linux-imx

// SPDX-License-Identifier: GPL-2.0

//

// Driver for AT91 USART Controllers as SPI

//

// Copyright (C) 2018 Microchip Technology Inc.

//

// Author: Radu Pirea <radu.pirea@microchip.com>

​

#include <linux/clk.h>

#include <linux/delay.h>

#include <linux/interrupt.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/of_gpio.h>

#include <linux/pinctrl/consumer.h>

#include <linux/platform_device.h>

#include <linux/pm_runtime.h>

​

#include <linux/spi/spi.h>

​

#define US_CR           0x00

#define US_MR           0x04

#define US_IER          0x08

#define US_IDR          0x0C

#define US_CSR          0x14

#define US_RHR          0x18

#define US_THR          0x1C

#define US_BRGR         0x20

#define US_VERSION      0xFC

​

#define US_CR_RSTRX     BIT(2)

#define US_CR_RSTTX     BIT(3)

#define US_CR_RXEN      BIT(4)

#define US_CR_RXDIS     BIT(5)

#define US_CR_TXEN      BIT(6)

#define US_CR_TXDIS     BIT(7)

​

#define US_MR_SPI_MASTER    0x0E

#define US_MR_CHRL      GENMASK(7, 6)

#define US_MR_CPHA      BIT(8)

#define US_MR_CPOL      BIT(16)

#define US_MR_CLKO      BIT(18)

#define US_MR_WRDBT     BIT(20)

#define US_MR_LOOP      BIT(15)

​

#define US_IR_RXRDY     BIT(0)

#define US_IR_TXRDY     BIT(1)

#define US_IR_OVRE      BIT(5)

​

#define US_BRGR_SIZE        BIT(16)

​

#define US_MIN_CLK_DIV      0x06

#define US_MAX_CLK_DIV      BIT(16)

​

#define US_RESET        (US_CR_RSTRX | US_CR_RSTTX)

#define US_DISABLE      (US_CR_RXDIS | US_CR_TXDIS)

#define US_ENABLE       (US_CR_RXEN | US_CR_TXEN)

#define US_OVRE_RXRDY_IRQS  (US_IR_OVRE | US_IR_RXRDY)

​

#define US_INIT \

    (US_MR_SPI_MASTER | US_MR_CHRL | US_MR_CLKO | US_MR_WRDBT)

​

/* Register access macros */

#define at91_usart_spi_readl(port, reg) \

    readl_relaxed((port)->regs + US_##reg)

#define at91_usart_spi_writel(port, reg, value) \

    writel_relaxed((value), (port)->regs + US_##reg)

​

#define at91_usart_spi_readb(port, reg) \

    readb_relaxed((port)->regs + US_##reg)

#define at91_usart_spi_writeb(port, reg, value) \

    writeb_relaxed((value), (port)->regs + US_##reg)

​

struct at91_usart_spi {

    struct spi_transfer *current_transfer;

    void __iomem        *regs;

    struct device       *dev;

    struct clk      *clk;

​

    /*used in interrupt to protect data reading*/

    spinlock_t      lock;

​

    int         irq;

    unsigned int        current_tx_remaining_bytes;

    unsigned int        current_rx_remaining_bytes;

​

    u32         spi_clk;

    u32         status;

​

    bool            xfer_failed;

};

​