serial: pic32_uart: Add PIC32 UART driver

This adds UART and a serial console driver for Microchip PIC32 class
devices.

[ralf@linux-mips.org: Resolved merge conflict.]
Signed-off-by: NAndrei Pistirica <andrei.pistirica@microchip.com>
Signed-off-by: NJoshua Henderson <joshua.henderson@microchip.com>
Reviewed-by: NAlan Cox <alan@linux.intel.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linux-serial@vger.kernel.org
Cc: linux-api@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/12101/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

drivers/tty/serial/Kconfig

@@ -900,6 +900,27 @@ config SERIAL_SGI_L1_CONSOLE
 		controller serial port as your console (you want this!),
 		say Y.  Otherwise, say N.
 
+config SERIAL_PIC32
+	tristate "Microchip PIC32 serial support"
+	depends on MACH_PIC32
+	select SERIAL_CORE
+	help
+	  If you have a PIC32, this driver supports the serial ports.
+
+	  Say Y or M to use PIC32 serial ports, otherwise say N. Note that
+	  to use a serial port as a console, this must be included in kernel and
+	  not as a module.
+
+config SERIAL_PIC32_CONSOLE
+	bool "PIC32 serial console support"
+	depends on SERIAL_PIC32
+	select SERIAL_CORE_CONSOLE
+	help
+	  If you have a PIC32, this driver supports the putting a console on one
+	  of the serial ports.
+
+	  Say Y to use the PIC32 console, otherwise say N.
+
 config SERIAL_MPC52xx
 	tristate "Freescale MPC52xx/MPC512x family PSC serial support"
 	depends on PPC_MPC52xx || PPC_MPC512x

drivers/tty/serial/Makefile

@@ -91,6 +91,7 @@ obj-$(CONFIG_SERIAL_MEN_Z135)	+= men_z135_uart.o
 obj-$(CONFIG_SERIAL_SPRD) += sprd_serial.o
 obj-$(CONFIG_SERIAL_STM32)	+= stm32-usart.o
 obj-$(CONFIG_SERIAL_MVEBU_UART)	+= mvebu-uart.o
+obj-$(CONFIG_SERIAL_PIC32)	+= pic32_uart.o
 
