Re: [PATCH][RFC] i2c: adds support for i2c bus on 8xx

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Hi Vitaly,

On Fri, 20 Apr 2007 08:27:14 +0400, Vitaly Bordug wrote:
> Utilized devicetree to store I2C data, ported i2c-algo-8xx.c
> from 2.4 approach(which remains nearly intact), refined i2c-rpx.c.
> I2C functionality has been validated on mpc885ads with EEPROM access.

Thanks for working on this. I was about to kill i2c-rpx because it's
broken for so long:
http://lists.lm-sensors.org/pipermail/i2c/2007-March/000970.html

> Signed-off-by: Vitaly Bordug <[email protected]>
> ---
> Jean, 
> 
> The patch below may have rough edges but I'd appreciate you to take a look.
> It adds I2C capabilities of PQ series (mpc8xx mostly) or, more correctly, takes
> them off from the 2.4 kernel and makes it work.

OK. I can't comment on the platform-specific part I am not familiar
with, but here's a quick review of the rest.

> Validated with quilt tree residing at
> http://khali.linux-fr.org/devel/linux-2.6/jdelvare-i2c/
> 
> 
>  arch/powerpc/boot/dts/mpc885ads.dts          |    7 
>  arch/powerpc/platforms/8xx/mpc885ads_setup.c |   14 +
>  arch/powerpc/sysdev/fsl_soc.c                |   61 +++
>  drivers/i2c/algos/Kconfig                    |    2 
>  drivers/i2c/algos/Makefile                   |    1 
>  drivers/i2c/algos/i2c-algo-8xx.c             |  622 ++++++++++++++++++++++++++
>  drivers/i2c/busses/Kconfig                   |    4 
>  drivers/i2c/busses/i2c-rpx.c                 |  129 ++++-
>  include/linux/i2c-algo-8xx.h                 |   29 +
>  9 files changed, 822 insertions(+), 47 deletions(-)

I wonder what's the point of having a separate i2c algorithm driver. We
don't expect any other driver than i2c-rpx to ever use it, do we? In
that case, all the code should be added to i2c-rpx directly, this will
makes things more simple and more efficient.

> diff --git a/arch/powerpc/boot/dts/mpc885ads.dts b/arch/powerpc/boot/dts/mpc885ads.dts
> index 19d2d79..90e047a 100644
> --- a/arch/powerpc/boot/dts/mpc885ads.dts
> +++ b/arch/powerpc/boot/dts/mpc885ads.dts
> @@ -188,6 +188,13 @@
>  				interrupts = <1d 3>;
>  				interrupt-parent = <930>;
>  			};
> +			i2c@860 {
> +				device_type = "i2c";
> +				compatible = "fsl-i2c-cpm";
> +				reg = <860 20 3c80 30>;
> +				interrupts = <10 3>;
> +				interrupt-parent = <930>;
> +			};
>  		};
>  	};
>  };
> diff --git a/arch/powerpc/platforms/8xx/mpc885ads_setup.c b/arch/powerpc/platforms/8xx/mpc885ads_setup.c
> index 9bd81c7..d32e066 100644
> --- a/arch/powerpc/platforms/8xx/mpc885ads_setup.c
> +++ b/arch/powerpc/platforms/8xx/mpc885ads_setup.c
> @@ -51,6 +51,7 @@ static void init_smc1_uart_ioports(struc
>  static void init_smc2_uart_ioports(struct fs_uart_platform_info* fpi);
>  static void init_scc3_ioports(struct fs_platform_info* ptr);
>  static void init_irda_ioports(void);
> +static void init_i2c_ioports(void);
>  
>  void __init mpc885ads_board_setup(void)
>  {
> @@ -120,6 +121,10 @@ #endif
>  #ifdef CONFIG_8XX_SIR
>  	init_irda_ioports();
>  #endif
> +
> +#ifdef CONFIG_I2C_RPXLITE
> +	init_i2c_ioports();
> +#endif
>  }
>  
>  
> @@ -361,6 +366,15 @@ static void init_irda_ioports()
>  	immr_unmap(cp);
>  }
>  
> +static void init_i2c_ioports()
> +{
> +	cpm8xx_t *cp = (cpm8xx_t *)immr_map(im_cpm);
> +
> +        setbits32(&cp->cp_pbpar, 0x00000030);
> +        setbits32(&cp->cp_pbdir, 0x00000030);
> +        setbits16(&cp->cp_pbodr, 0x0030);
> +}

If !CONFIG_I2C_RPXLITE, you define a static function which you never
use. This is inefficient, and gcc will complain.

