Input: synaptics-rmi4 - add SPI transport driver

Add the transport driver for devices using RMI4 over SPI.

Signed-off-by: Andrew Duggan <aduggan@synaptics.com>
Tested-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

4 files changed, 608 insertions, 0 deletions

diff --git a/drivers/input/rmi4/Kconfig b/drivers/input/rmi4/Kconfig
index 284faec30a7a..f73df2495fed 100644
--- a/drivers/input/rmi4/Kconfig
+++ b/drivers/input/rmi4/Kconfig
@@ -18,6 +18,15 @@ config RMI4_I2C
 
           If unsure, say Y.
 
+config RMI4_SPI
+        tristate "RMI4 SPI Support"
+        depends on RMI4_CORE && SPI
+        help
+          Say Y here if you want to support RMI4 devices connected to a SPI
+          bus.
+
+          If unsure, say N.
+
 config RMI4_2D_SENSOR
         bool
         depends on RMI4_CORE
diff --git a/drivers/input/rmi4/Makefile b/drivers/input/rmi4/Makefile
index ad7156d8252c..95c00a783992 100644
--- a/drivers/input/rmi4/Makefile
+++ b/drivers/input/rmi4/Makefile
@@ -10,3 +10,4 @@ rmi_core-$(CONFIG_RMI4_F30) += rmi_f30.o
 
 # Transports
 obj-$(CONFIG_RMI4_I2C) += rmi_i2c.o
+obj-$(CONFIG_RMI4_SPI) += rmi_spi.o
diff --git a/drivers/input/rmi4/rmi_spi.c b/drivers/input/rmi4/rmi_spi.c
new file mode 100644
index 000000000000..4319c634553f
--- /dev/null
+++ b/drivers/input/rmi4/rmi_spi.c
@@ -0,0 +1,547 @@
+/*
+ * Copyright (c) 2011-2016 Synaptics Incorporated
+ * Copyright (c) 2011 Unixphere
+ *
+ * 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 <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/rmi.h>
+#include <linux/slab.h>
+#include <linux/spi/spi.h>
+#include <linux/irq.h>
+#include "rmi_driver.h"
+
+#define RMI_SPI_DEFAULT_XFER_BUF_SIZE   64
+
+#define RMI_PAGE_SELECT_REGISTER        0x00FF
+#define RMI_SPI_PAGE(addr)              (((addr) >> 8) & 0x80)
+#define RMI_SPI_XFER_SIZE_LIMIT         255
+
+#define BUFFER_SIZE_INCREMENT 32
+
+enum rmi_spi_op {
+        RMI_SPI_WRITE = 0,
+        RMI_SPI_READ,
+        RMI_SPI_V2_READ_UNIFIED,
+        RMI_SPI_V2_READ_SPLIT,
+        RMI_SPI_V2_WRITE,
+};
+
+struct rmi_spi_cmd {
+        enum rmi_spi_op op;
+        u16 addr;
+};
+
+struct rmi_spi_xport {
+        struct rmi_transport_dev xport;
+        struct spi_device *spi;
+
+        struct mutex page_mutex;
+        int page;
+
+        int irq;
+
+        u8 *rx_buf;
+        u8 *tx_buf;
+        int xfer_buf_size;
+
+        struct spi_transfer *rx_xfers;
+        struct spi_transfer *tx_xfers;
+        int rx_xfer_count;
+        int tx_xfer_count;
+};
+
+static int rmi_spi_manage_pools(struct rmi_spi_xport *rmi_spi, int len)
+{
+        struct spi_device *spi = rmi_spi->spi;
+        int buf_size = rmi_spi->xfer_buf_size
+                ? rmi_spi->xfer_buf_size : RMI_SPI_DEFAULT_XFER_BUF_SIZE;
+        struct spi_transfer *xfer_buf;
+        void *buf;
+        void *tmp;
+
+        while (buf_size < len)
+                buf_size *= 2;
+
+        if (buf_size > RMI_SPI_XFER_SIZE_LIMIT)
+                buf_size = RMI_SPI_XFER_SIZE_LIMIT;
+
+        tmp = rmi_spi->rx_buf;
+        buf = devm_kzalloc(&spi->dev, buf_size * 2,
+                                GFP_KERNEL | GFP_DMA);
+        if (!buf)
+                return -ENOMEM;
+
+        rmi_spi->rx_buf = buf;
+        rmi_spi->tx_buf = &rmi_spi->rx_buf[buf_size];
+        rmi_spi->xfer_buf_size = buf_size;
+
+        if (tmp)
+                devm_kfree(&spi->dev, tmp);
+
+        if (rmi_spi->xport.pdata.spi_data.read_delay_us)
+                rmi_spi->rx_xfer_count = buf_size;
+        else
+                rmi_spi->rx_xfer_count = 1;
+
+        if (rmi_spi->xport.pdata.spi_data.write_delay_us)
+                rmi_spi->tx_xfer_count = buf_size;
+        else
+                rmi_spi->tx_xfer_count = 1;
+
+        /*
+         * Allocate a pool of spi_transfer buffers for devices which need
+         * per byte delays.
