Quelle  rmi_i2c.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2011-2016 Synaptics Incorporated
 * Copyright (c) 2011 Unixphere
 */

#include <linux/i2c.h>
#include <linux/rmi.h>
#include <linux/of.h>
#include <linux/delay.h>
#include <linux/regulator/consumer.h>
#include "rmi_driver.h"

#define BUFFER_SIZE_INCREMENT 32

/**
 * struct rmi_i2c_xport - stores information for i2c communication
 *
 * @xport: The transport interface structure
 * @client: The I2C client device 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
 *
 * @supplies: Array of voltage regulators
 * @startup_delay: Milliseconds to pause after powering up the regulators
 */
struct rmi_i2c_xport {
 struct rmi_transport_dev xport;
 struct i2c_client *client;

 struct mutex page_mutex;
 int page;

 u8 *tx_buf;
 size_t tx_buf_size;

 struct regulator_bulk_data supplies[2];
 u32 startup_delay;
};

#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,
};

#ifdef CONFIG_OF
static const struct of_device_id rmi_i2c_of_match[] = {
 { .compatible = "syna,rmi4-i2c" },
 {},
};
MODULE_DEVICE_TABLE(of, rmi_i2c_of_match);
#endif

static void rmi_i2c_regulator_bulk_disable(void *data)
{
 struct rmi_i2c_xport *rmi_i2c = data;

 regulator_bulk_disable(ARRAY_SIZE(rmi_i2c->supplies),
          rmi_i2c->supplies);
}

static void rmi_i2c_unregister_transport(void *data)
{
 struct rmi_i2c_xport *rmi_i2c = data;

 rmi_unregister_transport_device(&rmi_i2c->xport);
}

static int rmi_i2c_probe(struct i2c_client *client)
{
 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 error;

 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->dev.of_node && client_pdata)
  *pdata = *client_pdata;

 pdata->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->supplies[0].supply = "vdd";
 rmi_i2c->supplies[1].supply = "vio";
 error = devm_regulator_bulk_get(&client->dev,
      ARRAY_SIZE(rmi_i2c->supplies),
      rmi_i2c->supplies);
 if (error < 0)
  return error;

 error = regulator_bulk_enable(ARRAY_SIZE(rmi_i2c->supplies),
           rmi_i2c->supplies);
 if (error < 0)
  return error;

 error = devm_add_action_or_reset(&client->dev,
       rmi_i2c_regulator_bulk_disable,
       rmi_i2c);
 if (error)
  return error;

 of_property_read_u32(client->dev.of_node, "syna,startup-delay-ms",
        &rmi_i2c->startup_delay);

 msleep(rmi_i2c->startup_delay);

 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.
 */
 error = rmi_set_page(rmi_i2c, 0);
 if (error) {
  dev_err(&client->dev, "Failed to set page select to 0\n");
  return error;
 }

 dev_info(&client->dev, "registering I2C-connected sensor\n");

 error = rmi_register_transport_device(&rmi_i2c->xport);
 if (error) {
  dev_err(&client->dev, "failed to register sensor: %d\n", error);
  return error;
 }

 error = devm_add_action_or_reset(&client->dev,
       rmi_i2c_unregister_transport,
       rmi_i2c);
 if (error)
  return error;

 return 0;
}

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, true);
 if (ret)
  dev_warn(dev, "Failed to resume device: %d\n", ret);

 regulator_bulk_disable(ARRAY_SIZE(rmi_i2c->supplies),
          rmi_i2c->supplies);

 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;

 ret = regulator_bulk_enable(ARRAY_SIZE(rmi_i2c->supplies),
        rmi_i2c->supplies);
 if (ret)
  return ret;

 msleep(rmi_i2c->startup_delay);

 ret = rmi_driver_resume(rmi_i2c->xport.rmi_dev, true);
 if (ret)
  dev_warn(dev, "Failed to resume device: %d\n", ret);

 return ret;
}

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, false);
 if (ret)
  dev_warn(dev, "Failed to resume device: %d\n", ret);

 regulator_bulk_disable(ARRAY_SIZE(rmi_i2c->supplies),
          rmi_i2c->supplies);

 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;

 ret = regulator_bulk_enable(ARRAY_SIZE(rmi_i2c->supplies),
        rmi_i2c->supplies);
 if (ret)
  return ret;

 msleep(rmi_i2c->startup_delay);

 ret = rmi_driver_resume(rmi_i2c->xport.rmi_dev, false);
 if (ret)
  dev_warn(dev, "Failed to resume device: %d\n", ret);

 return 0;
}

static const struct dev_pm_ops rmi_i2c_pm = {
 SYSTEM_SLEEP_PM_OPS(rmi_i2c_suspend, rmi_i2c_resume)
 RUNTIME_PM_OPS(rmi_i2c_runtime_suspend, rmi_i2c_runtime_resume, NULL)
};

static const struct i2c_device_id rmi_id[] = {
 { "rmi4_i2c" },
 { }
};
MODULE_DEVICE_TABLE(i2c, rmi_id);

static struct i2c_driver rmi_i2c_driver = {
 .driver = {
  .name = "rmi4_i2c",
  .pm = pm_ptr(&rmi_i2c_pm),
  .of_match_table = of_match_ptr(rmi_i2c_of_match),
 },
 .id_table = rmi_id,
 .probe  = rmi_i2c_probe,
};

module_i2c_driver(rmi_i2c_driver);

MODULE_AUTHOR("Christopher Heiny ");
MODULE_AUTHOR("Andrew Duggan ");
MODULE_DESCRIPTION("RMI I2C driver");
MODULE_LICENSE("GPL");