diff options
Diffstat (limited to 'drivers/gpio/gpiolib-of.c')
| -rw-r--r-- | drivers/gpio/gpiolib-of.c | 50 |
1 files changed, 48 insertions, 2 deletions
diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c index 089783b11e87..9985b748b14d 100644 --- a/drivers/gpio/gpiolib-of.c +++ b/drivers/gpio/gpiolib-of.c @@ -57,7 +57,8 @@ static struct gpio_desc *of_xlate_and_get_gpiod_flags(struct gpio_chip *chip, } static void of_gpio_flags_quirks(struct device_node *np, - enum of_gpio_flags *flags) + enum of_gpio_flags *flags, + int index) { /* * Some GPIO fixed regulator quirks. @@ -91,6 +92,51 @@ static void of_gpio_flags_quirks(struct device_node *np, pr_info("%s uses legacy open drain flag - update the DTS if you can\n", of_node_full_name(np)); } + + /* + * Legacy handling of SPI active high chip select. If we have a + * property named "cs-gpios" we need to inspect the child node + * to determine if the flags should have inverted semantics. + */ + if (IS_ENABLED(CONFIG_SPI_MASTER) && + of_property_read_bool(np, "cs-gpios")) { + struct device_node *child; + u32 cs; + int ret; + + for_each_child_of_node(np, child) { + ret = of_property_read_u32(child, "reg", &cs); + if (!ret) + continue; + if (cs == index) { + /* + * SPI children have active low chip selects + * by default. This can be specified negatively + * by just omitting "spi-cs-high" in the + * device node, or actively by tagging on + * GPIO_ACTIVE_LOW as flag in the device + * tree. If the line is simultaneously + * tagged as active low in the device tree + * and has the "spi-cs-high" set, we get a + * conflict and the "spi-cs-high" flag will + * take precedence. + */ + if (of_property_read_bool(np, "spi-cs-high")) { + if (*flags & OF_GPIO_ACTIVE_LOW) { + pr_warn("%s GPIO handle specifies active low - ignored\n", + of_node_full_name(np)); + *flags &= ~OF_GPIO_ACTIVE_LOW; + } + } else { + if (!(*flags & OF_GPIO_ACTIVE_LOW)) + pr_info("%s enforce active low on chipselect handle\n", + of_node_full_name(np)); + *flags |= OF_GPIO_ACTIVE_LOW; + } + break; + } + } + } } /** @@ -131,7 +177,7 @@ struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np, goto out; if (flags) - of_gpio_flags_quirks(np, flags); + of_gpio_flags_quirks(np, flags, index); pr_debug("%s: parsed '%s' property of node '%pOF[%d]' - status (%d)\n", __func__, propname, np, index, |