Re: [PATCH v2 2/2] NFC: Add ACPI support for NXP PN544

From: Uwe Kleine-König
Date: Thu Feb 12 2015 - 03:15:14 EST


Hello,

On Mon, Jan 26, 2015 at 01:13:37PM +0200, Robert Dolca wrote:
> + /* Get EN GPIO from ACPI */
> + gpiod_en = devm_gpiod_get_index(dev, PN544_GPIO_NAME_EN, 1);
Actually devm_gpiod_get_index takes 4 arguments. In your case you should
also pass GPIOD_OUT_LOW, then you can skip the gpiod_direction_output
part below.

> + if (IS_ERR(gpiod_en)) {
> + nfc_err(dev,
> + "Unable to get EN GPIO\n");
> + return -ENODEV;
> + }
> +
> + phy->gpio_en = desc_to_gpio(gpiod_en);
Why don't you save a reference to the gpiod instead? Mixing usage of raw
and gpiod might result in surprising results. For example

gpiod_direction_output(gpiod_en, 0);

might actually have the same result as

gpio_direction_output(gpio_en, 1);

if the matching gpio is marked as active low.

> +
> + /* Configuration EN GPIO */
> + ret = gpiod_direction_output(gpiod_en, 0);
> + if (ret) {
> + nfc_err(dev, "Fail EN pin direction\n");
> + return ret;
> + }
> +
> + /* Get FW GPIO from ACPI */
> + gpiod_fw = devm_gpiod_get_index(dev, PN544_GPIO_NAME_FW, 2);
> + if (IS_ERR(gpiod_fw)) {
> + nfc_err(dev,
> + "Unable to get FW GPIO\n");
> + return -ENODEV;
> + }
> +
> + phy->gpio_fw = desc_to_gpio(gpiod_fw);
> +
> + /* Configuration FW GPIO */
> + ret = gpiod_direction_output(gpiod_fw, 0);
> + if (ret) {
> + nfc_err(dev, "Fail FW pin direction\n");
> + return ret;
> + }
The same comments apply here.

> +
> + /* Get IRQ GPIO */
> + gpiod_irq = devm_gpiod_get_index(dev, PN544_GPIO_NAME_IRQ, 0);
> + if (IS_ERR(gpiod_irq)) {
> + nfc_err(dev,
> + "Unable to get IRQ GPIO\n");
> + return -ENODEV;
> + }
> +
> + phy->gpio_irq = desc_to_gpio(gpiod_irq);
> +
> + /* Configure IRQ GPIO */
> + ret = gpiod_direction_input(gpiod_irq);
> + if (ret) {
> + nfc_err(dev, "Fail IRQ pin direction\n");
> + return ret;
> + }
> +
> + /* Map the pin to an IRQ */
> + ret = gpiod_to_irq(gpiod_irq);
> + if (ret < 0) {
> + nfc_err(dev, "Fail pin IRQ mapping\n");
> + return ret;
> + }
and here.

Best regards
Uwe

--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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