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Date: Tue, 13 Feb 2018 17:54:50 +0200
From: Andy Shevchenko <andy.shevchenko@...il.com>
To: David Daney <david.daney@...ium.com>
Cc: Alessandro Zummo <a.zummo@...ertech.it>,
Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>, linux-rtc@...r.kernel.org,
devicetree <devicetree@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] rtc: isl12026: Add driver.
On Mon, Feb 12, 2018 at 8:59 PM, David Daney <david.daney@...ium.com> wrote:
> The ISL12026 is a combination RTC and EEPROM device with I2C
> interface. The standard RTC driver interface is provided. The EEPROM
> is accessed via the NVMEM interface via the "eeprom0" directory in the
> sysfs entry for the device.
>
> Signed-off-by: David Daney <david.daney@...ium.com>
> ---
> .../devicetree/bindings/rtc/isil,isl12026.txt | 27 +
> drivers/rtc/Kconfig | 9 +
> drivers/rtc/Makefile | 1 +
> drivers/rtc/rtc-isl12026.c | 550 +++++++++++++++++++++
> 4 files changed, 587 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/rtc/isil,isl12026.txt
> create mode 100644 drivers/rtc/rtc-isl12026.c
>
> diff --git a/Documentation/devicetree/bindings/rtc/isil,isl12026.txt b/Documentation/devicetree/bindings/rtc/isil,isl12026.txt
> new file mode 100644
> index 000000000000..4b6c7177a95a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/rtc/isil,isl12026.txt
> @@ -0,0 +1,27 @@
> +ISL12026 I2C RTC/EEPROM
> +
> +ISL12026 is an I2C RTC/EEPROM combination device. The RTC and control
> +registers respond at bus address 0x6f, and the EEPROM array responds
> +at bus address 0x57. The canonical "reg" value will be for the RTC portion.
> +
> +Required properties supported by the device:
> +
> + - "compatible": must be "isil,isl12026"
> + - "reg": I2C bus address of the device (always 0x6f)
> +
> +Optional properties:
> +
> + - "isil,pwr-bsw": If present PWR.BSW bit must be set to the specified
> + value for proper operation.
> +
> + - "isil,pwr-sbib": If present PWR.SBIB bit must be set to the specified
> + value for proper operation.
> +
> +
> +Example:
> +
> + rtc@6f {
> + reg = <0x6f>;
> + isil,pwr-bsw = <0>;
> + isil,pwr-sbib = <1>;
> + }
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index 8ab5f0a5d323..85171e9e3ada 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -407,6 +407,15 @@ config RTC_DRV_ISL12022
> This driver can also be built as a module. If so, the module
> will be called rtc-isl12022.
>
> +config RTC_DRV_ISL12026
> + tristate "Intersil ISL12026"
> + help
> + If you say yes here you get support for the
> + Intersil ISL12026 RTC chip.
> +
> + This driver can also be built as a module. If so, the module
> + will be called rtc-isl12026.
> +
> config RTC_DRV_X1205
> tristate "Xicor/Intersil X1205"
> help
> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
> index 4fbf87e45a7c..f481661a6eae 100644
> --- a/drivers/rtc/Makefile
> +++ b/drivers/rtc/Makefile
> @@ -76,6 +76,7 @@ obj-$(CONFIG_RTC_DRV_HID_SENSOR_TIME) += rtc-hid-sensor-time.o
> obj-$(CONFIG_RTC_DRV_HYM8563) += rtc-hym8563.o
> obj-$(CONFIG_RTC_DRV_IMXDI) += rtc-imxdi.o
> obj-$(CONFIG_RTC_DRV_ISL12022) += rtc-isl12022.o
> +obj-$(CONFIG_RTC_DRV_ISL12026) += rtc-isl12026.o
> obj-$(CONFIG_RTC_DRV_ISL1208) += rtc-isl1208.o
> obj-$(CONFIG_RTC_DRV_JZ4740) += rtc-jz4740.o
> obj-$(CONFIG_RTC_DRV_LP8788) += rtc-lp8788.o
> diff --git a/drivers/rtc/rtc-isl12026.c b/drivers/rtc/rtc-isl12026.c
> new file mode 100644
> index 000000000000..a5f04e0faceb
> --- /dev/null
> +++ b/drivers/rtc/rtc-isl12026.c
> @@ -0,0 +1,550 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * An I2C driver for the Intersil ISL 12026
> + *
> + * Copyright (c) 2018 Cavium, Inc.
