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linux-stable/drivers/i2c/busses/i2c-kempld.c
Michael Brunner 647d908816 i2c: kempld: deprecate class based instantiation 
Warn users that class based instantiation is going away soon in favour
of more robust probing and faster bootup times.

Class based instantiation has already been removed for other controllers
and it makes absolutely sense to do it for this one too.

Signed-off-by: Michael Brunner <michael.brunner@kontron.com>
Acked-by: Ingmar Klein <ingmar.klein@kontron.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
2021-09-29 23:07:02 +02:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* I2C bus driver for Kontron COM modules
*
* Copyright (c) 2010-2013 Kontron Europe GmbH
* Author: Michael Brunner <michael.brunner@kontron.com>
*
* The driver is based on the i2c-ocores driver by Peter Korsgaard.
*/
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/mfd/kempld.h>
#define KEMPLD_I2C_PRELOW 0x0b
#define KEMPLD_I2C_PREHIGH 0x0c
#define KEMPLD_I2C_DATA 0x0e
#define KEMPLD_I2C_CTRL 0x0d
#define I2C_CTRL_IEN 0x40
#define I2C_CTRL_EN 0x80
#define KEMPLD_I2C_STAT 0x0f
#define I2C_STAT_IF 0x01
#define I2C_STAT_TIP 0x02
#define I2C_STAT_ARBLOST 0x20
#define I2C_STAT_BUSY 0x40
#define I2C_STAT_NACK 0x80
#define KEMPLD_I2C_CMD 0x0f
#define I2C_CMD_START 0x91
#define I2C_CMD_STOP 0x41
#define I2C_CMD_READ 0x21
#define I2C_CMD_WRITE 0x11
#define I2C_CMD_READ_ACK 0x21
#define I2C_CMD_READ_NACK 0x29
#define I2C_CMD_IACK 0x01
#define KEMPLD_I2C_FREQ_MAX 2700 /* 2.7 mHz */
#define KEMPLD_I2C_FREQ_STD 100 /* 100 kHz */
enum {
STATE_DONE = 0,
STATE_INIT,
STATE_ADDR,
STATE_ADDR10,
STATE_START,
STATE_WRITE,
STATE_READ,
STATE_ERROR,
};
struct kempld_i2c_data {
struct device *dev;
struct kempld_device_data *pld;
struct i2c_adapter adap;
struct i2c_msg *msg;
int pos;
int nmsgs;
int state;
bool was_active;
};
static unsigned int bus_frequency = KEMPLD_I2C_FREQ_STD;
module_param(bus_frequency, uint, 0);
MODULE_PARM_DESC(bus_frequency, "Set I2C bus frequency in kHz (default="
__MODULE_STRING(KEMPLD_I2C_FREQ_STD)")");
static int i2c_bus = -1;
module_param(i2c_bus, int, 0);
MODULE_PARM_DESC(i2c_bus, "Set I2C bus number (default=-1 for dynamic assignment)");
static bool i2c_gpio_mux;
module_param(i2c_gpio_mux, bool, 0);
MODULE_PARM_DESC(i2c_gpio_mux, "Enable I2C port on GPIO out (default=false)");
/*
* kempld_get_mutex must be called prior to calling this function.
*/
static int kempld_i2c_process(struct kempld_i2c_data *i2c)
{
struct kempld_device_data *pld = i2c->pld;
u8 stat = kempld_read8(pld, KEMPLD_I2C_STAT);
struct i2c_msg *msg = i2c->msg;
u8 addr;
/* Ready? */
if (stat & I2C_STAT_TIP)
return -EBUSY;
if (i2c->state == STATE_DONE || i2c->state == STATE_ERROR) {
/* Stop has been sent */
kempld_write8(pld, KEMPLD_I2C_CMD, I2C_CMD_IACK);
if (i2c->state == STATE_ERROR)
return -EIO;
return 0;
}
/* Error? */
if (stat & I2C_STAT_ARBLOST) {
i2c->state = STATE_ERROR;
kempld_write8(pld, KEMPLD_I2C_CMD, I2C_CMD_STOP);
return -EAGAIN;
}
if (i2c->state == STATE_INIT) {
if (stat & I2C_STAT_BUSY)
return -EBUSY;
i2c->state = STATE_ADDR;
}
if (i2c->state == STATE_ADDR) {
/* 10 bit address? */
if (i2c->msg->flags & I2C_M_TEN) {