 # GPIOLIB helpers for modem control lines
 obj-$(CONFIG_SERIAL_MCTRL_GPIO)	+= serial_mctrl_gpio.o

drivers/tty/serial/pic32_uart.h

+/*
+ * PIC32 Integrated Serial Driver.
+ *
+ * Copyright (C) 2015 Microchip Technology, Inc.
+ *
+ * Authors:
+ *   Sorin-Andrei Pistirica <andrei.pistirica@microchip.com>
+ *
+ * Licensed under GPLv2 or later.
+ */
+#ifndef __DT_PIC32_UART_H__
+#define __DT_PIC32_UART_H__
+
+#define PIC32_UART_DFLT_BRATE		(9600)
+#define PIC32_UART_TX_FIFO_DEPTH	(8)
+#define PIC32_UART_RX_FIFO_DEPTH	(8)
+
+#define PIC32_UART_MODE		0x00
+#define PIC32_UART_STA		0x10
+#define PIC32_UART_TX		0x20
+#define PIC32_UART_RX		0x30
+#define PIC32_UART_BRG		0x40
+
+struct pic32_console_opt {
+	int baud;
+	int parity;
+	int bits;
+	int flow;
+};
+
+/* struct pic32_sport - pic32 serial port descriptor
+ * @port: uart port descriptor
+ * @idx: port index
+ * @irq_fault: virtual fault interrupt number
+ * @irqflags_fault: flags related to fault irq
+ * @irq_fault_name: irq fault name
+ * @irq_rx: virtual rx interrupt number
+ * @irqflags_rx: flags related to rx irq
+ * @irq_rx_name: irq rx name
+ * @irq_tx: virtual tx interrupt number
+ * @irqflags_tx: : flags related to tx irq
+ * @irq_tx_name: irq tx name
+ * @cts_gpio: clear to send gpio
+ * @dev: device descriptor
+ **/
+struct pic32_sport {
+	struct uart_port port;
+	struct pic32_console_opt opt;
+	int idx;
+
+	int irq_fault;
+	int irqflags_fault;
+	const char *irq_fault_name;
+	int irq_rx;
+	int irqflags_rx;
+	const char *irq_rx_name;
+	int irq_tx;
+	int irqflags_tx;
+	const char *irq_tx_name;
+	u8 enable_tx_irq;
+
+	bool hw_flow_ctrl;
+	int cts_gpio;
+
+	int ref_clk;
+	struct clk *clk;
+
+	struct device *dev;
+};
+#define to_pic32_sport(c) container_of(c, struct pic32_sport, port)
+#define pic32_get_port(sport) (&sport->port)
+#define pic32_get_opt(sport) (&sport->opt)
+#define tx_irq_enabled(sport) (sport->enable_tx_irq)
+
+static inline void pic32_uart_writel(struct pic32_sport *sport,
+					u32 reg, u32 val)
+{
+	struct uart_port *port = pic32_get_port(sport);
+
+	__raw_writel(val, port->membase + reg);
+}
+
+static inline u32 pic32_uart_readl(struct pic32_sport *sport, u32 reg)
+{
+	struct uart_port *port = pic32_get_port(sport);
+
+	return	__raw_readl(port->membase + reg);
+}
+
+/* pic32 uart mode register bits */
+#define PIC32_UART_MODE_ON        BIT(15)
+#define PIC32_UART_MODE_FRZ       BIT(14)
+#define PIC32_UART_MODE_SIDL      BIT(13)
+#define PIC32_UART_MODE_IREN      BIT(12)
+#define PIC32_UART_MODE_RTSMD     BIT(11)
+#define PIC32_UART_MODE_RESV1     BIT(10)
+#define PIC32_UART_MODE_UEN1      BIT(9)
+#define PIC32_UART_MODE_UEN0      BIT(8)
+#define PIC32_UART_MODE_WAKE      BIT(7)
+#define PIC32_UART_MODE_LPBK      BIT(6)
+#define PIC32_UART_MODE_ABAUD     BIT(5)
+#define PIC32_UART_MODE_RXINV     BIT(4)
+#define PIC32_UART_MODE_BRGH      BIT(3)
+#define PIC32_UART_MODE_PDSEL1    BIT(2)
+#define PIC32_UART_MODE_PDSEL0    BIT(1)
+#define PIC32_UART_MODE_STSEL     BIT(0)
+
+/* pic32 uart status register bits */
+#define PIC32_UART_STA_UTXISEL1   BIT(15)
+#define PIC32_UART_STA_UTXISEL0   BIT(14)
+#define PIC32_UART_STA_UTXINV     BIT(13)
+#define PIC32_UART_STA_URXEN      BIT(12)
+#define PIC32_UART_STA_UTXBRK     BIT(11)
+#define PIC32_UART_STA_UTXEN      BIT(10)
+#define PIC32_UART_STA_UTXBF      BIT(9)
+#define PIC32_UART_STA_TRMT       BIT(8)
+#define PIC32_UART_STA_URXISEL1   BIT(7)
+#define PIC32_UART_STA_URXISEL0   BIT(6)
+#define PIC32_UART_STA_ADDEN      BIT(5)
+#define PIC32_UART_STA_RIDLE      BIT(4)
+#define PIC32_UART_STA_PERR       BIT(3)
+#define PIC32_UART_STA_FERR       BIT(2)
+#define PIC32_UART_STA_OERR       BIT(1)
+#define PIC32_UART_STA_URXDA      BIT(0)
+
+#endif /* __DT_PIC32_UART_H__ */

include/uapi/linux/serial_core.h

@@ -264,4 +264,7 @@
 /* MVEBU UART */
 #define PORT_MVEBU	114
 
+/* Microchip PIC32 UART */
+#define PORT_PIC32	114
+
 #endif /* _UAPILINUX_SERIAL_CORE_H */