ___\___XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXAAAAAAAAA___/ */ /* SCL \_/1\_/2\_/3\_/4\_/5\_/6\_/7\_/8\___/9\_____/ */ /* */ /* S D7 D6 D5 D4 D3 D2 D1 D0 P(*) */ /* ___ */ /* WAIT IRQ ________________________________/ \___________ */ /* TACK IRQ ____________________________________/ \_______ */ /* DTE IRQ __________________________________________/ \_ */ /* AL IRQ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX */ /* _______________________________________________ */ /* BUSY __/ \_ */ /* */ /* (*) The STOP condition is only sent by the master at the end of the last */ /* I2C message or if the I2C_M_STOP flag is set. Similarly, the BUSY bit is */ /* only cleared after the STOP condition, so, between messages we have to */ /* poll for the DTE bit. */ /* */ enum sh_mobile_i2c_op { OP_START = 0, OP_TX_FIRST, OP_TX, OP_TX_STOP, OP_TX_TO_RX, OP_RX, OP_RX_STOP, OP_RX_STOP_DATA, }; struct sh_mobile_i2c_data { struct device *dev; void __iomem *reg; struct i2c_adapter adap; unsigned long bus_speed; unsigned int clks_per_count; struct clk *clk; u_int8_t icic; u_int8_t flags; u_int16_t iccl; u_int16_t icch; spinlock_t lock; wait_queue_head_t wait; struct i2c_msg *msg; int pos; int sr; bool send_stop; }; #define IIC_FLAG_HAS_ICIC67 (1 << 0) #define STANDARD_MODE 100000 #define FAST_MODE 400000 /* Register offsets */ #define ICDR 0x00 #define ICCR 0x04 #define ICSR 0x08 #define ICIC 0x0c #define ICCL 0x10 #define ICCH 0x14 /* Register bits */ #define ICCR_ICE 0x80 #define ICCR_RACK 0x40 #define ICCR_TRS 0x10 #define ICCR_BBSY 0x04 #define ICCR_SCP 0x01 #define ICSR_SCLM 0x80 #define ICSR_SDAM 0x40 #define SW_DONE 0x20 #define ICSR_BUSY 0x10 #define ICSR_AL 0x08 #define ICSR_TACK 0x04 #define ICSR_WAIT 0x02 #define ICSR_DTE 0x01 #define ICIC_ICCLB8 0x80 #define ICIC_ICCHB8 0x40 #define ICIC_ALE 0x08 #define ICIC_TACKE 0x04 #define ICIC_WAITE 0x02 #define ICIC_DTEE 0x01 static void iic_wr(struct sh_mobile_i2c_data *pd, int offs, unsigned char data) { if (offs == ICIC) data |= pd->icic; iowrite8(data, pd->reg + offs); } static unsigned char iic_rd(struct sh_mobile_i2c_data *pd, int offs) { return ioread8(pd->reg + offs); } static void iic_set_clr(struct sh_mobile_i2c_data *pd, int offs, unsigned char set, unsigned char clr) { iic_wr(pd, offs, (iic_rd(pd, offs) | set) & ~clr); } static u32 sh_mobile_i2c_iccl(unsigned long count_khz, u32 tLOW, u32 tf) { /* * Conditional expression: * ICCL >= COUNT_CLK * (tLOW + tf) * * SH-Mobile IIC hardware starts counting the LOW period of * the SCL signal (tLOW) as soon as it pulls the SCL line. * In order to meet the tLOW timing spec, we need to take into * account the fall time of SCL signal (tf). Default tf value * should be 0.3 us, for safety. */ return (((count_khz * (tLOW + tf)) + 5000) / 10000); } static u32 sh_mobile_i2c_icch(unsigned long count_khz, u32 tHIGH, u32 tf) { /* * Conditional expression: * ICCH >= COUNT_CLK * (tHIGH + tf) * * SH-Mobile IIC hardware is aware of SCL transition period 'tr', * and can ignore it. SH-Mobile IIC controller starts counting * the HIGH period of the SCL signal (tHIGH) after the SCL input * voltage