[PATCH 1/5 v3] i2c/gpio: add DT support

Jean-Christophe PLAGNIOL-VILLARD plagnioj at jcrosoft.com
Tue Mar 13 20:11:04 EST 2012


On 08:37 Tue 13 Mar     , Wolfram Sang wrote:
> On Thu, Mar 08, 2012 at 09:50:31AM +0100, Jean-Christophe PLAGNIOL-VILLARD wrote:
> > Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
> > Cc: Nicolas Ferre <nicolas.ferre at atmel.com>
> > Cc: linux-i2c at vger.kernel.org
> > Cc: devicetree-discuss at lists.ozlabs.org
> 
> Your patch description says "add DT support" but you are doing a bit more.
> This should at least be described here.
> 
> > ---
> > v3:
> > 
> > 	update i2c binding (Rob comments)
> > 
> > 	Jean can I have a ack to apply it?
> > 
> > Best Regards,
> > J.
> >  .../devicetree/bindings/gpio/gpio_i2c.txt          |   32 +++++++
> >  drivers/i2c/busses/i2c-gpio.c                      |   94 +++++++++++++++----
> >  2 files changed, 106 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..4f8ec94
> > --- /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";
> 
> I assume people at "devicetree-discuss" have taken care of that, yet I wonder
> that this breaks the "vendor,product" syntax I know of for compatible entries.
yes but there no vendor here
get ack from Grant and Rob
> 
> > +	- 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
> > +	- i2c-gpio,delay-us: delay between GPIO operations (may depend on each platform)
> > +	- i2c-gpio,timeout-ms: timeout to get data
> > +
> > +Example nodes:
> > +
> > +i2c at 0 {
> > +	compatible = "i2c-gpio";
> > +	gpios = <&pioA 23 0 /* sda */
> > +		 &pioA 24 0 /* scl */
> > +		>;
> > +	i2c-gpio,sda-open-drain;
> > +	i2c-gpio,scl-open-drain;
> > +	i2c-gpio,delay-us = <2>;	/* ~100 kHz */
> > +	#address-cells = <1>;
> > +	#size-cells = <0>;
> > +
> > +	rv3029c2 at 56 {
> > +		compatible = "rv3029c2";
> > +		reg = <0x56>;
> > +	};
> > +};
> > diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
> > index a651779..98ae85b 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 +85,62 @@ 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) {
> 
> gpio_is_valid()?
> 
> > +		pr_err("%s: invalid GPIO pins, sda=%d/scl=%d\n",
> > +		       np->full_name, pdata->sda_pin, pdata->scl_pin);
> > +		return -ENODEV;
> > +	}
> > +
> > +	of_property_read_u32(np, "i2c-gpio,delay-us", &pdata->udelay);
> > +
> > +	if (of_property_read_u32(np, "i2c-gpio,timeout-ms", &reg))
> > +		pdata->timeout = msecs_to_jiffies(reg);
> > +
> > +	pdata->sda_is_open_drain =
> > +		!!of_property_read_bool(np, "i2c-gpio,sda-open-drain");
> > +	pdata->scl_is_open_drain =
> > +		!!of_property_read_bool(np, "i2c-gpio,scl-open-drain");
> > +	pdata->scl_is_output_only =
> > +		!!of_property_read_bool(np, "i2c-gpio,scl-output-only");
> > +
> > +	return 0;
> > +}
> > +
> >  static int __devinit i2c_gpio_probe(struct platform_device *pdev)
> >  {
> > +	struct i2c_gpio_private_data *priv;
> >  	struct i2c_gpio_platform_data *pdata;
> >  	struct i2c_algo_bit_data *bit_data;
> >  	struct i2c_adapter *adap;
> >  	int ret;
> >  
> > -	pdata = pdev->dev.platform_data;
> > -	if (!pdata)
> > -		return -ENXIO;
> > +	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
