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arch/mips/mti-sead3/sead3-pic32-i2c-drv.c 9.34 KB
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  /*
   * This file is subject to the terms and conditions of the GNU General Public
   * License.  See the file "COPYING" in the main directory of this archive
   * for more details.
   *
   * Copyright (C) 2012 MIPS Technologies, Inc.  All rights reserved.
   */
  #include <linux/delay.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/spinlock.h>
  #include <linux/platform_device.h>
  #include <linux/init.h>
  #include <linux/errno.h>
  #include <linux/i2c.h>
  #include <linux/slab.h>
  
  #define PIC32_I2CxCON		0x0000
  #define PIC32_I2CxCONCLR	0x0004
  #define PIC32_I2CxCONSET	0x0008
  #define PIC32_I2CxCONINV	0x000C
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  #define	 I2CCON_ON		(1<<15)
  #define	 I2CCON_FRZ		(1<<14)
  #define	 I2CCON_SIDL		(1<<13)
  #define	 I2CCON_SCLREL		(1<<12)
  #define	 I2CCON_STRICT		(1<<11)
  #define	 I2CCON_A10M		(1<<10)
  #define	 I2CCON_DISSLW		(1<<9)
  #define	 I2CCON_SMEN		(1<<8)
  #define	 I2CCON_GCEN		(1<<7)
  #define	 I2CCON_STREN		(1<<6)
  #define	 I2CCON_ACKDT		(1<<5)
  #define	 I2CCON_ACKEN		(1<<4)
  #define	 I2CCON_RCEN		(1<<3)
  #define	 I2CCON_PEN		(1<<2)
  #define	 I2CCON_RSEN		(1<<1)
  #define	 I2CCON_SEN		(1<<0)
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  #define PIC32_I2CxSTAT		0x0010
  #define PIC32_I2CxSTATCLR	0x0014
  #define PIC32_I2CxSTATSET	0x0018
  #define PIC32_I2CxSTATINV	0x001C
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  #define	 I2CSTAT_ACKSTAT	(1<<15)
  #define	 I2CSTAT_TRSTAT		(1<<14)
  #define	 I2CSTAT_BCL		(1<<10)
  #define	 I2CSTAT_GCSTAT		(1<<9)
  #define	 I2CSTAT_ADD10		(1<<8)
  #define	 I2CSTAT_IWCOL		(1<<7)
  #define	 I2CSTAT_I2COV		(1<<6)
  #define	 I2CSTAT_DA		(1<<5)
  #define	 I2CSTAT_P		(1<<4)
  #define	 I2CSTAT_S		(1<<3)
  #define	 I2CSTAT_RW		(1<<2)
  #define	 I2CSTAT_RBF		(1<<1)
  #define	 I2CSTAT_TBF		(1<<0)
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  #define PIC32_I2CxADD		0x0020
  #define PIC32_I2CxADDCLR	0x0024
  #define PIC32_I2CxADDSET	0x0028
  #define PIC32_I2CxADDINV	0x002C
  #define PIC32_I2CxMSK		0x0030
  #define PIC32_I2CxMSKCLR	0x0034
  #define PIC32_I2CxMSKSET	0x0038
  #define PIC32_I2CxMSKINV	0x003C
  #define PIC32_I2CxBRG		0x0040
  #define PIC32_I2CxBRGCLR	0x0044
  #define PIC32_I2CxBRGSET	0x0048
  #define PIC32_I2CxBRGINV	0x004C
  #define PIC32_I2CxTRN		0x0050
  #define PIC32_I2CxTRNCLR	0x0054
  #define PIC32_I2CxTRNSET	0x0058
  #define PIC32_I2CxTRNINV	0x005C
  #define PIC32_I2CxRCV		0x0060
  
  struct i2c_platform_data {
  	u32	base;
  	struct i2c_adapter adap;
  	u32	xfer_timeout;
  	u32	ack_timeout;
  	u32	ctl_timeout;
  };
  
  extern u32 pic32_bus_readl(u32 reg);
  extern void pic32_bus_writel(u32 val, u32 reg);
  
  static inline void
  StartI2C(struct i2c_platform_data *adap)
  {
  	pr_debug("StartI2C
  ");
  	pic32_bus_writel(I2CCON_SEN, adap->base + PIC32_I2CxCONSET);
  }
  
  static inline void
  StopI2C(struct i2c_platform_data *adap)
  {
  	pr_debug("StopI2C
  ");
  	pic32_bus_writel(I2CCON_PEN, adap->base + PIC32_I2CxCONSET);
  }
  
  static inline void
  AckI2C(struct i2c_platform_data *adap)
  {
  	pr_debug("AckI2C
  ");
  	pic32_bus_writel(I2CCON_ACKDT, adap->base + PIC32_I2CxCONCLR);
  	pic32_bus_writel(I2CCON_ACKEN, adap->base + PIC32_I2CxCONSET);
  }
  
