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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/spi/spi-bcm2835aux.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/spi/spi-bcm2835aux.c')
-rw-r--r--drivers/spi/spi-bcm2835aux.c605
1 files changed, 605 insertions, 0 deletions
diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c
new file mode 100644
index 000000000..e28521922
--- /dev/null
+++ b/drivers/spi/spi-bcm2835aux.c
@@ -0,0 +1,605 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Driver for Broadcom BCM2835 auxiliary SPI Controllers
+ *
+ * the driver does not rely on the native chipselects at all
+ * but only uses the gpio type chipselects
+ *
+ * Based on: spi-bcm2835.c
+ *
+ * Copyright (C) 2015 Martin Sperl
+ */
+
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/debugfs.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/of_irq.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+#include <linux/spinlock.h>
+
+/* define polling limits */
+static unsigned int polling_limit_us = 30;
+module_param(polling_limit_us, uint, 0664);
+MODULE_PARM_DESC(polling_limit_us,
+ "time in us to run a transfer in polling mode - if zero no polling is used\n");
+
+/*
+ * spi register defines
+ *
+ * note there is garbage in the "official" documentation,
+ * so some data is taken from the file:
+ * brcm_usrlib/dag/vmcsx/vcinclude/bcm2708_chip/aux_io.h
+ * inside of:
+ * http://www.broadcom.com/docs/support/videocore/Brcm_Android_ICS_Graphics_Stack.tar.gz
+ */
+
+/* SPI register offsets */
+#define BCM2835_AUX_SPI_CNTL0 0x00
+#define BCM2835_AUX_SPI_CNTL1 0x04
+#define BCM2835_AUX_SPI_STAT 0x08
+#define BCM2835_AUX_SPI_PEEK 0x0C
+#define BCM2835_AUX_SPI_IO 0x20
+#define BCM2835_AUX_SPI_TXHOLD 0x30
+
+/* Bitfields in CNTL0 */
+#define BCM2835_AUX_SPI_CNTL0_SPEED 0xFFF00000
+#define BCM2835_AUX_SPI_CNTL0_SPEED_MAX 0xFFF
+#define BCM2835_AUX_SPI_CNTL0_SPEED_SHIFT 20
+#define BCM2835_AUX_SPI_CNTL0_CS 0x000E0000
+#define BCM2835_AUX_SPI_CNTL0_POSTINPUT 0x00010000
+#define BCM2835_AUX_SPI_CNTL0_VAR_CS 0x00008000
+#define BCM2835_AUX_SPI_CNTL0_VAR_WIDTH 0x00004000
+#define BCM2835_AUX_SPI_CNTL0_DOUTHOLD 0x00003000
+#define BCM2835_AUX_SPI_CNTL0_ENABLE 0x00000800
+#define BCM2835_AUX_SPI_CNTL0_IN_RISING 0x00000400
+#define BCM2835_AUX_SPI_CNTL0_CLEARFIFO 0x00000200
+#define BCM2835_AUX_SPI_CNTL0_OUT_RISING 0x00000100
+#define BCM2835_AUX_SPI_CNTL0_CPOL 0x00000080
+#define BCM2835_AUX_SPI_CNTL0_MSBF_OUT 0x00000040
+#define BCM2835_AUX_SPI_CNTL0_SHIFTLEN 0x0000003F
+
+/* Bitfields in CNTL1 */
+#define BCM2835_AUX_SPI_CNTL1_CSHIGH 0x00000700
+#define BCM2835_AUX_SPI_CNTL1_TXEMPTY 0x00000080
+#define BCM2835_AUX_SPI_CNTL1_IDLE 0x00000040
+#define BCM2835_AUX_SPI_CNTL1_MSBF_IN 0x00000002
+#define BCM2835_AUX_SPI_CNTL1_KEEP_IN 0x00000001
+
+/* Bitfields in STAT */
+#define BCM2835_AUX_SPI_STAT_TX_LVL 0xFF000000
+#define BCM2835_AUX_SPI_STAT_RX_LVL 0x00FF0000
