OpenWrt – Rev 4
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From 683af4ebb91a1600df1946ac4769d916b8a1be65 Mon Sep 17 00:00:00 2001
From: John Crispin <blogic@openwrt.org>
Date: Sun, 27 Jul 2014 11:15:12 +0100
Subject: [PATCH 42/53] SPI: ralink: add Ralink SoC spi driver
Add the driver needed to make SPI work on Ralink SoC.
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Acked-by: John Crispin <blogic@openwrt.org>
---
drivers/spi/Kconfig | 6 +
drivers/spi/Makefile | 1 +
drivers/spi/spi-rt2880.c | 530 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 537 insertions(+)
create mode 100644 drivers/spi/spi-rt2880.c
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -563,6 +563,12 @@ config SPI_QUP
This driver can also be built as a module. If so, the module
will be called spi_qup.
+config SPI_RT2880
+ tristate "Ralink RT288x SPI Controller"
+ depends on RALINK
+ help
+ This selects a driver for the Ralink RT288x/RT305x SPI Controller.
+
config SPI_S3C24XX
tristate "Samsung S3C24XX series SPI"
depends on ARCH_S3C24XX
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -81,6 +81,7 @@ obj-$(CONFIG_SPI_QUP) += spi-qup.o
obj-$(CONFIG_SPI_ROCKCHIP) += spi-rockchip.o
obj-$(CONFIG_SPI_RB4XX) += spi-rb4xx.o
obj-$(CONFIG_SPI_RSPI) += spi-rspi.o
+obj-$(CONFIG_SPI_RT2880) += spi-rt2880.o
obj-$(CONFIG_SPI_S3C24XX) += spi-s3c24xx-hw.o
spi-s3c24xx-hw-y := spi-s3c24xx.o
spi-s3c24xx-hw-$(CONFIG_SPI_S3C24XX_FIQ) += spi-s3c24xx-fiq.o
--- /dev/null
+++ b/drivers/spi/spi-rt2880.c
@@ -0,0 +1,530 @@
+/*
+ * spi-rt2880.c -- Ralink RT288x/RT305x SPI controller driver
+ *
+ * Copyright (C) 2011 Sergiy <piratfm@gmail.com>
+ * Copyright (C) 2011-2013 Gabor Juhos <juhosg@openwrt.org>
+ *
+ * Some parts are based on spi-orion.c:
+ * Author: Shadi Ammouri <shadi@marvell.com>
+ * Copyright (C) 2007-2008 Marvell Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/reset.h>
+#include <linux/spi/spi.h>
+#include <linux/platform_device.h>
+#include <linux/gpio.h>
+
+#define DRIVER_NAME "spi-rt2880"
+
+#define RAMIPS_SPI_STAT 0x00
+#define RAMIPS_SPI_CFG 0x10
+#define RAMIPS_SPI_CTL 0x14
+#define RAMIPS_SPI_DATA 0x20
+#define RAMIPS_SPI_ADDR 0x24
+#define RAMIPS_SPI_BS 0x28
+#define RAMIPS_SPI_USER 0x2C
+#define RAMIPS_SPI_TXFIFO 0x30
+#define RAMIPS_SPI_RXFIFO 0x34
+#define RAMIPS_SPI_FIFO_STAT 0x38
+#define RAMIPS_SPI_MODE 0x3C
+#define RAMIPS_SPI_DEV_OFFSET 0x40
+#define RAMIPS_SPI_DMA 0x80
+#define RAMIPS_SPI_DMASTAT 0x84
+#define RAMIPS_SPI_ARBITER 0xF0
+
+/* SPISTAT register bit field */
+#define SPISTAT_BUSY BIT(0)
+
+/* SPICFG register bit field */
+#define SPICFG_ADDRMODE BIT(12)
+#define SPICFG_RXENVDIS BIT(11)
+#define SPICFG_RXCAP BIT(10)
+#define SPICFG_SPIENMODE BIT(9)
+#define SPICFG_MSBFIRST BIT(8)
+#define SPICFG_SPICLKPOL BIT(6)
+#define SPICFG_RXCLKEDGE_FALLING BIT(5)
+#define SPICFG_TXCLKEDGE_FALLING BIT(4)
+#define SPICFG_HIZSPI BIT(3)
+#define SPICFG_SPICLK_PRESCALE_MASK 0x7
