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Subject[PATCH v4 02/10] Input: synaptics-rmi4: Add I2C transport driver
Date
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>
---
drivers/input/rmi4/Kconfig | 9 +
drivers/input/rmi4/Makefile | 3 +
drivers/input/rmi4/rmi_i2c.c | 388 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 400 insertions(+)
create mode 100644 drivers/input/rmi4/rmi_i2c.c

diff --git a/drivers/input/rmi4/Kconfig b/drivers/input/rmi4/Kconfig
index 5ea60e3..cc3f7c5 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 12f2197..5539494 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 0000000..e67662a
--- /dev/null
+++ b/drivers/input/rmi4/rmi_i2c.c
@@ -0,0 +1,388 @@
+/*
+ * 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 = {
+ .owner = THIS_MODULE,
+ .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);
--
2.5.0
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