> +
>  int platform_device_skip(const char *model, int id)
>  {
>  #ifdef CONFIG_MPC8xx_SECOND_ETH_SCC3
> diff --git a/arch/powerpc/sysdev/fsl_soc.c b/arch/powerpc/sysdev/fsl_soc.c
> index 419b688..7ecd537 100644
> --- a/arch/powerpc/sysdev/fsl_soc.c
> +++ b/arch/powerpc/sysdev/fsl_soc.c
> @@ -331,7 +331,7 @@ static int __init fsl_i2c_of_init(void)
>  	for (np = NULL, i = 0;
>  	     (np = of_find_compatible_node(np, "i2c", "fsl-i2c")) != NULL;
>  	     i++) {
> -		struct resource r[2];
> +		struct resource r[3];
>  		struct fsl_i2c_platform_data i2c_data;
>  		const unsigned char *flags = NULL;
>  
> @@ -1215,4 +1215,63 @@ err:
>  
>  arch_initcall(fs_irda_of_init);
>  
> +static const char *i2c_regs = "regs";
> +static const char *i2c_pram = "pram";
> +static const char *i2c_irq = "interrupt";
> +
> +static int __init fsl_i2c_cpm_of_init(void)
> +{
> +	struct device_node *np;
> +	unsigned int i;
> +	struct platform_device *i2c_dev;
> +	int ret;
> +
> +	for (np = NULL, i = 0;
> +	     (np = of_find_compatible_node(np, "i2c", "fsl-i2c-cpm")) != NULL;
> +	     i++) {
> +		struct resource r[3];
> +		struct fsl_i2c_platform_data i2c_data;
> +
> +		memset(&r, 0, sizeof(r));
> +		memset(&i2c_data, 0, sizeof(i2c_data));
> +
> +		ret = of_address_to_resource(np, 0, &r[0]);
> +		if (ret)
> +			goto err;
> +		r[0].name = i2c_regs;
> +
> +		ret = of_address_to_resource(np, 1, &r[1]);
> +		if (ret)
> +			goto err;
> +		r[1].name = i2c_pram;
> +
> +		r[2].start = r[2].end = irq_of_parse_and_map(np, 0);
> +		r[2].flags = IORESOURCE_IRQ;
> +		r[2].name = i2c_irq;
> +
> +		i2c_dev = platform_device_register_simple("fsl-i2c-cpm", i, &r[0], 3);
> +		if (IS_ERR(i2c_dev)) {
> +			ret = PTR_ERR(i2c_dev);
> +			goto err;
> +		}
> +
> +		ret =
> +		    platform_device_add_data(i2c_dev, &i2c_data,
> +					     sizeof(struct
> +						    fsl_i2c_platform_data));
> +		if (ret)
> +			goto unreg;
> +	}
> +
> +	return 0;
> +
> +unreg:
> +	platform_device_unregister(i2c_dev);
> +err:
> +	return ret;
> +}
> +
> +arch_initcall(fsl_i2c_cpm_of_init);
> +
> +
>  #endif /* CONFIG_8xx */
> diff --git a/drivers/i2c/algos/Kconfig b/drivers/i2c/algos/Kconfig
> index 5889907..7d7fb87 100644
> --- a/drivers/i2c/algos/Kconfig
> +++ b/drivers/i2c/algos/Kconfig
> @@ -37,6 +37,8 @@ config I2C_ALGOPCA
>  config I2C_ALGO8XX
>  	tristate "MPC8xx CPM I2C interface"
>  	depends on 8xx
> +	help
> +	  8xx I2C Algorithm
>  
>  config I2C_ALGO_SGI
>  	tristate "I2C SGI interfaces"
> diff --git a/drivers/i2c/algos/Makefile b/drivers/i2c/algos/Makefile
> index cac1051..1bd3b37 100644
> --- a/drivers/i2c/algos/Makefile
> +++ b/drivers/i2c/algos/Makefile
> @@ -6,6 +6,7 @@ obj-$(CONFIG_I2C_ALGOBIT)	+= i2c-algo-bi
>  obj-$(CONFIG_I2C_ALGOPCF)	+= i2c-algo-pcf.o
>  obj-$(CONFIG_I2C_ALGOPCA)	+= i2c-algo-pca.o
>  obj-$(CONFIG_I2C_ALGO_SGI)	+= i2c-algo-sgi.o
> +obj-$(CONFIG_I2C_ALGO8XX)	+= i2c-algo-8xx.o
>  
>  ifeq ($(CONFIG_I2C_DEBUG_ALGO),y)
>  EXTRA_CFLAGS += -DDEBUG
> diff --git a/drivers/i2c/algos/i2c-algo-8xx.c b/drivers/i2c/algos/i2c-algo-8xx.c
> new file mode 100644
> index 0000000..b1f414a
> --- /dev/null
> +++ b/drivers/i2c/algos/i2c-algo-8xx.c

General comment for this file: all the printks need a level (KERN_*)
and some prefix so that the user knows they come from this driver. Or
you can switch to pr_info/pr_debug or even dev_info/dev_dbg.

> @@ -0,0 +1,622 @@
> +/*
> + * i2c-algo-8xx.c i2x driver algorithms for MPC8XX CPM
> + * Copyright (c) 1999 Dan Malek ([email protected]).
> + *
> +    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, or
> +    (at your option) any later version.
> +
> +    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., 675 Mass Ave, Cambridge, MA 02139, USA.
> + *
> + * moved into proper i2c interface; separated out platform specific
> + * parts into i2c-rpx.c
> + * Brad Parker ([email protected])
> + */
> +
> +
> +/* $Id: i2c-algo-8xx.c,v 1.15 2004/11/20 08:02:24 khali Exp $ */

Drop this.

> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/delay.h>
> +#include <linux/slab.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/errno.h>
> +#include <linux/sched.h>
> +#include <linux/i2c.h>
> +#include <linux/i2c-algo-8xx.h>
> +#include <asm/io.h>
> +#include <asm/cacheflush.h>
> +#include <asm/time.h>
> +#include <asm/mpc8xx.h>
> +
> +#define CPM_MAX_READ	513
> +#undef	I2C_CHIP_ERRATA /* Try ot define this if you have an older CPU(earlier than rev D4) */

Broken indentation, line too long, and typo in the comment.

> +
> +static wait_queue_head_t iic_wait;
> +static ushort r_tbase, r_rbase;
> +
> +int cpm_debug = 0;

Should be static and not initialized explicitly.

> +int cpm_scan = 0;

Please drop this, same can be done in a generic (and safer) way from user-space using
i2c-dev + i2cdetect.

