Re: [PATCH 1/5 v2] i2c/gpio: add DT support

[Jean-Christophe PLAGNIOL-VILLARD <plagnioj-sclMFOaUSTBWk0Htik3J/w@public.gmane.org>]

On 11:16 Wed 07 Mar     , Rob Herring wrote:
> On 02/29/2012 08:20 AM, Jean-Christophe PLAGNIOL-VILLARD wrote:
> > Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj-sclMFOaUSTBWk0Htik3J/w@public.gmane.org>
> > Cc: Nicolas Ferre <nicolas.ferre-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org>
> > Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> > Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org
> > ---
> > v2:
> > 
> > 	use devm_kzalloc
> > 	use i2c-gpio
> > 	use time name in the properties
> > 
> > Best Regars,
> > J.
> >  .../devicetree/bindings/gpio/gpio_i2c.txt          |   32 +++++++
> >  drivers/i2c/busses/i2c-gpio.c                      |   95 +++++++++++++++----
> >  2 files changed, 107 insertions(+), 20 deletions(-)
> >  create mode 100644 Documentation/devicetree/bindings/gpio/gpio_i2c.txt
> > 
> > diff --git a/Documentation/devicetree/bindings/gpio/gpio_i2c.txt b/Documentation/devicetree/bindings/gpio/gpio_i2c.txt
> > new file mode 100644
> > index 0000000..27e1b1a
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/gpio/gpio_i2c.txt
> > @@ -0,0 +1,32 @@
> > +Device-Tree bindings for i2c gpio driver
> > +
> > +Required properties:
> > +	- compatible = "i2c-gpio";
> > +	- gpios: sda and scl gpio
> > +
> > +
> > +Optional properties:
> > +	- i2c-gpio,sda-open-drain: sda as open drain
> > +	- i2c-gpio,scl-open-drain: scl as open drain
> > +	- i2c-gpio,scl-output-only: scl as output only
> > +	- udelay: delay between GPIO operations (may depend on each platform)
> 
> i2c-gpio,delay-us
> 
> > +	- i2c-algo-bit,timeout-milliseconds: timeout to get data
> 
> i2c-gpio,timeout-ms
it's algo-bit speficic no i2c-gpio that's why I use i2c-algo-bit
> 
> > +
> > +Example nodes:
> > +
> > +i2c-gpio@0 {
> 
> Should be "i2c@0"
ok
> 
> > +	compatible = "i2c-gpio";
> > +	gpios = <&pioA 23 0 /* sda */
> > +		 &pioA 24 0 /* scl */
> > +		>;
> > +	i2c-gpio,sda-open-drain;
> > +	i2c-gpio,scl-open-drain;
> > +	udelay = <2>;		/* ~100 kHz */
> > +	#address-cells = <1>;
> > +	#size-cells = <0>;
> > +
> > +	rv3029c2@56 {
> > +		compatible = "rv3029c2";
> > +		reg = <0x56>;
> > +	};
> > +};
> > diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
> > index a651779..71adba5 100644
> > --- a/drivers/i2c/busses/i2c-gpio.c
> > +++ b/drivers/i2c/busses/i2c-gpio.c
> > @@ -14,8 +14,15 @@
> >  #include <linux/module.h>
> >  #include <linux/slab.h>
> >  #include <linux/platform_device.h>
> > +#include <linux/gpio.h>
> > +#include <linux/of_gpio.h>
> > +#include <linux/of_i2c.h>
> >  
> > -#include <asm/gpio.h>
> > +struct i2c_gpio_private_data {
> > +	struct i2c_adapter adap;
> > +	struct i2c_algo_bit_data bit_data;
> > +	struct i2c_gpio_platform_data pdata;
> > +};
> >  
> >  /* Toggle SDA by changing the direction of the pin */
> >  static void i2c_gpio_setsda_dir(void *data, int state)
> > @@ -78,24 +85,63 @@ static int i2c_gpio_getscl(void *data)
> >  	return gpio_get_value(pdata->scl_pin);
> >  }
> >  
> > +static int __devinit of_i2c_gpio_probe(struct device_node *np,
> > +			     struct i2c_gpio_platform_data *pdata)
> > +{
> > +	u32 reg;
> > +
> > +	if (of_gpio_count(np) < 2)
> > +		return -ENODEV;
> > +
> > +	pdata->sda_pin = of_get_gpio(np, 0);
> > +	pdata->scl_pin = of_get_gpio(np, 1);
> > +
> > +	if (pdata->sda_pin < 0 || pdata->scl_pin < 0) {
> > +		pr_err("%s: invalid GPIO pins, sda=%d/scl=%d\n",
> > +		       np->full_name, pdata->sda_pin, pdata->scl_pin);
> > +		return -ENODEV;
> > +	}
> > +
> > +	if (of_property_read_u32(np, "udelay", &reg))
> > +		pdata->udelay = reg;
> 
> Why not of_property_read_u32(np, "udelay", &pdata->udelay)?
> 
> Also, reg may not be initialized here.
if udelay have any error we keep udelay as 0

Best Regards,
J.