+#define SPICFG_SPICLK_DIV2 0
+#define SPICFG_SPICLK_DIV4 1
+#define SPICFG_SPICLK_DIV8 2
+#define SPICFG_SPICLK_DIV16 3
+#define SPICFG_SPICLK_DIV32 4
+#define SPICFG_SPICLK_DIV64 5
+#define SPICFG_SPICLK_DIV128 6
+#define SPICFG_SPICLK_DISABLE 7
+
+/* SPICTL register bit field */
+#define SPICTL_START BIT(4)
+#define SPICTL_HIZSDO BIT(3)
+#define SPICTL_STARTWR BIT(2)
+#define SPICTL_STARTRD BIT(1)
+#define SPICTL_SPIENA BIT(0)
+
+/* SPIUSER register bit field */
+#define SPIUSER_USERMODE BIT(21)
+#define SPIUSER_INSTR_PHASE BIT(20)
+#define SPIUSER_ADDR_PHASE_MASK 0x7
+#define SPIUSER_ADDR_PHASE_OFFSET 17
+#define SPIUSER_MODE_PHASE BIT(16)
+#define SPIUSER_DUMMY_PHASE_MASK 0x3
+#define SPIUSER_DUMMY_PHASE_OFFSET 14
+#define SPIUSER_DATA_PHASE_MASK 0x3
+#define SPIUSER_DATA_PHASE_OFFSET 12
+#define SPIUSER_DATA_READ (BIT(0) << SPIUSER_DATA_PHASE_OFFSET)
+#define SPIUSER_DATA_WRITE (BIT(1) << SPIUSER_DATA_PHASE_OFFSET)
+#define SPIUSER_ADDR_TYPE_OFFSET 9
+#define SPIUSER_MODE_TYPE_OFFSET 6
+#define SPIUSER_DUMMY_TYPE_OFFSET 3
+#define SPIUSER_DATA_TYPE_OFFSET 0
+#define SPIUSER_TRANSFER_MASK 0x7
+#define SPIUSER_TRANSFER_SINGLE BIT(0)
+#define SPIUSER_TRANSFER_DUAL BIT(1)
+#define SPIUSER_TRANSFER_QUAD BIT(2)
+
+#define SPIUSER_TRANSFER_TYPE(type) ( \
+ (type << SPIUSER_ADDR_TYPE_OFFSET) | \
+ (type << SPIUSER_MODE_TYPE_OFFSET) | \
+ (type << SPIUSER_DUMMY_TYPE_OFFSET) | \
+ (type << SPIUSER_DATA_TYPE_OFFSET) \
+)
+
+/* SPIFIFOSTAT register bit field */
+#define SPIFIFOSTAT_TXEMPTY BIT(19)
+#define SPIFIFOSTAT_RXEMPTY BIT(18)
+#define SPIFIFOSTAT_TXFULL BIT(17)
+#define SPIFIFOSTAT_RXFULL BIT(16)
+#define SPIFIFOSTAT_FIFO_MASK 0xff
+#define SPIFIFOSTAT_TX_OFFSET 8
+#define SPIFIFOSTAT_RX_OFFSET 0
+
+#define SPI_FIFO_DEPTH 16
+
+/* SPIMODE register bit field */
+#define SPIMODE_MODE_OFFSET 24
+#define SPIMODE_DUMMY_OFFSET 0
+
+/* SPIARB register bit field */
+#define SPICTL_ARB_EN BIT(31)
+#define SPICTL_CSCTL1 BIT(16)
+#define SPI1_POR BIT(1)
+#define SPI0_POR BIT(0)
+
+#define RT2880_SPI_MODE_BITS (SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST | \
+ SPI_CS_HIGH)
+
+static atomic_t hw_reset_count = ATOMIC_INIT(0);
+
+struct rt2880_spi {
+ struct spi_master *master;
+ void __iomem *base;
+ u32 speed;
+ u16 wait_loops;
+ u16 mode;
+ struct clk *clk;
+};
+
+static inline struct rt2880_spi *spidev_to_rt2880_spi(struct spi_device *spi)
+{
+ return spi_master_get_devdata(spi->master);
+}
+
+static inline u32 rt2880_spi_read(struct rt2880_spi *rs, u32 reg)
+{
+ return ioread32(rs->base + reg);
+}
+
+static inline void rt2880_spi_write(struct rt2880_spi *rs, u32 reg,
+ const u32 val)
+{
+ iowrite32(val, rs->base + reg);
+}
+
+static inline void rt2880_spi_setbits(struct rt2880_spi *rs, u32 reg, u32 mask)
+{
+ void __iomem *addr = rs->base + reg;
+
+ iowrite32((ioread32(addr) | mask), addr);
+}
+
+static inline void rt2880_spi_clrbits(struct rt2880_spi *rs, u32 reg, u32 mask)
+{