> +
> +static irqreturn_t cpm_iic_interrupt(int irq, void *dev_id)
> +{
> +	i2c8xx_t *i2c = (i2c8xx_t *) dev_id;
> +	if (cpm_debug > 1)
> +		printk("cpm_iic_interrupt(dev_id=%p)\n", dev_id);
> +#if 0
> +	/* Chip errata, clear enable. This is not needed on rev D4 CPUs */
> +	/* This should probably be removed and replaced by I2C_CHIP_ERRATA stuff */
> +	/* Someone with a buggy CPU needs to confirm that */
> +	out_8(&i2c->i2c_i2mod, in_8(&i2c->i2c_i2mod) | ~1);
> +#endif
> +	/* Clear interrupt.
> +	 */
> +	out_8(&i2c->i2c_i2cer, 0xff);
> +
> +	/* Get 'me going again.
> +	 */
> +	wake_up_interruptible(&iic_wait);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static void cpm_iic_init(struct i2c_algo_8xx_data *cpm)
> +{
> +	iic_t *iip = cpm->iip;
> +	i2c8xx_t *i2c = cpm->i2c;
> +	unsigned char brg;
> +
> +	if (cpm_debug)
> +		printk(KERN_DEBUG "cpm_iic_init()\n");
> +
> +	/* Initialize the parameter ram.
> +	 * We need to make sure many things are initialized to zero,
> +	 * especially in the case of a microcode patch.
> +	 */
> +	iip->iic_rstate = 0;
> +	iip->iic_rdp = 0;
> +	iip->iic_rbptr = 0;
> +	iip->iic_rbc = 0;
> +	iip->iic_rxtmp = 0;
> +	iip->iic_tstate = 0;
> +	iip->iic_tdp = 0;
> +	iip->iic_tbptr = 0;
> +	iip->iic_tbc = 0;
> +	iip->iic_txtmp = 0;

Maybe a memset on the whole structure would be more efficient? Looks to
me like you're zeroing almost all fields.

> +
> +	/* Set up the IIC parameters in the parameter ram.
> +	 */
> +	iip->iic_tbase = r_tbase = cpm->dp_addr;
> +	iip->iic_rbase = r_rbase = cpm->dp_addr + sizeof(cbd_t) * 2;
> +
> +	if (cpm_debug) {
> +		printk("iip %p, dp_addr 0x%x\n", cpm->iip, cpm->dp_addr);
> +		printk("iic_tbase %d, r_tbase %d\n", iip->iic_tbase, r_tbase);
> +	}
> +
> +	iip->iic_tfcr = SMC_EB;
> +	iip->iic_rfcr = SMC_EB;
> +
> +	/* Set maximum receive size.
> +	 */
> +	iip->iic_mrblr = CPM_MAX_READ;
> +
> +	/* Initialize Tx/Rx parameters.
> +	 */
> +	if (cpm->reloc == 0) {
> +		cpm8xx_t *cp = cpm->cp;
> +		u16 v = mk_cr_cmd(CPM_CR_CH_I2C, CPM_CR_INIT_TRX) | CPM_CR_FLG;
> +
> +		out_be16(&cp->cp_cpcr, v);
> +		while (in_be16(&cp->cp_cpcr) & CPM_CR_FLG) ;

This could block, you need to add some form of timeout.

> +	} else {
> +		iip->iic_rbptr = iip->iic_rbase;
> +		iip->iic_tbptr = iip->iic_tbase;
> +		iip->iic_rstate = 0;
> +		iip->iic_tstate = 0;
> +	}
> +
> +	/* Select an arbitrary address.  Just make sure it is unique.
> +	 */
> +	out_8(&i2c->i2c_i2add, 0xfe);
> +
> +	/* Make clock run at 60 KHz.

kHz (small k)

> +	 */
> +	brg = (unsigned char)(ppc_proc_freq / (32 * 2 * 60000) - 3);

Useless cast.

