| /* |
| * 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 <carlos@kenati.com> |
| * |
| * 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 <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/init.h> |
| #include <linux/delay.h> |
| #include <linux/platform_device.h> |
| #include <linux/interrupt.h> |
| #include <linux/i2c.h> |
| #include <linux/err.h> |
| #include <linux/clk.h> |
| #include <linux/io.h> |
| |
| /* 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 __/ \_ */ |
| /* */ |
| |
| 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; |
| |
| struct clk *clk; |
| u_int8_t iccl; |
| u_int8_t icch; |
| |
| spinlock_t lock; |
| wait_queue_head_t wait; |
| struct i2c_msg *msg; |
| int pos; |
| int sr; |
| }; |
| |
| #define NORMAL_SPEED 100000 /* FAST_SPEED 400000 */ |
| |
| /* Register offsets */ |
| #define ICDR(pd) (pd->reg + 0x00) |
| #define ICCR(pd) (pd->reg + 0x04) |
| #define ICSR(pd) (pd->reg + 0x08) |
| #define ICIC(pd) (pd->reg + 0x0c) |
| #define ICCL(pd) (pd->reg + 0x10) |
| #define ICCH(pd) (pd->reg + 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_ALE 0x08 |
| #define ICIC_TACKE 0x04 |
| #define ICIC_WAITE 0x02 |
| #define ICIC_DTEE 0x01 |
| |
| static void activate_ch(struct sh_mobile_i2c_data *pd) |
| { |
| /* Make sure the clock is enabled */ |
| clk_enable(pd->clk); |
| |
| /* Enable channel and configure rx ack */ |
| iowrite8(ioread8(ICCR(pd)) | ICCR_ICE, ICCR(pd)); |
| |
| /* Mask all interrupts */ |
| iowrite8(0, ICIC(pd)); |
| |
| /* Set the clock */ |
| iowrite8(pd->iccl, ICCL(pd)); |
| iowrite8(pd->icch, ICCH(pd)); |
| } |
| |
| static void deactivate_ch(struct sh_mobile_i2c_data *pd) |
| { |
| /* Clear/disable interrupts */ |
| iowrite8(0, ICSR(pd)); |
| iowrite8(0, ICIC(pd)); |
| |
| /* Disable channel */ |
| iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd)); |
| |
| /* Disable clock */ |
| clk_disable(pd->clk); |
| } |
| |
| 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 */ |
| iowrite8(0x94, ICCR(pd)); |
| break; |
| case OP_TX_FIRST: /* disable DTE interrupt and write data */ |
| iowrite8(ICIC_WAITE | ICIC_ALE | ICIC_TACKE, ICIC(pd)); |
| iowrite8(data, ICDR(pd)); |
| break; |
| case OP_TX: /* write data */ |
| iowrite8(data, ICDR(pd)); |
| break; |
| case OP_TX_STOP: /* write data and issue a stop afterwards */ |
| iowrite8(data, ICDR(pd)); |
| iowrite8(0x90, ICCR(pd)); |
| break; |
| case OP_TX_TO_RX: /* select read mode */ |
| iowrite8(0x81, ICCR(pd)); |
| break; |
| case OP_RX: /* just read data */ |
| ret = ioread8(ICDR(pd)); |
| break; |
| case OP_RX_STOP: /* enable DTE interrupt, issue stop */ |
| iowrite8(ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE, |
| ICIC(pd)); |
| iowrite8(0xc0, ICCR(pd)); |
| break; |
| case OP_RX_STOP_DATA: /* enable DTE interrupt, read data, issue stop */ |
| iowrite8(ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE, |
| ICIC(pd)); |
| ret = ioread8(ICDR(pd)); |
| iowrite8(0xc0, ICCR(pd)); |
| break; |
| } |
| |
| spin_unlock_irqrestore(&pd->lock, flags); |
| |
| dev_dbg(pd->dev, "op %d, data out 0x%02x\n", op, ret); |
| return ret; |
| } |
| |