+ void __iomem *addr = rs->base + reg;
+
+ iowrite32((ioread32(addr) & ~mask), addr);
+}
+
+static u32 rt2880_spi_baudrate_get(struct spi_device *spi, unsigned int speed)
+{
+ struct rt2880_spi *rs = spidev_to_rt2880_spi(spi);
+ u32 rate;
+ u32 prescale;
+
+ /*
+ * the supported rates are: 2, 4, 8, ... 128
+ * round up as we look for equal or less speed
+ */
+ rate = DIV_ROUND_UP(clk_get_rate(rs->clk), speed);
+ rate = roundup_pow_of_two(rate);
+
+ /* Convert the rate to SPI clock divisor value. */
+ prescale = ilog2(rate / 2);
+
+ /* some tolerance. double and add 100 */
+ rs->wait_loops = (8 * HZ * loops_per_jiffy) /
+ (clk_get_rate(rs->clk) / rate);
+ rs->wait_loops = (rs->wait_loops << 1) + 100;
+ rs->speed = speed;
+
+ dev_dbg(&spi->dev, "speed: %lu/%u, rate: %u, prescal: %u, loops: %hu\n",
+ clk_get_rate(rs->clk) / rate, speed, rate, prescale,
+ rs->wait_loops);
+
+ return prescale;
+}
+
+static u32 get_arbiter_offset(struct spi_master *master)
+{
+ u32 offset;
+
+ offset = RAMIPS_SPI_ARBITER;
+ if (master->bus_num == 1)
+ offset -= RAMIPS_SPI_DEV_OFFSET;
+
+ return offset;
+}
+
+static void rt2880_spi_set_cs(struct spi_device *spi, bool enable)
+{
+ struct rt2880_spi *rs = spidev_to_rt2880_spi(spi);
+
+ if (enable)
+ rt2880_spi_setbits(rs, RAMIPS_SPI_CTL, SPICTL_SPIENA);
+ else
+ rt2880_spi_clrbits(rs, RAMIPS_SPI_CTL, SPICTL_SPIENA);
+}
+
+static int rt2880_spi_wait_ready(struct rt2880_spi *rs, int len)
+{
+ int loop = rs->wait_loops * len;
+
+ while ((rt2880_spi_read(rs, RAMIPS_SPI_STAT) & SPISTAT_BUSY) && --loop)
+ cpu_relax();
+
+ if (loop)
+ return 0;
+
+ return -ETIMEDOUT;
+}
+
+static void rt2880_dump_reg(struct spi_master *master)
+{
+ struct rt2880_spi *rs = spi_master_get_devdata(master);
+
+ dev_dbg(&master->dev, "stat: %08x, cfg: %08x, ctl: %08x, " \
+ "data: %08x, arb: %08x\n",
+ rt2880_spi_read(rs, RAMIPS_SPI_STAT),
+ rt2880_spi_read(rs, RAMIPS_SPI_CFG),
+ rt2880_spi_read(rs, RAMIPS_SPI_CTL),
+ rt2880_spi_read(rs, RAMIPS_SPI_DATA),
+ rt2880_spi_read(rs, get_arbiter_offset(master)));
+}
+
+static int rt2880_spi_transfer_one(struct spi_master *master,
+ struct spi_device *spi, struct spi_transfer *xfer)
+{
+ struct rt2880_spi *rs = spi_master_get_devdata(master);
+ unsigned len;
+ const u8 *tx = xfer->tx_buf;
+ u8 *rx = xfer->rx_buf;
+ int err = 0;
+
+ /* change clock speed */
+ if (unlikely(rs->speed != xfer->speed_hz)) {
+ u32 reg;
+ reg = rt2880_spi_read(rs, RAMIPS_SPI_CFG);
+ reg &= ~SPICFG_SPICLK_PRESCALE_MASK;
+ reg |= rt2880_spi_baudrate_get(spi, xfer->speed_hz);
+ rt2880_spi_write(rs, RAMIPS_SPI_CFG, reg);
+ }
+
+ if (tx) {
+ len = xfer->len;
+ while (len-- > 0) {
+ rt2880_spi_write(rs, RAMIPS_SPI_DATA, *tx++);
+ rt2880_spi_setbits(rs, RAMIPS_SPI_CTL, SPICTL_STARTWR);
+ err = rt2880_spi_wait_ready(rs, 1);
+ if (err) {
+ dev_err(&spi->dev, "TX failed, err=%d\n", err);
+ goto out;
+ }
+ }
+ }
+
+ if (rx) {
+ len = xfer->len;
+ while (len-- > 0) {
