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openwrt/target/linux/ramips/patches-3.10/0019-SPI-ralink-add-Ralink-...

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From 43c36279a0e822de608c1e825826bbac3238d8a2 Mon Sep 17 00:00:00 2001
From: Gabor Juhos <juhosg@openwrt.org>
Date: Mon, 22 Apr 2013 23:16:18 +0200
Subject: [PATCH 19/25] 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 | 450 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 457 insertions(+)
create mode 100644 drivers/spi/spi-rt2880.c
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -354,6 +354,12 @@ config SPI_RSPI
help
SPI driver for Renesas RSPI blocks.
+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
@@ -56,6 +56,7 @@ spi-pxa2xx-platform-$(CONFIG_SPI_PXA2XX_
obj-$(CONFIG_SPI_PXA2XX) += spi-pxa2xx-platform.o
obj-$(CONFIG_SPI_PXA2XX_PCI) += spi-pxa2xx-pci.o
obj-$(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 +1,432 @@
+/*
+ * 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>
+
+#define DRIVER_NAME "spi-rt2880"
+/* only one slave is supported*/
+#define RALINK_NUM_CHIPSELECTS 1
+/* in usec */
+#define RALINK_SPI_WAIT_MAX_LOOP 2000
+
+#define RAMIPS_SPI_STAT 0x00
+#define RAMIPS_SPI_CFG 0x10
+#define RAMIPS_SPI_CTL 0x14
+#define RAMIPS_SPI_DATA 0x20
+#define RAMIPS_SPI_FIFO_STAT 0x38
+
+/* SPISTAT register bit field */
+#define SPISTAT_BUSY BIT(0)
+
+/* SPICFG register bit field */
+#define SPICFG_LSBFIRST 0
+#define SPICFG_MSBFIRST BIT(8)
+#define SPICFG_SPICLKPOL BIT(6)
+#define SPICFG_RXCLKEDGE_FALLING BIT(5)
+#define SPICFG_TXCLKEDGE_FALLING BIT(4)
+#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_HIZSDO BIT(3)
+#define SPICTL_STARTWR BIT(2)
+#define SPICTL_STARTRD BIT(1)
+#define SPICTL_SPIENA BIT(0)
+
+/* SPIFIFOSTAT register bit field */
+#define SPIFIFOSTAT_TXFULL BIT(17)
+
+struct rt2880_spi {
+ struct spi_master *master;
+ void __iomem *base;
+ unsigned int sys_freq;
+ unsigned int speed;
+ struct clk *clk;
+ spinlock_t lock;
+};
+
+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, 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;
+ unsigned long flags;
+ u32 val;
+
+ spin_lock_irqsave(&rs->lock, flags);
+ val = ioread32(addr);
+ val |= mask;
+ iowrite32(val, addr);
+ spin_unlock_irqrestore(&rs->lock, flags);
+}
+
+static inline void rt2880_spi_clrbits(struct rt2880_spi *rs, u32 reg, u32 mask)
+{
+ void __iomem *addr = rs->base + reg;
+ unsigned long flags;
+ u32 val;
+
+ spin_lock_irqsave(&rs->lock, flags);
+ val = ioread32(addr);
+ val &= ~mask;
+ iowrite32(val, addr);
+ spin_unlock_irqrestore(&rs->lock, flags);
+}
+
+static int rt2880_spi_baudrate_set(struct spi_device *spi, unsigned int speed)
+{
+ struct rt2880_spi *rs = spidev_to_rt2880_spi(spi);
+ u32 rate;
+ u32 prescale;
+ u32 reg;
+
+ dev_dbg(&spi->dev, "speed:%u\n", speed);
+
+ /*
+ * the supported rates are: 2, 4, 8, ... 128
+ * round up as we look for equal or less speed
+ */
+ rate = DIV_ROUND_UP(rs->sys_freq, speed);
+ dev_dbg(&spi->dev, "rate-1:%u\n", rate);
+ rate = roundup_pow_of_two(rate);
+ dev_dbg(&spi->dev, "rate-2:%u\n", rate);