> + */
> +#include <linux/types.h>
> +#include <linux/nvmem-provider.h>
> +#include <linux/of_device.h>
> +#include <linux/module.h>
> +#include <linux/delay.h>
> +#include <linux/mutex.h>
> +#include <linux/slab.h>
> +#include <linux/bcd.h>
> +#include <linux/i2c.h>
> +#include <linux/rtc.h>
> +#include <linux/of.h>
Perhaps in alphabetical order.
> +/* register offsets */
> +#define ISL12026_REG_SC 0x30
> +
> +#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)
> +
> +/* ISL register bits */
> +#define ISL12026_HR_MIL BIT(7) /* military or 24 hour time */
> +
> +#define ISL12026_REG_PWR 0x14
Perhaps keep it ordered? (0x14 < 0x30 obviously)
> +# define ISL12026_REG_PWR_BSW BIT(6)
> +# define ISL12026_REG_PWR_SBIB BIT(7)
> +#define ISL12026_PAGESIZE 16
> +#define ISL12026_NVMEM_WRITE_TIME 20
> +
> +struct isl12026 {
> + struct rtc_device *rtc;
> + struct i2c_client *nvm_client;
> + struct nvmem_device *nvm_dev;
> + struct nvmem_config nvm_cfg;
> + /*
> + * RTC write operations require that multiple messages be
> + * transmitted, we hold the lock for all accesses to the
> + * device so that these sequences cannot be disrupted. Also,
> + * the write cycle to the nvmem takes many mS during which the
> + * device does not respond to commands, so holding the lock
> + * also prevents access during these times.
> + */
> + struct mutex lock;
> +};
> +
> +static int isl12026_read_reg(struct i2c_client *client, int reg)
> +{
> + struct isl12026 *priv = i2c_get_clientdata(client);
> + 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
> + }
> + };
> +
> + mutex_lock(&priv->lock);
> +
> + ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
> +
> + mutex_unlock(&priv->lock);
> +
> + if (ret != ARRAY_SIZE(msgs)) {
> + dev_err(&client->dev, "read reg error, ret=%d\n", ret);
> + return -EIO;
> + }
> + return val;
> +}
> +
> +static int isl12026_write_reg(struct i2c_client *client, int reg, u8 val)
> +{
> + struct isl12026 *priv = i2c_get_clientdata(client);
> + int rv = 0;
> + u8 op[3];
> +
> + struct i2c_msg msg = {
> + .addr = client->addr,
> + .flags = 0,
> + .len = 1,
> + .buf = op
> + };
> +
> + int ret;
> +
> + mutex_lock(&priv->lock);
> +
> + /* 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);
> + rv = -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);
> + rv = -EIO;
> + goto out;
> + }
> +
> + op[1] = reg;
> + op[2] = val;
> + msg.len = 3;
> + ret = i2c_transfer(client->adapter, &msg, 1);
> + if (ret != 1) {
> + dev_err(&client->dev, "write error CCR, ret=%d\n", ret);
> + rv = -EIO;
> + goto out;
> + }
> +
> + msleep(ISL12026_NVMEM_WRITE_TIME);
> +
> + /* Clear SR.WEL and SR.RWEL */
> + op[1] = ISL12026_REG_SR;
> + op[2] = 0;
> + msg.len = 3;
> + ret = i2c_transfer(client->adapter, &msg, 1);
> + if (ret != 1) {
> + dev_err(&client->dev, "write error SR, ret=%d\n", ret);
> + rv = -EIO;
> + goto out;
> + }
> +
> +out:
> + mutex_unlock(&priv->lock);
> +
> + return rv;
> +}
> +
> +static int isl12026_rtc_set_time(struct device *dev, struct rtc_time *tm)
> +{
> + struct i2c_client *client = to_i2c_client(dev);
> + struct isl12026 *priv = i2c_get_clientdata(client);
> + int rv = 0;
> + u8 op[10];
> +
> + struct i2c_msg msg = {
> + .addr = client->addr,
> + .flags = 0,
> + .len = 1,
> + .buf = op
> + };
> +
Redundant.
> + int ret;
rv, ret, ... ???
> +
> + mutex_lock(&priv->lock);
> +
> + /* 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) {
Can it return < 0? If so, why do you shadow the error code?