+#define BCM2835_AUX_SPI_STAT_TX_FULL 0x00000400
+#define BCM2835_AUX_SPI_STAT_TX_EMPTY 0x00000200
+#define BCM2835_AUX_SPI_STAT_RX_FULL 0x00000100
+#define BCM2835_AUX_SPI_STAT_RX_EMPTY 0x00000080
+#define BCM2835_AUX_SPI_STAT_BUSY 0x00000040
+#define BCM2835_AUX_SPI_STAT_BITCOUNT 0x0000003F
+
+struct bcm2835aux_spi {
+ void __iomem *regs;
+ struct clk *clk;
+ int irq;
+ u32 cntl[2];
+ const u8 *tx_buf;
+ u8 *rx_buf;
+ int tx_len;
+ int rx_len;
+ int pending;
+
+ u64 count_transfer_polling;
+ u64 count_transfer_irq;
+ u64 count_transfer_irq_after_poll;
+
+ struct dentry *debugfs_dir;
+};
+
+#if defined(CONFIG_DEBUG_FS)
+static void bcm2835aux_debugfs_create(struct bcm2835aux_spi *bs,
+ const char *dname)
+{
+ char name[64];
+ struct dentry *dir;
+
+ /* get full name */
+ snprintf(name, sizeof(name), "spi-bcm2835aux-%s", dname);
+
+ /* the base directory */
+ dir = debugfs_create_dir(name, NULL);
+ bs->debugfs_dir = dir;
+
+ /* the counters */
+ debugfs_create_u64("count_transfer_polling", 0444, dir,
+ &bs->count_transfer_polling);
+ debugfs_create_u64("count_transfer_irq", 0444, dir,
+ &bs->count_transfer_irq);
+ debugfs_create_u64("count_transfer_irq_after_poll", 0444, dir,
+ &bs->count_transfer_irq_after_poll);
+}
+
+static void bcm2835aux_debugfs_remove(struct bcm2835aux_spi *bs)
+{
+ debugfs_remove_recursive(bs->debugfs_dir);
+ bs->debugfs_dir = NULL;
+}
+#else
+static void bcm2835aux_debugfs_create(struct bcm2835aux_spi *bs,
+ const char *dname)
+{
+}
+
+static void bcm2835aux_debugfs_remove(struct bcm2835aux_spi *bs)
+{
+}
+#endif /* CONFIG_DEBUG_FS */
+
+static inline u32 bcm2835aux_rd(struct bcm2835aux_spi *bs, unsigned int reg)
+{
+ return readl(bs->regs + reg);
+}
+
+static inline void bcm2835aux_wr(struct bcm2835aux_spi *bs, unsigned int reg,
+ u32 val)
+{
+ writel(val, bs->regs + reg);
+}
+
+static inline void bcm2835aux_rd_fifo(struct bcm2835aux_spi *bs)
+{
+ u32 data;
+ int count = min(bs->rx_len, 3);
+
+ data = bcm2835aux_rd(bs, BCM2835_AUX_SPI_IO);
+ if (bs->rx_buf) {
+ switch (count) {
+ case 3:
+ *bs->rx_buf++ = (data >> 16) & 0xff;
+ fallthrough;
+ case 2:
+ *bs->rx_buf++ = (data >> 8) & 0xff;
+ fallthrough;
+ case 1:
+ *bs->rx_buf++ = (data >> 0) & 0xff;
+ /* fallthrough - no default */
+ }
+ }
+ bs->rx_len -= count;
+ bs->pending -= count;
+}
+
+static inline void bcm2835aux_wr_fifo(struct bcm2835aux_spi *bs)
+{
+ u32 data;
+ u8 byte;
+ int count;
+ int i;
+
+ /* gather up to 3 bytes to write to the FIFO */
+ count = min(bs->tx_len, 3);
+ data = 0;
+ for (i = 0; i < count; i++) {
+ byte = bs->tx_buf ? *bs->tx_buf++ : 0;
+ data |= byte << (8 * (2 - i));
+ }
+
+ /* and set the variable bit-length */
+ data |= (count * 8) << 24;
+
+ /* and decrement length */
+ bs->tx_len -= count;
+ bs->pending += count;
+
+ /* write to the correct TX-register */
+ if (bs->tx_len)
+ bcm2835aux_wr(bs, BCM2835_AUX_SPI_TXHOLD, data);
+ else