  static inline void
  NotAckI2C(struct i2c_platform_data *adap)
  {
  	pr_debug("NakI2C
  ");
  	pic32_bus_writel(I2CCON_ACKDT, adap->base + PIC32_I2CxCONSET);
  	pic32_bus_writel(I2CCON_ACKEN, adap->base + PIC32_I2CxCONSET);
  }
  
  static inline int
  IdleI2C(struct i2c_platform_data *adap)
  {
  	int i;
  
  	pr_debug("IdleI2C
  ");
  	for (i = 0; i < adap->ctl_timeout; i++) {
  		if (((pic32_bus_readl(adap->base + PIC32_I2CxCON) &
  		     (I2CCON_ACKEN | I2CCON_RCEN | I2CCON_PEN | I2CCON_RSEN |
  		      I2CCON_SEN)) == 0) &&
  		    ((pic32_bus_readl(adap->base + PIC32_I2CxSTAT) &
  		     (I2CSTAT_TRSTAT)) == 0))
  			return 0;
  		udelay(1);
  	}
  	return -ETIMEDOUT;
  }
  
  static inline u32
  MasterWriteI2C(struct i2c_platform_data *adap, u32 byte)
  {
  	pr_debug("MasterWriteI2C
  ");
  
  	pic32_bus_writel(byte, adap->base + PIC32_I2CxTRN);
  
  	return pic32_bus_readl(adap->base + PIC32_I2CxSTAT) & I2CSTAT_IWCOL;
  }
  
  static inline u32
  MasterReadI2C(struct i2c_platform_data *adap)
  {
  	pr_debug("MasterReadI2C
  ");
  
  	pic32_bus_writel(I2CCON_RCEN, adap->base + PIC32_I2CxCONSET);
  
  	while (pic32_bus_readl(adap->base + PIC32_I2CxCON) & I2CCON_RCEN)
  		;
  
  	pic32_bus_writel(I2CSTAT_I2COV, adap->base + PIC32_I2CxSTATCLR);
  
  	return pic32_bus_readl(adap->base + PIC32_I2CxRCV);
  }
  
  static int
  do_address(struct i2c_platform_data *adap, unsigned int addr, int rd)
  {
  	pr_debug("doaddress
  ");
  
  	IdleI2C(adap);
  	StartI2C(adap);
  	IdleI2C(adap);
  
  	addr <<= 1;
  	if (rd)
  		addr |= 1;
  
  	if (MasterWriteI2C(adap, addr))
  		return -EIO;
  	IdleI2C(adap);
  	if (pic32_bus_readl(adap->base + PIC32_I2CxSTAT) & I2CSTAT_ACKSTAT)
  		return -EIO;
  	return 0;
  }
  
  static int
  i2c_read(struct i2c_platform_data *adap, unsigned char *buf,
  		    unsigned int len)
  {
  	int	i;
  	u32	data;
  
  	pr_debug("i2c_read
  ");
  
  	i = 0;
  	while (i < len) {
  		data = MasterReadI2C(adap);
  		buf[i++] = data;
  		if (i < len)
  			AckI2C(adap);
  		else
  			NotAckI2C(adap);
  	}
  
  	StopI2C(adap);
  	IdleI2C(adap);
  	return 0;
  }
  
  static int
  i2c_write(struct i2c_platform_data *adap, unsigned char *buf,
  		     unsigned int len)
  {
  	int	i;
  	u32	data;
  
  	pr_debug("i2c_write
  ");
  
  	i = 0;
  	while (i < len) {
  		data = buf[i];
  		if (MasterWriteI2C(adap, data))
  			return -EIO;
  		IdleI2C(adap);
  		if (pic32_bus_readl(adap->base + PIC32_I2CxSTAT) &
  		    I2CSTAT_ACKSTAT)
  			return -EIO;
  		i++;
  	}
  
  	StopI2C(adap);
  	IdleI2C(adap);
  	return 0;
  }
  
  static int
  platform_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num)
  {
  	struct i2c_platform_data *adap = i2c_adap->algo_data;
  	struct i2c_msg *p;
  	int i, err = 0;
  
  	pr_debug("platform_xfer
  ");
  	for (i = 0; i < num; i++) {
  #define __BUFSIZE 80
  		int ii;
  		static char buf[__BUFSIZE];
  		char *b = buf;
  
  		p = &msgs[i];
  		b += sprintf(buf, " [%d bytes]", p->len);
  		if ((p->flags & I2C_M_RD) == 0) {
  			for (ii = 0; ii < p->len; ii++) {
  				if (b < &buf[__BUFSIZE-4]) {
  					b += sprintf(b, " %02x", p->buf[ii]);
  				} else {
  					strcat(b, "...");
  					break;
  				}
  			}
  		}
  		pr_debug("xfer%d: DevAddr: %04x Op:%s Data:%s
  ", i, p->addr,
  			 (p->flags & I2C_M_RD) ? "Rd" : "Wr", buf);
  	}
  
  
  	for (i = 0; !err && i < num; i++) {
  		p = &msgs[i];
  		err = do_address(adap, p->addr, p->flags & I2C_M_RD);
  		if (err || !p->len)
  			continue;
  		if (p->flags & I2C_M_RD)
  			err = i2c_read(adap, p->buf, p->len);
  		else
  			err = i2c_write(adap, p->buf, p->len);
  	}
  
