Issue
I've written an I2C driver. I want to make the GPIO which it uses configurable from the device tree.
My device tree entry is currently:
&i2c1 {
clock-frequency = <100000>;
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_i2c1>;
status = "okay";
...
myi2c: [email protected] {
compatible = "fsl,myi2c";
reg = <0x43>;
};
I'd like to add this line into the myi2c stanza:
myi2c-gpios = <&gpio4 29 GPIO_ACTIVE_HIGH>;
I can see how to do this, if I was writing a platform driver:
static int gpio_init_probe(struct platform_device *pdev)
{
int i = 0;
printk("GPIO example init\n");
/* "greenled" label is matching the device tree declaration. OUT_LOW is the value at init */
green = devm_gpiod_get(&pdev->dev, "greenled", GPIOD_OUT_LOW);
but in my driver's i2c_probe()
, I have no access to a struct platform_device *
:
static int myi2c_i2c_probe(struct i2c_client *i2c, const struct i2c_device_id *id)
How can I read the value of myi2c-gpios
from the device tree and use it in my i2c driver?
Solution
I found this driver to use as an example:
static int sn65dsi84_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
...
struct gpio_desc *enable_gpio;
enable_gpio = devm_gpiod_get_optional(&client->dev, "enable", GPIOD_OUT_HIGH);
if (enable_gpio)
gpiod_set_value_cansleep(enable_gpio, 1);
and its device tree is:
&i2c2 {
clock-frequency = <100000>;
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_i2c2>;
status = "okay";
dsi_lvds_bridge: [email protected] {
status = "disabled";
reg = <0x2c>;
compatible = "ti,sn65dsi84";
enable-gpios = <&gpio4 28 GPIO_ACTIVE_HIGH>;
So devm_gpiod_get_optional()
seems to be the answer.
Answered By - fadedbee Answer Checked By - Mildred Charles (WPSolving Admin)