Messages in this thread | | | Subject | Re: [PATCH] gpio: tegra: Implement gpio_get_direction callback | From | Stephen Warren <> | Date | Fri, 29 Apr 2016 10:17:23 -0600 |
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On 04/29/2016 06:31 AM, Laxman Dewangan wrote: > Implement gpio_get_direction() callback for Tegra GPIO. > The direction is only valid if the pin is configured as > GPIO. If pin is not configured in GPIO mode then this > function return error. > > This makes debugfs and initial reading of the state of > the lines more accurate.
> +static int tegra_gpio_get_direction(struct gpio_chip *chip, unsigned offset) > +{ > + struct tegra_gpio_info *tgi = gpiochip_get_data(chip); > + u32 pin_mask = BIT(GPIO_BIT(offset)); > + u32 cnf, oe; > + > + cnf = tegra_gpio_readl(tgi, GPIO_CNF(tgi, offset)); > + oe = tegra_gpio_readl(tgi, GPIO_OE(tgi, offset)); > + if (cnf & pin_mask) { > + if (oe & pin_mask) > + return GPIOF_DIR_OUT; > + > + return GPIOF_DIR_IN; > + } > + > + return -EINVAL; > +}
Conceptually looks fine, but I have similar comments to Jon; whenever there's an error condition, just fail immediately. That way you avoid the entire rest of the function being indented:
cnf = ... if (!(cnf ...) return -EINVAL; oe = ... return ...
The only indented code there is the error handling. At least to me, this makes the code a lot more readable since there are far fewer combinations of conditionals.
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