+ rt2880_spi_setbits(rs, RAMIPS_SPI_CTL, SPICTL_STARTRD);
+ err = rt2880_spi_wait_ready(rs, 1);
+ if (err) {
+ dev_err(&spi->dev, "RX failed, err=%d\n", err);
+ goto out;
+ }
+ *rx++ = (u8) rt2880_spi_read(rs, RAMIPS_SPI_DATA);
+ }
+ }
+
+out:
+ return err;
+}
+
+/* copy from spi.c */
+static void spi_set_cs(struct spi_device *spi, bool enable)
+{
+ if (spi->mode & SPI_CS_HIGH)
+ enable = !enable;
+
+ if (spi->cs_gpio >= 0)
+ gpio_set_value(spi->cs_gpio, !enable);
+ else if (spi->master->set_cs)
+ spi->master->set_cs(spi, !enable);
+}
+
+static int rt2880_spi_setup(struct spi_device *spi)
+{
+ struct spi_master *master = spi->master;
+ struct rt2880_spi *rs = spi_master_get_devdata(master);
+ u32 reg, old_reg, arbit_off;
+
+ if ((spi->max_speed_hz > master->max_speed_hz) ||
+ (spi->max_speed_hz < master->min_speed_hz)) {
+ dev_err(&spi->dev, "invalide requested speed %d Hz\n",
+ spi->max_speed_hz);
+ return -EINVAL;
+ }
+
+ if (!(master->bits_per_word_mask &
+ BIT(spi->bits_per_word - 1))) {
+ dev_err(&spi->dev, "invalide bits_per_word %d\n",
+ spi->bits_per_word);
+ return -EINVAL;
+ }
+
+ /* the hardware seems can't work on mode0 force it to mode3 */
+ if ((spi->mode & (SPI_CPOL | SPI_CPHA)) == SPI_MODE_0) {
+ dev_warn(&spi->dev, "force spi mode3\n");
+ spi->mode |= SPI_MODE_3;
+ }
+
+ /* chip polarity */
+ arbit_off = get_arbiter_offset(master);
+ reg = old_reg = rt2880_spi_read(rs, arbit_off);
+ if (spi->mode & SPI_CS_HIGH) {
+ switch (master->bus_num) {
+ case 1:
+ reg |= SPI1_POR;
+ break;
+ default:
+ reg |= SPI0_POR;
+ break;
+ }
+ } else {
+ switch (master->bus_num) {
+ case 1:
+ reg &= ~SPI1_POR;
+ break;
+ default:
+ reg &= ~SPI0_POR;
+ break;
+ }
+ }
+
+ /* enable spi1 */
+ if (master->bus_num == 1)
+ reg |= SPICTL_ARB_EN;
+
+ if (reg != old_reg)
+ rt2880_spi_write(rs, arbit_off, reg);
+
+ /* deselected the spi device */
+ spi_set_cs(spi, false);
+
+ rt2880_dump_reg(master);
+
+ return 0;
+}
+
+static int rt2880_spi_prepare_message(struct spi_master *master,
+ struct spi_message *msg)
+{
+ struct rt2880_spi *rs = spi_master_get_devdata(master);
+ struct spi_device *spi = msg->spi;
+ u32 reg;
+
+ if ((rs->mode == spi->mode) && (rs->speed == spi->max_speed_hz))
+ return 0;
+
+#if 0
+ /* set spido to tri-state */
+ rt2880_spi_setbits(rs, RAMIPS_SPI_CTL, SPICTL_HIZSDO);
+#endif
+
+ reg = rt2880_spi_read(rs, RAMIPS_SPI_CFG);
+
+ reg &= ~(SPICFG_MSBFIRST | SPICFG_SPICLKPOL |
+ SPICFG_RXCLKEDGE_FALLING |
+ SPICFG_TXCLKEDGE_FALLING |
+ SPICFG_SPICLK_PRESCALE_MASK);
+
+ /* MSB */
+ if (!(spi->mode & SPI_LSB_FIRST))
+ reg |= SPICFG_MSBFIRST;
+
+ /* spi mode */
+ switch (spi->mode & (SPI_CPOL | SPI_CPHA)) {
+ case SPI_MODE_0:
+ reg |= SPICFG_TXCLKEDGE_FALLING;
+ break;
+ case SPI_MODE_1:
+ reg |= SPICFG_RXCLKEDGE_FALLING;
+ break;
+ case SPI_MODE_2:
+ reg |= SPICFG_SPICLKPOL | SPICFG_RXCLKEDGE_FALLING;
+ break;
+ case SPI_MODE_3:
+ reg |= SPICFG_SPICLKPOL | SPICFG_TXCLKEDGE_FALLING;
+ break;
+ }