> +	out_8(&i2c->i2c_i2brg, brg);
> +
> +	out_8(&i2c->i2c_i2mod, 0x00);
> +	out_8(&i2c->i2c_i2com, 0x01);	/* Master mode */
> +
> +	/* Disable interrupts.
> +	 */
> +	out_8(&i2c->i2c_i2cmr, 0);
> +	out_8(&i2c->i2c_i2cer, 0xff);
> +
> +	init_waitqueue_head(&iic_wait);
> +
> +	/* Install interrupt handler.
> +	 */
> +	if (cpm_debug) {
> +		printk("%s[%d] Install ISR for IRQ %d\n",
> +		       __func__, __LINE__, CPMVEC_I2C);
> +	}
> +	request_irq(cpm->irq, cpm_iic_interrupt, 0, "8xx_i2c", i2c);
> +}
> +
> +static int cpm_iic_shutdown(struct i2c_algo_8xx_data *cpm)
> +{
> +	i2c8xx_t *i2c = cpm->i2c;
> +
> +	/* Shut down IIC.
> +	 */
> +	out_8(&i2c->i2c_i2mod, in_8(&i2c->i2c_i2mod) | ~1);
> +	out_8(&i2c->i2c_i2cmr, 0);
> +	out_8(&i2c->i2c_i2cer, 0xff);
> +
> +	return (0);
> +}
> +
> +static void cpm_reset_iic_params(iic_t * iip)
> +{
> +	iip->iic_tbase = r_tbase;
> +	iip->iic_rbase = r_rbase;
> +
> +	iip->iic_tfcr = SMC_EB;
> +	iip->iic_rfcr = SMC_EB;
> +
> +	iip->iic_mrblr = CPM_MAX_READ;
> +
> +	iip->iic_rstate = 0;
> +	iip->iic_rdp = 0;
> +	iip->iic_rbptr = iip->iic_rbase;
> +	iip->iic_rbc = 0;
> +	iip->iic_rxtmp = 0;
> +	iip->iic_tstate = 0;
> +	iip->iic_tdp = 0;
> +	iip->iic_tbptr = iip->iic_tbase;
> +	iip->iic_tbc = 0;
> +	iip->iic_txtmp = 0;
> +}
> +
> +#define BD_SC_NAK		((ushort)0x0004)	/* NAK - did not respond */
> +#define BD_SC_OV		((ushort)0x0002)	/* OV - receive overrun */
> +#define CPM_CR_CLOSE_RXBD	((ushort)0x0007)
> +
> +static void force_close(struct i2c_algo_8xx_data *cpm)
> +{
> +	i2c8xx_t *i2c = cpm->i2c;
> +	if (cpm->reloc == 0) {	/* micro code disabled */
> +		cpm8xx_t *cp = cpm->cp;
> +		u16 v = mk_cr_cmd(CPM_CR_CH_I2C, CPM_CR_CLOSE_RXBD) | CPM_CR_FLG;
> +
> +		if (cpm_debug)
> +			printk("force_close()\n");
> +
> +		out_be16(&cp->cp_cpcr, v);
> +		while (in_be16(&cp->cp_cpcr) & CPM_CR_FLG) ;
> +	}
> +	out_8(&i2c->i2c_i2cmr, 0x00);	/* Disable all interrupts */
> +	out_8(&i2c->i2c_i2cer, 0xff);
> +}
> +
> +/* Read from IIC...
> + * abyte = address byte, with r/w flag already set
> + */
> +static int
> +cpm_iic_read(struct i2c_algo_8xx_data *cpm, u_char abyte, char *buf, int count)
> +{
> +	iic_t *iip = cpm->iip;
> +	i2c8xx_t *i2c = cpm->i2c;
> +	cbd_t *tbdf, *rbdf;
> +	u_char *tb;
> +	unsigned long tmo;
> +	int res = 0;
> +
> +	if (count >= CPM_MAX_READ)
> +		return -EINVAL;
> +
> +	/* check for and use a microcode relocation patch */
> +	if (cpm->reloc) {
> +		cpm_reset_iic_params(iip);
> +	}
> +
> +	tbdf = (cbd_t *) cpm_dpram_addr(iip->iic_tbase);
> +	rbdf = (cbd_t *) cpm_dpram_addr(iip->iic_rbase);
> +
> +	/* To read, we need an empty buffer of the proper length.
> +	 * All that is used is the first byte for address, the remainder
> +	 * is just used for timing (and doesn't really have to exist).
> +	 */
> +	tb = cpm->temp;
> +	tb = (u_char *) (((uint) tb + 15) & ~15);
> +	tb[0] = abyte;		/* Device address byte w/rw flag */
> +
> +	flush_dcache_range((unsigned long)tb, (unsigned long)(tb + 1));
> +
> +	if (cpm_debug)
> +		printk("cpm_iic_read(abyte=0x%x)\n", abyte);
> +
> +	tbdf->cbd_bufaddr = __pa(tb);
> +	tbdf->cbd_datlen = count + 1;
> +	tbdf->cbd_sc = BD_SC_READY | BD_SC_LAST | BD_SC_WRAP | BD_IIC_START;
> +
> +	iip->iic_mrblr = count + 1;	/* prevent excessive read, +1
> +					   is needed otherwise will the
> +					   RXB interrupt come too early */
> +
> +	/* flush will invalidate too. */
> +	flush_dcache_range((unsigned long)buf, (unsigned long)(buf + count));
> +
> +	rbdf->cbd_datlen = 0;
> +	rbdf->cbd_bufaddr = __pa(buf);
> +	rbdf->cbd_sc = BD_SC_EMPTY | BD_SC_WRAP | BD_SC_INTRPT;
> +
> +	if (count > 16) {
> +		/* Chip bug, set enable here */
> +		out_8(&i2c->i2c_i2cmr, 0x13);	/* Enable some interupts */
> +		out_8(&i2c->i2c_i2cer, 0xff);
> +		out_8(&i2c->i2c_i2mod, in_8(&i2c->i2c_i2mod) | 1);	/* Enable */
> +		out_8(&i2c->i2c_i2com, in_8(&i2c->i2c_i2com) | 0x80);	/* Begin transmission */
> +
> +		/* Wait for IIC transfer */
> +		res = wait_event_interruptible_timeout(iic_wait, 0, 1 * HZ);
> +	} else {		/* busy wait for small transfers, its faster */
> +		out_8(&i2c->i2c_i2cmr, 0x00);	/* Disable I2C interupts */
> +		out_8(&i2c->i2c_i2cer, 0xff);
> +		out_8(&i2c->i2c_i2mod, in_8(&i2c->i2c_i2mod) | 1);	/* Enable */
> +		out_8(&i2c->i2c_i2com, in_8(&i2c->i2c_i2com) | 0x80);	/* Begin transmission */
> +
> +		tmo = jiffies + 1 * HZ;
> +		while (!(in_8(&i2c->i2c_i2cer) & 0x11 || time_after(jiffies, tmo))) ;/* Busy wait, with a timeout */

This could result in a one-second busy loop, not very friendly for other
drivers. It should sleep while waiting. Line too long, please fold.

> +	}
> +
> +	if ( res < 0) {
> +		force_close(cpm);
> +		if (cpm_debug)
> +			printk("IIC read: timeout!\n");
> +		return -EIO;
> +	}
> +#ifdef I2C_CHIP_ERRATA
> +	/* Chip errata, clear enable. This is not needed on rev D4 CPUs.
> +	   Disabling I2C too early may cause too short stop condition */
> +	udelay(4);
> +	out_8(&i2c->i2c_i2mod, in_8(&i2c->i2c_i2mod) | ~1);
> +#endif
> +	if (cpm_debug) {
> +		printk("tx sc %04x, rx sc %04x\n", tbdf->cbd_sc, rbdf->cbd_sc);
> +	}
> +
> +	if (tbdf->cbd_sc & BD_SC_READY) {
> +		printk("IIC read; complete but tbuf ready\n");
> +		force_close(cpm);
> +		printk("tx sc %04x, rx sc %04x\n", tbdf->cbd_sc, rbdf->cbd_sc);
> +	}
> +
> +	if (tbdf->cbd_sc & BD_SC_NAK) {
> +		if (cpm_debug)
> +			printk("IIC read; no ack\n");
> +		return -EREMOTEIO;
> +	}
> +
> +	if (rbdf->cbd_sc & BD_SC_EMPTY) {
> +		/* force_close(cpm); */
> +		if (cpm_debug) {
> +			printk("IIC read; complete but rbuf empty\n");
> +			printk("tx sc %04x, rx sc %04x\n",
> +			       tbdf->cbd_sc, rbdf->cbd_sc);
> +		}
> +		return -EREMOTEIO;
> +	}
> +
> +	if (rbdf->cbd_sc & BD_SC_OV) {
> +		if (cpm_debug)
> +			printk("IIC read; Overrun\n");
> +		return -EREMOTEIO;;

Doubled semi-colon.

