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linux/drivers/rtc/rtc-isl12026.c
Bartosz Golaszewski fdcfd85433 rtc: rework rtc_register_device() resource management 
rtc_register_device() is a managed interface but it doesn't use devres
by itself - instead it marks an rtc_device as "registered" and the devres
callback for devm_rtc_allocate_device() takes care of resource release.

This doesn't correspond with the design behind devres where managed
structures should not be aware of being managed. The correct solution
here is to register a separate devres callback for unregistering the
device.

While at it: rename rtc_register_device() to devm_rtc_register_device()
and add it to the list of managed interfaces in devres.rst. This way we
can avoid any potential confusion of driver developers who may expect
there to exist a corresponding unregister function.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20201109163409.24301-8-brgl@bgdev.pl
2020-11-19 12:50:12 +01:00

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// SPDX-License-Identifier: GPL-2.0+
/*
* An I2C driver for the Intersil ISL 12026
*
* Copyright (c) 2018 Cavium, Inc.
*/
#include <linux/bcd.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/nvmem-provider.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/rtc.h>
#include <linux/slab.h>
/* register offsets */
#define ISL12026_REG_PWR 0x14
# define ISL12026_REG_PWR_BSW BIT(6)
# define ISL12026_REG_PWR_SBIB BIT(7)
#define ISL12026_REG_SC 0x30
#define ISL12026_REG_HR 0x32
# define ISL12026_REG_HR_MIL BIT(7) /* military or 24 hour time */
#define ISL12026_REG_SR 0x3f
# define ISL12026_REG_SR_RTCF BIT(0)
# define ISL12026_REG_SR_WEL BIT(1)
# define ISL12026_REG_SR_RWEL BIT(2)
# define ISL12026_REG_SR_MBZ BIT(3)
# define ISL12026_REG_SR_OSCF BIT(4)
/* The EEPROM array responds at i2c address 0x57 */
#define ISL12026_EEPROM_ADDR 0x57
#define ISL12026_PAGESIZE 16
#define ISL12026_NVMEM_WRITE_TIME 20
struct isl12026 {
struct rtc_device *rtc;
struct i2c_client *nvm_client;
};
static int isl12026_read_reg(struct i2c_client *client, int reg)
{
u8 addr[] = {0, reg};
u8 val;
int ret;
struct i2c_msg msgs[] = {
{
.addr = client->addr,
.flags = 0,
.len = sizeof(addr),
.buf = addr
}, {
.addr = client->addr,
.flags = I2C_M_RD,
.len = 1,
.buf = &val
}
};
ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
if (ret != ARRAY_SIZE(msgs)) {
dev_err(&client->dev, "read reg error, ret=%d\n", ret);
ret = ret < 0 ? ret : -EIO;
} else {
ret = val;
}
return ret;
}
static int isl12026_arm_write(struct i2c_client *client)
{
int ret;
u8 op[3];
struct i2c_msg msg = {
.addr = client->addr,
.flags = 0,
.len = 1,
.buf = op
};
/* Set SR.WEL */
op[0] = 0;
op[1] = ISL12026_REG_SR;
op[2] = ISL12026_REG_SR_WEL;
msg.len = 3;
ret = i2c_transfer(client->adapter, &msg, 1);
if (ret != 1) {
dev_err(&client->dev, "write error SR.WEL, ret=%d\n", ret);
ret = ret < 0 ? ret : -EIO;
goto out;
}
/* Set SR.WEL and SR.RWEL */
op[2] = ISL12026_REG_SR_WEL | ISL12026_REG_SR_RWEL;
msg.len = 3;
ret = i2c_transfer(client->adapter, &msg, 1);
if (ret != 1) {
dev_err(&client->dev,
"write error SR.WEL|SR.RWEL, ret=%d\n", ret);
ret = ret < 0 ? ret : -EIO;
goto out;
} else {
ret = 0;
}
out:
return ret;
}
static int isl12026_disarm_write(struct i2c_client *client)
{
int ret;
u8 op[3] = {0, ISL12026_REG_SR, 0};
struct i2c_msg msg = {
.addr = client->addr,
.flags = 0,
.len = sizeof(op),
.buf = op
};
ret = i2c_transfer(client->adapter, &msg, 1);
if (ret != 1) {
dev_err(&client->dev,
"write error SR, ret=%d\n", ret);
ret = ret < 0 ? ret : -EIO;
} else {
ret = 0;
}
return ret;
}
static int isl12026_write_reg(struct i2c_client *client, int reg, u8 val)
{
int ret;
u8 op[3] = {0, reg, val};
struct i2c_msg msg = {
.addr = client->addr,
.flags = 0,
.len = sizeof(op),
.buf = op
};
ret = isl12026_arm_write(client);
if (ret)
return ret;
ret = i2c_transfer(client->adapter, &msg, 1);
if (ret != 1) {