+ rs->mode = spi->mode;
+
+#if 0
+ /* set spiclk and spiena to tri-state */
+ reg |= SPICFG_HIZSPI;
+#endif
+
+ /* clock divide */
+ reg |= rt2880_spi_baudrate_get(spi, spi->max_speed_hz);
+
+ rt2880_spi_write(rs, RAMIPS_SPI_CFG, reg);
+
+ return 0;
+}
+
+static int rt2880_spi_probe(struct platform_device *pdev)
+{
+ struct spi_master *master;
+ struct rt2880_spi *rs;
+ void __iomem *base;
+ struct resource *r;
+ struct clk *clk;
+ int ret;
+
+ r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ base = devm_ioremap_resource(&pdev->dev, r);
+ if (IS_ERR(base))
+ return PTR_ERR(base);
+
+ clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(clk)) {
+ dev_err(&pdev->dev, "unable to get SYS clock\n");
+ return PTR_ERR(clk);
+ }
+
+ ret = clk_prepare_enable(clk);
+ if (ret)
+ goto err_clk;
+
+ master = spi_alloc_master(&pdev->dev, sizeof(*rs));
+ if (master == NULL) {
+ dev_dbg(&pdev->dev, "master allocation failed\n");
+ ret = -ENOMEM;
+ goto err_clk;
+ }
+
+ master->dev.of_node = pdev->dev.of_node;
+ master->mode_bits = RT2880_SPI_MODE_BITS;
+ master->bits_per_word_mask = SPI_BPW_MASK(8);
+ master->min_speed_hz = clk_get_rate(clk) / 128;
+ master->max_speed_hz = clk_get_rate(clk) / 2;
+ master->flags = SPI_MASTER_HALF_DUPLEX;
+ master->setup = rt2880_spi_setup;
+ master->prepare_message = rt2880_spi_prepare_message;
+ master->set_cs = rt2880_spi_set_cs;
+ master->transfer_one = rt2880_spi_transfer_one,
+
+ dev_set_drvdata(&pdev->dev, master);
+
+ rs = spi_master_get_devdata(master);
+ rs->master = master;
+ rs->base = base;
+ rs->clk = clk;
+
+ if (atomic_inc_return(&hw_reset_count) == 1)
+ device_reset(&pdev->dev);
+
+ ret = devm_spi_register_master(&pdev->dev, master);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "devm_spi_register_master error.\n");
+ goto err_master;
+ }
+
+ return ret;
+
+err_master:
+ spi_master_put(master);
+ kfree(master);
+err_clk:
+ clk_disable_unprepare(clk);
+
+ return ret;
+}
+
+static int rt2880_spi_remove(struct platform_device *pdev)
+{
+ struct spi_master *master;
+ struct rt2880_spi *rs;
+
+ master = dev_get_drvdata(&pdev->dev);
+ rs = spi_master_get_devdata(master);
+
+ clk_disable_unprepare(rs->clk);
+ atomic_dec(&hw_reset_count);
+
+ return 0;
+}
+
+MODULE_ALIAS("platform:" DRIVER_NAME);
+
+static const struct of_device_id rt2880_spi_match[] = {
+ { .compatible = "ralink,rt2880-spi" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, rt2880_spi_match);
+
+static struct platform_driver rt2880_spi_driver = {
+ .driver = {
+ .name = DRIVER_NAME,
+ .owner = THIS_MODULE,
+ .of_match_table = rt2880_spi_match,
+ },
+ .probe = rt2880_spi_probe,
+ .remove = rt2880_spi_remove,
+};
+
+module_platform_driver(rt2880_spi_driver);
+
+MODULE_DESCRIPTION("Ralink SPI driver");
+MODULE_AUTHOR("Sergiy <piratfm@gmail.com>");
+MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
+MODULE_LICENSE("GPL");
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