+         */
+        tmp = rmi_spi->rx_xfers;
+        xfer_buf = devm_kzalloc(&spi->dev,
+                (rmi_spi->rx_xfer_count + rmi_spi->tx_xfer_count)
+                * sizeof(struct spi_transfer), GFP_KERNEL);
+        if (!xfer_buf)
+                return -ENOMEM;
+
+        rmi_spi->rx_xfers = xfer_buf;
+        rmi_spi->tx_xfers = &xfer_buf[rmi_spi->rx_xfer_count];
+
+        if (tmp)
+                devm_kfree(&spi->dev, tmp);
+
+        return 0;
+}
+
+static int rmi_spi_xfer(struct rmi_spi_xport *rmi_spi,
+                        const struct rmi_spi_cmd *cmd, const u8 *tx_buf,
+                        int tx_len, u8 *rx_buf, int rx_len)
+{
+        struct spi_device *spi = rmi_spi->spi;
+        struct rmi_device_platform_data_spi *spi_data =
+                                        &rmi_spi->xport.pdata.spi_data;
+        struct spi_message msg;
+        struct spi_transfer *xfer;
+        int ret = 0;
+        int len;
+        int cmd_len = 0;
+        int total_tx_len;
+        int i;
+        u16 addr = cmd->addr;
+
+        spi_message_init(&msg);
+
+        switch (cmd->op) {
+        case RMI_SPI_WRITE:
+        case RMI_SPI_READ:
+                cmd_len += 2;
+                break;
+        case RMI_SPI_V2_READ_UNIFIED:
+        case RMI_SPI_V2_READ_SPLIT:
+        case RMI_SPI_V2_WRITE:
+                cmd_len += 4;
+                break;
+        }
+
+        total_tx_len = cmd_len + tx_len;
+        len = max(total_tx_len, rx_len);
+
+        if (len > RMI_SPI_XFER_SIZE_LIMIT)
+                return -EINVAL;
+
+        if (rmi_spi->xfer_buf_size < len)
+                rmi_spi_manage_pools(rmi_spi, len);
+
+        if (addr == 0)
+                /*
+                 * SPI needs an address. Use 0x7FF if we want to keep
+                 * reading from the last position of the register pointer.
