Input: synaptics-rmi4 - add I2C transport driver

Add the transport driver for devices using RMI4 over I2C.

Signed-off-by: Andrew Duggan <aduggan@synaptics.com>
Signed-off-by: Christopher Heiny <cheiny@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>

3 files changed, 399 insertions, 0 deletions

diff --git a/drivers/input/rmi4/Kconfig b/drivers/input/rmi4/Kconfig
index 5ea60e338093..cc3f7c508c19 100644
--- a/drivers/input/rmi4/Kconfig
+++ b/drivers/input/rmi4/Kconfig
@@ -8,3 +8,12 @@ config RMI4_CORE
           required for all RMI4 device support.
 
           If unsure, say Y.
+
+config RMI4_I2C
+        tristate "RMI4 I2C Support"
+        depends on RMI4_CORE && I2C
+        help
+          Say Y here if you want to support RMI4 devices connected to an I2C
+          bus.
+
+          If unsure, say Y.
diff --git a/drivers/input/rmi4/Makefile b/drivers/input/rmi4/Makefile
index 12f219779b74..5539494aecd1 100644
--- a/drivers/input/rmi4/Makefile
+++ b/drivers/input/rmi4/Makefile
@@ -1,2 +1,5 @@
 obj-$(CONFIG_RMI4_CORE) += rmi_core.o
 rmi_core-y := rmi_bus.o rmi_driver.o rmi_f01.o
+
+# Transports
+obj-$(CONFIG_RMI4_I2C) += rmi_i2c.o
diff --git a/drivers/input/rmi4/rmi_i2c.c b/drivers/input/rmi4/rmi_i2c.c
new file mode 100644
index 000000000000..f93742b6537e
--- /dev/null
+++ b/drivers/input/rmi4/rmi_i2c.c
@@ -0,0 +1,387 @@
+/*
+ * 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/i2c.h>
+#include <linux/rmi.h>
+#include <linux/irq.h>
+#include "rmi_driver.h"
+
+#define BUFFER_SIZE_INCREMENT 32
+
+/**
+ * struct rmi_i2c_xport - stores information for i2c communication
+ *
+ * @xport: The transport interface structure
+ *
+ * @page_mutex: Locks current page to avoid changing pages in unexpected ways.
+ * @page: Keeps track of the current virtual page
+ *
+ * @tx_buf: Buffer used for transmitting data to the sensor over i2c.
+ * @tx_buf_size: Size of the buffer
+ */
+struct rmi_i2c_xport {
+        struct rmi_transport_dev xport;
+        struct i2c_client *client;
+
+        struct mutex page_mutex;
+        int page;
+
+        int irq;
+
+        u8 *tx_buf;
+        size_t tx_buf_size;
+};
+
+#define RMI_PAGE_SELECT_REGISTER 0xff
+#define RMI_I2C_PAGE(addr) (((addr) >> 8) & 0xff)
+
+/*
+ * 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_i2c_xport *rmi_i2c, u8 page)
+{
+        struct i2c_client *client = rmi_i2c->client;
+        u8 txbuf[2] = {RMI_PAGE_SELECT_REGISTER, page};
+        int retval;
+
+        retval = i2c_master_send(client, txbuf, sizeof(txbuf));
+        if (retval != sizeof(txbuf)) {
+                dev_err(&client->dev,
+                        "%s: set page failed: %d.", __func__, retval);
+                return (retval < 0) ? retval : -EIO;
+        }
+
+        rmi_i2c->page = page;
+        return 0;
+}
+
+static int rmi_i2c_write_block(struct rmi_transport_dev *xport, u16 addr,
+                               const void *buf, size_t len)
+{
+        struct rmi_i2c_xport *rmi_i2c =
+                container_of(xport, struct rmi_i2c_xport, xport);
+        struct i2c_client *client = rmi_i2c->client;
+        size_t tx_size = len + 1;
+        int retval;
+
+        mutex_lock(&rmi_i2c->page_mutex);
+
+        if (!rmi_i2c->tx_buf || rmi_i2c->tx_buf_size < tx_size) {
+                if (rmi_i2c->tx_buf)
+                        devm_kfree(&client->dev, rmi_i2c->tx_buf);
+                rmi_i2c->tx_buf_size = tx_size + BUFFER_SIZE_INCREMENT;
+                rmi_i2c->tx_buf = devm_kzalloc(&client->dev,
+                                               rmi_i2c->tx_buf_size,
+                                               GFP_KERNEL);
+                if (!rmi_i2c->tx_buf) {
+                        rmi_i2c->tx_buf_size = 0;
+                        retval = -ENOMEM;
+                        goto exit;
+                }
+        }
+
+        rmi_i2c->tx_buf[0] = addr & 0xff;
+        memcpy(rmi_i2c->tx_buf + 1, buf, len);
+
+        if (RMI_I2C_PAGE(addr) != rmi_i2c->page) {
+                retval = rmi_set_page(rmi_i2c, RMI_I2C_PAGE(addr));
+                if (retval)
+                        goto exit;
+        }
+
