Quelle  i2c-pca-platform.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/*
 *  i2c_pca_platform.c
 *
 *  Platform driver for the PCA9564 I2C controller.
 *
 *  Copyright (C) 2008 Pengutronix
 *

 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/jiffies.h>
#include <linux/errno.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/i2c-algo-pca.h>
#include <linux/platform_data/i2c-pca-platform.h>
#include <linux/gpio/consumer.h>
#include <linux/io.h>
#include <linux/of.h>

#include <asm/irq.h>

struct i2c_pca_pf_data {
 void __iomem   *reg_base;
 int    irq; /* if 0, use polling */
 struct gpio_desc  *gpio;
 wait_queue_head_t  wait;
 struct i2c_adapter  adap;
 struct i2c_algo_pca_data algo_data;
};

/* Read/Write functions for different register alignments */

static int i2c_pca_pf_readbyte8(void *pd, int reg)
{
 struct i2c_pca_pf_data *i2c = pd;
 return ioread8(i2c->reg_base + reg);
}

static int i2c_pca_pf_readbyte16(void *pd, int reg)
{
 struct i2c_pca_pf_data *i2c = pd;
 return ioread8(i2c->reg_base + reg * 2);
}

static int i2c_pca_pf_readbyte32(void *pd, int reg)
{
 struct i2c_pca_pf_data *i2c = pd;
 return ioread8(i2c->reg_base + reg * 4);
}

static void i2c_pca_pf_writebyte8(void *pd, int reg, int val)
{
 struct i2c_pca_pf_data *i2c = pd;
 iowrite8(val, i2c->reg_base + reg);
}

static void i2c_pca_pf_writebyte16(void *pd, int reg, int val)
{
 struct i2c_pca_pf_data *i2c = pd;
 iowrite8(val, i2c->reg_base + reg * 2);
}

static void i2c_pca_pf_writebyte32(void *pd, int reg, int val)
{
 struct i2c_pca_pf_data *i2c = pd;
 iowrite8(val, i2c->reg_base + reg * 4);
}


static int i2c_pca_pf_waitforcompletion(void *pd)
{
 struct i2c_pca_pf_data *i2c = pd;
 unsigned long timeout;
 long ret;

 if (i2c->irq) {
  ret = wait_event_timeout(i2c->wait,
   i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
   & I2C_PCA_CON_SI, i2c->adap.timeout);
 } else {
  /* Do polling */
  timeout = jiffies + i2c->adap.timeout;
  do {
   ret = time_before(jiffies, timeout);
   if (i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
     & I2C_PCA_CON_SI)
    break;
   udelay(100);
  } while (ret);
 }

 return ret > 0;
}

static void i2c_pca_pf_dummyreset(void *pd)
{
 struct i2c_pca_pf_data *i2c = pd;

 dev_warn(&i2c->adap.dev, "No reset-pin found. Chip may get stuck!\n");
}

static void i2c_pca_pf_resetchip(void *pd)
{
 struct i2c_pca_pf_data *i2c = pd;

 gpiod_set_value(i2c->gpio, 1);
 ndelay(100);
 gpiod_set_value(i2c->gpio, 0);
}

static irqreturn_t i2c_pca_pf_handler(int this_irq, void *dev_id)
{
 struct i2c_pca_pf_data *i2c = dev_id;

 if ((i2c->algo_data.read_byte(i2c, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0)
  return IRQ_NONE;

 wake_up(&i2c->wait);

 return IRQ_HANDLED;
}


static int i2c_pca_pf_probe(struct platform_device *pdev)
{
 struct i2c_pca_pf_data *i2c;
 struct resource *res;
 struct i2c_pca9564_pf_platform_data *platform_data =
    dev_get_platdata(&pdev->dev);
 struct device_node *np = pdev->dev.of_node;
 int ret = 0;
 int irq;

 irq = platform_get_irq_optional(pdev, 0);
 /* If irq is 0, we do polling. */
 if (irq < 0)
  irq = 0;

