diff options
Diffstat (limited to 'drivers/tty/serial/serial_port.c')
| -rw-r--r-- | drivers/tty/serial/serial_port.c | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/drivers/tty/serial/serial_port.c b/drivers/tty/serial/serial_port.c index 72b6f4f326e2..22b9eeb23e68 100644 --- a/drivers/tty/serial/serial_port.c +++ b/drivers/tty/serial/serial_port.c @@ -8,7 +8,10 @@ #include <linux/device.h> #include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> #include <linux/pm_runtime.h> +#include <linux/property.h> #include <linux/serial_core.h> #include <linux/spinlock.h> @@ -105,6 +108,148 @@ void uart_remove_one_port(struct uart_driver *drv, struct uart_port *port) } EXPORT_SYMBOL(uart_remove_one_port); +/** + * __uart_read_properties - read firmware properties of the given UART port + * @port: corresponding port + * @use_defaults: apply defaults (when %true) or validate the values (when %false) + * + * The following device properties are supported: + * - clock-frequency (optional) + * - fifo-size (optional) + * - no-loopback-test (optional) + * - reg-shift (defaults may apply) + * - reg-offset (value may be validated) + * - reg-io-width (defaults may apply or value may be validated) + * - interrupts (OF only) + * - serial [alias ID] (OF only) + * + * If the port->dev is of struct platform_device type the interrupt line + * will be retrieved via platform_get_irq() call against that device. + * Otherwise it will be assigned by fwnode_irq_get() call. In both cases + * the index 0 of the resource is used. + * + * The caller is responsible to initialize the following fields of the @port + * ->dev (must be valid) + * ->flags + * ->mapbase + * ->mapsize + * ->regshift (if @use_defaults is false) + * before calling this function. Alternatively the above mentioned fields + * may be zeroed, in such case the only ones, that have associated properties + * found, will be set to the respective values. + * + * If no error happened, the ->irq, ->mapbase, ->mapsize will be altered. + * The ->iotype is always altered. + * + * When @use_defaults is true and the respective property is not found + * the following values will be applied: + * ->regshift = 0 + * In this case IRQ must be provided, otherwise an error will be returned. + * + * When @use_defaults is false and the respective property is found + * the following values will be validated: + * - reg-io-width (->iotype) + * - reg-offset (->mapsize against ->mapbase) + * + * Returns: 0 on success or negative errno on failure + */ +static int __uart_read_properties(struct uart_port *port, bool use_defaults) +{ + struct device *dev = port->dev; + u32 value; + int ret; + + /* Read optional UART functional clock frequency */ + device_property_read_u32(dev, "clock-frequency", &port->uartclk); + + /* Read the registers alignment (default: 8-bit) */ + ret = device_property_read_u32(dev, "reg-shift", &value); + if (ret) + port->regshift = use_defaults ? 0 : port->regshift; + else + port->regshift = value; + + /* Read the registers I/O access type (default: MMIO 8-bit) */ + ret = device_property_read_u32(dev, "reg-io-width", &value); + if (ret) { + port->iotype = UPIO_MEM; + } else { + switch (value) { + case 1: + port->iotype = UPIO_MEM; + break; + case 2: + port->iotype = UPIO_MEM16; + break; + case 4: + port->iotype = device_is_big_endian(dev) ? UPIO_MEM32BE : UPIO_MEM32; + break; + default: + if (!use_defaults) { + dev_err(dev, "Unsupported reg-io-width (%u)\n", value); + return -EINVAL; + } + port->iotype = UPIO_UNKNOWN; + break; + } + } + + /* Read the address mapping base offset (default: no offset) */ + ret = device_property_read_u32(dev, "reg-offset", &value); + if (ret) + value = 0; + + /* Check for shifted address mapping overflow */ + if (!use_defaults && port->mapsize < value) { + dev_err(dev, "reg-offset %u exceeds region size %pa\n", value, &port->mapsize); + return -EINVAL; + } + + port->mapbase += value; + port->mapsize -= value; + + /* Read optional FIFO size */ + device_property_read_u32(dev, "fifo-size", &port->fifosize); + + if (device_property_read_bool(dev, "no-loopback-test")) + port->flags |= UPF_SKIP_TEST; + + /* Get index of serial line, if found in DT aliases */ + ret = of_alias_get_id(dev_of_node(dev), "serial"); + if (ret >= 0) + port->line = ret; + + if (dev_is_platform(dev)) + ret = platform_get_irq(to_platform_device(dev), 0); + else + ret = fwnode_irq_get(dev_fwnode(dev), 0); + if (ret == -EPROBE_DEFER) + return ret; + if (ret > 0) + port->irq = ret; + else if (use_defaults) + /* By default IRQ support is mandatory */ + return ret; + else + port->irq = 0; + + port->flags |= UPF_SHARE_IRQ; + + return 0; +} + +int uart_read_port_properties(struct uart_port *port) +{ + return __uart_read_properties(port, true); +} +EXPORT_SYMBOL_GPL(uart_read_port_properties); + +int uart_read_and_validate_port_properties(struct uart_port *port) +{ + return __uart_read_properties(port, false); +} +EXPORT_SYMBOL_GPL(uart_read_and_validate_port_properties); + static struct device_driver serial_port_driver = { .name = "port", .suppress_bind_attrs = true, |