+                 */
+                addr = 0x7FF;
+
+        switch (cmd->op) {
+        case RMI_SPI_WRITE:
+                rmi_spi->tx_buf[0] = (addr >> 8);
+                rmi_spi->tx_buf[1] = addr & 0xFF;
+                break;
+        case RMI_SPI_READ:
+                rmi_spi->tx_buf[0] = (addr >> 8) | 0x80;
+                rmi_spi->tx_buf[1] = addr & 0xFF;
+                break;
+        case RMI_SPI_V2_READ_UNIFIED:
+                break;
+        case RMI_SPI_V2_READ_SPLIT:
+                break;
+        case RMI_SPI_V2_WRITE:
+                rmi_spi->tx_buf[0] = 0x40;
+                rmi_spi->tx_buf[1] = (addr >> 8) & 0xFF;
+                rmi_spi->tx_buf[2] = addr & 0xFF;
+                rmi_spi->tx_buf[3] = tx_len;
+                break;
+        }
+
+        if (tx_buf)
+                memcpy(&rmi_spi->tx_buf[cmd_len], tx_buf, tx_len);
+
+        if (rmi_spi->tx_xfer_count > 1) {
+                for (i = 0; i < total_tx_len; i++) {
+                        xfer = &rmi_spi->tx_xfers[i];
+                        memset(xfer, 0, sizeof(struct spi_transfer));
+                        xfer->tx_buf = &rmi_spi->tx_buf[i];
+                        xfer->len = 1;
+                        xfer->delay_usecs = spi_data->write_delay_us;
+                        spi_message_add_tail(xfer, &msg);
+                }
+        } else {
+                xfer = rmi_spi->tx_xfers;
+                memset(xfer, 0, sizeof(struct spi_transfer));
+                xfer->tx_buf = rmi_spi->tx_buf;
+                xfer->len = total_tx_len;
+                spi_message_add_tail(xfer, &msg);
+        }
+
+        rmi_dbg(RMI_DEBUG_XPORT, &spi->dev, "%s: cmd: %s tx_buf len: %d tx_buf: %*ph\n",
+                __func__, cmd->op == RMI_SPI_WRITE ? "WRITE" : "READ",
+                total_tx_len, total_tx_len, rmi_spi->tx_buf);
+
+        if (rx_buf) {
+                if (rmi_spi->rx_xfer_count > 1) {
+                        for (i = 0; i < rx_len; i++) {
+                                xfer = &rmi_spi->rx_xfers[i];
+                                memset(xfer, 0, sizeof(struct spi_transfer));
+                                xfer->rx_buf = &rmi_spi->rx_buf[i];
+                                xfer->len = 1;
+                                xfer->delay_usecs = spi_data->read_delay_us;
+                                spi_message_add_tail(xfer, &msg);
+                        }
+                } else {
+                        xfer = rmi_spi->rx_xfers;
+                        memset(xfer, 0, sizeof(struct spi_transfer));
+                        xfer->rx_buf = rmi_spi->rx_buf;
+                        xfer->len = rx_len;
+                        spi_message_add_tail(xfer, &msg);
+                }
+        }
+
+        ret = spi_sync(spi, &msg);
+        if (ret < 0) {
+                dev_err(&spi->dev, "spi xfer failed: %d\n", ret);
+                return ret;
+        }
+
+        if (rx_buf) {
+                memcpy(rx_buf, rmi_spi->rx_buf, rx_len);
+                rmi_dbg(RMI_DEBUG_XPORT, &spi->dev, "%s: (%d) %*ph\n",
+                        __func__, rx_len, rx_len, rx_buf);
+        }
+
+        return 0;
+}
+
+/*
+ * rmi_set_page - Set RMI page
+ * @xport: The pointer to the rmi_transport_dev struct
+ * @page: The new page address.
+ *
+ * RMI devices have 16-bit addressing, but some of the transport
+ * implementations (like SMBus) only have 8-bit addressing. So RMI implements
+ * a page address at 0xff of every page so we can reliable page addresses
+ * every 256 registers.
+ *
+ * The page_mutex lock must be held when this function is entered.
+ *
+ * Returns zero on success, non-zero on failure.