> +	}
> +
> +	if (cpm_debug)
> +		printk("read %d bytes\n", rbdf->cbd_datlen);
> +
> +	if (rbdf->cbd_datlen < count) {
> +		if (cpm_debug)
> +			printk("IIC read; short, wanted %d got %d\n",
> +			       count, rbdf->cbd_datlen);
> +		return 0;
> +	}
> +
> +	return count;
> +}
> +
> +/* Write to IIC...
> + * addr = address byte, with r/w flag already set
> + */
> +static int
> +cpm_iic_write(struct i2c_algo_8xx_data *cpm, u_char abyte, char *buf, int count)
> +{
> +	iic_t *iip = cpm->iip;
> +	i2c8xx_t *i2c = cpm->i2c;
> +	cbd_t *tbdf;
> +	u_char *tb;
> +	unsigned long tmo;
> +	int res = 0;
> +
> +	/* check for and use a microcode relocation patch */
> +	if (cpm->reloc) {
> +		cpm_reset_iic_params(iip);
> +	}
> +	tb = cpm->temp;
> +	tb = (u_char *) (((uint) tb + 15) & ~15);
> +	*tb = abyte;		/* Device address byte w/rw flag */
> +
> +	flush_dcache_range((unsigned long)tb, (unsigned long)(tb + 1));
> +	flush_dcache_range((unsigned long)buf, (unsigned long)(buf + count));
> +
> +	if (cpm_debug)
> +		printk("cpm_iic_write(abyte=0x%x)\n", abyte);
> +
> +	/* set up 2 descriptors */
> +
> +

Doubled blank line.

> +	tbdf = (cbd_t *) cpm_dpram_addr(iip->iic_tbase);
> +
> +	tbdf[0].cbd_bufaddr = __pa(tb);
> +	tbdf[0].cbd_datlen = 1;
> +	tbdf[0].cbd_sc = BD_SC_READY | BD_IIC_START;
> +
> +	tbdf[1].cbd_bufaddr = __pa(buf);
> +	tbdf[1].cbd_datlen = count;
> +	tbdf[1].cbd_sc = BD_SC_READY | BD_SC_INTRPT | BD_SC_LAST | BD_SC_WRAP;
> +
> +	if (count > 16) {
> +		/* Chip bug, set enable here */
> +		out_8(&i2c->i2c_i2cmr, 0x13);	/* Enable some interupts */
> +		out_8(&i2c->i2c_i2cer, 0xff);
> +		out_8(&i2c->i2c_i2mod, in_8(&i2c->i2c_i2mod) | 1);	/* Enable */
> +		out_8(&i2c->i2c_i2com, in_8(&i2c->i2c_i2com) | 0x80);	/* Begin transmission */
> +
> +		/* Wait for IIC transfer */
> +		res = wait_event_interruptible_timeout(iic_wait, 0, 1 * HZ);
> +	} else {		/* busy wait for small transfers, its faster */
> +		out_8(&i2c->i2c_i2cmr, 0x00);	/* Disable I2C interupts */
> +		out_8(&i2c->i2c_i2cer, 0xff);
> +		out_8(&i2c->i2c_i2mod, in_8(&i2c->i2c_i2mod) | 1);	/* Enable */
> +		out_8(&i2c->i2c_i2com, in_8(&i2c->i2c_i2com) | 0x80);	/* Begin transmission */
> +		tmo = jiffies + 1 * HZ;
> +		while (!(in_8(&i2c->i2c_i2cer) & 0x12 || time_after(jiffies, tmo))) ;/* Busy wait, with a timeout */

Same as above, should sleep, and line to long.