+ bcm2835aux_wr(bs, BCM2835_AUX_SPI_IO, data);
+}
+
+static void bcm2835aux_spi_reset_hw(struct bcm2835aux_spi *bs)
+{
+ /* disable spi clearing fifo and interrupts */
+ bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL1, 0);
+ bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL0,
+ BCM2835_AUX_SPI_CNTL0_CLEARFIFO);
+}
+
+static void bcm2835aux_spi_transfer_helper(struct bcm2835aux_spi *bs)
+{
+ u32 stat = bcm2835aux_rd(bs, BCM2835_AUX_SPI_STAT);
+
+ /* check if we have data to read */
+ for (; bs->rx_len && (stat & BCM2835_AUX_SPI_STAT_RX_LVL);
+ stat = bcm2835aux_rd(bs, BCM2835_AUX_SPI_STAT))
+ bcm2835aux_rd_fifo(bs);
+
+ /* check if we have data to write */
+ while (bs->tx_len &&
+ (bs->pending < 12) &&
+ (!(bcm2835aux_rd(bs, BCM2835_AUX_SPI_STAT) &
+ BCM2835_AUX_SPI_STAT_TX_FULL))) {
+ bcm2835aux_wr_fifo(bs);
+ }
+}
+
+static irqreturn_t bcm2835aux_spi_interrupt(int irq, void *dev_id)
+{
+ struct spi_master *master = dev_id;
+ struct bcm2835aux_spi *bs = spi_master_get_devdata(master);
+
+ /* IRQ may be shared, so return if our interrupts are disabled */
+ if (!(bcm2835aux_rd(bs, BCM2835_AUX_SPI_CNTL1) &
+ (BCM2835_AUX_SPI_CNTL1_TXEMPTY | BCM2835_AUX_SPI_CNTL1_IDLE)))
+ return IRQ_NONE;
+
+ /* do common fifo handling */
+ bcm2835aux_spi_transfer_helper(bs);
+
+ if (!bs->tx_len) {
+ /* disable tx fifo empty interrupt */
+ bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL1, bs->cntl[1] |
+ BCM2835_AUX_SPI_CNTL1_IDLE);
+ }
+
+ /* and if rx_len is 0 then disable interrupts and wake up completion */
+ if (!bs->rx_len) {
+ bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL1, bs->cntl[1]);
+ spi_finalize_current_transfer(master);
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int __bcm2835aux_spi_transfer_one_irq(struct spi_master *master,
+ struct spi_device *spi,
+ struct spi_transfer *tfr)
+{
+ struct bcm2835aux_spi *bs = spi_master_get_devdata(master);
+
+ /* enable interrupts */
+ bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL1, bs->cntl[1] |
+ BCM2835_AUX_SPI_CNTL1_TXEMPTY |
+ BCM2835_AUX_SPI_CNTL1_IDLE);
+
+ /* and wait for finish... */
+ return 1;
+}
+
+static int bcm2835aux_spi_transfer_one_irq(struct spi_master *master,
+ struct spi_device *spi,
+ struct spi_transfer *tfr)
+{
+ struct bcm2835aux_spi *bs = spi_master_get_devdata(master);
+
+ /* update statistics */
+ bs->count_transfer_irq++;
+
+ /* fill in registers and fifos before enabling interrupts */
+ bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL1, bs->cntl[1]);
+ bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL0, bs->cntl[0]);
+
+ /* fill in tx fifo with data before enabling interrupts */
+ while ((bs->tx_len) &&
+ (bs->pending < 12) &&
+ (!(bcm2835aux_rd(bs, BCM2835_AUX_SPI_STAT) &
+ BCM2835_AUX_SPI_STAT_TX_FULL))) {
+ bcm2835aux_wr_fifo(bs);
+ }
+
+ /* now run the interrupt mode */
+ return __bcm2835aux_spi_transfer_one_irq(master, spi, tfr);