+ */
+static int rmi_set_page(struct rmi_spi_xport *rmi_spi, u8 page)
+{
+        struct rmi_spi_cmd cmd;
+        int ret;
+
+        cmd.op = RMI_SPI_WRITE;
+        cmd.addr = RMI_PAGE_SELECT_REGISTER;
+
+        ret = rmi_spi_xfer(rmi_spi, &cmd, &page, 1, NULL, 0);
+
+        if (ret)
+                rmi_spi->page = page;
+
+        return ret;
+}
+
+static int rmi_spi_write_block(struct rmi_transport_dev *xport, u16 addr,
+                               const void *buf, size_t len)
+{
+        struct rmi_spi_xport *rmi_spi =
+                container_of(xport, struct rmi_spi_xport, xport);
+        struct rmi_spi_cmd cmd;
+        int ret;
+
+        mutex_lock(&rmi_spi->page_mutex);
+
+        if (RMI_SPI_PAGE(addr) != rmi_spi->page) {
+                ret = rmi_set_page(rmi_spi, RMI_SPI_PAGE(addr));
+                if (ret)
+                        goto exit;
+        }
+
+        cmd.op = RMI_SPI_WRITE;
+        cmd.addr = addr;
+
+        ret = rmi_spi_xfer(rmi_spi, &cmd, buf, len, NULL, 0);
+
+exit:
+        mutex_unlock(&rmi_spi->page_mutex);
+        return ret;
+}
+
+static int rmi_spi_read_block(struct rmi_transport_dev *xport, u16 addr,
+                              void *buf, size_t len)
+{
+        struct rmi_spi_xport *rmi_spi =
+                container_of(xport, struct rmi_spi_xport, xport);
+        struct rmi_spi_cmd cmd;
+        int ret;
+
+        mutex_lock(&rmi_spi->page_mutex);
+
+        if (RMI_SPI_PAGE(addr) != rmi_spi->page) {
+                ret = rmi_set_page(rmi_spi, RMI_SPI_PAGE(addr));
+                if (ret)
+                        goto exit;
+        }
+
+        cmd.op = RMI_SPI_READ;
+        cmd.addr = addr;
+
+        ret = rmi_spi_xfer(rmi_spi, &cmd, NULL, 0, buf, len);
+
+exit:
+        mutex_unlock(&rmi_spi->page_mutex);
+        return ret;
+}
+
+static const struct rmi_transport_ops rmi_spi_ops = {
+        .write_block    = rmi_spi_write_block,
+        .read_block     = rmi_spi_read_block,
+};
+
+static irqreturn_t rmi_spi_irq(int irq, void *dev_id)
+{
+        struct rmi_spi_xport *rmi_spi = dev_id;
+        struct rmi_device *rmi_dev = rmi_spi->xport.rmi_dev;
+        int ret;
+
+        ret = rmi_process_interrupt_requests(rmi_dev);
+        if (ret)
+                rmi_dbg(RMI_DEBUG_XPORT, &rmi_dev->dev,
+                        "Failed to process interrupt request: %d\n", ret);
+
+        return IRQ_HANDLED;
+}
+
+static int rmi_spi_init_irq(struct spi_device *spi)
+{
+        struct rmi_spi_xport *rmi_spi = spi_get_drvdata(spi);
+        int irq_flags = irqd_get_trigger_type(irq_get_irq_data(rmi_spi->irq));
+        int ret;
+
+        if (!irq_flags)
+                irq_flags = IRQF_TRIGGER_LOW;
+
+        ret = devm_request_threaded_irq(&spi->dev, rmi_spi->irq, NULL,
+                        rmi_spi_irq, irq_flags | IRQF_ONESHOT,
+                        dev_name(&spi->dev), rmi_spi);
+        if (ret < 0) {
+                dev_warn(&spi->dev, "Failed to register interrupt %d\n",
+                        rmi_spi->irq);
+                return ret;
+        }
+
+        return 0;
+}
+
+static int rmi_spi_probe(struct spi_device *spi)
+{
+        struct rmi_spi_xport *rmi_spi;
+        struct rmi_device_platform_data *pdata;
+        struct rmi_device_platform_data *spi_pdata = spi->dev.platform_data;
+        int retval;
+
+        if (spi->master->flags & SPI_MASTER_HALF_DUPLEX)
+                return -EINVAL;
+
+        rmi_spi = devm_kzalloc(&spi->dev, sizeof(struct rmi_spi_xport),
+                        GFP_KERNEL);
+        if (!rmi_spi)
+                return -ENOMEM;
+
+        pdata = &rmi_spi->xport.pdata;
+
+        if (spi_pdata)
+                *pdata = *spi_pdata;
+
+        if (pdata->spi_data.bits_per_word)
+                spi->bits_per_word = pdata->spi_data.bits_per_word;
+
+        if (pdata->spi_data.mode)
+                spi->mode = pdata->spi_data.mode;
+
+        retval = spi_setup(spi);
+        if (retval < 0) {
+                dev_err(&spi->dev, "spi_setup failed!\n");
+                return retval;
+        }
+
+        if (spi->irq > 0)
+                rmi_spi->irq = spi->irq;
+
+        rmi_spi->spi = spi;
+        mutex_init(&rmi_spi->page_mutex);
+
+        rmi_spi->xport.dev = &spi->dev;
+        rmi_spi->xport.proto_name = "spi";
+        rmi_spi->xport.ops = &rmi_spi_ops;
+
+        spi_set_drvdata(spi, rmi_spi);
+
+        retval = rmi_spi_manage_pools(rmi_spi, RMI_SPI_DEFAULT_XFER_BUF_SIZE);
+        if (retval)
+                return retval;
+
+        /*
+         * Setting the page to zero will (a) make sure the PSR is in a
+         * known state, and (b) make sure we can talk to the device.