> +	}
> +
> +	if ( res < 0) {
> +		force_close(cpm);
> +		if (cpm_debug)
> +			printk("IIC write: timeout!\n");
> +		return -EIO;
> +	}
> +#ifdef I2C_CHIP_ERRATA
> +	/* Chip errata, clear enable. This is not needed on rev D4 CPUs.
> +	   Disabling I2C too early may cause too short stop condition */
> +	udelay(4);
> +	out_8(&i2c->i2c_i2mod, in_8(&i2c->i2c_i2mod) | ~1);
> +#endif
> +	if (cpm_debug) {
> +		printk("tx0 sc %04x, tx1 sc %04x\n",
> +		       tbdf[0].cbd_sc, tbdf[1].cbd_sc);
> +	}
> +
> +	if (tbdf->cbd_sc & BD_SC_NAK) {
> +		if (cpm_debug)
> +			printk("IIC write; no ack\n");
> +		return 0;
> +	}
> +
> +	if (tbdf->cbd_sc & BD_SC_READY) {
> +		if (cpm_debug)
> +			printk("IIC write; complete but tbuf ready\n");
> +		return 0;
> +	}
> +
> +	return count;
> +}
> +
> +/* See if an IIC address exists..
> + * addr = 7 bit address, unshifted
> + */
> +static int cpm_iic_tryaddress(struct i2c_algo_8xx_data *cpm, int addr)
> +{
> +	iic_t *iip = cpm->iip;
> +	i2c8xx_t *i2c = cpm->i2c;
> +	cbd_t *tbdf, *rbdf;
> +	u_char *tb;
> +	unsigned long len;
> +	int res = 0;
> +
> +	if (cpm_debug > 1)
> +		printk("cpm_iic_tryaddress(cpm=%p,addr=%d)\n", cpm, addr);
> +
> +	/* check for and use a microcode relocation patch */
> +	if (cpm->reloc) {
> +		cpm_reset_iic_params(iip);
> +	}
> +
> +	if (cpm_debug && addr == 0) {
> +		printk("iip %p, dp_addr 0x%x\n", cpm->iip, cpm->dp_addr);
> +		printk("iic_tbase %d, r_tbase %d\n", iip->iic_tbase, r_tbase);
> +	}
> +
> +	tbdf = (cbd_t *) cpm_dpram_addr(iip->iic_tbase);
> +	rbdf = (cbd_t *) cpm_dpram_addr(iip->iic_rbase);
> +
> +	tb = cpm->temp;
> +	tb = (u_char *) (((uint) tb + 15) & ~15);
> +
> +	/* do a simple read */
> +	tb[0] = (addr << 1) | 1;	/* device address (+ read) */
> +	len = 2;
> +
> +	flush_dcache_range((unsigned long)tb, (unsigned long)(tb + 2));
> +
> +	tbdf->cbd_bufaddr = __pa(tb);
> +	tbdf->cbd_datlen = len;
> +	tbdf->cbd_sc = BD_SC_READY | BD_SC_LAST | BD_SC_WRAP | BD_IIC_START;
> +
> +	rbdf->cbd_datlen = 0;
> +	rbdf->cbd_bufaddr = __pa(tb + 2);
> +	rbdf->cbd_sc = BD_SC_EMPTY | BD_SC_WRAP | BD_SC_INTRPT;
> +
> +	out_8(&i2c->i2c_i2cmr, 0x13);	/* Enable some interupts */
> +	out_8(&i2c->i2c_i2cer, 0xff);
> +	out_8(&i2c->i2c_i2mod, in_8(&i2c->i2c_i2mod) | 1);	/* Enable */
> +	out_8(&i2c->i2c_i2com, in_8(&i2c->i2c_i2com) | 0x80);	/* Begin transmission */
> +
> +	if (cpm_debug > 1)
> +		printk("about to sleep\n");
> +
> +	/* wait for IIC transfer */
> +	res = wait_event_interruptible_timeout(iic_wait, 0, 1 * HZ);
> +
> +#ifdef I2C_CHIP_ERRATA
> +	/* Chip errata, clear enable. This is not needed on rev D4 CPUs.
> +	   Disabling I2C too early may cause too short stop condition */
> +	udelay(4);
> +	out_8(&i2c->i2c_i2mod, in_8(&i2c->i2c_i2mod) | ~1);
> +#endif
> +
> +	if ( res < 0) {
> +		force_close(cpm);
> +		if (cpm_debug)
> +			printk("IIC tryaddress: timeout!\n");
> +		return -EIO;
> +	}
> +
> +	if (cpm_debug > 1)
> +		printk("back from sleep\n");
> +
> +	if (tbdf->cbd_sc & BD_SC_NAK) {
> +		if (cpm_debug > 1)
> +			printk("IIC try; no ack\n");
> +		return 0;
> +	}
> +
> +	if (tbdf->cbd_sc & BD_SC_READY) {
> +		printk("IIC try; complete but tbuf ready\n");
> +	}
> +
> +	return 1;
> +}
> +
> +static int cpm_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)

Use *msgs instead of msgs[].

> +{
> +	struct i2c_algo_8xx_data *cpm = adap->algo_data;
> +	struct i2c_msg *pmsg;
> +	int i, ret;
> +	u_char addr;
> +
> +	for (i = 0; i < num; i++) {
> +		pmsg = &msgs[i];
> +
> +		if (cpm_debug)
> +			printk("i2c-algo-8xx.o: "
> +			       "#%d addr=0x%x flags=0x%x len=%d\n buf=%lx\n",
> +			       i, pmsg->addr, pmsg->flags, pmsg->len,
> +			       (unsigned long)pmsg->buf);
> +
> +		addr = pmsg->addr << 1;
> +		if (pmsg->flags & I2C_M_RD)
> +			addr |= 1;
> +		if (pmsg->flags & I2C_M_REV_DIR_ADDR)
> +			addr ^= 1;
> +
> +		if (!(pmsg->flags & I2C_M_NOSTART)) {
> +		}

Either something is missing here and you must add it, or this statement
is useless and you should drop it.

> +		if (pmsg->flags & I2C_M_RD) {
> +			/* read bytes into buffer */
> +			ret = cpm_iic_read(cpm, addr, pmsg->buf, pmsg->len);
> +			if (cpm_debug)
> +				printk("i2c-algo-8xx.o: read %d bytes\n", ret);
> +			if (ret < pmsg->len) {
> +				return (ret < 0) ? ret : -EREMOTEIO;
> +			}
> +		} else {
> +			/* write bytes from buffer */
> +			ret = cpm_iic_write(cpm, addr, pmsg->buf, pmsg->len);
> +			if (cpm_debug)
> +				printk("i2c-algo-8xx.o: wrote %d\n", ret);
> +			if (ret < pmsg->len) {
> +				return (ret < 0) ? ret : -EREMOTEIO;
> +			}
> +		}
> +	}
> +	return (num);

Useless parentheses.

> +}

You do not appear to handle repeated start. I can tell because the code
handles all messages the exact same way, be they the first, second or
last message of a group. This means that you don't really implement the
I2C protocol, but an approximation of it. It might be sufficient for
some I2C chips, but others will break. Look in the specifications of
your device for how this could be fixed.