+}
+
+static int bcm2835aux_spi_transfer_one_poll(struct spi_master *master,
+ struct spi_device *spi,
+ struct spi_transfer *tfr)
+{
+ struct bcm2835aux_spi *bs = spi_master_get_devdata(master);
+ unsigned long timeout;
+
+ /* update statistics */
+ bs->count_transfer_polling++;
+
+ /* configure spi */
+ bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL1, bs->cntl[1]);
+ bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL0, bs->cntl[0]);
+
+ /* set the timeout to at least 2 jiffies */
+ timeout = jiffies + 2 + HZ * polling_limit_us / 1000000;
+
+ /* loop until finished the transfer */
+ while (bs->rx_len) {
+
+ /* do common fifo handling */
+ bcm2835aux_spi_transfer_helper(bs);
+
+ /* there is still data pending to read check the timeout */
+ if (bs->rx_len && time_after(jiffies, timeout)) {
+ dev_dbg_ratelimited(&spi->dev,
+ "timeout period reached: jiffies: %lu remaining tx/rx: %d/%d - falling back to interrupt mode\n",
+ jiffies - timeout,
+ bs->tx_len, bs->rx_len);
+ /* forward to interrupt handler */
+ bs->count_transfer_irq_after_poll++;
+ return __bcm2835aux_spi_transfer_one_irq(master,
+ spi, tfr);
+ }
+ }
+
+ /* and return without waiting for completion */
+ return 0;
+}
+
+static int bcm2835aux_spi_transfer_one(struct spi_master *master,
+ struct spi_device *spi,
+ struct spi_transfer *tfr)
+{
+ struct bcm2835aux_spi *bs = spi_master_get_devdata(master);
+ unsigned long spi_hz, clk_hz, speed;
+ unsigned long hz_per_byte, byte_limit;
+
+ /* calculate the registers to handle
+ *
+ * note that we use the variable data mode, which
+ * is not optimal for longer transfers as we waste registers
+ * resulting (potentially) in more interrupts when transferring
+ * more than 12 bytes
+ */
+
+ /* set clock */
+ spi_hz = tfr->speed_hz;
+ clk_hz = clk_get_rate(bs->clk);
+
+ if (spi_hz >= clk_hz / 2) {
+ speed = 0;
+ } else if (spi_hz) {
+ speed = DIV_ROUND_UP(clk_hz, 2 * spi_hz) - 1;
+ if (speed > BCM2835_AUX_SPI_CNTL0_SPEED_MAX)
+ speed = BCM2835_AUX_SPI_CNTL0_SPEED_MAX;
+ } else { /* the slowest we can go */
+ speed = BCM2835_AUX_SPI_CNTL0_SPEED_MAX;
+ }
+ /* mask out old speed from previous spi_transfer */
+ bs->cntl[0] &= ~(BCM2835_AUX_SPI_CNTL0_SPEED);
+ /* set the new speed */
+ bs->cntl[0] |= speed << BCM2835_AUX_SPI_CNTL0_SPEED_SHIFT;
+
+ tfr->effective_speed_hz = clk_hz / (2 * (speed + 1));
+
+ /* set transmit buffers and length */
+ bs->tx_buf = tfr->tx_buf;
+ bs->rx_buf = tfr->rx_buf;
+ bs->tx_len = tfr->len;
+ bs->rx_len = tfr->len;
+ bs->pending = 0;
+
+ /* Calculate the estimated time in us the transfer runs. Note that
+ * there are 2 idle clocks cycles after each chunk getting
+ * transferred - in our case the chunk size is 3 bytes, so we
+ * approximate this by 9 cycles/byte. This is used to find the number
+ * of Hz per byte per polling limit. E.g., we can transfer 1 byte in
+ * 30 µs per 300,000 Hz of bus clock.