> > +	if (!priv)
> > +		return -ENOMEM;
> > +	adap = &priv->adap;
> > +	bit_data = &priv->bit_data;
> > +	pdata = &priv->pdata;
> >  
> > -	ret = -ENOMEM;
> > -	adap = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
> > -	if (!adap)
> > -		goto err_alloc_adap;
> > -	bit_data = kzalloc(sizeof(struct i2c_algo_bit_data), GFP_KERNEL);
> > -	if (!bit_data)
> > -		goto err_alloc_bit_data;
> > +	if (pdev->dev.of_node) {
> > +		ret = of_i2c_gpio_probe(pdev->dev.of_node, pdata);
> > +		if (ret)
> > +			return ret;
> > +	} else {
> > +		if (!pdev->dev.platform_data)
> > +			return -ENXIO;
> > +		memcpy(pdata, pdev->dev.platform_data, sizeof(*pdata));
> > +	}
> >  
> >  	ret = gpio_request(pdata->sda_pin, "sda");
> >  	if (ret)
> > @@ -143,6 +188,7 @@ static int __devinit i2c_gpio_probe(struct platform_device *pdev)
> >  	adap->algo_data = bit_data;
> >  	adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
> >  	adap->dev.parent = &pdev->dev;
> > +	adap->dev.of_node = pdev->dev.of_node;
> >  
> >  	/*
> >  	 * If "dev->id" is negative we consider it as zero.
> > @@ -154,7 +200,9 @@ static int __devinit i2c_gpio_probe(struct platform_device *pdev)
> >  	if (ret)
> >  		goto err_add_bus;
> >  
> > -	platform_set_drvdata(pdev, adap);
> > +	of_i2c_register_devices(adap);
> > +
> > +	platform_set_drvdata(pdev, priv);
> >  
> >  	dev_info(&pdev->dev, "using pins %u (SDA) and %u (SCL%s)\n",
> >  		 pdata->sda_pin, pdata->scl_pin,
> > @@ -168,34 +216,40 @@ err_add_bus:
> >  err_request_scl:
> >  	gpio_free(pdata->sda_pin);
> >  err_request_sda:
> > -	kfree(bit_data);
> > -err_alloc_bit_data:
> > -	kfree(adap);
> > -err_alloc_adap:
> >  	return ret;
> >  }
> >  
> >  static int __devexit i2c_gpio_remove(struct platform_device *pdev)
> >  {
> > +	struct i2c_gpio_private_data *priv;
> >  	struct i2c_gpio_platform_data *pdata;
> >  	struct i2c_adapter *adap;
> >  
> > -	adap = platform_get_drvdata(pdev);
> > -	pdata = pdev->dev.platform_data;
> > +	priv = platform_get_drvdata(pdev);
> > +	adap = &priv->adap;
> > +	pdata = &priv->pdata;
> >  
> >  	i2c_del_adapter(adap);
> >  	gpio_free(pdata->scl_pin);
> >  	gpio_free(pdata->sda_pin);
> > -	kfree(adap->algo_data);
> > -	kfree(adap);
> >  
> >  	return 0;
> >  }
> >  
> > +#if defined(CONFIG_OF)
> > +static const struct of_device_id i2c_gpio_dt_ids[] = {
> > +	{ .compatible = "i2c-gpio", },
> > +	{ /* sentinel */ }
> > +};
> > +
> > +MODULE_DEVICE_TABLE(of, i2c_gpio_dt_ids);
> > +#endif
> > +
> >  static struct platform_driver i2c_gpio_driver = {
> >  	.driver		= {
> >  		.name	= "i2c-gpio",
> >  		.owner	= THIS_MODULE,
> > +		.of_match_table	= of_match_ptr(i2c_gpio_dt_ids),
> >  	},
> >  	.probe		= i2c_gpio_probe,
> >  	.remove		= __devexit_p(i2c_gpio_remove),
> 
> Otherwise looks good in general. What was your test scenario?
AT91 support on 3 different SoC

will update and send it via AT91  with your ack

Best Regards,
J.
> 
> Thanks,
> 
>    Wolfram
> 
> -- 
> Pengutronix e.K.                           | Wolfram Sang                |
> Industrial Linux Solutions                 | http://www.pengutronix.de/  |




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