increases at VIH. * * Afterward it turned out calculating ICCH using only tHIGH spec * will result in violation of the tHD;STA timing spec. We need * to take into account the fall time of SDA signal (tf) at START * condition, in order to meet both tHIGH and tHD;STA specs. */ return (((count_khz * (tHIGH + tf)) + 5000) / 10000); } static int sh_mobile_i2c_init(struct sh_mobile_i2c_data *pd) { unsigned long i2c_clk_khz; u32 tHIGH, tLOW, tf; /* Get clock rate after clock is enabled */ clk_prepare_enable(pd->clk); i2c_clk_khz = clk_get_rate(pd->clk) / 1000; clk_disable_unprepare(pd->clk); i2c_clk_khz /= pd->clks_per_count; if (pd->bus_speed == STANDARD_MODE) { tLOW = 47; /* tLOW = 4.7 us */ tHIGH = 40; /* tHD;STA = tHIGH = 4.0 us */ tf = 3; /* tf = 0.3 us */ } else if (pd->bus_speed == FAST_MODE) { tLOW = 13; /* tLOW = 1.3 us */ tHIGH = 6; /* tHD;STA = tHIGH = 0.6 us */ tf = 3; /* tf = 0.3 us */ } else { dev_err(pd->dev, "unrecognized bus speed %lu Hz\n", pd->bus_speed); return -EINVAL; } pd->iccl = sh_mobile_i2c_iccl(i2c_clk_khz, tLOW, tf); /* one more bit of ICCL in ICIC */ if ((pd->iccl > 0xff) && (pd->flags & IIC_FLAG_HAS_ICIC67)) pd->icic |= ICIC_ICCLB8; else pd->icic &= ~ICIC_ICCLB8; pd->icch = sh_mobile_i2c_icch(i2c_clk_khz, tHIGH, tf); /* one more bit of ICCH in ICIC */ if ((pd->icch > 0xff) && (pd->flags & IIC_FLAG_HAS_ICIC67)) pd->icic |= ICIC_ICCHB8; else pd->icic &= ~ICIC_ICCHB8; return 0; } static void activate_ch(struct sh_mobile_i2c_data *pd) { /* Wake up device and enable clock */ pm_runtime_get_sync(pd->dev); clk_prepare_enable(pd->clk); /* Enable channel and configure rx ack */ iic_set_clr(pd, ICCR, ICCR_ICE, 0); /* Mask all interrupts */ iic_wr(pd, ICIC, 0); /* Set the clock */ iic_wr(pd, ICCL, pd->iccl & 0xff); iic_wr(pd, ICCH, pd->icch & 0xff); } static void deactivate_ch(struct sh_mobile_i2c_data *pd) { /* Clear/disable interrupts */ iic_wr(pd, ICSR, 0); iic_wr(pd, ICIC, 0); /* Disable channel */ iic_set_clr(pd, ICCR, 0, ICCR_ICE); /* Disable clock and mark device as idle */ clk_disable_unprepare(pd->clk); pm_runtime_put_sync(pd->dev); } static unsigned char i2c_op(struct sh_mobile_i2c_data *pd, enum sh_mobile_i2c_op op, unsigned char data) { unsigned char ret = 0; unsigned long flags; dev_dbg(pd->dev, "op %d, data in 0x%02x\n", op, data); spin_lock_irqsave(&pd->lock, flags); switch (op) { case OP_START: /* issue start and trigger DTE interrupt */ iic_wr(pd, ICCR, ICCR_ICE | ICCR_TRS | ICCR_BBSY); break; case OP_TX_FIRST: /* disable DTE interrupt and write data */ iic_wr(pd, ICIC, ICIC_WAITE | ICIC_ALE | ICIC_TACKE); iic_wr(pd, ICDR, data); break; case OP_TX: /* write data */ iic_wr(pd, ICDR, data); break; case OP_TX_STOP: /* write data and issue a stop afterwards */ iic_wr(pd, ICDR, data); iic_wr(pd, ICCR, pd->send_stop ? ICCR_ICE | ICCR_TRS : ICCR_ICE | ICCR_TRS | ICCR_BBSY); break; case OP_TX_TO_RX: /* select read mode */ iic_wr(pd, ICCR, ICCR_ICE | ICCR_SCP); break; case OP_RX: /* just read data */ ret = iic_rd(pd, ICDR); break; case OP_RX_STOP: /* enable DTE interrupt, issue stop */ iic_wr(pd, ICIC, ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE); iic_wr(pd, ICCR, ICCR_ICE | ICCR_RACK); break; case OP_RX_STOP_DATA: /* enable DTE interrupt, read data, issue stop */ iic_wr(pd, ICIC, ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE); ret = iic_rd(pd, ICDR); iic_wr(pd, ICCR, ICCR_ICE | ICCR_RACK); break; } spin_unlock_irqrestore(&pd->lock, flags); dev_dbg(pd->dev, "op %d, data out 0x%02x\n", op, ret); return ret; } static bool sh_mobile_i2c_is_first_byte(struct sh_mobile_i2c_data *pd) { return pd->pos == -1; } static bool sh_mobile_i2c_is_last_byte(struct sh_mobile_i2c_data *pd) { return pd->pos == pd->msg->len - 1; } static void sh_mobile_i2c_get_data(struct sh_mobile_i2c_data *pd, unsigned char *buf) { switch (pd->pos) { case -1: *buf = (pd->msg->addr & 0x7f) << 1; *buf |= (pd->msg->flags & I2C_M_RD) ? 1 : 0; break; default: *buf = pd->msg->buf[pd->pos]; } } static int sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data *pd) { unsigned char data; if (pd->pos == pd->msg->len) return 1; sh_mobile_i2c_get_data(pd, &data); if (sh_mobile_i2c_is_last_byte(pd)) i2c_op(pd, OP_TX_STOP, data); else if (sh_mobile_i2c_is_first_byte(pd)) i2c_op(pd, OP_TX_FIRST, data); else i2c_op(pd, OP_TX, data); pd->pos++; return 0; } static int sh_mobile_i2c_isr_rx(struct sh_mobile_i2c_data *pd) { unsigned char data; int real_pos; do { if (pd->pos <= -1) { sh_mobile_i2c_get_data(pd, &data); if (sh_mobile_i2c_is_first_byte(pd)) i2c_op(pd, OP_TX_FIRST, data); else i2c_op(pd, OP_TX, data); break; } if (pd->pos == 0) { i2c_op(pd, OP_TX_TO_RX, 0); break; } real_pos = pd->pos - 2; if (pd->pos == pd->msg->len) { if (real_pos < 0) { i2c_op(pd, OP_RX_STOP, 0); break; } data = i2c_op(pd, OP_RX_STOP_DATA, 0); } else data = i2c_op(pd, OP_RX, 0); if (real_pos >= 0) pd->msg->buf[real_pos] = data; } while (0); pd->pos++; return pd->pos == (pd->msg->len + 2); } static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id) { struct platform_device *dev = dev_id; struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev); unsigned char sr; int wakeup; sr = iic_rd(pd, ICSR); pd->sr |= sr; /* remember state */ dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr, (pd->msg->flags & I2C_M_RD) ? "read" : "write", pd->pos, pd->msg->len); if (sr & (ICSR_AL | ICSR_TACK)) { /* don't interrupt transaction - continue to issue stop */ iic_wr(pd, ICSR, sr & ~(ICSR_AL | ICSR_TACK)); wakeup = 0; } else if (pd->msg->flags & I2C_M_RD) wakeup = sh_mobile_i2c_isr_rx(pd); else wakeup = sh_mobile_i2c_isr_tx(pd); if (sr & ICSR_WAIT) /* TODO: add delay here to support slow acks */ iic_wr(pd, ICSR, sr & ~ICSR_WAIT); if (wakeup) { pd->sr |= SW_DONE; wake_up(&pd->wait); } /* defeat write posting to avoid spurious WAIT interrupts */ iic_rd(pd, ICSR); return IRQ_HANDLED; } static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg, bool do_init) { if (usr_msg->len == 0 && (usr_msg->flags & I2C_M_RD)) { dev_err(pd->dev, "Unsupported zero length i2c read\n"); return -EOPNOTSUPP; } if (do_init) { /* Initialize channel registers */ iic_set_clr(pd, ICCR, 0, ICCR_ICE); /* Enable channel and configure rx ack */ iic_set_clr(pd, ICCR, ICCR_ICE, 0); /* Set the clock */ iic_wr(pd, ICCL, pd->iccl & 0xff); iic_wr(pd, ICCH, pd->icch & 0xff); } pd->msg = usr_msg; pd->pos = -1; pd->sr = 0; /* Enable all interrupts to begin with */ iic_wr(pd, ICIC, ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE); return 0; } static int poll_dte(struct sh_mobile_i2c_data *pd) { int i; for (i = 1000; i; i--) { u_int8_t val = iic_rd(pd, ICSR); if (val & ICSR_DTE) break; if (val & ICSR_TACK) return -ENXIO; udelay(10); } return i ? 