| static int sh_mobile_i2c_is_first_byte(struct sh_mobile_i2c_data *pd) |
| { |
| if (pd->pos == -1) |
| return 1; |
| |
| return 0; |
| } |
| |
| static int sh_mobile_i2c_is_last_byte(struct sh_mobile_i2c_data *pd) |
| { |
| if (pd->pos == (pd->msg->len - 1)) |
| return 1; |
| |
| return 0; |
| } |
| |
| 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); |
| |
| 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 = ioread8(ICSR(pd)); |
| 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 */ |
| iowrite8(sr & ~(ICSR_AL | ICSR_TACK), ICSR(pd)); |
| 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 */ |
| iowrite8(sr & ~ICSR_WAIT, ICSR(pd)); |
| |
| if (wakeup) { |
| pd->sr |= SW_DONE; |
| wake_up(&pd->wait); |
| } |
| |
| return IRQ_HANDLED; |
| } |
| |
| static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg) |
| { |
| if (usr_msg->len == 0 && (usr_msg->flags & I2C_M_RD)) { |
| dev_err(pd->dev, "Unsupported zero length i2c read\n"); |
| return -EIO; |
| } |
| |
| /* Initialize channel registers */ |
| iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd)); |
| |
| /* Enable channel and configure rx ack */ |
| iowrite8(ioread8(ICCR(pd)) | ICCR_ICE, ICCR(pd)); |
| |
| /* Set the clock */ |
| iowrite8(pd->iccl, ICCL(pd)); |
| iowrite8(pd->icch, ICCH(pd)); |
| |
| pd->msg = usr_msg; |
| pd->pos = -1; |
| pd->sr = 0; |
| |
| /* Enable all interrupts to begin with */ |
| iowrite8(ICIC_WAITE | ICIC_ALE | ICIC_TACKE | ICIC_DTEE, ICIC(pd)); |
| return 0; |
| } |
| |
| 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; |
| u_int8_t val; |
| int i, k, retry_count; |
| |
| activate_ch(pd); |
| |
| /* Process all messages */ |
| for (i = 0; i < num; i++) { |
| msg = &msgs[i]; |
| |
| err = start_ch(pd, msg); |
| if (err) |
| break; |
| |
| 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"); |
| |
| retry_count = 1000; |
| again: |
| val = ioread8(ICSR(pd)); |
| |
| 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) { |
| udelay(10); |
| if (retry_count--) |
| goto again; |
| |
| err = -EIO; |
| dev_err(pd->dev, "Polling timed out\n"); |
| break; |
| } |
| |
| /* handle missing acknowledge and arbitration lost */ |
| if ((val | pd->sr) & (ICSR_TACK | ICSR_AL)) { |
| err = -EIO; |
| 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; |
| } |
| |
| static struct i2c_algorithm sh_mobile_i2c_algorithm = { |
| .functionality = sh_mobile_i2c_func, |
| .master_xfer = sh_mobile_i2c_xfer, |
| }; |
| |
| static void sh_mobile_i2c_setup_channel(struct platform_device *dev) |
| { |
| struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev); |
| unsigned long peripheral_clk = clk_get_rate(pd->clk); |
| u_int32_t num; |
| u_int32_t denom; |
| u_int32_t tmp; |
| |
| spin_lock_init(&pd->lock); |
| init_waitqueue_head(&pd->wait); |
| |
| /* Calculate the value for iccl. From the data sheet: |
| * iccl = (p clock / transfer rate) * (L / (L + H)) |
| * where L and H are the SCL low/high ratio (5/4 in this case). |
| * We also round off the result. |
| */ |
| num = peripheral_clk * 5; |
| denom = NORMAL_SPEED * 9; |
| tmp = num * 10 / denom; |
| if (tmp % 10 >= 5) |
| pd->iccl = (u_int8_t)((num/denom) + 1); |
| else |
