diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-nuc900.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-nuc900.c | 709 |
1 files changed, 0 insertions, 709 deletions
diff --git a/drivers/i2c/busses/i2c-nuc900.c b/drivers/i2c/busses/i2c-nuc900.c deleted file mode 100644 index 36394d737fa..00000000000 --- a/drivers/i2c/busses/i2c-nuc900.c +++ /dev/null @@ -1,709 +0,0 @@ -/* - * linux/drivers/i2c/busses/i2c-nuc900.c - * - * Copyright (c) 2010 Nuvoton technology corporation. - * - * This driver based on S3C2410 I2C driver of Ben Dooks <ben-Y5A6D6n0/KfQXOPxS62xeg@public.gmane.org>. - * Written by Wan ZongShun <mcuos.com-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> - * - * 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. - * - */ - -#include <linux/kernel.h> -#include <linux/module.h> - -#include <linux/i2c.h> -#include <linux/init.h> -#include <linux/time.h> -#include <linux/interrupt.h> -#include <linux/delay.h> -#include <linux/errno.h> -#include <linux/err.h> -#include <linux/platform_device.h> -#include <linux/clk.h> -#include <linux/cpufreq.h> -#include <linux/slab.h> -#include <linux/io.h> - -#include <mach/mfp.h> -#include <linux/platform_data/i2c-nuc900.h> - -/* nuc900 i2c registers offset */ - -#define CSR 0x00 -#define DIVIDER 0x04 -#define CMDR 0x08 -#define SWR 0x0C -#define RXR 0x10 -#define TXR 0x14 - -/* nuc900 i2c CSR register bits */ - -#define IRQEN 0x003 -#define I2CBUSY 0x400 -#define I2CSTART 0x018 -#define IRQFLAG 0x004 -#define ARBIT_LOST 0x200 -#define SLAVE_ACK 0x800 - -/* nuc900 i2c CMDR register bits */ - -#define I2C_CMD_START 0x10 -#define I2C_CMD_STOP 0x08 -#define I2C_CMD_READ 0x04 -#define I2C_CMD_WRITE 0x02 -#define I2C_CMD_NACK 0x01 - -/* i2c controller state */ - -enum nuc900_i2c_state { - STATE_IDLE, - STATE_START, - STATE_READ, - STATE_WRITE, - STATE_STOP -}; - -/* i2c controller private data */ - -struct nuc900_i2c { - spinlock_t lock; - wait_queue_head_t wait; - - struct i2c_msg *msg; - unsigned int msg_num; - unsigned int msg_idx; - unsigned int msg_ptr; - unsigned int irq; - - enum nuc900_i2c_state state; - - void __iomem *regs; - struct clk *clk; - struct device *dev; - struct resource *ioarea; - struct i2c_adapter adap; -}; - -/* nuc900_i2c_master_complete - * - * complete the message and wake up the caller, using the given return code, - * or zero to mean ok. -*/ - -static inline void nuc900_i2c_master_complete(struct nuc900_i2c *i2c, int ret) -{ - dev_dbg(i2c->dev, "master_complete %d\n", ret); - - i2c->msg_ptr = 0; - i2c->msg = NULL; - i2c->msg_idx++; - i2c->msg_num = 0; - if (ret) - i2c->msg_idx = ret; - - wake_up(&i2c->wait); -} - -/* irq enable/disable functions */ - -static inline void nuc900_i2c_disable_irq(struct nuc900_i2c *i2c) -{ - unsigned long tmp; - - tmp = readl(i2c->regs + CSR); - writel(tmp & ~IRQEN, i2c->regs + CSR); -} - -static inline void nuc900_i2c_enable_irq(struct nuc900_i2c *i2c) -{ - unsigned long tmp; - - tmp = readl(i2c->regs + CSR); - writel(tmp | IRQEN, i2c->regs + CSR); -} - - -/* nuc900_i2c_message_start - * - * put the start