+
+ /* check if requested speed is too small */
+ if (rate > 128)
+ return -EINVAL;
+
+ if (rate < 2)
+ rate = 2;
+
+ /* Convert the rate to SPI clock divisor value. */
+ prescale = ilog2(rate / 2);
+ dev_dbg(&spi->dev, "prescale:%u\n", prescale);
+
+ reg = rt2880_spi_read(rs, RAMIPS_SPI_CFG);
+ reg = ((reg & ~SPICFG_SPICLK_PRESCALE_MASK) | prescale);
+ rt2880_spi_write(rs, RAMIPS_SPI_CFG, reg);
+ rs->speed = speed;
+ return 0;
+}
+
+/*
+ * called only when no transfer is active on the bus
+ */
+static int
+rt2880_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
+{
+ struct rt2880_spi *rs = spidev_to_rt2880_spi(spi);
+ unsigned int speed = spi->max_speed_hz;
+ int rc;
+
+ if ((t != NULL) && t->speed_hz)
+ speed = t->speed_hz;
+
+ if (rs->speed != speed) {
+ dev_dbg(&spi->dev, "speed_hz:%u\n", speed);
+ rc = rt2880_spi_baudrate_set(spi, speed);
+ if (rc)
+ return rc;
+ }
+
+ return 0;
+}
+
+static void rt2880_spi_set_cs(struct rt2880_spi *rs, int enable)
+{
+ if (enable)
+ rt2880_spi_clrbits(rs, RAMIPS_SPI_CTL, SPICTL_SPIENA);
+ else
+ rt2880_spi_setbits(rs, RAMIPS_SPI_CTL, SPICTL_SPIENA);
+}
+
+static inline int rt2880_spi_wait_till_ready(struct rt2880_spi *rs)
+{
+ int i;
+
+ for (i = 0; i < RALINK_SPI_WAIT_MAX_LOOP; i++) {
+ u32 status;
+
+ status = rt2880_spi_read(rs, RAMIPS_SPI_STAT);
+ if ((status & SPISTAT_BUSY) == 0)
+ return 0;
+
+ cpu_relax();
+ udelay(1);
+ }
+
+ return -ETIMEDOUT;
+}
+
+static unsigned int
+rt2880_spi_write_read(struct spi_device *spi, struct spi_transfer *xfer)
+{
+ struct rt2880_spi *rs = spidev_to_rt2880_spi(spi);
+ unsigned count = 0;
+ u8 *rx = xfer->rx_buf;
+ const u8 *tx = xfer->tx_buf;
+ int err;
+
+ dev_dbg(&spi->dev, "read (%d): %s %s\n", xfer->len,
+ (tx != NULL) ? "tx" : " ",
+ (rx != NULL) ? "rx" : " ");
+
+ if (tx) {
+ for (count = 0; count < xfer->len; count++) {
+ rt2880_spi_write(rs, RAMIPS_SPI_DATA, tx[count]);
+ rt2880_spi_setbits(rs, RAMIPS_SPI_CTL, SPICTL_STARTWR);
+ err = rt2880_spi_wait_till_ready(rs);
+ if (err) {
+ dev_err(&spi->dev, "TX failed, err=%d\n", err);
+ goto out;
+ }
+ }
+ }
+
+ if (rx) {
+ for (count = 0; count < xfer->len; count++) {
+ rt2880_spi_setbits(rs, RAMIPS_SPI_CTL, SPICTL_STARTRD);
+ err = rt2880_spi_wait_till_ready(rs);
+ if (err) {
+ dev_err(&spi->dev, "RX failed, err=%d\n", err);
+ goto out;
+ }
+ rx[count] = (u8) rt2880_spi_read(rs, RAMIPS_SPI_DATA);
+ }
+ }
+
+out:
+ return count;
+}
+
+static int rt2880_spi_transfer_one_message(struct spi_master *master,
+ struct spi_message *m)
+{
+ struct rt2880_spi *rs = spi_master_get_devdata(master);
+ struct spi_device *spi = m->spi;
+ struct spi_transfer *t = NULL;
+ int par_override = 0;
+ int status = 0;
+ int cs_active = 0;
+
+ /* Load defaults */
+ status = rt2880_spi_setup_transfer(spi, NULL);
+ if (status < 0)
+ goto msg_done;
+
+ list_for_each_entry(t, &m->transfers, transfer_list) {
+ if (t->tx_buf == NULL && t->rx_buf == NULL && t->len) {
+ dev_err(&spi->dev,
+ "message rejected: invalid transfer data buffers\n");
+ status = -EIO;
+ goto msg_done;
+ }
+
