/* * OMAP7xx SPI 100k controller driver * Author: Fabrice Crohas <fcrohas@gmail.com> * from original omap1_mcspi driver * * Copyright (C) 2005, 2006 Nokia Corporation * Author: Samuel Ortiz <samuel.ortiz@nokia.com> and * Juha Yrj�l� <juha.yrjola@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 program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */ #include <linux/kernel.h> #include <linux/init.h> #include <linux/interrupt.h> #include <linux/module.h> #include <linux/device.h> #include <linux/delay.h> #include <linux/platform_device.h> #include <linux/err.h> #include <linux/clk.h> #include <linux/io.h> #include <linux/gpio.h> #include <linux/slab.h> #include <linux/spi/spi.h> #define OMAP1_SPI100K_MAX_FREQ 48000000 #define ICR_SPITAS (OMAP7XX_ICR_BASE + 0x12) #define SPI_SETUP1 0x00 #define SPI_SETUP2 0x02 #define SPI_CTRL 0x04 #define SPI_STATUS 0x06 #define SPI_TX_LSB 0x08 #define SPI_TX_MSB 0x0a #define SPI_RX_LSB 0x0c #define SPI_RX_MSB 0x0e #define SPI_SETUP1_INT_READ_ENABLE (1UL << 5) #define SPI_SETUP1_INT_WRITE_ENABLE (1UL << 4) #define SPI_SETUP1_CLOCK_DIVISOR(x) ((x) << 1) #define SPI_SETUP1_CLOCK_ENABLE (1UL << 0) #define SPI_SETUP2_ACTIVE_EDGE_FALLING (0UL << 0) #define SPI_SETUP2_ACTIVE_EDGE_RISING (1UL << 0) #define SPI_SETUP2_NEGATIVE_LEVEL (0UL << 5) #define SPI_SETUP2_POSITIVE_LEVEL (1UL << 5) #define SPI_SETUP2_LEVEL_TRIGGER (0UL << 10) #define SPI_SETUP2_EDGE_TRIGGER (1UL << 10) #define SPI_CTRL_SEN(x) ((x) << 7) #define SPI_CTRL_WORD_SIZE(x) (((x) - 1) << 2) #define SPI_CTRL_WR (1UL << 1) #define SPI_CTRL_RD (1UL << 0) #define SPI_STATUS_WE (1UL << 1) #define SPI_STATUS_RD (1UL << 0) #define WRITE 0 #define READ 1 /* use PIO for small transfers, avoiding DMA setup/teardown overhead and * cache operations; better heuristics consider wordsize and bitrate. */ #define DMA_MIN_BYTES 8 #define SPI_RUNNING 0 #define SPI_SHUTDOWN 1 struct omap1_spi100k { struct clk *ick; struct clk *fck; /* Virtual base address of the controller */ void __iomem *base; }; struct omap1_spi100k_cs { void __iomem *base; int word_len; }; static void spi100k_enable_clock(struct spi_master *master) { unsigned int val; struct omap1_spi100k *spi100k = spi_master_get_devdata(master); /* enable SPI */ val = readw(spi100k->base + SPI_SETUP1); val |= SPI_SETUP1_CLOCK_ENABLE; writew(val, spi100k->base + SPI_SETUP1); } static void spi100k_disable_clock(struct spi_master *master) { unsigned int val; struct omap1_spi100k *spi100k = spi_master_get_devdata(master); /* disable SPI */ val = readw(spi100k->base + SPI_SETUP1); val &= ~SPI_SETUP1_CLOCK_ENABLE; writew(val, spi100k->base + SPI_SETUP1); } static void spi100k_write_data(struct spi_master *master, int len, int data) { struct omap1_spi100k *spi100k = spi_master_get_devdata(master); /* write 16-bit word, shifting 8-bit data if necessary */ if (len <= 8) { data <<= 8; len = 16; } spi100k_enable_clock(master); writew(data , spi100k->base + SPI_TX_MSB); writew(SPI_CTRL_SEN(0) | SPI_CTRL_WORD_SIZE(len) | SPI_CTRL_WR, spi100k->base + SPI_CTRL); /* Wait for bit ack send change */ while ((readw(spi100k->base + SPI_STATUS) & SPI_STATUS_WE) != SPI_STATUS_WE) ; udelay(1000); spi100k_disable_clock(master); } static int spi100k_read_data(struct spi_master *master, int len) { int dataH, dataL; struct omap1_spi100k *spi100k = spi_master_get_devdata(master); /* Always do at least 16 bits */ if (len <= 8) len = 16; spi100k_enable_clock(master); writew(SPI_CTRL_SEN(0) | SPI_CTRL_WORD_SIZE(len) | SPI_CTRL_RD, spi100k->base + SPI_CTRL); while ((readw(spi100k->base + SPI_STATUS) & SPI_STATUS_RD) != SPI_STATUS_RD) ; udelay(1000); dataL = readw(spi100k->base + SPI_RX_LSB); dataH = readw(spi100k->base + SPI_RX_MSB); spi100k_disable_clock(master); return dataL; } static void spi100k_open(struct spi_master *master) { /* get control of SPI */ struct omap1_spi100k *spi100k = spi_master_get_devdata(master); writew(SPI_SETUP1_INT_READ_ENABLE | SPI_SETUP1_INT_WRITE_ENABLE | SPI_SETUP1_CLOCK_DIVISOR(0), spi100k->base + SPI_SETUP1); /* configure clock and interrupts */ writew(SPI_SETUP2_ACTIVE_EDGE_FALLING | SPI_SETUP2_NEGATIVE_LEVEL | SPI_SETUP2_LEVEL_TRIGGER, spi100k->base + SPI_SETUP2); } static void omap1_spi100k_force_cs(struct omap1_spi100k *spi100k, int enable) { if (enable) writew(0x05fc, spi100k->base + SPI_CTRL); else writew(0x05fd, spi100k->base + SPI_CTRL); } static unsigned omap1_spi100k_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer) { struct omap1_spi100k_cs *cs = spi->controller_state; unsigned int count, c; int word_len; count = xfer->len; c = count; word_len = cs->word_len; if (word_len <= 8) { u8 *rx; const u8 *tx; rx = xfer->rx_buf; tx = xfer->tx_buf; do { c -= 1; if (xfer->tx_buf != NULL) spi100k_write_data(spi->master, word_len, *tx++); if (xfer->rx_buf != NULL) *rx++ = spi100k_read_data(spi->master, word_len); } while (c); } else if (word_len <= 16) { u16 *rx; const u16 *tx; rx = xfer->rx_buf; tx = xfer->tx_buf; do { c -= 2; if (xfer->tx_buf != NULL) spi100k_write_data(spi->master, word_len, *tx++); if (xfer->rx_buf != NULL) *rx++ = spi100k_read_data(spi->master, word_len); } while (c); } else if (word_len <= 32) { u32 *rx; const u32 *tx; rx = xfer->rx_buf; tx = xfer->tx_buf; do { c -= 4; if (xfer->tx_buf != NULL) spi100k_write_data(spi->master, word_len, *tx); if (xfer->rx_buf != NULL) *rx = spi100k_read_data(spi->master, word_len); } while (c); } return count - c; } /* called only when no transfer is active to this device */ static int omap1_spi100k_setup_transfer(struct spi_device *spi, struct spi_transfer *t) { struct omap1_spi100k *spi100k = spi_master_get_devdata(spi->master); struct omap1_spi100k_cs *cs = spi->controller_state; u8 word_len = spi->bits_per_word; if (t != NULL && t->bits_per_word) word_len = t->bits_per_word; if (!word_len) word_len = 8; if (spi->bits_per_word > 32) return -EINVAL; cs->word_len = word_len; /* SPI init before transfer */ writew(0x3e , spi100k->base + SPI_SETUP1); writew(0x00 , spi100k->base + SPI_STATUS); writew(0x3e , spi100k->base + SPI_CTRL); return 0; } /* the spi->mode bits understood by this driver: */ #define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH) static int omap1_spi100k_setup(struct spi_device *spi) { int ret; struct omap1_spi100k *spi100k; struct omap1_spi100k_cs *cs = spi->controller_state; spi100k = spi_master_get_devdata(spi->master); if (!cs) { cs = devm_kzalloc(&spi->dev, sizeof(*cs), GFP_KERNEL); if (!cs) return -ENOMEM; cs->base = spi100k->base + spi->chip_select * 0x14; spi->controller_state = cs; } spi100k_open(spi->master); clk_prepare_enable(spi100k->ick); clk_prepare_enable(spi100k->fck); ret = omap1_spi100k_setup_transfer(spi, NULL); clk_disable_unprepare(spi100k->ick); clk_disable_unprepare(spi100k->fck); return ret; } static int omap1_spi100k_prepare_hardware(struct spi_master *master) { struct omap1_spi100k *spi100k = spi_master_get_devdata(master); clk_prepare_enable(spi100k->ick); clk_prepare_enable(spi100k->fck); return 