> + dev_err(&client->dev, "write error SR.WEL, ret=%d\n", ret);
> + rv = -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);
> + rv = -EIO;
> + goto out;
> + }
> +
> + /* Set the CCR registers */
> + 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_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 */
> + msg.len = 10;
> + ret = i2c_transfer(client->adapter, &msg, 1);
> + if (ret != 1) {
> + dev_err(&client->dev, "write error CCR, ret=%d\n", ret);
> + rv = -EIO;
> + goto out;
> + }
> +
> + /* Clear SR.WEL and SR.RWEL */
> + op[1] = ISL12026_REG_SR;
> + op[2] = 0;
> + msg.len = 3;
> + ret = i2c_transfer(client->adapter, &msg, 1);
> + if (ret != 1) {
> + dev_err(&client->dev, "write error SR, ret=%d\n", ret);
> + rv = -EIO;
> + goto out;
> + }
> +
> +out:
> + mutex_unlock(&priv->lock);
> +
> + return rv;
> +}
> +
> +static int isl12026_rtc_read_time(struct device *dev, struct rtc_time *tm)
> +{
> + struct i2c_client *client = to_i2c_client(dev);
> + struct isl12026 *priv = i2c_get_clientdata(client);
> + u8 ccr[8];
> + u8 addr[2];
> + u8 sr;
> + int ret;
> + int rv = 0;
> +
> + struct i2c_msg msgs[] = {
> + {
> + .addr = client->addr,
> + .flags = 0,
> + .len = sizeof(addr),
> + .buf = addr
> + },
> + {
> + .addr = client->addr,
> + .flags = I2C_M_RD,
> + }
> + };
> +
> + mutex_lock(&priv->lock);
> +
> + /* 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);
> + rv = -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");
Can you get them together?
if not, perhaps consider 'else' keyword.
> +
> + /* 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);
> + rv = -EIO;
> + goto out;
> + }
> +
> + dev_dbg(&client->dev,
> + "raw data is sec=%02x, min=%02x, hr=%02x, mday=%02x, mon=%02x, year=%02x, wday=%02x, y2k=%02x\n",
> + ccr[0], ccr[1], ccr[2], ccr[3],
> + ccr[4], ccr[5], ccr[6], ccr[7]);
Ouch.
> +
> + tm->tm_sec = bcd2bin(ccr[0] & 0x7F);
> + tm->tm_min = bcd2bin(ccr[1] & 0x7F);
> + if (ccr[2] & ISL12026_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;
> +
> + dev_dbg(&client->dev, "secs=%d, mins=%d, hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
> + tm->tm_sec, tm->tm_min, tm->tm_hour,
> + tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
> + rv = rtc_valid_tm(tm);
> +out:
> + mutex_unlock(&priv->lock);
Here one pattern, below another...
Hey, you have to learn being consistent.
> + return rv;
> +}
> +
> +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 r;
> + 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
> + }
> + };
> +
> + if (offset >= priv->nvm_cfg.size)
> + return 0; /* End-of-file */
> + if (offset + bytes > priv->nvm_cfg.size)
> + bytes = priv->nvm_cfg.size - offset;
> +
> + addr[0] = (offset >> 8) & 0xff;
> + addr[1] = offset & 0xff;
Useless & 0xff:s.
Isn't endianess handled by i2c core?
> + msgs[1].len = bytes;
> + mutex_lock(&priv->lock);
> + r = i2c_transfer(priv->nvm_client->adapter, msgs, ARRAY_SIZE(msgs));
> +
> + mutex_unlock(&priv->lock);
> +
> + if (r != ARRAY_SIZE(msgs)) {
A bit unusual pattern,
what about
mutex_lock();
r = ...;
if (r...) {
...
mutex_unlock();
return -Exxx;
}
mutex_unlock();
?
> + dev_err(priv->nvm_cfg.dev, "nvmem read error, ret=%d\n", r);
> + return -EIO;
> + }
> +
> + return bytes;
> +}
> +
> +static int isl12026_nvm_write(void *p, unsigned int offset,
> + void *val, size_t bytes)
> +{
> + struct isl12026 *priv = p;
> + int r;
Use consistent style, either r everywhere, or ret, or rc, or rval.
> + 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
> + }
> + };
> +
> + if (offset >= priv->nvm_cfg.size)
> + return 0; /* End-of-file */
> + if (offset + bytes > priv->nvm_cfg.size)
> + bytes = priv->nvm_cfg.size - offset;
> +
> + mutex_lock(&priv->lock);
> +
> + num_written = 0;
> + while (bytes) {
> + chunk_size = round_down(offset, ISL12026_PAGESIZE) +
> + ISL12026_PAGESIZE - offset;
> + chunk_size = min(bytes, chunk_size);
> + memcpy(payload + 2, v + num_written, chunk_size);
> + payload[0] = (offset >> 8) & 0xff;
> + payload[1] = offset & 0xff;
Useless & 0xff:s.