+        retval = i2c_master_send(client, rmi_i2c->tx_buf, tx_size);
+        if (retval == tx_size)
+                retval = 0;
+        else if (retval >= 0)
+                retval = -EIO;
+
+exit:
+        rmi_dbg(RMI_DEBUG_XPORT, &client->dev,
+                "write %zd bytes at %#06x: %d (%*ph)\n",
+                len, addr, retval, (int)len, buf);
+
+        mutex_unlock(&rmi_i2c->page_mutex);
+        return retval;
+}
+
+static int rmi_i2c_read_block(struct rmi_transport_dev *xport, u16 addr,
+                              void *buf, size_t len)
+{
+        struct rmi_i2c_xport *rmi_i2c =
+                container_of(xport, struct rmi_i2c_xport, xport);
+        struct i2c_client *client = rmi_i2c->client;
+        u8 addr_offset = addr & 0xff;
+        int retval;
+        struct i2c_msg msgs[] = {
+                {
+                        .addr   = client->addr,
+                        .len    = sizeof(addr_offset),
+                        .buf    = &addr_offset,
+                },
+                {
+                        .addr   = client->addr,
+                        .flags  = I2C_M_RD,
+                        .len    = len,
+                        .buf    = buf,
+                },
+        };
+
+        mutex_lock(&rmi_i2c->page_mutex);
+
+        if (RMI_I2C_PAGE(addr) != rmi_i2c->page) {
+                retval = rmi_set_page(rmi_i2c, RMI_I2C_PAGE(addr));
+                if (retval)
+                        goto exit;
+        }
+
+        retval = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
+        if (retval == ARRAY_SIZE(msgs))
+                retval = 0; /* success */
+        else if (retval >= 0)
+                retval = -EIO;
+
+exit:
+        rmi_dbg(RMI_DEBUG_XPORT, &client->dev,
+                "read %zd bytes at %#06x: %d (%*ph)\n",
+                len, addr, retval, (int)len, buf);
+
+        mutex_unlock(&rmi_i2c->page_mutex);
+        return retval;
+}
+
+static const struct rmi_transport_ops rmi_i2c_ops = {
+        .write_block    = rmi_i2c_write_block,
+        .read_block     = rmi_i2c_read_block,
+};
+
+static irqreturn_t rmi_i2c_irq(int irq, void *dev_id)
+{
+        struct rmi_i2c_xport *rmi_i2c = dev_id;
+        struct rmi_device *rmi_dev = rmi_i2c->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_i2c_init_irq(struct i2c_client *client)
+{
+        struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
+        int irq_flags = irqd_get_trigger_type(irq_get_irq_data(rmi_i2c->irq));
+        int ret;
+
+        if (!irq_flags)
+                irq_flags = IRQF_TRIGGER_LOW;
+
+        ret = devm_request_threaded_irq(&client->dev, rmi_i2c->irq, NULL,
+                        rmi_i2c_irq, irq_flags | IRQF_ONESHOT, client->name,
+                        rmi_i2c);
+        if (ret < 0) {
+                dev_warn(&client->dev, "Failed to register interrupt %d\n",
+                        rmi_i2c->irq);
+
+                return ret;
+        }
+
+        return 0;
+}
+
+static int rmi_i2c_probe(struct i2c_client *client,
+                         const struct i2c_device_id *id)
+{
+        struct rmi_device_platform_data *pdata;
+        struct rmi_device_platform_data *client_pdata =
+                                        dev_get_platdata(&client->dev);
+        struct rmi_i2c_xport *rmi_i2c;
+        int retval;
+
+        rmi_i2c = devm_kzalloc(&client->dev, sizeof(struct rmi_i2c_xport),
+                                GFP_KERNEL);
+        if (!rmi_i2c)
+                return -ENOMEM;
+
+        pdata = &rmi_i2c->xport.pdata;
+
+        if (client_pdata)
+                *pdata = *client_pdata;
+
+        if (client->irq > 0)
+                rmi_i2c->irq = client->irq;
+
+        rmi_dbg(RMI_DEBUG_XPORT, &client->dev, "Probing %s.\n",
+                        dev_name(&client->dev));
+        if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+                dev_err(&client->dev,
+                        "adapter does not support required functionality.\n");
+                return -ENODEV;
+        }
+
+        rmi_i2c->client = client;
+        mutex_init(&rmi_i2c->page_mutex);