| pd->iccl = (u_int8_t)(num/denom); |
| |
| /* Calculate the value for icch. From the data sheet: |
| icch = (p clock / transfer rate) * (H / (L + H)) */ |
| num = peripheral_clk * 4; |
| tmp = num * 10 / denom; |
| if (tmp % 10 >= 5) |
| pd->icch = (u_int8_t)((num/denom) + 1); |
| else |
| pd->icch = (u_int8_t)(num/denom); |
| } |
| |
| static int sh_mobile_i2c_hook_irqs(struct platform_device *dev, int hook) |
| { |
| struct resource *res; |
| int ret = -ENXIO; |
| int q, m; |
| int k = 0; |
| int n = 0; |
| |
| while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) { |
| for (n = res->start; hook && n <= res->end; n++) { |
| if (request_irq(n, sh_mobile_i2c_isr, IRQF_DISABLED, |
| dev->dev.bus_id, dev)) |
| goto rollback; |
| } |
| k++; |
| } |
| |
| if (hook) |
| return k > 0 ? 0 : -ENOENT; |
| |
| k--; |
| ret = 0; |
| |
| rollback: |
| for (q = k; k >= 0; k--) { |
| for (m = n; m >= res->start; m--) |
| free_irq(m, dev); |
| |
| res = platform_get_resource(dev, IORESOURCE_IRQ, k - 1); |
| m = res->end; |
| } |
| |
| return ret; |
| } |
| |
| static int sh_mobile_i2c_probe(struct platform_device *dev) |
| { |
| struct sh_mobile_i2c_data *pd; |
| struct i2c_adapter *adap; |
| struct resource *res; |
| int size; |
| int ret; |
| |
| pd = kzalloc(sizeof(struct sh_mobile_i2c_data), GFP_KERNEL); |
| if (pd == NULL) { |
| dev_err(&dev->dev, "cannot allocate private data\n"); |
| return -ENOMEM; |
| } |
| |
| pd->clk = clk_get(&dev->dev, "peripheral_clk"); |
| if (IS_ERR(pd->clk)) { |
| dev_err(&dev->dev, "cannot get peripheral clock\n"); |
| ret = PTR_ERR(pd->clk); |
| goto err; |
| } |
| |
| ret = sh_mobile_i2c_hook_irqs(dev, 1); |
| if (ret) { |
| dev_err(&dev->dev, "cannot request IRQ\n"); |
| goto err_clk; |
| } |
| |
| pd->dev = &dev->dev; |
| platform_set_drvdata(dev, pd); |
| |
| res = platform_get_resource(dev, IORESOURCE_MEM, 0); |
| if (res == NULL) { |
| dev_err(&dev->dev, "cannot find IO resource\n"); |
| ret = -ENOENT; |
| goto err_irq; |
| } |
| |
| size = (res->end - res->start) + 1; |
| |
| pd->reg = ioremap(res->start, size); |
| if (pd->reg == NULL) { |
| dev_err(&dev->dev, "cannot map IO\n"); |
| ret = -ENXIO; |
| goto err_irq; |
| } |
| |
| /* 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; |
| |
| strlcpy(adap->name, dev->name, sizeof(adap->name)); |
| |
| sh_mobile_i2c_setup_channel(dev); |
| |
| ret = i2c_add_numbered_adapter(adap); |
| if (ret < 0) { |
| dev_err(&dev->dev, "cannot add numbered adapter\n"); |
| goto err_all; |
| } |
| |
| return 0; |
| |
| err_all: |
| iounmap(pd->reg); |
| err_irq: |
| sh_mobile_i2c_hook_irqs(dev, 0); |
| err_clk: |
| clk_put(pd->clk); |
| err: |
| kfree(pd); |
| return ret; |
| } |
| |
| 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); |
| iounmap(pd->reg); |
| sh_mobile_i2c_hook_irqs(dev, 0); |
| clk_put(pd->clk); |
| kfree(pd); |
| return 0; |
| } |
| |
| static struct platform_driver sh_mobile_i2c_driver = { |
| .driver = { |
| .name = "i2c-sh_mobile", |
| .owner = THIS_MODULE, |
| }, |
| .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); |
| } |
| |
| module_init(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"); |