> +
> +static u32 cpm_func(struct i2c_adapter *adap)
> +{
> +	return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR |
> +	    I2C_FUNC_PROTOCOL_MANGLING;
> +}

I2C_FUNC_I2C is missing. I2C_FUNC_10BIT_ADDR isn't implemented so it
shouldn't be advertised. I2C_FUNC_PROTOCOL_MANGLING should only be
implemented if really needed, so I'd suggest that you drop it for now
(together with I2C_M_REV_DIR_ADDR and I2C_M_NOSTART above).

> +
> +/* -----exported algorithm data: -------------------------------------	*/
> +
> +static struct i2c_algorithm cpm_algo = {
> +	.master_xfer = cpm_xfer,
> +	.functionality = cpm_func,
> +};
> +
> +/*
> + * registering functions to load algorithms at runtime
> + */
> +int i2c_8xx_add_bus(struct i2c_adapter *adap)
> +{
> +	struct i2c_algo_8xx_data *cpm = adap->algo_data;
> +	int i;
> +
> +	if (cpm_debug)
> +		printk("i2c-algo-8xx.o: hw routines for %s registered.\n",
> +		       adap->name);
> +
> +	/* register new adapter to i2c module... */
> +
> +	adap->algo = &cpm_algo;
> +
> +	i2c_add_adapter(adap);
> +	cpm_iic_init(cpm);

Should be in the reverse order, init first, register second.

> +
> +	/* scan bus */
> +	if (cpm_scan) {
> +		printk(KERN_INFO " i2c-algo-8xx.o: scanning bus %s...\n",
> +			adap->name);
> +		for (i = 0; i < 128; i++) {
> +			if (cpm_iic_tryaddress(cpm, i))
> +				printk("(%02x)",i<<1);
> +		}
> +		printk("\n");
> +	}

As explained above, please remove this.

> +
> +	return 0;
> +}
> +
> +int i2c_8xx_del_bus(struct i2c_adapter *adap)
> +{
> +	struct i2c_algo_8xx_data *cpm = adap->algo_data;
> +
> +	cpm_iic_shutdown(cpm);
> +
> +	return i2c_del_adapter(adap);

Should be in the reverse order, unregister first, shutdown second.

> +}
> +
> +EXPORT_SYMBOL(i2c_8xx_add_bus);
> +EXPORT_SYMBOL(i2c_8xx_del_bus);
> +
> +MODULE_AUTHOR("Brad Parker <[email protected]>");
> +MODULE_DESCRIPTION("I2C-Bus MPC8XX algorithm");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index 4afc795..83d9aef 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -385,8 +385,8 @@ config I2C_PROSAVAGE
>  	  will be called i2c-prosavage.
>  
>  config I2C_RPXLITE
> -	tristate "Embedded Planet RPX Lite/Classic support"
> -	depends on RPXLITE || RPXCLASSIC
> +	tristate "Embedded Planet RPX Lite/Classic and Freescale 86x/885 ads support"
> +	depends on RPXLITE || RPXCLASSIC || MPC86XADS || MPC885ADS
>  	select I2C_ALGO8XX

Please add a help text.

>  
>  config I2C_S3C2410
> diff --git a/drivers/i2c/busses/i2c-rpx.c b/drivers/i2c/busses/i2c-rpx.c
> index 8764df0..ebddd94 100644
> --- a/drivers/i2c/busses/i2c-rpx.c
> +++ b/drivers/i2c/busses/i2c-rpx.c
> @@ -14,88 +14,129 @@
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <linux/init.h>
> +#include <linux/io.h>
>  #include <linux/stddef.h>
> +#include <linux/platform_device.h>
>  #include <linux/i2c.h>
>  #include <linux/i2c-algo-8xx.h>
>  #include <asm/mpc8xx.h>
>  #include <asm/commproc.h>
> +#include <asm/fs_pd.h>
>  
>  
> -static void
> -rpx_iic_init(struct i2c_algo_8xx_data *data)
> +struct m8xx_i2c {
> +	char *base;
> +	struct device *dev;
> +	struct i2c_adapter adap;
> +	struct i2c_algo_8xx_data *algo_8xx;
> +};
> +
> +static struct i2c_algo_8xx_data rpx_data;
> +
> +static struct i2c_adapter rpx_ops = {

Could be const?

> +	.owner		= THIS_MODULE,
> +	.name		= "m8xx",

Find a better name (e.g. "i2c-rpx").

> +	.id		= I2C_HW_MPC8XX_EPON,
> +	.algo_data	= &rpx_data,
> +};
> +
> +static int rpx_iic_init(struct m8xx_i2c *i2c)
>  {
>  	volatile cpm8xx_t *cp;
> -	volatile immap_t *immap;
> +	struct resource *r;
> +	struct i2c_algo_8xx_data *data = i2c->algo_8xx;
> +	struct platform_device *pdev = to_platform_device(i2c->dev);
> +
> +	cp = data->cp = (cpm8xx_t *)immr_map(im_cpm);	/* pointer to Communication Processor */

Line too long.

>  
> -	cp = cpmp;	/* Get pointer to Communication Processor */
> -	immap = (immap_t *)IMAP_ADDR;	/* and to internal registers */
> +	data->irq = platform_get_irq_byname(pdev, "interrupt");
> +  

No blank line between assignation and test please.