dev_err(&client->dev, "write error CCR, ret=%d\n", ret);
ret = ret < 0 ? ret : -EIO;
goto out;
}
msleep(ISL12026_NVMEM_WRITE_TIME);
ret = isl12026_disarm_write(client);
out:
return ret;
}
static int isl12026_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct i2c_client *client = to_i2c_client(dev);
int ret;
u8 op[10];
struct i2c_msg msg = {
.addr = client->addr,
.flags = 0,
.len = sizeof(op),
.buf = op
};
ret = isl12026_arm_write(client);
if (ret)
return ret;
/* Set the CCR registers */
op[0] = 0;
op[1] = ISL12026_REG_SC;
op[2] = bin2bcd(tm->tm_sec); /* SC */
op[3] = bin2bcd(tm->tm_min); /* MN */
op[4] = bin2bcd(tm->tm_hour) | ISL12026_REG_HR_MIL; /* HR */
op[5] = bin2bcd(tm->tm_mday); /* DT */
op[6] = bin2bcd(tm->tm_mon + 1); /* MO */
op[7] = bin2bcd(tm->tm_year % 100); /* YR */
op[8] = bin2bcd(tm->tm_wday & 7); /* DW */
op[9] = bin2bcd(tm->tm_year >= 100 ? 20 : 19); /* Y2K */
ret = i2c_transfer(client->adapter, &msg, 1);
if (ret != 1) {
dev_err(&client->dev, "write error CCR, ret=%d\n", ret);
ret = ret < 0 ? ret : -EIO;
goto out;
}
ret = isl12026_disarm_write(client);
out:
return ret;
}
static int isl12026_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct i2c_client *client = to_i2c_client(dev);
u8 ccr[8];
u8 addr[2];
u8 sr;
int ret;
struct i2c_msg msgs[] = {
{
.addr = client->addr,
.flags = 0,
.len = sizeof(addr),
.buf = addr
}, {
.addr = client->addr,
.flags = I2C_M_RD,
}
};
/* First, read SR */
addr[0] = 0;
addr[1] = ISL12026_REG_SR;
msgs[1].len = 1;
msgs[1].buf = &sr;
ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
if (ret != ARRAY_SIZE(msgs)) {
dev_err(&client->dev, "read error, ret=%d\n", ret);
ret = ret < 0 ? ret : -EIO;
goto out;
}
if (sr & ISL12026_REG_SR_RTCF)
dev_warn(&client->dev, "Real-Time Clock Failure on read\n");
if (sr & ISL12026_REG_SR_OSCF)
dev_warn(&client->dev, "Oscillator Failure on read\n");
/* Second, CCR regs */
addr[0] = 0;
addr[1] = ISL12026_REG_SC;
msgs[1].len = sizeof(ccr);
msgs[1].buf = ccr;
ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
if (ret != ARRAY_SIZE(msgs)) {
dev_err(&client->dev, "read error, ret=%d\n", ret);
ret = ret < 0 ? ret : -EIO;
goto out;
}
tm->tm_sec = bcd2bin(ccr[0] & 0x7F);
tm->tm_min = bcd2bin(ccr[1] & 0x7F);
if (ccr[2] & ISL12026_REG_HR_MIL)
tm->tm_hour = bcd2bin(ccr[2] & 0x3F);
else
tm->tm_hour = bcd2bin(ccr[2] & 0x1F) +
((ccr[2] & 0x20) ? 12 : 0);
tm->tm_mday = bcd2bin(ccr[3] & 0x3F);
tm->tm_mon = bcd2bin(ccr[4] & 0x1F) - 1;
tm->tm_year = bcd2bin(ccr[5]);
if (bcd2bin(ccr[7]) == 20)
tm->tm_year += 100;
tm->tm_wday = ccr[6] & 0x07;
ret = 0;
out:
return ret;
}
static const struct rtc_class_ops isl12026_rtc_ops = {
.read_time = isl12026_rtc_read_time,
.set_time = isl12026_rtc_set_time,
};
static int isl12026_nvm_read(void *p, unsigned int offset,
void *val, size_t bytes)
{
struct isl12026 *priv = p;
int ret;
u8 addr[2];
struct i2c_msg msgs[] = {
{
.addr = priv->nvm_client->addr,
.flags = 0,
.len = sizeof(addr),
.buf = addr
}, {
.addr = priv->nvm_client->addr,
.flags = I2C_M_RD,
.buf = val
}
};
/*
* offset and bytes checked and limited by nvmem core, so
* proceed without further checks.
*/
ret = mutex_lock_interruptible(&priv->rtc->ops_lock);
if (ret)
return ret;
/* 2 bytes of address, most significant first */
addr[0] = offset >> 8;
addr[1] = offset;
msgs[1].len = bytes;
ret = i2c_transfer(priv->nvm_client->adapter, msgs, ARRAY_SIZE(msgs));
mutex_unlock(&priv->rtc->ops_lock);
if (ret != ARRAY_SIZE(msgs)) {
dev_err(&priv->nvm_client->dev,
"nvmem read error, ret=%d\n", ret);
return ret < 0 ? ret : -EIO;
}
return 0;
}
static int isl12026_nvm_write(void *p, unsigned int offset,
void *val, size_t bytes)
{
struct isl12026 *priv = p;
int ret;
u8 *v = val;
size_t chunk_size, num_written;
u8 payload[ISL12026_PAGESIZE + 2]; /* page + 2 address bytes */
struct i2c_msg msgs[] = {
{
.addr = priv->nvm_client->addr,
.flags = 0,
.buf = payload
}
};
/*
* offset and bytes checked and limited by nvmem core, so
* proceed without further checks.