Isn't endianess handled by i2c core?
> + msgs[0].len = chunk_size + 2;
> + r = i2c_transfer(priv->nvm_client->adapter,
> + msgs, ARRAY_SIZE(msgs));
> + if (r != ARRAY_SIZE(msgs)) {
> + dev_err(priv->nvm_cfg.dev,
> + "nvmem write error, ret=%d\n", r);
> + break;
> + }
> + bytes -= chunk_size;
> + offset += chunk_size;
> + num_written += chunk_size;
> + msleep(ISL12026_NVMEM_WRITE_TIME);
> + }
> +
> + mutex_unlock(&priv->lock);
> +
> + return num_written > 0 ? num_written : -EIO;
> +}
> +
> +static int isl12026_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct isl12026 *priv;
> + int pwr, requested_pwr;
> + int ret;
> + u32 bsw_val, sbib_val;
> + bool set_bsw, set_sbib;
> + priv = devm_kzalloc(&client->dev, sizeof(struct isl12026), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
sizeof(*priv) ?
> + 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) {
> + pwr = isl12026_read_reg(client, ISL12026_REG_PWR);
> + if (pwr < 0)
> + dev_err(&client->dev,
> + "Error: Failed to read PWR %d\n", pwr);
...and what? No recovery? No nothing except the message?
> +
> + requested_pwr = pwr;
> +
> + if (set_bsw) {
> + if (bsw_val)
> + requested_pwr |= ISL12026_REG_PWR_BSW;
> + else
> + requested_pwr &= ~ISL12026_REG_PWR_BSW;
> + }
> + if (set_sbib) {
> + if (sbib_val)
> + requested_pwr |= ISL12026_REG_PWR_SBIB;
> + else
> + requested_pwr &= ~ISL12026_REG_PWR_SBIB;
> + }
> +
> + if (pwr >= 0 && pwr != requested_pwr) {
> + dev_info(&client->dev, "PWR: %02x\n", pwr);
> + dev_info(&client->dev,
> + "Updating PWR to: %02x\n", (u8)requested_pwr);
> + isl12026_write_reg(client,
> + ISL12026_REG_PWR, requested_pwr);
> + }
> + }
Can you refactor above to a separate function?
> + priv->rtc = devm_rtc_device_register(&client->dev, "rtc-isl12026",
> + &isl12026_rtc_ops, THIS_MODULE);
> +
Redundant empty line.
> + ret = PTR_ERR_OR_ZERO(priv->rtc);
> + if (ret)
> + return ret;
> + if (IS_ENABLED(CONFIG_NVMEM)) {
I think you don't need this, see below.
> + priv->nvm_client = i2c_new_dummy(client->adapter, 0x57);
> + if (!priv->nvm_client)
> + return -ENOMEM;
i2c_new_secondary_device() ?
> + priv->nvm_dev = nvmem_register(&priv->nvm_cfg);
> +
Redundant empty line.
> + if (!priv->nvm_dev)
Should it be IS_ERR() ?
> + return -ENOMEM;
After all rtc_nvmem_register() ?
> + }
> + return 0;
> +}
> +
> +static int isl12026_remove(struct i2c_client *client)
> +{
> + struct isl12026 *priv = i2c_get_clientdata(client);
> +
> + if (priv->nvm_dev)
How is it
> + nvmem_unregister(priv->nvm_dev);
> + if (priv->nvm_client)
Check with v4.16-rc1. This is duplicate check.
> + i2c_unregister_device(priv->nvm_client);
> +
> + return 0;
> +}
> +#ifdef CONFIG_OF
Useless.
> +static const struct of_device_id isl12026_dt_match[] = {
> + { .compatible = "isil,isl12026" },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, isl12026_dt_match);
> +#endif
> +
> +static const struct i2c_device_id isl12026_id[] = {
> + { "isl12026", 0 },
> + { }
> +};
> +MODULE_DEVICE_TABLE(i2c, isl12026_id);
Useless. Use ->probe_new() approach.
> +#ifdef CONFIG_OF
Ugly and useless.
> + .of_match_table = of_match_ptr(isl12026_dt_match),
> +#endif
--
With Best Regards,
Andy Shevchenko
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