On Thu, Feb 09, 2012 at 03:25:05AM +0100, Jean-Christophe PLAGNIOL-VILLARD wrote:
> Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@xxxxxxxxxxxx>
> Cc: Nicolas Ferre <nicolas.ferre@xxxxxxxxx>
> Cc: linux-i2c@xxxxxxxxxxxxxxx
> Cc: devicetree-discuss@xxxxxxxxxxxxxxxx
> ---
> v2:
>
> use devm
> update DT bindings to i2c-gpio and sda-open-drain...
> update against "of: introduce helper to manage boolean"
>
> Best Regards,
> 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..9710ed2
> --- /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)
> + - timeout: timeout to get data (ms)
> +
> +Example nodes:
> +
> +i2c-gpio@0 {
> + 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..d7032c1 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;
Hmm, there's no error print and unless updated recently I think the
driver core will not produce any warnings if ->probe returns an
-ENODEV. I would prefer to see this printing a warning as for the
case below if an GPIO fails to be found.
Maybe return -EINVAL as it is not a valid configuration.
> +
> + 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", ®))
> + pdata->udelay = reg;
This sounds like a "linux" specific property. I would think about
giving it a name like frequency, or ask Grant if we have a base set
of properties that a i2c controller should think about implementing.
> + if (of_property_read_u32(np, "timeout", ®))
> + 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");
I hate !!, why does of_property_read_bool() not return a bool? Also,
why can't I find of_property_read_bool() in include/linux/* ?
Also, does of_property_read_bool() consitently return a useful value if
the property does not exist, or is not readable? I am most concerned
with the behaviour if one of these properties has un-parsable contents.
> + 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));
I'd moan about the error return, but that's the original driver for you.
> + }
>
> ret = gpio_request(pdata->sda_pin, "sda");
> if (ret)
> @@ -143,6 +189,7 @@ 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;
Do we need to keep this around, surely we can get back to the of_node from
what we already have in adap->dev.parent?
>
> /*
> * If "dev->id" is negative we consider it as zero.
> @@ -154,7 +201,9 @@ 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 +217,40 @@ 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),
> --
> 1.7.7
>
> --
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