+ if (t->speed_hz && t->speed_hz < (rs->sys_freq / 128)) {
+ dev_err(&spi->dev,
+ "message rejected: device min speed (%d Hz) exceeds required transfer speed (%d Hz)\n",
+ (rs->sys_freq / 128), t->speed_hz);
+ status = -EIO;
+ goto msg_done;
+ }
+
+ if (par_override || t->speed_hz || t->bits_per_word) {
+ par_override = 1;
+ status = rt2880_spi_setup_transfer(spi, t);
+ if (status < 0)
+ goto msg_done;
+ if (!t->speed_hz && !t->bits_per_word)
+ par_override = 0;
+ }
+
+ if (!cs_active) {
+ rt2880_spi_set_cs(rs, 1);
+ cs_active = 1;
+ }
+
+ if (t->len)
+ m->actual_length += rt2880_spi_write_read(spi, t);
+
+ if (t->delay_usecs)
+ udelay(t->delay_usecs);
+
+ if (t->cs_change) {
+ rt2880_spi_set_cs(rs, 0);
+ cs_active = 0;
+ }
+ }
+
+msg_done:
+ if (cs_active)
+ rt2880_spi_set_cs(rs, 0);
+
+ m->status = status;
+ spi_finalize_current_message(master);
+
+ return 0;
+}
+
+static int rt2880_spi_setup(struct spi_device *spi)
+{
+ struct rt2880_spi *rs = spidev_to_rt2880_spi(spi);
+
+ if ((spi->max_speed_hz == 0) ||
+ (spi->max_speed_hz > (rs->sys_freq / 2)))
+ spi->max_speed_hz = (rs->sys_freq / 2);
+
+ if (spi->max_speed_hz < (rs->sys_freq / 128)) {
+ dev_err(&spi->dev, "setup: requested speed is too low %d Hz\n",
+ spi->max_speed_hz);
+ return -EINVAL;
+ }
+
+ /*
+ * baudrate & width will be set rt2880_spi_setup_transfer
+ */
+ return 0;
+}
+
+static void rt2880_spi_reset(struct rt2880_spi *rs)
+{
+ rt2880_spi_write(rs, RAMIPS_SPI_CFG,
+ SPICFG_MSBFIRST | SPICFG_TXCLKEDGE_FALLING |
+ SPICFG_SPICLK_DIV16 | SPICFG_SPICLKPOL);
+ rt2880_spi_write(rs, RAMIPS_SPI_CTL, SPICTL_HIZSDO | SPICTL_SPIENA);
+}
+
+static int rt2880_spi_probe(struct platform_device *pdev)
+{
+ struct spi_master *master;
+ struct rt2880_spi *rs;
+ unsigned long flags;
+ void __iomem *base;
+ struct resource *r;
+ int status = 0;
+ struct clk *clk;
+
+ 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, err=%d\n",
+ status);
+ return PTR_ERR(clk);
+ }
+
+ status = clk_prepare_enable(clk);
+ if (status)
+ return status;
+
+ master = spi_alloc_master(&pdev->dev, sizeof(*rs));
+ if (master == NULL) {
+ dev_dbg(&pdev->dev, "master allocation failed\n");
+ return -ENOMEM;
+ }
+
+ /* we support only mode 0, and no options */
+ master->mode_bits = 0;
+
+ master->setup = rt2880_spi_setup;
+ master->transfer_one_message = rt2880_spi_transfer_one_message;
+ master->num_chipselect = RALINK_NUM_CHIPSELECTS;
+ master->bits_per_word_mask = SPI_BPW_MASK(8);
+ master->dev.of_node = pdev->dev.of_node;
+
+ dev_set_drvdata(&pdev->dev, master);
+
+ rs = spi_master_get_devdata(master);
+ rs->base = base;
+ rs->clk = clk;
+ rs->master = master;
+ rs->sys_freq = clk_get_rate(rs->clk);
+ dev_dbg(&pdev->dev, "sys_freq: %u\n", rs->sys_freq);
+ spin_lock_irqsave(&rs->lock, flags);
+
+ device_reset(&pdev->dev);
+
+ rt2880_spi_reset(rs);
+
+ return spi_register_master(master);
+}
+
+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(rs->clk);
+ spi_unregister_master(master);
+
+ 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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