addr = 0xf0 | ((i2c->msg->addr >> 7) & 0x6);
/* Set read bit if necessary */
addr |= (i2c->msg->flags & I2C_M_RD) ? 1 : 0;
i2c->state = STATE_ADDR10;
} else {
addr = i2c_8bit_addr_from_msg(i2c->msg);
i2c->state = STATE_START;
}
kempld_write8(pld, KEMPLD_I2C_DATA, addr);
kempld_write8(pld, KEMPLD_I2C_CMD, I2C_CMD_START);
return 0;
}
/* Second part of 10 bit addressing */
if (i2c->state == STATE_ADDR10) {
kempld_write8(pld, KEMPLD_I2C_DATA, i2c->msg->addr & 0xff);
kempld_write8(pld, KEMPLD_I2C_CMD, I2C_CMD_WRITE);
i2c->state = STATE_START;
return 0;
}
if (i2c->state == STATE_START || i2c->state == STATE_WRITE) {
i2c->state = (msg->flags & I2C_M_RD) ? STATE_READ : STATE_WRITE;
if (stat & I2C_STAT_NACK) {
i2c->state = STATE_ERROR;
kempld_write8(pld, KEMPLD_I2C_CMD, I2C_CMD_STOP);
return -ENXIO;
}
} else {
msg->buf[i2c->pos++] = kempld_read8(pld, KEMPLD_I2C_DATA);
}
if (i2c->pos >= msg->len) {
i2c->nmsgs--;
i2c->msg++;
i2c->pos = 0;
msg = i2c->msg;
if (i2c->nmsgs) {
if (!(msg->flags & I2C_M_NOSTART)) {
i2c->state = STATE_ADDR;
return 0;
} else {
i2c->state = (msg->flags & I2C_M_RD)
? STATE_READ : STATE_WRITE;
}
} else {
i2c->state = STATE_DONE;
kempld_write8(pld, KEMPLD_I2C_CMD, I2C_CMD_STOP);
return 0;
}
}
if (i2c->state == STATE_READ) {
kempld_write8(pld, KEMPLD_I2C_CMD, i2c->pos == (msg->len - 1) ?
I2C_CMD_READ_NACK : I2C_CMD_READ_ACK);
} else {
kempld_write8(pld, KEMPLD_I2C_DATA, msg->buf[i2c->pos++]);
kempld_write8(pld, KEMPLD_I2C_CMD, I2C_CMD_WRITE);
}
return 0;
}
static int kempld_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
int num)
{
struct kempld_i2c_data *i2c = i2c_get_adapdata(adap);
struct kempld_device_data *pld = i2c->pld;
unsigned long timeout = jiffies + HZ;
int ret;
i2c->msg = msgs;
i2c->pos = 0;
i2c->nmsgs = num;
i2c->state = STATE_INIT;
/* Handle the transfer */
while (time_before(jiffies, timeout)) {
kempld_get_mutex(pld);
ret = kempld_i2c_process(i2c);
kempld_release_mutex(pld);
if (i2c->state == STATE_DONE || i2c->state == STATE_ERROR)
return (i2c->state == STATE_DONE) ? num : ret;
if (ret == 0)
timeout = jiffies + HZ;
usleep_range(5, 15);
}
i2c->state = STATE_ERROR;
return -ETIMEDOUT;
}
/*
* kempld_get_mutex must be called prior to calling this function.
*/
static void kempld_i2c_device_init(struct kempld_i2c_data *i2c)
{
struct kempld_device_data *pld = i2c->pld;
u16 prescale_corr;
long prescale;
u8 ctrl;
u8 stat;
u8 cfg;
/* Make sure the device is disabled */
ctrl = kempld_read8(pld, KEMPLD_I2C_CTRL);
ctrl &= ~(I2C_CTRL_EN | I2C_CTRL_IEN);
kempld_write8(pld, KEMPLD_I2C_CTRL, ctrl);
if (bus_frequency > KEMPLD_I2C_FREQ_MAX)
bus_frequency = KEMPLD_I2C_FREQ_MAX;
if (pld->info.spec_major == 1)
prescale = pld->pld_clock / (bus_frequency * 5) - 1000;
else
prescale = pld->pld_clock / (bus_frequency * 4) - 3000;
if (prescale < 0)
prescale = 0;
/* Round to the best matching value */
prescale_corr = prescale / 1000;
if (prescale % 1000 >= 500)
prescale_corr++;
kempld_write8(pld, KEMPLD_I2C_PRELOW, prescale_corr & 0xff);
kempld_write8(pld, KEMPLD_I2C_PREHIGH, prescale_corr >> 8);
/* Activate I2C bus output on GPIO pins */
cfg = kempld_read8(pld, KEMPLD_CFG);
if (i2c_gpio_mux)
cfg |= KEMPLD_CFG_GPIO_I2C_MUX;
else
cfg &= ~KEMPLD_CFG_GPIO_I2C_MUX;
