From fc006d0622ab8c43086b2c9018c03012db332033 Mon Sep 17 00:00:00 2001 From: John Crispin Date: Sun, 27 Jul 2014 11:15:12 +0100 Subject: [PATCH 50/57] SPI: ralink: add Ralink SoC spi driver Add the driver needed to make SPI work on Ralink SoC. Signed-off-by: Gabor Juhos Acked-by: John Crispin --- drivers/spi/Kconfig | 6 + drivers/spi/Makefile | 1 + drivers/spi/spi-rt2880.c | 432 ++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 439 insertions(+) create mode 100644 drivers/spi/spi-rt2880.c --- a/drivers/spi/Kconfig +++ b/drivers/spi/Kconfig @@ -433,6 +433,12 @@ 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 @@ -65,6 +65,7 @@ obj-$(CONFIG_SPI_PXA2XX_PCI) += spi-pxa obj-$(CONFIG_SPI_QUP) += spi-qup.o obj-$(CONFIG_SPI_ROCKCHIP) += spi-rockchip.o obj-$(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 + * Copyright (C) 2011-2013 Gabor Juhos + * + * Some parts are based on spi-orion.c: + * Author: Shadi Ammouri + * 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 +#include +#include +#include +#include +#include +#include +#include +#include + +#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 "); +MODULE_AUTHOR("Gabor Juhos "); +MODULE_LICENSE("GPL");