diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-sh_mobile.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-sh_mobile.c | 500 |
1 files changed, 500 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c new file mode 100644 index 0000000..840e634f --- /dev/null +++ b/drivers/i2c/busses/i2c-sh_mobile.c @@ -0,0 +1,500 @@ +/* + * 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> + +enum sh_mobile_i2c_op { + OP_START = 0, + OP_TX_ONLY, + OP_TX_STOP, + OP_TX_TO_RX, + OP_RX_ONLY, + OP_RX_STOP, +}; + +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: + iowrite8(0x94, ICCR(pd)); + break; + case OP_TX_ONLY: + iowrite8(data, ICDR(pd)); + break; + case OP_TX_STOP: + iowrite8(data, ICDR(pd)); + iowrite8(0x90, ICCR(pd)); + iowrite8(ICIC_ALE | ICIC_TACKE, ICIC(pd)); + break; + case OP_TX_TO_RX: + iowrite8(data, ICDR(pd)); + iowrite8(0x81, ICCR(pd)); + break; + case OP_RX_ONLY: + ret = ioread8(ICDR(pd)); + break; + case OP_RX_STOP: + 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 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); + struct i2c_msg *msg = pd->msg; + unsigned char data, sr; + int wakeup = 0; + + sr = ioread8(ICSR(pd)); + pd->sr |= sr; + + dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr, + (msg->flags & I2C_M_RD) ? "read" : "write", + pd->pos, msg->len); + + if (sr & (ICSR_AL | ICSR_TACK)) { + iowrite8(0, ICIC(pd)); /* disable interrupts */ + wakeup = 1; + goto do_wakeup; + } + + if (pd->pos == msg->len) { + i2c_op(pd, OP_RX_ONLY, 0); + wakeup = 1; + goto do_wakeup; + } + + if (pd->pos == -1) { + data = (msg->addr & 0x7f) << 1; + data |= (msg->flags & I2C_M_RD) ? 1 : 0; + } else + data = msg->buf[pd->pos]; + + if ((pd->pos == -1) || !(msg->flags & I2C_M_RD)) { + if (msg->flags & I2C_M_RD) + i2c_op(pd, OP_TX_TO_RX, data); + else if (pd->pos == (msg->len - 1)) { + i2c_op(pd, OP_TX_STOP, data); + wakeup = 1; + } else + i2c_op(pd, OP_TX_ONLY, data); + } else { + if (pd->pos == (msg->len - 1)) + data = i2c_op(pd, OP_RX_STOP, 0); + else + data = i2c_op(pd, OP_RX_ONLY, 0); + + msg->buf[pd->pos] = data; + } + pd->pos++; + + do_wakeup: + 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) +{ + /* 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 except wait */ + iowrite8(ioread8(ICIC(pd)) | 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 = 10; +again: + val = ioread8(ICSR(pd)); + + dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr); + + if ((val | pd->sr) & (ICSR_TACK | ICSR_AL)) { + err = -EIO; + break; + } + + /* the interrupt handler may wake us up before the + * transfer is finished, so poll the hardware + * until we're done. + */ + + if (!(!(val & ICSR_BUSY) && (val & ICSR_SCLM) && + (val & ICSR_SDAM))) { + msleep(1); + if (retry_count--) + goto again; + + err = -EIO; + dev_err(pd->dev, "Polling timed out\n"); + 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"); |
