Commit 7da62cb1 authored by Wolfram Sang's avatar Wolfram Sang
Browse files

i2c: nuc900: remove driver 



Arnd said in another patch:

"As far as I can tell, this driver must have produced this
error for as long as it has been merged into the mainline kernel, but
it was never part of the normal build tests:

drivers/i2c/busses/i2c-nuc900.c: In function 'nuc900_i2c_probe':
drivers/i2c/busses/i2c-nuc900.c:601:17: error: request for member
'apbfreq' in something not a structure or union
  ret = (i2c->clk.apbfreq)/(pdata->bus_freq * 5) - 1;
                 ^
This is an attempt to get the driver to build and possibly
work correctly, although I do wonder whether we should just
remove it, as it has clearly never worked."

I agree with removing it since nobody showed interest in Arnd's fixup
patch.

Reported-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
Cc: Wan ZongShun <mcuos.com@gmail.org>
Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
parent 9b2a6da3

drivers/i2c/busses/Kconfig

+0 −7
Original line number Diff line number Diff line
@@ -570,13 +570,6 @@ config I2C_NOMADIK 
	  I2C interface from ST-Ericsson's Nomadik and Ux500 architectures,

	  as well as the STA2X11 PCIe I/O HUB.



config I2C_NUC900

	tristate "NUC900 I2C Driver"

	depends on ARCH_W90X900

	help

	  Say Y here to include support for I2C controller in the

	  Winbond/Nuvoton NUC900 based System-on-Chip devices.



config I2C_OCORES

	tristate "OpenCores I2C Controller"

	help

drivers/i2c/busses/Makefile

+0 −1
Original line number Diff line number Diff line
@@ -55,7 +55,6 @@ obj-$(CONFIG_I2C_MPC) += i2c-mpc.o 
obj-$(CONFIG_I2C_MV64XXX)	+= i2c-mv64xxx.o

obj-$(CONFIG_I2C_MXS)		+= i2c-mxs.o

obj-$(CONFIG_I2C_NOMADIK)	+= i2c-nomadik.o

obj-$(CONFIG_I2C_NUC900)	+= i2c-nuc900.o

obj-$(CONFIG_I2C_OCORES)	+= i2c-ocores.o

obj-$(CONFIG_I2C_OMAP)		+= i2c-omap.o

obj-$(CONFIG_I2C_PASEMI)	+= i2c-pasemi.o

drivers/i2c/busses/i2c-nuc900.c

deleted100644 → 0
+0 −709
Original line number Diff line number Diff line 
/*

 * 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");

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