  	/* Return the number of messages processed, or the error code. */
  	if (err == 0)
  		err = num;
  
  	return err;
  }
  
  static u32
  platform_func(struct i2c_adapter *adap)
  {
  	pr_debug("platform_algo
  ");
  	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
  }
  
  static const struct i2c_algorithm platform_algo = {
  	.master_xfer	= platform_xfer,
  	.functionality	= platform_func,
  };
  
  static void i2c_platform_setup(struct i2c_platform_data *priv)
  {
  	pr_debug("i2c_platform_setup
  ");
  
  	pic32_bus_writel(500, priv->base + PIC32_I2CxBRG);
  	pic32_bus_writel(I2CCON_ON, priv->base + PIC32_I2CxCONCLR);
  	pic32_bus_writel(I2CCON_ON, priv->base + PIC32_I2CxCONSET);
  	pic32_bus_writel((I2CSTAT_BCL | I2CSTAT_IWCOL),
  		(priv->base + PIC32_I2CxSTATCLR));
  }
  
  static void i2c_platform_disable(struct i2c_platform_data *priv)
  {
  	pr_debug("i2c_platform_disable
  ");
  }
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  static int i2c_platform_probe(struct platform_device *pdev)
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  {
  	struct i2c_platform_data *priv;
  	struct resource *r;
  	int ret;
  
  	pr_debug("i2c_platform_probe
  ");
  	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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  	if (!r)
  		return -ENODEV;
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  	priv = devm_kzalloc(&pdev->dev, sizeof(struct i2c_platform_data),
  			    GFP_KERNEL);
  	if (!priv)
  		return -ENOMEM;
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  	/* FIXME: need to allocate resource in PIC32 space */
  #if 0
  	priv->base = bus_request_region(r->start, resource_size(r),
  					  pdev->name);
  #else
  	priv->base = r->start;
  #endif
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  	if (!priv->base)
  		return -EBUSY;
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  	priv->xfer_timeout = 200;
  	priv->ack_timeout = 200;
  	priv->ctl_timeout = 200;
  
  	priv->adap.nr = pdev->id;
  	priv->adap.algo = &platform_algo;
  	priv->adap.algo_data = priv;
  	priv->adap.dev.parent = &pdev->dev;
  	strlcpy(priv->adap.name, "PIC32 I2C", sizeof(priv->adap.name));
  
  	i2c_platform_setup(priv);
  
  	ret = i2c_add_numbered_adapter(&priv->adap);
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  	if (ret) {
  		i2c_platform_disable(priv);
  		return ret;
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  	}
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  	platform_set_drvdata(pdev, priv);
  	return 0;
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  }
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  static int i2c_platform_remove(struct platform_device *pdev)
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  {
  	struct i2c_platform_data *priv = platform_get_drvdata(pdev);
  
  	pr_debug("i2c_platform_remove
  ");
  	platform_set_drvdata(pdev, NULL);
  	i2c_del_adapter(&priv->adap);
  	i2c_platform_disable(priv);
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  	return 0;
  }
  
  #ifdef CONFIG_PM
  static int
  i2c_platform_suspend(struct platform_device *pdev, pm_message_t state)
  {
  	struct i2c_platform_data *priv = platform_get_drvdata(pdev);
  
  	dev_dbg(&pdev->dev, "i2c_platform_disable
  ");
  	i2c_platform_disable(priv);
  
  	return 0;
  }
  
  static int
  i2c_platform_resume(struct platform_device *pdev)
  {
  	struct i2c_platform_data *priv = platform_get_drvdata(pdev);
  
  	dev_dbg(&pdev->dev, "i2c_platform_setup
  ");
  	i2c_platform_setup(priv);
  
  	return 0;
  }
  #else
  #define i2c_platform_suspend	NULL
  #define i2c_platform_resume	NULL
  #endif
  
  static struct platform_driver i2c_platform_driver = {
  	.driver = {
  		.name	= "i2c_pic32",
  		.owner	= THIS_MODULE,
  	},
  	.probe		= i2c_platform_probe,
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  	.remove		= i2c_platform_remove,
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  	.suspend	= i2c_platform_suspend,
  	.resume		= i2c_platform_resume,
  };
  
  static int __init
  i2c_platform_init(void)
  {
  	pr_debug("i2c_platform_init
  ");
  	return platform_driver_register(&i2c_platform_driver);
  }
  
  static void __exit
  i2c_platform_exit(void)
  {
  	pr_debug("i2c_platform_exit
  ");
  	platform_driver_unregister(&i2c_platform_driver);
  }
  
  MODULE_AUTHOR("Chris Dearman, MIPS Technologies INC.");
  MODULE_DESCRIPTION("PIC32 I2C driver");
  MODULE_LICENSE("GPL");
  
  module_init(i2c_platform_init);
  module_exit(i2c_platform_exit);