of a message onto the bus -*/ - -static void nuc900_i2c_message_start(struct nuc900_i2c *i2c, - struct i2c_msg *msg) -{ - unsigned int addr = (msg->addr & 0x7f) << 1; - - if (msg->flags & I2C_M_RD) - addr |= 0x1; - writel(addr & 0xff, i2c->regs + TXR); - writel(I2C_CMD_START | I2C_CMD_WRITE, i2c->regs + CMDR); -} - -static inline void nuc900_i2c_stop(struct nuc900_i2c *i2c, int ret) -{ - - dev_dbg(i2c->dev, "STOP\n"); - - /* stop the transfer */ - i2c->state = STATE_STOP; - writel(I2C_CMD_STOP, i2c->regs + CMDR); - - nuc900_i2c_master_complete(i2c, ret); - nuc900_i2c_disable_irq(i2c); -} - -/* helper functions to determine the current state in the set of - * messages we are sending -*/ - -/* is_lastmsg() - * - * returns TRUE if the current message is the last in the set -*/ - -static inline int is_lastmsg(struct nuc900_i2c *i2c) -{ - return i2c->msg_idx >= (i2c->msg_num - 1); -} - -/* is_msglast - * - * returns TRUE if we this is the last byte in the current message -*/ - -static inline int is_msglast(struct nuc900_i2c *i2c) -{ - return i2c->msg_ptr == i2c->msg->len-1; -} - -/* is_msgend - * - * returns TRUE if we reached the end of the current message -*/ - -static inline int is_msgend(struct nuc900_i2c *i2c) -{ - return i2c->msg_ptr >= i2c->msg->len; -} - -/* i2c_nuc900_irq_nextbyte - * - * process an interrupt and work out what to do - */ - -static void i2c_nuc900_irq_nextbyte(struct nuc900_i2c *i2c, - unsigned long iicstat) -{ - unsigned char byte; - - switch (i2c->state) { - - case STATE_IDLE: - dev_err(i2c->dev, "%s: called in STATE_IDLE\n", __func__); - break; - - case STATE_STOP: - dev_err(i2c->dev, "%s: called in STATE_STOP\n", __func__); - nuc900_i2c_disable_irq(i2c); - break; - - case STATE_START: - /* last thing we did was send a start condition on the - * bus, or started a new i2c message - */ - - if (iicstat & SLAVE_ACK && - !(i2c->msg->flags & I2C_M_IGNORE_NAK)) { - /* ack was not received... */ - - dev_dbg(i2c->dev, "ack was not received\n"); - nuc900_i2c_stop(i2c, -ENXIO); - break; - } - - if (i2c->msg->flags & I2C_M_RD) - i2c->state = STATE_READ; - else - i2c->state = STATE_WRITE; - - /* terminate the transfer if there is nothing to do - * as this is used by the i2c probe to find devices. - */ - - if (is_lastmsg(i2c) && i2c->msg->len == 0) { - nuc900_i2c_stop(i2c, 0); - break; - } - - if (i2c->state == STATE_READ) - goto prepare_read; - - /* fall through to the write state, as we will need to - * send a byte as well - */ - - case STATE_WRITE: - /* we are writing data to the device... check for the - * end of the message, and if so, work out what to do - */ - - if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) { - if (iicstat & SLAVE_ACK) { - dev_dbg(i2c->dev, "WRITE: No Ack\n"); - - nuc900_i2c_stop(i2c, -ECONNREFUSED); - break; - } - } - -retry_write: - - if (!is_msgend(i2c)) { - byte = i2c->msg->buf[i2c->msg_ptr++]; - writeb(byte, i2c->regs + TXR); - writel(I2C_CMD_WRITE, i2c->regs + CMDR); - - } else if (!is_lastmsg(i2c)) { - /* we need to go to the next i2c message */ - - dev_dbg(i2c->dev, "WRITE: Next Message\n"); - - i2c->msg_ptr = 0; - i2c->msg_idx++; - i2c->msg++; - - /* check to see if we need to do another message */ - if (i2c->msg->flags & I2C_M_NOSTART) { - - if (i2c->msg->flags & I2C_M_RD) { - /* cannot do this, the controller - * forces us to send a new START - * when we change direction - */ - - nuc900_i2c_stop(i2c, -EINVAL); - } - - goto retry_write; - } else { - /* send the new start */ - nuc900_i2c_message_start(i2c, i2c->msg); - i2c->state = STATE_START; - } - - } else { - /* send stop */ - - nuc900_i2c_stop(i2c, 0); - } - break; - - case STATE_READ: - /* we have a byte of data in the data register, do - * something with it, and then work out whether we are - * going to do any more read/write - */ - - byte = readb(i2c->regs + RXR); - i2c->msg->buf[i2c->msg_ptr++] = byte; - -prepare_read: - if (is_msglast(i2c)) { - /* last byte of buffer */ - - if (is_lastmsg(i2c)) - writel(I2C_CMD_READ | I2C_CMD_NACK, - i2c->regs + CMDR); - - } else if (is_msgend(i2c)) { - /* ok, we've read the entire buffer, see if there - * is anything else we need to do - */ - - if (is_lastmsg(i2c)) { - /* last message, send stop and complete */ - dev_dbg(i2c->dev, "READ: Send Stop\n"); - - nuc900_i2c_stop(i2c, 0); - } else { - /* go to the next transfer */ - dev_dbg(i2c->dev, "READ: Next Transfer\n"); - - i2c->msg_ptr = 0; - i2c->msg_idx++; - i2c->msg++; - - writel(I2C_CMD_READ, i2c->regs + CMDR); - } - - } else { - writel(I2C_CMD_READ, i2c->regs + CMDR); - } - - break; - } -} - -/* nuc900_i2c_irq - * - * top level IRQ servicing routine -*/ - -static irqreturn_t nuc900_i2c_irq(int irqno, void *dev_id) -{ - struct nuc900_i2c *i2c = dev_id; - unsigned long status; - - status = readl(i2c->regs + CSR); - writel(status | IRQFLAG, i2c->regs + CSR); - - if (status & ARBIT_LOST) { - /* deal with arbitration loss */ - dev_err(i2c->dev, "deal with arbitration loss\n"); - goto out; - } - - if (i2c->state == STATE_IDLE) { - dev_dbg(i2c->dev, "IRQ: error i2c->state == IDLE\n"); - goto out; - } - - /* pretty much this leaves us with the fact that we've - * transmitted or received whatever byte we last sent - */ - - i2c_nuc900_irq_nextbyte(i2c, status); - - out: - return IRQ_HANDLED; -} - - -/* nuc900_i2c_set_master - * - * get the i2c bus for a master transaction -*/ - -static int nuc900_i2c_set_master(struct nuc900_i2c *i2c) -{ - int timeout = 400; - - while (timeout-- > 0) { - if (((readl(i2c->regs + SWR) & I2CSTART) == I2CSTART) && - ((readl(i2c->regs + CSR) & I2CBUSY) == 0)) { - return 0; - } - - msleep(1); - } - - return -ETIMEDOUT; -} - -/* nuc900_i2c_doxfer - * - * this starts an i2c transfer -*/ - -static int nuc900_i2c_doxfer(struct nuc900_i2c *i2c, - struct i2c_msg *msgs, int num) -{ - unsigned long iicstat, timeout; - int spins = 20; - int ret; - - ret = nuc900_i2c_set_master(i2c); - if (ret != 0) { - dev_err(i2c->dev, "cannot get bus (error %d)\n", ret); - ret = -EAGAIN; - goto out; - } - - spin_lock_irq(&i2c->lock); - - i2c->msg = msgs; - i2c->msg_num = num; - i2c->msg_ptr = 0; - i2c->msg_idx = 0; - i2c->state = STATE_START; - - nuc900_i2c_message_start(i2c, msgs); - spin_unlock_irq(&i2c->lock); - - timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5); - - ret = i2c->msg_idx; - - /* having these next two as dev_err() makes life very - * noisy when doing an i2cdetect - */ - - if (timeout == 0) - dev_dbg(i2c->dev, "timeout\n"); - else if (ret != num) - dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret); - - /* ensure the stop has been through the bus */ - - dev_dbg(i2c->dev, "waiting for bus idle\n"); - - /* first, try busy waiting briefly */ - do { - iicstat = readl(i2c->regs + CSR); - } while ((iicstat & I2CBUSY) && --spins); - - /* if that timed out sleep */ - if (!spins) { - msleep(1); - iicstat = readl(i2c->regs + CSR); - } - - if (iicstat & I2CBUSY) - dev_warn(i2c->dev, "timeout waiting for bus idle\n"); - - out: - return ret; -} - -/* nuc900_i2c_xfer - * - * first port of call from the i2c bus code when an message needs - * transferring across the i2c bus. -*/ - -static int nuc900_i2c_xfer(struct i2c_adapter *adap, - struct i2c_msg *msgs, int num) -{ - struct nuc900_i2c *i2c = (struct nuc900_i2c *)adap->algo_data; - int retry; - int ret; - - nuc900_i2c_enable_irq(i2c); - - for (retry = 0; retry < adap->retries; retry++) { - - ret = nuc900_i2c_doxfer(i2c, msgs, num); - - if (ret != -EAGAIN) - return ret; - - dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry); - - udelay(100); - } - - return -EREMOTEIO; -} - -/* declare our i2c functionality */ -static u32 nuc900_i2c_func(struct i2c_adapter *adap) -{ - return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_NOSTART | - I2C_FUNC_PROTOCOL_MANGLING; -} - -/* i2c bus registration info */ - -static const struct i2c_algorithm nuc900_i2c_algorithm = { - .master_xfer = nuc900_i2c_xfer, - .functionality = nuc900_i2c_func, -}; - -/* nuc900_i2c_probe - * - * called by the bus driver when a suitable device is found -*/ - -static int nuc900_i2c_probe(struct platform_device *pdev) -{ - struct nuc900_i2c *i2c; - struct nuc900_platform_i2c *pdata; - struct resource *res; - int ret; - - pdata = dev_get_platdata(&pdev->dev); - if (!pdata) { - dev_err(&pdev->dev, "no platform data\n"); - return -EINVAL; - } - - i2c = kzalloc(sizeof(struct nuc900_i2c), GFP_KERNEL); - if (!i2c) { - dev_err(&pdev->dev, "no memory for state\n"); - return -ENOMEM; - } - - strlcpy(i2c->adap.name, "nuc900-i2c0", sizeof(i2c->adap.name)); - i2c->adap.owner = THIS_MODULE; - i2c->adap.algo = &nuc900_i2c_algorithm; - i2c->adap.retries = 2; - i2c->adap.class = I2C_CLASS_HWMON | I2C_CLASS_SPD; - - spin_lock_init(&i2c->lock); - init_waitqueue_head(&i2c->wait); - - /* find the clock and enable it */ - - i2c->dev = &pdev->dev; - i2c->clk = clk_get(&pdev->dev, NULL); - if (IS_ERR(i2c->clk)) { - dev_err(&pdev->dev, "cannot get clock\n"); - ret = -ENOENT; - goto err_noclk; - } - - dev_dbg(&pdev->dev, "clock source %p\n", i2c->clk); - - clk_enable(i2c->clk); - - /* map the registers */ - - res = platform_get_resource(pdev, IORESOURCE_MEM, 0); - if (res == NULL) { - dev_err(&pdev->dev, "cannot find IO resource\n"); - ret = -ENOENT; - goto err_clk; - } - - i2c->ioarea = request_mem_region(res->start, resource_size(res), - pdev->name); - - if (i2c->ioarea == NULL) { - dev_err(&pdev->dev, "cannot request IO\n"); - ret = -ENXIO; - goto err_clk; - } - - i2c->regs = ioremap(res->start, resource_size(res)); - - if (i2c->regs == NULL) { - dev_err(&pdev->dev, "cannot map IO\n"); - ret = -ENXIO; - goto err_ioarea; - } - - dev_dbg(&pdev->dev, "registers %p (%p, %p)\n", - i2c->regs, i2c->ioarea, res); - - /* setup info block for the i2c core */ - - i2c->adap.algo_data = i2c; - i2c->adap.dev.parent = &pdev->dev; - - mfp_set_groupg(&pdev->dev, NULL); - - clk_get_rate(i2c->clk); - - ret = (i2c->clk.apbfreq)/(pdata->bus_freq * 5) - 1; - writel(ret & 0xffff, i2c->regs + DIVIDER); - - /* find the IRQ for this unit (note, this relies on the init call to - * ensure no current IRQs pending - */ - - i2c->irq = ret = platform_get_irq(pdev, 0); - if (ret <= 0) { - dev_err(&pdev->dev, "cannot find IRQ\n"); - goto err_iomap; - } - - ret = request_irq(i2c->irq, nuc900_i2c_irq, IRQF_SHARED, - dev_name(&pdev->dev), i2c); - - if (ret != 0) { - dev_err(&pdev->dev, "cannot claim IRQ %d\n", i2c->irq); - goto err_iomap; - } - - /* Note, previous versions of the driver used i2c_add_adapter() - * to add the bus at any number. We now pass the bus number via - * the platform data, so if unset it will now default to always - * being bus 0. - */ - - i2c->adap.nr = pdata->bus_num; - - ret = i2c_add_numbered_adapter(&i2c->adap); - if (ret < 0) { - dev_err(&pdev->dev, "failed to add bus to i2c core\n"); - goto err_irq; - } - - platform_set_drvdata(pdev, i2c); - - dev_info(&pdev->dev, "%s: NUC900 I2C adapter\n", - dev_name(&i2c->adap.dev)); - return 0; - - err_irq: - free_irq(i2c->irq, i2c); - - err_iomap: - iounmap(i2c->regs); - - err_ioarea: - release_resource(i2c->ioarea); - kfree(i2c->ioarea); - - err_clk: - clk_disable(i2c->clk); - clk_put(i2c->clk); - - err_noclk: - kfree(i2c); - return ret; -} - -/* nuc900_i2c_remove - * - * called when device is removed from the bus -*/ - -static int nuc900_i2c_remove(struct platform_device *pdev) -{ - struct nuc900_i2c *i2c = platform_get_drvdata(pdev); - - i2c_del_adapter(&i2c->adap); - free_irq(i2c->irq, i2c); - - clk_disable(i2c->clk); - clk_put(i2c->clk); - - iounmap(i2c->regs); - - release_resource(i2c->ioarea); - kfree(i2c->ioarea); - kfree(i2c); - - return 0; -} - -static struct platform_driver nuc900_i2c_driver = { - .probe = nuc900_i2c_probe, - .remove = nuc900_i2c_remove, - .driver = { - .owner = THIS_MODULE, - .name = "nuc900-i2c0", - }, -}; - -static int __init i2c_adap_nuc900_init(void) -{ - return platform_driver_register(&nuc900_i2c_driver); -} - -static void __exit i2c_adap_nuc900_exit(void) -{ - platform_driver_unregister(&nuc900_i2c_driver); -} -subsys_initcall(i2c_adap_nuc900_init); -module_exit(i2c_adap_nuc900_exit); - -MODULE_DESCRIPTION("NUC900 I2C Bus driver"); -MODULE_AUTHOR("Wan ZongShun, <mcuos.com-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>"); -MODULE_LICENSE("GPL"); -MODULE_ALIAS("platform:nuc900-i2c0"); |