> +	if (data->irq < 0)
> +		return -EINVAL;
>  
> -	data->iip = (iic_t *)&cp->cp_dparam[PROFF_IIC];
> +	r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "pram");
> +	data->iip = ioremap(r->start, r->end - r->start + 1);
> +	if (data->iip == NULL)
> +		return -EINVAL;
>  
>  	/* Check for and use a microcode relocation patch.
> -	*/
> +	 */
>  	if ((data->reloc = data->iip->iic_rpbase))
>  		data->iip = (iic_t *)&cp->cp_dpmem[data->iip->iic_rpbase];
>  		
> -	data->i2c = (i2c8xx_t *)&(immap->im_i2c);
> -	data->cp = cp;
> -
> -	/* Initialize Port B IIC pins.
> -	*/
> -	cp->cp_pbpar |= 0x00000030;
> -	cp->cp_pbdir |= 0x00000030;
> -	cp->cp_pbodr |= 0x00000030;
> +	r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "regs");
> +	data->i2c = ioremap(r->start, r->end - r->start + 1);
> +	if (data->i2c == NULL)
> +		return -EINVAL;
>  
>  	/* Allocate space for two transmit and two receive buffer
>  	 * descriptors in the DP ram.
>  	 */
>  	data->dp_addr = cpm_dpalloc(sizeof(cbd_t) * 4, 8);
> -		
> -	/* ptr to i2c area */
> -	data->i2c = (i2c8xx_t *)&(((immap_t *)IMAP_ADDR)->im_i2c);
>  }
>  
> -static int rpx_install_isr(int irq, void (*func)(void *), void *data)
> +static int i2c_rpx_probe(struct device *device)
>  {
> -	/* install interrupt handler */
> -	cpm_install_handler(irq, func, data);
> -
> -	return 0;
> -}
> +	int result = 0;

Useless initialization.

> +	struct m8xx_i2c *i2c;
> +	struct platform_device *pdev = to_platform_device(device);
>  
> -static struct i2c_algo_8xx_data rpx_data = {
> -	.setisr = rpx_install_isr
> -};
> +	if (!(i2c = kmalloc(sizeof(*i2c), GFP_KERNEL))) {
> +		return -ENOMEM;
> +	}
> +	memset(i2c, 0, sizeof(*i2c));

Use kzalloc() instead.

> +	i2c->dev = device;
> +	i2c->algo_8xx = &rpx_data;
>  
> -static struct i2c_adapter rpx_ops = {
> -	.owner		= THIS_MODULE,
> -	.name		= "m8xx",
> -	.id		= I2C_HW_MPC8XX_EPON,
> -	.algo_data	= &rpx_data,
> -};
> +	rpx_iic_init(i2c);
>  
> -int __init i2c_rpx_init(void)
> -{
> -	printk(KERN_INFO "i2c-rpx: i2c MPC8xx driver\n");
> +	dev_set_drvdata(device, i2c);
>  
> -	/* reset hardware to sane state */
> -	rpx_iic_init(&rpx_data);
> +	i2c->adap = rpx_ops;
> +	i2c_set_adapdata(&i2c->adap, i2c);
> +	i2c->adap.dev.parent = &pdev->dev;
>  
> -	if (i2c_8xx_add_bus(&rpx_ops) < 0) {
> +	if ((result = i2c_8xx_add_bus(&rpx_ops) < 0)) {
>  		printk(KERN_ERR "i2c-rpx: Unable to register with I2C\n");
> -		return -ENODEV;
> +		kfree(i2c);
>  	}
>  
> +	return result;
> +}
> +
> +
> +static int i2c_rpx_remove(struct device *device)
> +{
> +	struct m8xx_i2c *i2c = dev_get_drvdata(device);
> +
> +	i2c_8xx_del_bus(&i2c->adap);
> +	dev_set_drvdata(device, NULL);
> +
> +	kfree(i2c);
>  	return 0;
>  }
>  
> -void __exit i2c_rpx_exit(void)
> +
> +/* Structure for a device driver */
> +static struct device_driver i2c_rpx_driver = {
> +	.name = "fsl-i2c-cpm",
> +	.bus = &platform_bus_type,
> +	.probe = i2c_rpx_probe,
> +	.remove = i2c_rpx_remove,
> +};

Why don't you declare it as a struct platform_driver, register it with
platform_driver_register() and unregister it with
platform_driver_unregister()?

> +
> +static int __init i2c_rpx_init(void)
>  {
> -	i2c_8xx_del_bus(&rpx_ops);
> +	return driver_register(&i2c_rpx_driver);
>  }
>  
> -MODULE_AUTHOR("Dan Malek <[email protected]>");
> -MODULE_DESCRIPTION("I2C-Bus adapter routines for MPC8xx boards");
> +static void __exit i2c_rpx_exit(void)
> +{
> +	driver_unregister(&i2c_rpx_driver);
> +}
>  
>  module_init(i2c_rpx_init);
>  module_exit(i2c_rpx_exit);
> +
> +MODULE_AUTHOR("Dan Malek <[email protected]>");
> +MODULE_DESCRIPTION("I2C-Bus adapter routines for MPC8xx boards");
> diff --git a/include/linux/i2c-algo-8xx.h b/include/linux/i2c-algo-8xx.h
> new file mode 100644
> index 0000000..a644512
> --- /dev/null
> +++ b/include/linux/i2c-algo-8xx.h
> @@ -0,0 +1,29 @@
> +/* ------------------------------------------------------------------------- */
> +/* i2c-algo-8xx.h i2c driver algorithms for MPX8XX CPM			     */
> +/* ------------------------------------------------------------------------- */
> +
> +/* $Id$ */

Delete this.

> +
> +#ifndef I2C_ALGO_8XX_H
> +#define I2C_ALGO_8XX_H
> +
> +#include <linux/i2c.h>
> +#include <asm/8xx_immap.h>
> +#include <asm/commproc.h>
> +
> +struct i2c_algo_8xx_data {
> +	uint dp_addr;
> +	int reloc;
> +	int irq;
> +	i2c8xx_t *i2c;
> +	iic_t	*iip;
> +	cpm8xx_t *cp;
> +
> +	u_char	temp[513];

Shouldn't this be CPM_MAX_READ instead of a hard-coded value?

> +};

Alignment in this structure is inconsistent, some lines use tabs other
use spaces. Please don't mix.

> +
> +extern int i2c_8xx_add_bus(struct i2c_adapter *);
> +extern int i2c_8xx_del_bus(struct i2c_adapter *);
> +
> +#endif /* I2C_ALGO_8XX_H */
> +


-- 
Jean Delvare
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