+         */
+        retval = rmi_set_page(rmi_spi, 0);
+        if (retval) {
+                dev_err(&spi->dev, "Failed to set page select to 0.\n");
+                return retval;
+        }
+
+        retval = rmi_register_transport_device(&rmi_spi->xport);
+        if (retval) {
+                dev_err(&spi->dev, "failed to register transport.\n");
+                return retval;
+        }
+
+        retval = rmi_spi_init_irq(spi);
+        if (retval < 0)
+                return retval;
+
+        dev_info(&spi->dev, "registered RMI SPI driver\n");
+        return 0;
+}
+
+static int rmi_spi_remove(struct spi_device *spi)
+{
+        struct rmi_spi_xport *rmi_spi = spi_get_drvdata(spi);
+
+        rmi_unregister_transport_device(&rmi_spi->xport);
+
+        return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int rmi_spi_suspend(struct device *dev)
+{
+        struct spi_device *spi = to_spi_device(dev);
+        struct rmi_spi_xport *rmi_spi = spi_get_drvdata(spi);
+        int ret;
+
+        ret = rmi_driver_suspend(rmi_spi->xport.rmi_dev);
+        if (ret)
+                dev_warn(dev, "Failed to resume device: %d\n", ret);
+
+        disable_irq(rmi_spi->irq);
+        if (device_may_wakeup(&spi->dev)) {
+                ret = enable_irq_wake(rmi_spi->irq);
+                if (!ret)
+                        dev_warn(dev, "Failed to enable irq for wake: %d\n",
+                                ret);
+        }
+        return ret;
+}
+
+static int rmi_spi_resume(struct device *dev)
+{
+        struct spi_device *spi = to_spi_device(dev);
+        struct rmi_spi_xport *rmi_spi = spi_get_drvdata(spi);
+        int ret;
+
+        enable_irq(rmi_spi->irq);
+        if (device_may_wakeup(&spi->dev)) {
+                ret = disable_irq_wake(rmi_spi->irq);
+                if (!ret)
+                        dev_warn(dev, "Failed to disable irq for wake: %d\n",
+                                ret);
+        }
+
+        ret = rmi_driver_resume(rmi_spi->xport.rmi_dev);
+        if (ret)
+                dev_warn(dev, "Failed to resume device: %d\n", ret);
+
+        return ret;
+}
+#endif
+
+#ifdef CONFIG_PM
+static int rmi_spi_runtime_suspend(struct device *dev)
+{
+        struct spi_device *spi = to_spi_device(dev);
+        struct rmi_spi_xport *rmi_spi = spi_get_drvdata(spi);
+        int ret;
+
+        ret = rmi_driver_suspend(rmi_spi->xport.rmi_dev);
+        if (ret)
+                dev_warn(dev, "Failed to resume device: %d\n", ret);
+
+        disable_irq(rmi_spi->irq);
+
+        return 0;
+}
+
+static int rmi_spi_runtime_resume(struct device *dev)
+{
+        struct spi_device *spi = to_spi_device(dev);
+        struct rmi_spi_xport *rmi_spi = spi_get_drvdata(spi);
+        int ret;
+
+        enable_irq(rmi_spi->irq);
+
+        ret = rmi_driver_resume(rmi_spi->xport.rmi_dev);
+        if (ret)
+                dev_warn(dev, "Failed to resume device: %d\n", ret);
+
+        return 0;
+}
+#endif
+
+static const struct dev_pm_ops rmi_spi_pm = {
+        SET_SYSTEM_SLEEP_PM_OPS(rmi_spi_suspend, rmi_spi_resume)
+        SET_RUNTIME_PM_OPS(rmi_spi_runtime_suspend, rmi_spi_runtime_resume,
+                           NULL)
+};
+
+static const struct spi_device_id rmi_id[] = {
+        { "rmi4_spi", 0 },
+        { }
+};
+MODULE_DEVICE_TABLE(spi, rmi_id);
+
+static struct spi_driver rmi_spi_driver = {
+        .driver = {
+                .name   = "rmi4_spi",
