@@ -19,6 +19,7 @@
#include <linux/kthread.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
+#include <linux/of_gpio.h>
#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/sched.h>
@@ -1467,6 +1468,27 @@ static const struct serial_rs485 sc16is7xx_rs485_supported = {
.delay_rts_after_send = 1, /* Not supported but keep returning -EINVAL */
};
+void sc16is7xx_setup_reset_pin(struct device *dev)
+{
+ struct device_node *np = dev->of_node;
+ int reset_gpio, err;
+
+ reset_gpio = of_get_named_gpio(np, "reset-gpios", 0);
+ if (!gpio_is_valid(reset_gpio))
+ return;
+
+ err = devm_gpio_request_one(dev, reset_gpio, GPIOF_OUT_INIT_LOW,
+ "sc16is7xx-reset");
+ if (err) {
+ dev_err(dev, "failed to request sc16is7xx-reset-gpios: %d\n", err);
+ return;
+ }
+
+ /* Deassert the reset pin */
+ gpio_set_value_cansleep(reset_gpio, 1);
+}
+EXPORT_SYMBOL_GPL(sc16is7xx_setup_reset_pin);
+
int sc16is7xx_probe(struct device *dev, const struct sc16is7xx_devtype *devtype,
struct regmap *regmaps[], int irq)
{
@@ -33,6 +33,8 @@ const char *sc16is7xx_regmap_name(u8 port_id);
unsigned int sc16is7xx_regmap_port_mask(unsigned int port_id);
+void sc16is7xx_setup_reset_pin(struct device *dev);
+
int sc16is7xx_probe(struct device *dev, const struct sc16is7xx_devtype *devtype,
struct regmap *regmaps[], int irq);
@@ -21,6 +21,8 @@ static int sc16is7xx_i2c_probe(struct i2c_client *i2c)
if (!devtype)
return dev_err_probe(&i2c->dev, -ENODEV, "Failed to match device\n");
+ sc16is7xx_setup_reset_pin(&i2c->dev);
+
memcpy(®cfg, &sc16is7xx_regcfg, sizeof(struct regmap_config));
for (i = 0; i < devtype->nr_uart; i++) {
@@ -38,6 +38,8 @@ static int sc16is7xx_spi_probe(struct spi_device *spi)
if (!devtype)
return dev_err_probe(&spi->dev, -ENODEV, "Failed to match device\n");
+ sc16is7xx_setup_reset_pin(&spi->dev);
+
memcpy(®cfg, &sc16is7xx_regcfg, sizeof(struct regmap_config));
for (i = 0; i < devtype->nr_uart; i++) {
Certain designs connect a gpio to the reset pin, and the reset pin needs to be setup correctly before accessing the chip. Here adding a function to handle the reset pin. This change has no impact if there is no reset_gpios defined in the device tree. Signed-off-by: Hui Wang <hui.wang@canonical.com> --- drivers/tty/serial/sc16is7xx.c | 22 ++++++++++++++++++++++ drivers/tty/serial/sc16is7xx.h | 2 ++ drivers/tty/serial/sc16is7xx_i2c.c | 2 ++ drivers/tty/serial/sc16is7xx_spi.c | 2 ++ 4 files changed, 28 insertions(+)