diff options
Diffstat (limited to 'drivers/spi/spi-omap-uwire.c')
| -rw-r--r-- | drivers/spi/spi-omap-uwire.c | 593 |
1 files changed, 593 insertions, 0 deletions
diff --git a/drivers/spi/spi-omap-uwire.c b/drivers/spi/spi-omap-uwire.c new file mode 100644 index 00000000000..00a8e9d7dbe --- /dev/null +++ b/drivers/spi/spi-omap-uwire.c @@ -0,0 +1,593 @@ +/* + * MicroWire interface driver for OMAP + * + * Copyright 2003 MontaVista Software Inc. <source@mvista.com> + * + * Ported to 2.6 OMAP uwire interface. + * Copyright (C) 2004 Texas Instruments. + * + * Generalization patches by Juha Yrjola <juha.yrjola@nokia.com> + * + * Copyright (C) 2005 David Brownell (ported to 2.6 SPI interface) + * Copyright (C) 2006 Nokia + * + * Many updates by Imre Deak <imre.deak@nokia.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. + * + * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED + * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF + * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON + * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 675 Mass Ave, Cambridge, MA 02139, USA. + */ +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/delay.h> +#include <linux/platform_device.h> +#include <linux/workqueue.h> +#include <linux/interrupt.h> +#include <linux/err.h> +#include <linux/clk.h> +#include <linux/slab.h> + +#include <linux/spi/spi.h> +#include <linux/spi/spi_bitbang.h> + +#include <asm/system.h> +#include <asm/irq.h> +#include <mach/hardware.h> +#include <asm/io.h> +#include <asm/mach-types.h> + +#include <plat/mux.h> +#include <plat/omap7xx.h> /* OMAP7XX_IO_CONF registers */ + + +/* FIXME address is now a platform device resource, + * and irqs should show there too... + */ +#define UWIRE_BASE_PHYS 0xFFFB3000 + +/* uWire Registers: */ +#define UWIRE_IO_SIZE 0x20 +#define UWIRE_TDR 0x00 +#define UWIRE_RDR 0x00 +#define UWIRE_CSR 0x01 +#define UWIRE_SR1 0x02 +#define UWIRE_SR2 0x03 +#define UWIRE_SR3 0x04 +#define UWIRE_SR4 0x05 +#define UWIRE_SR5 0x06 + +/* CSR bits */ +#define RDRB (1 << 15) +#define CSRB (1 << 14) +#define START (1 << 13) +#define CS_CMD (1 << 12) + +/* SR1 or SR2 bits */ +#define UWIRE_READ_FALLING_EDGE 0x0001 +#define UWIRE_READ_RISING_EDGE 0x0000 +#define UWIRE_WRITE_FALLING_EDGE 0x0000 +#define UWIRE_WRITE_RISING_EDGE 0x0002 +#define UWIRE_CS_ACTIVE_LOW 0x0000 +#define UWIRE_CS_ACTIVE_HIGH 0x0004 +#define UWIRE_FREQ_DIV_2 0x0000 +#define UWIRE_FREQ_DIV_4 0x0008 +#define UWIRE_FREQ_DIV_8 0x0010 +#define UWIRE_CHK_READY 0x0020 +#define UWIRE_CLK_INVERTED 0x0040 + + +struct uwire_spi { + struct spi_bitbang bitbang; + struct clk *ck; +}; + +struct uwire_state { + unsigned bits_per_word; + unsigned div1_idx; +}; + +/* REVISIT compile time constant for idx_shift? */ +/* + * Or, put it in a structure which is used throughout the driver; + * that avoids having to issue two loads for each bit of static data. + */ +static unsigned int uwire_idx_shift; +static void __iomem *uwire_base; + +static inline void uwire_write_reg(int idx, u16 val) +{ + __raw_writew(val, uwire_base + (idx << uwire_idx_shift)); +} + +static inline u16 uwire_read_reg(int idx) +{ + return __raw_readw(uwire_base + (idx << uwire_idx_shift)); +} + +static inline void omap_uwire_configure_mode(u8 cs, unsigned long flags) +{ + u16 w, val = 0; + int shift, reg; + + if (flags & UWIRE_CLK_INVERTED) + val ^= 0x03; + val = flags & 0x3f; + if (cs & 1) + shift = 6; + else + shift = 0; + if (cs <= 1) + reg = UWIRE_SR1; + else + reg = UWIRE_SR2; + + w = uwire_read_reg(reg); + w &= ~(0x3f << shift); + w |= val << shift; + uwire_write_reg(reg, w); +} + +static int wait_uwire_csr_flag(u16 mask, u16 val, int might_not_catch) +{ + u16 w; + int c = 0; + unsigned long max_jiffies = jiffies + HZ; + + for (;;) { + w = uwire_read_reg(UWIRE_CSR); + if ((w & mask) == val) + break; + if (time_after(jiffies, max_jiffies)) { + printk(KERN_ERR "%s: timeout. reg=%#06x " + "mask=%#06x val=%#06x\n", + __func__, w, mask, val); + return -1; + } + c++; + if (might_not_catch && c > 64) + break; + } + return 0; +} + +static void uwire_set_clk1_div(int div1_idx) +{ + u16 w; + + w = uwire_read_reg(UWIRE_SR3); + w &= ~(0x03 << 1); + w |= div1_idx << 1; + uwire_write_reg(UWIRE_SR3, w); +} + +static void uwire_chipselect(struct spi_device *spi, int value) +{ + struct uwire_state *ust = spi->controller_state; + u16 w; + int old_cs; + + + BUG_ON(wait_uwire_csr_flag(CSRB, 0, 0)); + + w = uwire_read_reg(UWIRE_CSR); + old_cs = (w >> 10) & 0x03; + if (value == BITBANG_CS_INACTIVE || old_cs != spi->chip_select) { + /* Deselect this CS, or the previous CS */ + w &= ~CS_CMD; + uwire_write_reg(UWIRE_CSR, w); + } + /* activate specfied chipselect */ + if (value == BITBANG_CS_ACTIVE) { + uwire_set_clk1_div(ust->div1_idx); + /* invert clock? */ + if (spi->mode & SPI_CPOL) + uwire_write_reg(UWIRE_SR4, 1); + else + uwire_write_reg(UWIRE_SR4, 0); + + w = spi->chip_select << 10; + w |= CS_CMD; + uwire_write_reg(UWIRE_CSR, w); + } +} + +static int uwire_txrx(struct spi_device *spi, struct spi_transfer *t) +{ + struct uwire_state *ust = spi->controller_state; + unsigned len = t->len; + unsigned bits = ust->bits_per_word; + unsigned bytes; + u16 val, w; + int status = 0; + + if (!t->tx_buf && !t->rx_buf) + return 0; + + /* Microwire doesn't read and write concurrently */ + if (t->tx_buf && t->rx_buf) + return -EPERM; + + w = spi->chip_select << 10; + w |= CS_CMD; + + if (t->tx_buf) { + const u8 *buf = t->tx_buf; + + /* NOTE: DMA could be used for TX transfers */ + + /* write one or two bytes at a time */ + while (len >= 1) { + /* tx bit 15 is first sent; we byteswap multibyte words + * (msb-first) on the way out from memory. + */ + val = *buf++; + if (bits > 8) { + bytes = 2; + val |= *buf++ << 8; + } else + bytes = 1; + val <<= 16 - bits; + +#ifdef VERBOSE + pr_debug("%s: write-%d =%04x\n", + dev_name(&spi->dev), bits, val); +#endif + if (wait_uwire_csr_flag(CSRB, 0, 0)) + goto eio; + + uwire_write_reg(UWIRE_TDR, val); + + /* start write */ + val = START | w | (bits << 5); + + uwire_write_reg(UWIRE_CSR, val); + len -= bytes; + + /* Wait till write actually starts. + * This is needed with MPU clock 60+ MHz. + * REVISIT: we may not have time to catch it... + */ + if (wait_uwire_csr_flag(CSRB, CSRB, 1)) + goto eio; + + status += bytes; + } + + /* REVISIT: save this for later to get more i/o overlap */ + if (wait_uwire_csr_flag(CSRB, 0, 0)) + goto eio; + + } else if (t->rx_buf) { + u8 *buf = t->rx_buf; + + /* read one or two bytes at a time */ + while (len) { + if (bits > 8) { + bytes = 2; + } else + bytes = 1; + + /* start read */ + val = START | w | (bits << 0); + uwire_write_reg(UWIRE_CSR, val); + len -= bytes; + + /* Wait till read actually starts */ + (void) wait_uwire_csr_flag(CSRB, CSRB, 1); + + if (wait_uwire_csr_flag(RDRB | CSRB, + RDRB, 0)) + goto eio; + + /* rx bit 0 is last received; multibyte words will + * be properly byteswapped on the way to memory. + */ + val = uwire_read_reg(UWIRE_RDR); + val &= (1 << bits) - 1; + *buf++ = (u8) val; + if (bytes == 2) + *buf++ = val >> 8; + status += bytes; +#ifdef VERBOSE + pr_debug("%s: read-%d =%04x\n", + dev_name(&spi->dev), bits, val); +#endif + + } + } + return status; +eio: + return -EIO; +} + +static int uwire_setup_transfer(struct spi_device *spi, struct spi_transfer *t) +{ + struct uwire_state *ust = spi->controller_state; + struct uwire_spi *uwire; + unsigned flags = 0; + unsigned bits; + unsigned hz; + unsigned long rate; + int div1_idx; + int div1; + int div2; + int status; + + uwire = spi_master_get_devdata(spi->master); + + if (spi->chip_select > 3) { + pr_debug("%s: cs%d?\n", dev_name(&spi->dev), spi->chip_select); + status = -ENODEV; + goto done; + } + + bits = spi->bits_per_word; + if (t != NULL && t->bits_per_word) + bits = t->bits_per_word; + + if (bits > 16) { + pr_debug("%s: wordsize %d?\n", dev_name(&spi->dev), bits); + status = -ENODEV; + goto done; + } + ust->bits_per_word = bits; + + /* mode 0..3, clock inverted separately; + * standard nCS signaling; + * don't treat DI=high as "not ready" + */ + if (spi->mode & SPI_CS_HIGH) + flags |= UWIRE_CS_ACTIVE_HIGH; + + if (spi->mode & SPI_CPOL) + flags |= UWIRE_CLK_INVERTED; + + switch (spi->mode & (SPI_CPOL | SPI_CPHA)) { + case SPI_MODE_0: + case SPI_MODE_3: + flags |= UWIRE_WRITE_FALLING_EDGE | UWIRE_READ_RISING_EDGE; + break; + case SPI_MODE_1: + case SPI_MODE_2: + flags |= UWIRE_WRITE_RISING_EDGE | UWIRE_READ_FALLING_EDGE; + break; + } + + /* assume it's already enabled */ + rate = clk_get_rate(uwire->ck); + + hz = spi->max_speed_hz; + if (t != NULL && t->speed_hz) + hz = t->speed_hz; + + if (!hz) { + pr_debug("%s: zero speed?\n", dev_name(&spi->dev)); + status = -EINVAL; + goto done; + } + + /* F_INT = mpu_xor_clk / DIV1 */ + for (div1_idx = 0; div1_idx < 4; div1_idx++) { + switch (div1_idx) { + case 0: + div1 = 2; + break; + case 1: + div1 = 4; + break; + case 2: + div1 = 7; + break; + default: + case 3: + div1 = 10; + break; + } + div2 = (rate / div1 + hz - 1) / hz; + if (div2 <= 8) + break; + } + if (div1_idx == 4) { + pr_debug("%s: lowest clock %ld, need %d\n", + dev_name(&spi->dev), rate / 10 / 8, hz); + status = -EDOM; + goto done; + } + + /* we have to cache this and reset in uwire_chipselect as this is a + * global parameter and another uwire device can change it under + * us */ + ust->div1_idx = div1_idx; + uwire_set_clk1_div(div1_idx); + + rate /= div1; + + switch (div2) { + case 0: + case 1: + case 2: + flags |= UWIRE_FREQ_DIV_2; + rate /= 2; + break; + case 3: + case 4: + flags |= UWIRE_FREQ_DIV_4; + rate /= 4; + break; + case 5: + case 6: + case 7: + case 8: + flags |= UWIRE_FREQ_DIV_8; + rate /= 8; + break; + } + omap_uwire_configure_mode(spi->chip_select, flags); + pr_debug("%s: uwire flags %02x, armxor %lu KHz, SCK %lu KHz\n", + __func__, flags, + clk_get_rate(uwire->ck) / 1000, + rate / 1000); + status = 0; +done: + return status; +} + +static int uwire_setup(struct spi_device *spi) +{ + struct uwire_state *ust = spi->controller_state; + + if (ust == NULL) { + ust = kzalloc(sizeof(*ust), GFP_KERNEL); + if (ust == NULL) + return -ENOMEM; + spi->controller_state = ust; + } + + return uwire_setup_transfer(spi, NULL); +} + +static void uwire_cleanup(struct spi_device *spi) +{ + kfree(spi->controller_state); +} + +static void uwire_off(struct uwire_spi *uwire) +{ + uwire_write_reg(UWIRE_SR3, 0); + clk_disable(uwire->ck); + clk_put(uwire->ck); + spi_master_put(uwire->bitbang.master); +} + +static int __init uwire_probe(struct platform_device *pdev) +{ + struct spi_master *master; + struct uwire_spi *uwire; + int status; + + master = spi_alloc_master(&pdev->dev, sizeof *uwire); + if (!master) + return -ENODEV; + + uwire = spi_master_get_devdata(master); + + uwire_base = ioremap(UWIRE_BASE_PHYS, UWIRE_IO_SIZE); + if (!uwire_base) { + dev_dbg(&pdev->dev, "can't ioremap UWIRE\n"); + spi_master_put(master); + return -ENOMEM; + } + + dev_set_drvdata(&pdev->dev, uwire); + + uwire->ck = clk_get(&pdev->dev, "fck"); + if (IS_ERR(uwire->ck)) { + status = PTR_ERR(uwire->ck); + dev_dbg(&pdev->dev, "no functional clock?\n"); + spi_master_put(master); + return status; + } + clk_enable(uwire->ck); + + if (cpu_is_omap7xx()) + uwire_idx_shift = 1; + else + uwire_idx_shift = 2; + + uwire_write_reg(UWIRE_SR3, 1); + + /* the spi->mode bits understood by this driver: */ + master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH; + + master->flags = SPI_MASTER_HALF_DUPLEX; + + master->bus_num = 2; /* "official" */ + master->num_chipselect = 4; + master->setup = uwire_setup; + master->cleanup = uwire_cleanup; + + uwire->bitbang.master = master; + uwire->bitbang.chipselect = uwire_chipselect; + uwire->bitbang.setup_transfer = uwire_setup_transfer; + uwire->bitbang.txrx_bufs = uwire_txrx; + + status = spi_bitbang_start(&uwire->bitbang); + if (status < 0) { + uwire_off(uwire); + iounmap(uwire_base); + } + return status; +} + +static int __exit uwire_remove(struct platform_device *pdev) +{ + struct uwire_spi *uwire = dev_get_drvdata(&pdev->dev); + int status; + + // FIXME remove all child devices, somewhere ... + + status = spi_bitbang_stop(&uwire->bitbang); + uwire_off(uwire); + iounmap(uwire_base); + return status; +} + +/* work with hotplug and coldplug */ +MODULE_ALIAS("platform:omap_uwire"); + +static struct platform_driver uwire_driver = { + .driver = { + .name = "omap_uwire", + .owner = THIS_MODULE, + }, + .remove = __exit_p(uwire_remove), + // suspend ... unuse ck + // resume ... use ck +}; + +static int __init omap_uwire_init(void) +{ + /* FIXME move these into the relevant board init code. also, include + * H3 support; it uses tsc2101 like H2 (on a different chipselect). + */ + + if (machine_is_omap_h2()) { + /* defaults: W21 SDO, U18 SDI, V19 SCL */ + omap_cfg_reg(N14_1610_UWIRE_CS0); + omap_cfg_reg(N15_1610_UWIRE_CS1); + } + if (machine_is_omap_perseus2()) { + /* configure pins: MPU_UW_nSCS1, MPU_UW_SDO, MPU_UW_SCLK */ + int val = omap_readl(OMAP7XX_IO_CONF_9) & ~0x00EEE000; + omap_writel(val | 0x00AAA000, OMAP7XX_IO_CONF_9); + } + + return platform_driver_probe(&uwire_driver, uwire_probe); +} + +static void __exit omap_uwire_exit(void) +{ + platform_driver_unregister(&uwire_driver); +} + +subsys_initcall(omap_uwire_init); +module_exit(omap_uwire_exit); + +MODULE_LICENSE("GPL"); + |