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path: root/drivers/spi/omap_uwire.c
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Diffstat (limited to 'drivers/spi/omap_uwire.c')
-rw-r--r--drivers/spi/omap_uwire.c593
1 files changed, 593 insertions, 0 deletions
diff --git a/drivers/spi/omap_uwire.c b/drivers/spi/omap_uwire.c
new file mode 100644
index 00000000..160d3266
--- /dev/null
+++ b/drivers/spi/omap_uwire.c
@@ -0,0 +1,593 @@
+/*
+ * omap_uwire.c -- 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");
+
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