[PATCH v5] i2c-gpio: add devicetree support
Grant Likely
grant.likely at secretlab.ca
Wed Feb 16 16:49:56 EST 2011
On Mon, Feb 14, 2011 at 10:30:10AM +0800, Thomas Chou wrote:
> From: Albert Herranz <albert_herranz at yahoo.es>
>
> This patch adds devicetree support to i2c-gpio driver. The allocation
> of local data is integrated to a private structure, and use devm_*
> helper for easy cleanup.
>
> It is base on an earlier patch for gc-linux from
> Albert Herranz <albert_herranz at yahoo.es>.
>
> Signed-off-by: Thomas Chou <thomas at wytron.com.tw>
> CC: Albert Herranz <albert_herranz at yahoo.es>
> Acked-by: Haavard Skinnemoen <hskinnemoen at gmail.com>
One minor nitpick below, but I'd be fine with cleaning that up via a
followup patch. This one looks correct to me.
Acked-by: Grant Likely <grant.likely at secretlab.ca>
Ben, this one depends on a patch in my devicetree/next tree. How do
you want to handle it?
g.
> ---
> for v2.6.39
> v2 move of nodes probing to a hook, which will be optimized out
> when devicetree is not used.
> use linux/gpio.h.
> move binding doc to i2c/i2c-gpio.txt.
> v3 use speed-hz instead of udelay in dts binding.
> condition the devicetree probe.
> v4 simplify private allocation.
> v5 condition module device table export for of.
>
> Documentation/devicetree/bindings/i2c/i2c-gpio.txt | 40 +++++++
> drivers/i2c/busses/i2c-gpio.c | 113 ++++++++++++++++----
> 2 files changed, 133 insertions(+), 20 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/i2c/i2c-gpio.txt
>
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-gpio.txt b/Documentation/devicetree/bindings/i2c/i2c-gpio.txt
> new file mode 100644
> index 0000000..38ef4f2
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/i2c/i2c-gpio.txt
> @@ -0,0 +1,40 @@
> +GPIO-based I2C
> +
> +Required properties:
> +- compatible : should be "i2c-gpio".
> +- gpios : should specify GPIOs used for SDA and SCL lines, in that order.
> +Optional properties:
> +- sda-is-open-drain : present if SDA gpio is open-drain.
> +- scl-is-open-drain : present if SCL gpio is open-drain.
> +- scl-is-output-only : present if the output driver for SCL cannot be
> + turned off. this will prevent clock stretching from working.
> +- speed-hz : SCL frequency.
> +- timeout : clock stretching timeout in milliseconds.
> +
> +Example:
> +
> +gpio0: starlet-gpio at 0d8000c0 {
> + compatible = "nintendo,starlet-gpio";
> + reg = <0d8000c0 4>;
> + gpio-controller;
> + #gpio-cells = <2>;
> +};
> +
> +i2c-video {
> + #address-cells = <1>;
> + #size-cells = <0>;
> + compatible = "i2c-gpio";
> +
> + gpios = <&gpio0 10 0 /* SDA line */
> + &gpio0 11 0 /* SCL line */
> + >;
> + sda-is-open-drain;
> + scl-is-open-drain;
> + scl-is-output-only;
> + speed-hz = <250000>;
> +
> + audio-video-encoder {
> + compatible = "nintendo,wii-ave-rvl";
> + reg = <70>;
> + };
> +};
> diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
> index d9aa9a6..6cc5f15 100644
> --- a/drivers/i2c/busses/i2c-gpio.c
> +++ b/drivers/i2c/busses/i2c-gpio.c
> @@ -14,8 +14,14 @@
> #include <linux/module.h>
> #include <linux/slab.h>
> #include <linux/platform_device.h>
> +#include <linux/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 +84,80 @@ static int i2c_gpio_getscl(void *data)
> return gpio_get_value(pdata->scl_pin);
> }
>
> +#ifdef CONFIG_OF
> +#include <linux/of_gpio.h>
Instead of putting the include here, please add #ifdef CONFIG_OF
protection around the contents of linux/of_gpio.h itself. I fully
support that change so that includes can remain at the top where they
belong.
> +
> +/* Check if devicetree nodes exist and build platform data */
> +static int i2c_gpio_of_probe(struct platform_device *pdev,
> + struct i2c_gpio_platform_data *pdata)
> +{
> + struct device_node *np = pdev->dev.of_node;
> + const __be32 *prop;
> + int sda_pin, scl_pin;
> + int len;
> +
> + if (!np || of_gpio_count(np) < 2)
> + return -ENXIO;
> +
> + sda_pin = of_get_gpio_flags(np, 0, NULL);
> + scl_pin = of_get_gpio_flags(np, 1, NULL);
> + if (sda_pin < 0 || scl_pin < 0) {
> + pr_err("%s: invalid GPIO pins, sda=%d/scl=%d\n",
> + np->full_name, sda_pin, scl_pin);
> + return -ENXIO;
> + }
> +
> + pdata->sda_pin = sda_pin;
> + pdata->scl_pin = scl_pin;
> + prop = of_get_property(np, "sda-is-open-drain", NULL);
> + if (prop)
> + pdata->sda_is_open_drain = 1;
> + prop = of_get_property(np, "scl-is-open-drain", NULL);
> + if (prop)
> + pdata->scl_is_open_drain = 1;
> + prop = of_get_property(np, "scl-is-output-only", NULL);
> + if (prop)
> + pdata->scl_is_output_only = 1;
> + prop = of_get_property(np, "speed-hz", &len);
> + if (prop && len >= sizeof(__be32))
> + pdata->udelay = DIV_ROUND_UP(1000000, be32_to_cpup(prop) * 2);
> + prop = of_get_property(np, "timeout", &len);
> + if (prop && len >= sizeof(__be32))
> + pdata->timeout = msecs_to_jiffies(be32_to_cpup(prop));
> +
> + return 0;
> +}
> +#else
> +static int i2c_gpio_of_probe(struct platform_device *pdev,
> + struct i2c_gpio_platform_data *pdata)
> +{
> + return -ENXIO;
> +}
> +#endif
> +
> 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.platform_data) {
> + *pdata = *(struct i2c_gpio_platform_data *)
> + pdev->dev.platform_data;
> + } else {
> + ret = i2c_gpio_of_probe(pdev, pdata);
> + if (ret)
> + return ret;
> + }
>
> ret = gpio_request(pdata->sda_pin, "sda");
> if (ret)
> @@ -143,6 +205,7 @@ 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.
> @@ -154,13 +217,16 @@ static int __devinit i2c_gpio_probe(struct platform_device *pdev)
> if (ret)
> goto err_add_bus;
>
> - platform_set_drvdata(pdev, 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,
> pdata->scl_is_output_only
> ? ", no clock stretching" : "");
>
> + /* Now register all the child nodes */
> + of_i2c_register_devices(adap);
> +
> return 0;
>
> err_add_bus:
> @@ -168,34 +234,41 @@ 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;
> }
>
> +#ifdef CONFIG_OF
> +static const struct of_device_id i2c_gpio_match[] = {
> + { .compatible = "i2c-gpio", },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, i2c_gpio_match);
> +#else /* CONFIG_OF */
> +#define i2c_gpio_match NULL
> +#endif /* CONFIG_OF */
> +
> static struct platform_driver i2c_gpio_driver = {
> .driver = {
> .name = "i2c-gpio",
> .owner = THIS_MODULE,
> + .of_match_table = i2c_gpio_match,
> },
> .probe = i2c_gpio_probe,
> .remove = __devexit_p(i2c_gpio_remove),
> --
> 1.7.4
>
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