+ */
+ hz_per_byte = polling_limit_us ? (9 * 1000000) / polling_limit_us : 0;
+ byte_limit = hz_per_byte ? tfr->effective_speed_hz / hz_per_byte : 1;
+
+ /* run in polling mode for short transfers */
+ if (tfr->len < byte_limit)
+ return bcm2835aux_spi_transfer_one_poll(master, spi, tfr);
+
+ /* run in interrupt mode for all others */
+ return bcm2835aux_spi_transfer_one_irq(master, spi, tfr);
+}
+
+static int bcm2835aux_spi_prepare_message(struct spi_master *master,
+ struct spi_message *msg)
+{
+ struct spi_device *spi = msg->spi;
+ struct bcm2835aux_spi *bs = spi_master_get_devdata(master);
+
+ bs->cntl[0] = BCM2835_AUX_SPI_CNTL0_ENABLE |
+ BCM2835_AUX_SPI_CNTL0_VAR_WIDTH |
+ BCM2835_AUX_SPI_CNTL0_MSBF_OUT;
+ bs->cntl[1] = BCM2835_AUX_SPI_CNTL1_MSBF_IN;
+
+ /* handle all the modes */
+ if (spi->mode & SPI_CPOL) {
+ bs->cntl[0] |= BCM2835_AUX_SPI_CNTL0_CPOL;
+ bs->cntl[0] |= BCM2835_AUX_SPI_CNTL0_OUT_RISING;
+ } else {
+ bs->cntl[0] |= BCM2835_AUX_SPI_CNTL0_IN_RISING;
+ }
+ bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL1, bs->cntl[1]);
+ bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL0, bs->cntl[0]);
+
+ return 0;
+}
+
+static int bcm2835aux_spi_unprepare_message(struct spi_master *master,
+ struct spi_message *msg)
+{
+ struct bcm2835aux_spi *bs = spi_master_get_devdata(master);
+
+ bcm2835aux_spi_reset_hw(bs);
+
+ return 0;
+}
+
+static void bcm2835aux_spi_handle_err(struct spi_master *master,
+ struct spi_message *msg)
+{
+ struct bcm2835aux_spi *bs = spi_master_get_devdata(master);
+
+ bcm2835aux_spi_reset_hw(bs);
+}
+
+static int bcm2835aux_spi_setup(struct spi_device *spi)
+{
+ /* sanity check for native cs */
+ if (spi->mode & SPI_NO_CS)
+ return 0;
+
+ if (spi->cs_gpiod)
+ return 0;
+
+ /* for dt-backwards compatibility: only support native on CS0
+ * known things not supported with broken native CS:
+ * * multiple chip-selects: cs0-cs2 are all
+ * simultaniously asserted whenever there is a transfer
+ * this even includes SPI_NO_CS
+ * * SPI_CS_HIGH: cs are always asserted low
+ * * cs_change: cs is deasserted after each spi_transfer
+ * * cs_delay_usec: cs is always deasserted one SCK cycle
+ * after the last transfer
+ * probably more...
+ */
+ dev_warn(&spi->dev,
+ "Native CS is not supported - please configure cs-gpio in device-tree\n");
+
+ if (spi->chip_select == 0)
+ return 0;
+
+ dev_warn(&spi->dev, "Native CS is not working for cs > 0\n");
+
+ return -EINVAL;
+}
+
+static int bcm2835aux_spi_probe(struct platform_device *pdev)
+{
+ struct spi_master *master;
+ struct bcm2835aux_spi *bs;
+ unsigned long clk_hz;
+ int err;
+
+ master = devm_spi_alloc_master(&pdev->dev, sizeof(*bs));
+ if (!master)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, master);
+ master->mode_bits = (SPI_CPOL | SPI_CS_HIGH | SPI_NO_CS);
+ master->bits_per_word_mask = SPI_BPW_MASK(8);
+ /* even though the driver never officially supported native CS
+ * allow a single native CS for legacy DT support purposes when
+ * no cs-gpio is configured.