0; } static int omap1_spi100k_transfer_one_message(struct spi_master *master, struct spi_message *m) { struct omap1_spi100k *spi100k = spi_master_get_devdata(master); struct spi_device *spi = m->spi; struct spi_transfer *t = NULL; int cs_active = 0; int par_override = 0; int status = 0; list_for_each_entry(t, &m->transfers, transfer_list) { if (t->tx_buf == NULL && t->rx_buf == NULL && t->len) { status = -EINVAL; break; } if (par_override || t->speed_hz || t->bits_per_word) { par_override = 1; status = omap1_spi100k_setup_transfer(spi, t); if (status < 0) break; if (!t->speed_hz && !t->bits_per_word) par_override = 0; } if (!cs_active) { omap1_spi100k_force_cs(spi100k, 1); cs_active = 1; } if (t->len) { unsigned count; count = omap1_spi100k_txrx_pio(spi, t); m->actual_length += count; if (count != t->len) { status = -EIO; break; } } if (t->delay_usecs) udelay(t->delay_usecs); /* ignore the "leave it on after last xfer" hint */ if (t->cs_change) { omap1_spi100k_force_cs(spi100k, 0); cs_active = 0; } } /* Restore defaults if they were overriden */ if (par_override) { par_override = 0; status = omap1_spi100k_setup_transfer(spi, NULL); } if (cs_active) omap1_spi100k_force_cs(spi100k, 0); m->status = status; spi_finalize_current_message(master); return status; } static int omap1_spi100k_unprepare_hardware(struct spi_master *master) { struct omap1_spi100k *spi100k = spi_master_get_devdata(master); clk_disable_unprepare(spi100k->ick); clk_disable_unprepare(spi100k->fck); return 0; } static int omap1_spi100k_probe(struct platform_device *pdev) { struct spi_master *master; struct omap1_spi100k *spi100k; int status = 0; if (!pdev->id) return -EINVAL; master = spi_alloc_master(&pdev->dev, sizeof(*spi100k)); if (master == NULL) { dev_dbg(&pdev->dev, "master allocation failed\n"); return -ENOMEM; } if (pdev->id != -1) master->bus_num = pdev->id; master->setup = omap1_spi100k_setup; master->transfer_one_message = omap1_spi100k_transfer_one_message; master->prepare_transfer_hardware = omap1_spi100k_prepare_hardware; master->unprepare_transfer_hardware = omap1_spi100k_unprepare_hardware; master->cleanup = NULL; master->num_chipselect = 2; master->mode_bits = MODEBITS; master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32); master->min_speed_hz = OMAP1_SPI100K_MAX_FREQ/(1<<16); master->max_speed_hz = OMAP1_SPI100K_MAX_FREQ; platform_set_drvdata(pdev, master); spi100k = spi_master_get_devdata(master); /* * The memory region base address is taken as the platform_data. * You should allocate this with ioremap() before initializing * the SPI. */ spi100k->base = (void __iomem *)dev_get_platdata(&pdev->dev); spi100k->ick = devm_clk_get(&pdev->dev, "ick"); if (IS_ERR(spi100k->ick)) { dev_dbg(&pdev->dev, "can't get spi100k_ick\n"); status = PTR_ERR(spi100k->ick); goto err; } spi100k->fck = devm_clk_get(&pdev->dev, "fck"); if (IS_ERR(spi100k->fck)) { dev_dbg(&pdev->dev, "can't get spi100k_fck\n"); status = PTR_ERR(spi100k->fck); goto err; } status = devm_spi_register_master(&pdev->dev, master); if (status < 0) goto err; return status; err: spi_master_put(master); return status; } static struct platform_driver omap1_spi100k_driver = { .driver = { .name = "omap1_spi100k", .owner = THIS_MODULE, }, .probe = omap1_spi100k_probe, }; module_platform_driver(omap1_spi100k_driver); MODULE_DESCRIPTION("OMAP7xx SPI 100k controller driver"); MODULE_AUTHOR("Fabrice Crohas <fcrohas@gmail.com>"); MODULE_LICENSE("GPL");