*/
ret = mutex_lock_interruptible(&priv->rtc->ops_lock);
if (ret)
return ret;
num_written = 0;
while (bytes) {
chunk_size = round_down(offset, ISL12026_PAGESIZE) +
ISL12026_PAGESIZE - offset;
chunk_size = min(bytes, chunk_size);
/*
* 2 bytes of address, most significant first, followed
* by page data bytes
*/
memcpy(payload + 2, v + num_written, chunk_size);
payload[0] = offset >> 8;
payload[1] = offset;
msgs[0].len = chunk_size + 2;
ret = i2c_transfer(priv->nvm_client->adapter,
msgs, ARRAY_SIZE(msgs));
if (ret != ARRAY_SIZE(msgs)) {
dev_err(&priv->nvm_client->dev,
"nvmem write error, ret=%d\n", ret);
ret = ret < 0 ? ret : -EIO;
break;
}
ret = 0;
bytes -= chunk_size;
offset += chunk_size;
num_written += chunk_size;
msleep(ISL12026_NVMEM_WRITE_TIME);
}
mutex_unlock(&priv->rtc->ops_lock);
return ret;
}
static void isl12026_force_power_modes(struct i2c_client *client)
{
int ret;
int pwr, requested_pwr;
u32 bsw_val, sbib_val;
bool set_bsw, set_sbib;
/*
* If we can read the of_property, set the specified value.
* If there is an error reading the of_property (likely
* because it does not exist), keep the current value.
*/
ret = of_property_read_u32(client->dev.of_node,
"isil,pwr-bsw", &bsw_val);
set_bsw = (ret == 0);
ret = of_property_read_u32(client->dev.of_node,
"isil,pwr-sbib", &sbib_val);
set_sbib = (ret == 0);
/* Check if PWR.BSW and/or PWR.SBIB need specified values */
if (!set_bsw && !set_sbib)
return;
pwr = isl12026_read_reg(client, ISL12026_REG_PWR);
if (pwr < 0) {
dev_warn(&client->dev, "Error: Failed to read PWR %d\n", pwr);
return;
}
requested_pwr = pwr;
if (set_bsw) {
if (bsw_val)
requested_pwr |= ISL12026_REG_PWR_BSW;
else
requested_pwr &= ~ISL12026_REG_PWR_BSW;
} /* else keep current BSW */
if (set_sbib) {
if (sbib_val)
requested_pwr |= ISL12026_REG_PWR_SBIB;
else
requested_pwr &= ~ISL12026_REG_PWR_SBIB;
} /* else keep current SBIB */
if (pwr >= 0 && pwr != requested_pwr) {
dev_dbg(&client->dev, "PWR: %02x\n", pwr);
dev_dbg(&client->dev, "Updating PWR to: %02x\n", requested_pwr);
isl12026_write_reg(client, ISL12026_REG_PWR, requested_pwr);
}
}
static int isl12026_probe_new(struct i2c_client *client)
{
struct isl12026 *priv;
int ret;
struct nvmem_config nvm_cfg = {
.name = "isl12026-",
.base_dev = &client->dev,
.stride = 1,
.word_size = 1,
.size = 512,
.reg_read = isl12026_nvm_read,
.reg_write = isl12026_nvm_write,
};
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
return -ENODEV;
priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
i2c_set_clientdata(client, priv);
isl12026_force_power_modes(client);
priv->nvm_client = i2c_new_dummy_device(client->adapter, ISL12026_EEPROM_ADDR);
if (IS_ERR(priv->nvm_client))
return PTR_ERR(priv->nvm_client);
priv->rtc = devm_rtc_allocate_device(&client->dev);
ret = PTR_ERR_OR_ZERO(priv->rtc);
if (ret)
return ret;
priv->rtc->ops = &isl12026_rtc_ops;
nvm_cfg.priv = priv;
ret = devm_rtc_nvmem_register(priv->rtc, &nvm_cfg);
if (ret)
return ret;
return devm_rtc_register_device(priv->rtc);
}
static int isl12026_remove(struct i2c_client *client)
{
struct isl12026 *priv = i2c_get_clientdata(client);
i2c_unregister_device(priv->nvm_client);
return 0;
}
static const struct of_device_id isl12026_dt_match[] = {
{ .compatible = "isil,isl12026" },
{ }
};
MODULE_DEVICE_TABLE(of, isl12026_dt_match);
static struct i2c_driver isl12026_driver = {
.driver = {
.name = "rtc-isl12026",
.of_match_table = isl12026_dt_match,
},
.probe_new = isl12026_probe_new,
.remove = isl12026_remove,
};
module_i2c_driver(isl12026_driver);
MODULE_DESCRIPTION("ISL 12026 RTC driver");
MODULE_LICENSE("GPL");
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