 i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
 if (!i2c)
  return -ENOMEM;

 i2c->reg_base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
 if (IS_ERR(i2c->reg_base))
  return PTR_ERR(i2c->reg_base);


 init_waitqueue_head(&i2c->wait);

 i2c->irq = irq;

 i2c->adap.nr = pdev->id;
 i2c->adap.owner = THIS_MODULE;
 snprintf(i2c->adap.name, sizeof(i2c->adap.name),
   "PCA9564/PCA9665 at 0x%08lx",
   (unsigned long) res->start);
 i2c->adap.algo_data = &i2c->algo_data;
 i2c->adap.dev.parent = &pdev->dev;
 i2c->adap.dev.of_node = np;

 i2c->gpio = devm_gpiod_get_optional(&pdev->dev, "reset", GPIOD_OUT_LOW);
 if (IS_ERR(i2c->gpio))
  return PTR_ERR(i2c->gpio);

 i2c->adap.timeout = HZ;
 ret = device_property_read_u32(&pdev->dev, "clock-frequency",
           &i2c->algo_data.i2c_clock);
 if (ret)
  i2c->algo_data.i2c_clock = 59000;

 if (platform_data) {
  i2c->adap.timeout = platform_data->timeout;
  i2c->algo_data.i2c_clock = platform_data->i2c_clock_speed;
 }

 i2c->algo_data.data = i2c;
 i2c->algo_data.wait_for_completion = i2c_pca_pf_waitforcompletion;
 if (i2c->gpio)
  i2c->algo_data.reset_chip = i2c_pca_pf_resetchip;
 else
  i2c->algo_data.reset_chip = i2c_pca_pf_dummyreset;

 switch (res->flags & IORESOURCE_MEM_TYPE_MASK) {
 case IORESOURCE_MEM_32BIT:
  i2c->algo_data.write_byte = i2c_pca_pf_writebyte32;
  i2c->algo_data.read_byte = i2c_pca_pf_readbyte32;
  break;
 case IORESOURCE_MEM_16BIT:
  i2c->algo_data.write_byte = i2c_pca_pf_writebyte16;
  i2c->algo_data.read_byte = i2c_pca_pf_readbyte16;
  break;
 case IORESOURCE_MEM_8BIT:
 default:
  i2c->algo_data.write_byte = i2c_pca_pf_writebyte8;
  i2c->algo_data.read_byte = i2c_pca_pf_readbyte8;
  break;
 }

 if (irq) {
  ret = devm_request_irq(&pdev->dev, irq, i2c_pca_pf_handler,
   IRQF_TRIGGER_FALLING, pdev->name, i2c);
  if (ret)
   return ret;
 }

 ret = i2c_pca_add_numbered_bus(&i2c->adap);
 if (ret)
  return ret;

 platform_set_drvdata(pdev, i2c);

 dev_info(&pdev->dev, "registered.\n");

 return 0;
}

static void i2c_pca_pf_remove(struct platform_device *pdev)
{
 struct i2c_pca_pf_data *i2c = platform_get_drvdata(pdev);

 i2c_del_adapter(&i2c->adap);
}

#ifdef CONFIG_OF
static const struct of_device_id i2c_pca_of_match_table[] = {
 { .compatible = "nxp,pca9564" },
 { .compatible = "nxp,pca9665" },
 {},
};
MODULE_DEVICE_TABLE(of, i2c_pca_of_match_table);
#endif

static struct platform_driver i2c_pca_pf_driver = {
 .probe = i2c_pca_pf_probe,
 .remove = i2c_pca_pf_remove,
 .driver = {
  .name = "i2c-pca-platform",
  .of_match_table = of_match_ptr(i2c_pca_of_match_table),
 },
};

module_platform_driver(i2c_pca_pf_driver);

MODULE_AUTHOR("Wolfram Sang ");
MODULE_DESCRIPTION("I2C-PCA9564/PCA9665 platform driver");
MODULE_LICENSE("GPL");