kempld_write8(pld, KEMPLD_CFG, cfg);
/* Enable the device */
kempld_write8(pld, KEMPLD_I2C_CMD, I2C_CMD_IACK);
ctrl |= I2C_CTRL_EN;
kempld_write8(pld, KEMPLD_I2C_CTRL, ctrl);
stat = kempld_read8(pld, KEMPLD_I2C_STAT);
if (stat & I2C_STAT_BUSY)
kempld_write8(pld, KEMPLD_I2C_CMD, I2C_CMD_STOP);
}
static u32 kempld_i2c_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR | I2C_FUNC_SMBUS_EMUL;
}
static const struct i2c_algorithm kempld_i2c_algorithm = {
.master_xfer = kempld_i2c_xfer,
.functionality = kempld_i2c_func,
};
static const struct i2c_adapter kempld_i2c_adapter = {
.owner = THIS_MODULE,
.name = "i2c-kempld",
.class = I2C_CLASS_HWMON | I2C_CLASS_SPD |
I2C_CLASS_DEPRECATED,
.algo = &kempld_i2c_algorithm,
};
static int kempld_i2c_probe(struct platform_device *pdev)
{
struct kempld_device_data *pld = dev_get_drvdata(pdev->dev.parent);
struct kempld_i2c_data *i2c;
int ret;
u8 ctrl;
i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
if (!i2c)
return -ENOMEM;
i2c->pld = pld;
i2c->dev = &pdev->dev;
i2c->adap = kempld_i2c_adapter;
i2c->adap.dev.parent = i2c->dev;
i2c_set_adapdata(&i2c->adap, i2c);
platform_set_drvdata(pdev, i2c);
kempld_get_mutex(pld);
ctrl = kempld_read8(pld, KEMPLD_I2C_CTRL);
if (ctrl & I2C_CTRL_EN)
i2c->was_active = true;
kempld_i2c_device_init(i2c);
kempld_release_mutex(pld);
/* Add I2C adapter to I2C tree */
if (i2c_bus >= -1)
i2c->adap.nr = i2c_bus;
ret = i2c_add_numbered_adapter(&i2c->adap);
if (ret)
return ret;
dev_info(i2c->dev, "I2C bus initialized at %dkHz\n",
bus_frequency);
return 0;
}
static int kempld_i2c_remove(struct platform_device *pdev)
{
struct kempld_i2c_data *i2c = platform_get_drvdata(pdev);
struct kempld_device_data *pld = i2c->pld;
u8 ctrl;
kempld_get_mutex(pld);
/*
* Disable I2C logic if it was not activated before the
* driver loaded
*/
if (!i2c->was_active) {
ctrl = kempld_read8(pld, KEMPLD_I2C_CTRL);
ctrl &= ~I2C_CTRL_EN;
kempld_write8(pld, KEMPLD_I2C_CTRL, ctrl);
}
kempld_release_mutex(pld);
i2c_del_adapter(&i2c->adap);
return 0;
}
#ifdef CONFIG_PM
static int kempld_i2c_suspend(struct platform_device *pdev, pm_message_t state)
{
struct kempld_i2c_data *i2c = platform_get_drvdata(pdev);
struct kempld_device_data *pld = i2c->pld;
u8 ctrl;
kempld_get_mutex(pld);
ctrl = kempld_read8(pld, KEMPLD_I2C_CTRL);
ctrl &= ~I2C_CTRL_EN;
kempld_write8(pld, KEMPLD_I2C_CTRL, ctrl);
kempld_release_mutex(pld);
return 0;
}
static int kempld_i2c_resume(struct platform_device *pdev)
{
struct kempld_i2c_data *i2c = platform_get_drvdata(pdev);
struct kempld_device_data *pld = i2c->pld;
kempld_get_mutex(pld);
kempld_i2c_device_init(i2c);
kempld_release_mutex(pld);
return 0;
}
#else
#define kempld_i2c_suspend NULL
#define kempld_i2c_resume NULL
#endif
static struct platform_driver kempld_i2c_driver = {
.driver = {
.name = "kempld-i2c",
},
.probe = kempld_i2c_probe,
.remove = kempld_i2c_remove,
.suspend = kempld_i2c_suspend,
.resume = kempld_i2c_resume,
};
module_platform_driver(kempld_i2c_driver);
MODULE_DESCRIPTION("KEM PLD I2C Driver");
MODULE_AUTHOR("Michael Brunner <michael.brunner@kontron.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:kempld_i2c");
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