linux-kernel - Re: [PATCH 1/1] mfd: intel_quark_i2c

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Date:	Thu, 26 Mar 2015 13:08:05 +0200
From:	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:	Lee Jones <lee.jones@...aro.org>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] mfd: intel_quark_i2c_gpio: don't crash if !DMI

On Thu, 2015-03-26 at 08:29 +0000, Lee Jones wrote:
> On Wed, 25 Mar 2015, Andy Shevchenko wrote:
> 
> > dmi_get_system_info() may return NULL either when CONFIG_DMI is not set or when
> > board has an old firmware. The patch prevents a crash and changes the default
> > frequency to be in align with older board.
> > 
> > Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> > ---
> >  drivers/mfd/intel_quark_i2c_gpio.c | 23 +++++++++++++++--------
> >  1 file changed, 15 insertions(+), 8 deletions(-)
> > 
> > diff --git a/drivers/mfd/intel_quark_i2c_gpio.c b/drivers/mfd/intel_quark_i2c_gpio.c
> > index 006f2a1..35291c2 100644
> > --- a/drivers/mfd/intel_quark_i2c_gpio.c
> > +++ b/drivers/mfd/intel_quark_i2c_gpio.c
> > @@ -70,6 +70,9 @@ static const struct i2c_mode_info platform_i2c_mode_info[] = {
> >  		.name = "GalileoGen2",
> >  		.i2c_scl_freq = 400000,
> >  	},
> > +	{
> > +		/* Sentinel */
> > +	}
> >  };
> 
> There's no need for this overt NULL entry.

I had changed the loop condition, thus this additional item is appeared.
I can't see how to prevent crash here if ID is matched but board name is
not.

> 
> I'll apply the patch and change this.
> 
> Applied, thanks.
> 
> >  static struct resource intel_quark_i2c_res[] = {
> > @@ -153,10 +156,10 @@ static void intel_quark_unregister_i2c_clk(struct pci_dev *pdev)
> >  static int intel_quark_i2c_setup(struct pci_dev *pdev, struct mfd_cell *cell)
> >  {
> >  	const char *board_name = dmi_get_system_info(DMI_BOARD_NAME);
> > +	const struct i2c_mode_info *info;
> >  	struct dw_i2c_platform_data *pdata;
> >  	struct resource *res = (struct resource *)cell->resources;
> >  	struct device *dev = &pdev->dev;
> > -	unsigned int i;
> >  
> >  	res[INTEL_QUARK_IORES_MEM].start =
> >  		pci_resource_start(pdev, MFD_I2C_BAR);
> > @@ -170,13 +173,17 @@ static int intel_quark_i2c_setup(struct pci_dev *pdev, struct mfd_cell *cell)
> >  	if (!pdata)
> >  		return -ENOMEM;
> >  
> > -	/* Fast mode by default */
> > -	pdata->i2c_scl_freq = 400000;
> > -
> > -	for (i = 0; i < ARRAY_SIZE(platform_i2c_mode_info); i++)
> > -		if (!strcmp(board_name, platform_i2c_mode_info[i].name))
> > -			pdata->i2c_scl_freq
> > -				= platform_i2c_mode_info[i].i2c_scl_freq;
> > +	/* Normal mode by default */
> > +	pdata->i2c_scl_freq = 100000;
> > +
> > +	if (board_name) {
> > +		for (info = platform_i2c_mode_info; info->name; info++) {
> > +			if (!strcmp(board_name, info->name)) {
> > +				pdata->i2c_scl_freq = info->i2c_scl_freq;
> > +				break;
> > +			}
> > +		}
> > +	}
> >  
> >  	cell->platform_data = pdata;
> >  	cell->pdata_size = sizeof(*pdata);
> 


-- 
Andy Shevchenko <andriy.shevchenko@...el.com>
Intel Finland Oy

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