+ * Known limitations for native cs are:
+ * * multiple chip-selects: cs0-cs2 are all simultaniously asserted
+ * whenever there is a transfer - this even includes SPI_NO_CS
+ * * SPI_CS_HIGH: is ignores - cs are always asserted low
+ * * cs_change: cs is deasserted after each spi_transfer
+ * * cs_delay_usec: cs is always deasserted one SCK cycle after
+ * a spi_transfer
+ */
+ master->num_chipselect = 1;
+ master->setup = bcm2835aux_spi_setup;
+ master->transfer_one = bcm2835aux_spi_transfer_one;
+ master->handle_err = bcm2835aux_spi_handle_err;
+ master->prepare_message = bcm2835aux_spi_prepare_message;
+ master->unprepare_message = bcm2835aux_spi_unprepare_message;
+ master->dev.of_node = pdev->dev.of_node;
+ master->use_gpio_descriptors = true;
+
+ bs = spi_master_get_devdata(master);
+
+ /* the main area */
+ bs->regs = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(bs->regs))
+ return PTR_ERR(bs->regs);
+
+ bs->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(bs->clk)) {
+ err = PTR_ERR(bs->clk);
+ dev_err(&pdev->dev, "could not get clk: %d\n", err);
+ return err;
+ }
+
+ bs->irq = platform_get_irq(pdev, 0);
+ if (bs->irq <= 0)
+ return bs->irq ? bs->irq : -ENODEV;
+
+ /* this also enables the HW block */
+ err = clk_prepare_enable(bs->clk);
+ if (err) {
+ dev_err(&pdev->dev, "could not prepare clock: %d\n", err);
+ return err;
+ }
+
+ /* just checking if the clock returns a sane value */
+ clk_hz = clk_get_rate(bs->clk);
+ if (!clk_hz) {
+ dev_err(&pdev->dev, "clock returns 0 Hz\n");
+ err = -ENODEV;
+ goto out_clk_disable;
+ }
+
+ /* reset SPI-HW block */
+ bcm2835aux_spi_reset_hw(bs);
+
+ err = devm_request_irq(&pdev->dev, bs->irq,
+ bcm2835aux_spi_interrupt,
+ IRQF_SHARED,
+ dev_name(&pdev->dev), master);
+ if (err) {
+ dev_err(&pdev->dev, "could not request IRQ: %d\n", err);
+ goto out_clk_disable;
+ }
+
+ err = spi_register_master(master);
+ if (err) {
+ dev_err(&pdev->dev, "could not register SPI master: %d\n", err);
+ goto out_clk_disable;
+ }
+
+ bcm2835aux_debugfs_create(bs, dev_name(&pdev->dev));
+
+ return 0;
+
+out_clk_disable:
+ clk_disable_unprepare(bs->clk);
+ return err;
+}
+
+static int bcm2835aux_spi_remove(struct platform_device *pdev)
+{
+ struct spi_master *master = platform_get_drvdata(pdev);
+ struct bcm2835aux_spi *bs = spi_master_get_devdata(master);
+
+ bcm2835aux_debugfs_remove(bs);
+
+ spi_unregister_master(master);
+
+ bcm2835aux_spi_reset_hw(bs);
+
+ /* disable the HW block by releasing the clock */
+ clk_disable_unprepare(bs->clk);
+
+ return 0;
+}
+
+static const struct of_device_id bcm2835aux_spi_match[] = {
+ { .compatible = "brcm,bcm2835-aux-spi", },
+ {}
+};
+MODULE_DEVICE_TABLE(of, bcm2835aux_spi_match);
+
+static struct platform_driver bcm2835aux_spi_driver = {
+ .driver = {
+ .name = "spi-bcm2835aux",
+ .of_match_table = bcm2835aux_spi_match,
+ },
+ .probe = bcm2835aux_spi_probe,
+ .remove = bcm2835aux_spi_remove,
+};
+module_platform_driver(bcm2835aux_spi_driver);
+
+MODULE_DESCRIPTION("SPI controller driver for Broadcom BCM2835 aux");
+MODULE_AUTHOR("Martin Sperl <kernel@martin.sperl.org>");
+MODULE_LICENSE("GPL");