+
+        rmi_i2c->xport.dev = &client->dev;
+        rmi_i2c->xport.proto_name = "i2c";
+        rmi_i2c->xport.ops = &rmi_i2c_ops;
+
+        i2c_set_clientdata(client, rmi_i2c);
+
+        /*
+         * 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_i2c, 0);
+        if (retval) {
+                dev_err(&client->dev, "Failed to set page select to 0.\n");
+                return retval;
+        }
+
+        retval = rmi_register_transport_device(&rmi_i2c->xport);
+        if (retval) {
+                dev_err(&client->dev, "Failed to register transport driver at 0x%.2X.\n",
+                        client->addr);
+                return retval;
+        }
+
+        retval = rmi_i2c_init_irq(client);
+        if (retval < 0)
+                return retval;
+
+        dev_info(&client->dev, "registered rmi i2c driver at %#04x.\n",
+                        client->addr);
+        return 0;
+}
+
+static int rmi_i2c_remove(struct i2c_client *client)
+{
+        struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
+
+        rmi_unregister_transport_device(&rmi_i2c->xport);
+
+        return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int rmi_i2c_suspend(struct device *dev)
+{
+        struct i2c_client *client = to_i2c_client(dev);
+        struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
+        int ret;
+
+        ret = rmi_driver_suspend(rmi_i2c->xport.rmi_dev);
+        if (ret)
+                dev_warn(dev, "Failed to resume device: %d\n", ret);
+
+        disable_irq(rmi_i2c->irq);
+        if (device_may_wakeup(&client->dev)) {
+                ret = enable_irq_wake(rmi_i2c->irq);
+                if (!ret)
+                        dev_warn(dev, "Failed to enable irq for wake: %d\n",
+                                ret);
+        }
+        return ret;
+}
+
+static int rmi_i2c_resume(struct device *dev)
+{
+        struct i2c_client *client = to_i2c_client(dev);
+        struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
+        int ret;
+
+        enable_irq(rmi_i2c->irq);
+        if (device_may_wakeup(&client->dev)) {
+                ret = disable_irq_wake(rmi_i2c->irq);
+                if (!ret)
+                        dev_warn(dev, "Failed to disable irq for wake: %d\n",
+                                ret);
+        }
+
+        ret = rmi_driver_resume(rmi_i2c->xport.rmi_dev);
+        if (ret)
+                dev_warn(dev, "Failed to resume device: %d\n", ret);
+
+        return ret;
+}
+#endif
+
+#ifdef CONFIG_PM
+static int rmi_i2c_runtime_suspend(struct device *dev)
+{
+        struct i2c_client *client = to_i2c_client(dev);
+        struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
+        int ret;
+
+        ret = rmi_driver_suspend(rmi_i2c->xport.rmi_dev);
+        if (ret)
+                dev_warn(dev, "Failed to resume device: %d\n", ret);
+
+        disable_irq(rmi_i2c->irq);
+
+        return 0;
+}
+
+static int rmi_i2c_runtime_resume(struct device *dev)
+{
+        struct i2c_client *client = to_i2c_client(dev);
+        struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
+        int ret;
+
+        enable_irq(rmi_i2c->irq);
+
+        ret = rmi_driver_resume(rmi_i2c->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_i2c_pm = {
+        SET_SYSTEM_SLEEP_PM_OPS(rmi_i2c_suspend, rmi_i2c_resume)
+        SET_RUNTIME_PM_OPS(rmi_i2c_runtime_suspend, rmi_i2c_runtime_resume,
+                           NULL)
+};
+
+static const struct i2c_device_id rmi_id[] = {
+        { "rmi4_i2c", 0 },
+        { }
+};
+MODULE_DEVICE_TABLE(i2c, rmi_id);
+
+static struct i2c_driver rmi_i2c_driver = {
+        .driver = {
+                .name   = "rmi4_i2c",
+                .pm     = &rmi_i2c_pm,
+        },
+        .id_table       = rmi_id,
+        .probe          = rmi_i2c_probe,
+        .remove         = rmi_i2c_remove,
+};
+
+module_i2c_driver(rmi_i2c_driver);
+
+MODULE_AUTHOR("Christopher Heiny <cheiny@synaptics.com>");
+MODULE_AUTHOR("Andrew Duggan <aduggan@synaptics.com>");
+MODULE_DESCRIPTION("RMI I2C driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(RMI_DRIVER_VERSION);