0 : -ETIMEDOUT; } static int poll_busy(struct sh_mobile_i2c_data *pd) { int i; for (i = 1000; i; i--) { u_int8_t val = iic_rd(pd, ICSR); dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr); /* the interrupt handler may wake us up before the * transfer is finished, so poll the hardware * until we're done. */ if (!(val & ICSR_BUSY)) { /* handle missing acknowledge and arbitration lost */ val |= pd->sr; if (val & ICSR_TACK) return -ENXIO; if (val & ICSR_AL) return -EAGAIN; break; } udelay(10); } return i ? 0 : -ETIMEDOUT; } static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num) { struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter); struct i2c_msg *msg; int err = 0; int i, k; activate_ch(pd); /* Process all messages */ for (i = 0; i < num; i++) { bool do_start = pd->send_stop || !i; msg = &msgs[i]; pd->send_stop = i == num - 1 || msg->flags & I2C_M_STOP; err = start_ch(pd, msg, do_start); if (err) break; if (do_start) i2c_op(pd, OP_START, 0); /* The interrupt handler takes care of the rest... */ k = wait_event_timeout(pd->wait, pd->sr & (ICSR_TACK | SW_DONE), 5 * HZ); if (!k) { dev_err(pd->dev, "Transfer request timed out\n"); err = -ETIMEDOUT; break; } if (pd->send_stop) err = poll_busy(pd); else err = poll_dte(pd); if (err < 0) break; } deactivate_ch(pd); if (!err) err = num; return err; } static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter) { return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING; } static struct i2c_algorithm sh_mobile_i2c_algorithm = { .functionality = sh_mobile_i2c_func, .master_xfer = sh_mobile_i2c_xfer, }; static int sh_mobile_i2c_hook_irqs(struct platform_device *dev) { struct resource *res; resource_size_t n; int k = 0, ret; while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) { for (n = res->start; n <= res->end; n++) { ret = devm_request_irq(&dev->dev, n, sh_mobile_i2c_isr, 0, dev_name(&dev->dev), dev); if (ret) { dev_err(&dev->dev, "cannot request IRQ %pa\n", &n); return ret; } } k++; } return k > 0 ? 0 : -ENOENT; } static int sh_mobile_i2c_probe(struct platform_device *dev) { struct i2c_sh_mobile_platform_data *pdata = dev_get_platdata(&dev->dev); struct sh_mobile_i2c_data *pd; struct i2c_adapter *adap; struct resource *res; int ret; u32 bus_speed; pd = devm_kzalloc(&dev->dev, sizeof(struct sh_mobile_i2c_data), GFP_KERNEL); if (!pd) return -ENOMEM; pd->clk = devm_clk_get(&dev->dev, NULL); if (IS_ERR(pd->clk)) { dev_err(&dev->dev, "cannot get clock\n"); return PTR_ERR(pd->clk); } ret = sh_mobile_i2c_hook_irqs(dev); if (ret) return ret; pd->dev = &dev->dev; platform_set_drvdata(dev, pd); res = platform_get_resource(dev, IORESOURCE_MEM, 0); pd->reg = devm_ioremap_resource(&dev->dev, res); if (IS_ERR(pd->reg)) return PTR_ERR(pd->reg); /* Use platform data bus speed or STANDARD_MODE */ ret = of_property_read_u32(dev->dev.of_node, "clock-frequency", &bus_speed); pd->bus_speed = ret ? STANDARD_MODE : bus_speed; if (pdata && pdata->bus_speed) pd->bus_speed = pdata->bus_speed; pd->clks_per_count = 1; if (pdata && pdata->clks_per_count) pd->clks_per_count = pdata->clks_per_count; /* The IIC blocks on SH-Mobile ARM processors * come with two new bits in ICIC. */ if (resource_size(res) > 0x17) pd->flags |= IIC_FLAG_HAS_ICIC67; ret = sh_mobile_i2c_init(pd); if (ret) return ret; /* Enable Runtime PM for this device. * * Also tell the Runtime PM core to ignore children * for this device since it is valid for us to suspend * this I2C master driver even though the slave devices * on the I2C bus may not be suspended. * * The state of the I2C hardware bus is unaffected by * the Runtime PM state. */ pm_suspend_ignore_children(&dev->dev, true); pm_runtime_enable(&dev->dev); /* setup the private data */ adap = &pd->adap; i2c_set_adapdata(adap, pd); adap->owner = THIS_MODULE; adap->algo = &sh_mobile_i2c_algorithm; adap->dev.parent = &dev->dev; adap->retries = 5; adap->nr = dev->id; adap->dev.of_node = dev->dev.of_node; strlcpy(adap->name, dev->name, sizeof(adap->name)); spin_lock_init(&pd->lock); init_waitqueue_head(&pd->wait); ret = i2c_add_numbered_adapter(adap); if (ret < 0) { dev_err(&dev->dev, "cannot add numbered adapter\n"); return ret; } dev_info(&dev->dev, "I2C adapter %d with bus speed %lu Hz (L/H=%x/%x)\n", adap->nr, pd->bus_speed, pd->iccl, pd->icch); return 0; } static int sh_mobile_i2c_remove(struct platform_device *dev) { struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev); i2c_del_adapter(&pd->adap); pm_runtime_disable(&dev->dev); return 0; } static int sh_mobile_i2c_runtime_nop(struct device *dev) { /* Runtime PM callback shared between ->runtime_suspend() * and ->runtime_resume(). Simply returns success. * * This driver re-initializes all registers after * pm_runtime_get_sync() anyway so there is no need * to save and restore registers here. */ return 0; } static const struct dev_pm_ops sh_mobile_i2c_dev_pm_ops = { .runtime_suspend = sh_mobile_i2c_runtime_nop, .runtime_resume = sh_mobile_i2c_runtime_nop, }; static const struct of_device_id sh_mobile_i2c_dt_ids[] = { { .compatible = "renesas,rmobile-iic", }, {}, }; MODULE_DEVICE_TABLE(of, sh_mobile_i2c_dt_ids); static struct platform_driver sh_mobile_i2c_driver = { .driver = { .name = "i2c-sh_mobile", .owner = THIS_MODULE, .pm = &sh_mobile_i2c_dev_pm_ops, .of_match_table = sh_mobile_i2c_dt_ids, }, .probe = sh_mobile_i2c_probe, .remove = sh_mobile_i2c_remove, }; static int __init sh_mobile_i2c_adap_init(void) { return platform_driver_register(&sh_mobile_i2c_driver); } static void __exit sh_mobile_i2c_adap_exit(void) { platform_driver_unregister(&sh_mobile_i2c_driver); } subsys_initcall(sh_mobile_i2c_adap_init); module_exit(sh_mobile_i2c_adap_exit); MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver"); MODULE_AUTHOR("Magnus Damm"); MODULE_LICENSE("GPL v2"); MODULE_ALIAS("platform:i2c-sh_mobile");