path: root/drivers/usb/gadget/udc/max3420_udc.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * MAX3420 Device Controller driver for USB.
 *
 * Author: Jaswinder Singh Brar <jaswinder.singh@linaro.org>
 * (C) Copyright 2019-2020 Linaro Ltd
 *
 * Based on:
 *	o MAX3420E datasheet
 *		https://datasheets.maximintegrated.com/en/ds/MAX3420E.pdf
 *	o MAX342{0,1}E Programming Guides
 *		https://pdfserv.maximintegrated.com/en/an/AN3598.pdf
 *		https://pdfserv.maximintegrated.com/en/an/AN3785.pdf
 */

#include <linux/delay.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/bitfield.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/prefetch.h>
#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>
#include <linux/spi/spi.h>
#include <linux/gpio/consumer.h>

#define MAX3420_MAX_EPS		4
#define MAX3420_EP_MAX_PACKET		64  /* Same for all Endpoints */
#define MAX3420_EPNAME_SIZE		16  /* Buffer size for endpoint name */

#define MAX3420_ACKSTAT		BIT(0)

#define MAX3420_SPI_DIR_RD	0	/* read register from MAX3420 */
#define MAX3420_SPI_DIR_WR	1	/* write register to MAX3420 */

/* SPI commands: */
#define MAX3420_SPI_DIR_SHIFT	1
#define MAX3420_SPI_REG_SHIFT	3

#define MAX3420_REG_EP0FIFO	0
#define MAX3420_REG_EP1FIFO	1
#define MAX3420_REG_EP2FIFO	2
#define MAX3420_REG_EP3FIFO	3
#define MAX3420_REG_SUDFIFO	4
#define MAX3420_REG_EP0BC	5
#define MAX3420_REG_EP1BC	6
#define MAX3420_REG_EP2BC	7
#define MAX3420_REG_EP3BC	8

#define MAX3420_REG_EPSTALLS	9
	#define ACKSTAT		BIT(6)
	#define STLSTAT		BIT(5)
	#define STLEP3IN	BIT(4)
	#define STLEP2IN	BIT(3)
	#define STLEP1OUT	BIT(2)
	#define STLEP0OUT	BIT(1)
	#define STLEP0IN	BIT(0)

#define MAX3420_REG_CLRTOGS	10
	#define EP3DISAB	BIT(7)
	#define EP2DISAB	BIT(6)
	#define EP1DISAB	BIT(5)
	#define CTGEP3IN	BIT(4)
	#define CTGEP2IN	BIT(3)
	#define CTGEP1OUT	BIT(2)

#define MAX3420_REG_EPIRQ	11
#define MAX3420_REG_EPIEN	12
	#define SUDAVIRQ	BIT(5)
	#define IN3BAVIRQ	BIT(4)
	#define IN2BAVIRQ	BIT(3)
	#define OUT1DAVIRQ	BIT(2)
	#define OUT0DAVIRQ	BIT(1)
	#define IN0BAVIRQ	BIT(0)

#define MAX3420_REG_USBIRQ	13
#define MAX3420_REG_USBIEN	14
	#define OSCOKIRQ	BIT(0)
	#define RWUDNIRQ	BIT(1)
	#define BUSACTIRQ	BIT(2)
	#define URESIRQ		BIT(3)
	#define SUSPIRQ		BIT(4)
	#define NOVBUSIRQ	BIT(5)
	#define VBUSIRQ		BIT(6)
	#define URESDNIRQ	BIT(7)

#define MAX3420_REG_USBCTL	15
	#define HOSCSTEN	BIT(7)
	#define VBGATE		BIT(6)
	#define CHIPRES		BIT(5)
	#define PWRDOWN		BIT(4)
	#define CONNECT		BIT(3)
	#define SIGRWU		BIT(2)

#define MAX3420_REG_CPUCTL	16
	#define IE		BIT(0)

#define MAX3420_REG_PINCTL	17
	#define EP3INAK		BIT(7)
	#define EP2INAK		BIT(6)
	#define EP0INAK		BIT(5)
	#define FDUPSPI		BIT(4)
	#define INTLEVEL	BIT(3)
	#define POSINT		BIT(2)
	#define GPXB		BIT(1)
	#define GPXA		BIT(0)

#define MAX3420_REG_REVISION	18

#define MAX3420_REG_FNADDR	19
	#define FNADDR_MASK	0x7f

#define MAX3420_REG_IOPINS	20
#define MAX3420_REG_IOPINS2	21
#define MAX3420_REG_GPINIRQ	22
#define MAX3420_REG_GPINIEN	23
#define MAX3420_REG_GPINPOL	24
#define MAX3420_REG_HIRQ	25
#define MAX3420_REG_HIEN	26
#define MAX3420_REG_MODE	27
#define MAX3420_REG_PERADDR	28
#define MAX3420_REG_HCTL	29
#define MAX3420_REG_HXFR	30
#define MAX3420_REG_HRSL	31

#define ENABLE_IRQ	BIT(0)
#define IOPIN_UPDATE	BIT(1)
#define REMOTE_WAKEUP	BIT(2)
#define CONNECT_HOST	GENMASK(4, 3)
#define	HCONNECT	(1 << 3)
#define	HDISCONNECT	(3 << 3)
#define UDC_START	GENMASK(6, 5)
#define	START		(1 << 5)
#define	STOP		(3 << 5)
#define ENABLE_EP	GENMASK(8, 7)
#define	ENABLE		(1 << 7)
#define	DISABLE		(3 << 7)
#define STALL_EP	GENMASK(10, 9)
#define	STALL		(1 << 9)
#define	UNSTALL		(3 << 9)

#define MAX3420_CMD(c)		FIELD_PREP(GENMASK(7, 3), c)
#define MAX3420_SPI_CMD_RD(c)	(MAX3420_CMD(c) | (0 << 1))
#define MAX3420_SPI_CMD_WR(c)	(MAX3420_CMD(c) | (1 << 1))

struct max3420_req {
	struct usb_request usb_req;
	struct list_head queue;
	struct max3420_ep *ep;
};

struct max3420_ep {
	struct usb_ep ep_usb;
	struct max3420_udc *udc;
	struct list_head queue;
	char name[MAX3420_EPNAME_SIZE];
	unsigned int maxpacket;
	spinlock_t lock;
	int halted;
	u32 todo;
	int id;
};

struct max3420_udc {
	struct usb_gadget gadget;
	struct max3420_ep ep[MAX3420_MAX_EPS];
	struct usb_gadget_driver *driver;
	struct task_struct *thread_task;
	int remote_wkp, is_selfpowered;
	bool vbus_active, softconnect;
	struct usb_ctrlrequest setup