+                .pm     = &rmi_spi_pm,
+        },
+        .id_table       = rmi_id,
+        .probe          = rmi_spi_probe,
+        .remove         = rmi_spi_remove,
+};
+
+module_spi_driver(rmi_spi_driver);
+
+MODULE_AUTHOR("Christopher Heiny <cheiny@synaptics.com>");
+MODULE_AUTHOR("Andrew Duggan <aduggan@synaptics.com>");
+MODULE_DESCRIPTION("RMI SPI driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(RMI_DRIVER_VERSION);
diff --git a/include/linux/rmi.h b/include/linux/rmi.h
index ac89d1e731dc..e0aca1476001 100644
--- a/include/linux/rmi.h
+++ b/include/linux/rmi.h
@@ -150,6 +150,55 @@ struct rmi_f01_power_management {
 };
 
 /**
+ * struct rmi_device_platform_data_spi - provides parameters used in SPI
+ * communications.  All Synaptics SPI products support a standard SPI
+ * interface; some also support what is called SPI V2 mode, depending on
+ * firmware and/or ASIC limitations.  In V2 mode, the touch sensor can
+ * support shorter delays during certain operations, and these are specified
+ * separately from the standard mode delays.
+ *
+ * @block_delay - for standard SPI transactions consisting of both a read and
+ * write operation, the delay (in microseconds) between the read and write
+ * operations.
+ * @split_read_block_delay_us - for V2 SPI transactions consisting of both a
+ * read and write operation, the delay (in microseconds) between the read and
+ * write operations.
+ * @read_delay_us - the delay between each byte of a read operation in normal
+ * SPI mode.
+ * @write_delay_us - the delay between each byte of a write operation in normal
+ * SPI mode.
+ * @split_read_byte_delay_us - the delay between each byte of a read operation
+ * in V2 mode.
+ * @pre_delay_us - the delay before the start of a SPI transaction.  This is
+ * typically useful in conjunction with custom chip select assertions (see
+ * below).
+ * @post_delay_us - the delay after the completion of an SPI transaction.  This
+ * is typically useful in conjunction with custom chip select assertions (see
+ * below).
+ * @cs_assert - For systems where the SPI subsystem does not control the CS/SSB
+ * line, or where such control is broken, you can provide a custom routine to
+ * handle a GPIO as CS/SSB.  This routine will be called at the beginning and
+ * end of each SPI transaction.  The RMI SPI implementation will wait
+ * pre_delay_us after this routine returns before starting the SPI transfer;
+ * and post_delay_us after completion of the SPI transfer(s) before calling it
+ * with assert==FALSE.
+ */
+struct rmi_device_platform_data_spi {
+        u32 block_delay_us;
+        u32 split_read_block_delay_us;
+        u32 read_delay_us;
+        u32 write_delay_us;
+        u32 split_read_byte_delay_us;
+        u32 pre_delay_us;
+        u32 post_delay_us;
+        u8 bits_per_word;
+        u16 mode;
+
+        void *cs_assert_data;
+        int (*cs_assert)(const void *cs_assert_data, const bool assert);
+};
+
+/**
  * struct rmi_device_platform_data - system specific configuration info.
  *
  * @reset_delay_ms - after issuing a reset command to the touch sensor, the
@@ -159,6 +208,8 @@ struct rmi_f01_power_management {
 struct rmi_device_platform_data {
         int reset_delay_ms;
 
+        struct rmi_device_platform_data_spi spi_data;
+
         /* function handler pdata */
         struct rmi_2d_sensor_platform_data *sensor_pdata;
         struct rmi_f01_power_management power_management;