* [PATCH v3 2/3] iio: distance: srf08: add IIO driver for us ranger
From: Andreas Klinger @ 2017-01-17 13:49 UTC (permalink / raw)
To: jic23-DgEjT+Ai2ygdnm+yROfE0A, knaack.h-Mmb7MZpHnFY,
lars-Qo5EllUWu/uELgA04lAiVw, pmeerw-jW+XmwGofnusTnJN9+BGXg,
linux-iio-u79uwXL29TY76Z2rM5mHXA,
linux-kernel-u79uwXL29TY76Z2rM5mHXA, ktsai-GubuWUlQtMwciDkP5Hr2oA,
wsa-z923LK4zBo2bacvFa/9K2g, robh+dt-DgEjT+Ai2ygdnm+yROfE0A,
pawel.moll-5wv7dgnIgG8, mark.rutland-5wv7dgnIgG8,
ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg,
galak-sgV2jX0FEOL9JmXXK+q4OQ, trivial-DgEjT+Ai2ygdnm+yROfE0A,
mranostay-Re5JQEeQqe8AvxtiuMwx3w,
linux-i2c-u79uwXL29TY76Z2rM5mHXA,
devicetree-u79uwXL29TY76Z2rM5mHXA
Cc: ak-n176/SwNRljddJNmlsFzeA
This is the IIO driver for devantech srf08 ultrasonic ranger which can be
used to measure the distances to an object.
The sensor supports I2C with some registers.
Supported Features include:
- read the distance in ranging mode in centimeters
- output of the driver is directly the read value
- together with the scale the driver delivers the distance in meters
- only the first echo of the nearest object is delivered
- set sensitivity as analog value in the range of 0-31 means setting
gain register on device
- set range registers; userspace enters max. range in millimeters in
43 mm steps
Features not supported by this driver:
- ranging mode in inches or in microseconds
- ANN mode
- change I2C address through this driver
- light sensor
The driver was added in the directory "proximity" of the iio subsystem and
the menu in den config is now called "Proximity and distance sensors"
Signed-off-by: Andreas Klinger <ak-n176/SwNRljddJNmlsFzeA@public.gmane.org>
---
drivers/iio/proximity/Kconfig | 13 +-
drivers/iio/proximity/Makefile | 1 +
drivers/iio/proximity/srf08.c | 405 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 418 insertions(+), 1 deletion(-)
create mode 100644 drivers/iio/proximity/srf08.c
diff --git a/drivers/iio/proximity/Kconfig b/drivers/iio/proximity/Kconfig
index ef4c73db5b53..ab96cb7a0054 100644
--- a/drivers/iio/proximity/Kconfig
+++ b/drivers/iio/proximity/Kconfig
@@ -18,7 +18,7 @@ config AS3935
endmenu
-menu "Proximity sensors"
+menu "Proximity and distance sensors"
config LIDAR_LITE_V2
tristate "PulsedLight LIDAR sensor"
@@ -45,4 +45,15 @@ config SX9500
To compile this driver as a module, choose M here: the
module will be called sx9500.
+config SRF08
+ tristate "Devantech SRF08 ultrasonic ranger sensor"
+ depends on I2C
+ help
+ Say Y here to build a driver for Devantech SRF08 ultrasonic
+ ranger sensor. This driver can be used to measure the distance
+ of objects.
+
+ To compile this driver as a module, choose M here: the
+ module will be called srf08.
+
endmenu
diff --git a/drivers/iio/proximity/Makefile b/drivers/iio/proximity/Makefile
index 9aadd9a8ee99..e914c2a5dd49 100644
--- a/drivers/iio/proximity/Makefile
+++ b/drivers/iio/proximity/Makefile
@@ -5,4 +5,5 @@
# When adding new entries keep the list in alphabetical order
obj-$(CONFIG_AS3935) += as3935.o
obj-$(CONFIG_LIDAR_LITE_V2) += pulsedlight-lidar-lite-v2.o
+obj-$(CONFIG_SRF08) += srf08.o
obj-$(CONFIG_SX9500) += sx9500.o
diff --git a/drivers/iio/proximity/srf08.c b/drivers/iio/proximity/srf08.c
new file mode 100644
index 000000000000..faab6cf3f1a2
--- /dev/null
+++ b/drivers/iio/proximity/srf08.c
@@ -0,0 +1,405 @@
+/*
+ * srf08.c - Support for Devantech SRF08 ultrasonic ranger
+ *
+ * Copyright (c) 2016 Andreas Klinger <ak-n176/SwNRljddJNmlsFzeA@public.gmane.org>
+ *
+ * This file is subject to the terms and conditions of version 2 of
+ * the GNU General Public License. See the file COPYING in the main
+ * directory of this archive for more details.
+ *
+ * For details about the device see:
+ * http://www.robot-electronics.co.uk/htm/srf08tech.html
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/bitops.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+/* registers of SRF08 device */
+#define SRF08_WRITE_COMMAND 0x00 /* Command Register */
+#define SRF08_WRITE_MAX_GAIN 0x01 /* Max Gain Register: 0 .. 31 */
+#define SRF08_WRITE_RANGE 0x02 /* Range Register: 0 .. 255 */
+#define SRF08_READ_SW_REVISION 0x00 /* Software Revision */
+#define SRF08_READ_LIGHT 0x01 /* Light Sensor during last echo */
+#define SRF08_READ_ECHO_1_HIGH 0x02 /* Range of first echo received */
+#define SRF08_READ_ECHO_1_LOW 0x03 /* Range of first echo received */
+
+#define SRF08_CMD_RANGING_CM 0x51 /* Ranging Mode - Result in cm */
+
+#define SRF08_DEFAULT_GAIN 1025 /* default analogue value of Gain */
+#define SRF08_DEFAULT_RANGE 6020 /* default value of Range in mm */
+
+struct srf08_data {
+ struct i2c_client *client;
+ int sensitivity; /* Gain */
+ int range_mm; /* max. Range in mm */
+ struct mutex lock;
+};
+
+/*
+ * in the documentation one can read about the "Gain" of the device
+ * which is used here for amplifying the signal and filtering out unwanted
+ * ones.
+ * But with ADC's this term is already used differently and that's why it
+ * is called "Sensitivity" here.
+ */
+static const int srf08_sensitivity[] = {
+ 94, 97, 100, 103, 107, 110, 114, 118,
+ 123, 128, 133, 139, 145, 152, 159, 168,
+ 177, 187, 199, 212, 227, 245, 265, 288,
+ 317, 352, 395, 450, 524, 626, 777, 1025 };
+
+static int srf08_read_ranging(struct srf08_data *data)
+{
+ struct i2c_client *client = data->client;
+ int ret, i;
+ int waittime;
+
+ mutex_lock(&data->lock);
+
+ ret = i2c_smbus_write_byte_data(data->client,
+ SRF08_WRITE_COMMAND, SRF08_CMD_RANGING_CM);
+ if (ret < 0) {
+ dev_err(&client->dev, "write command - err: %d\n", ret);
+ mutex_unlock(&data->lock);
+ return ret;
+ }
+
+ /*
+ * we read here until a correct version number shows up as
+ * suggested by the documentation
+ *
+ * with an ultrasonic speed of 343 m/s and a roundtrip of it
+ * sleep the expected duration and try to read from the device
+ * if nothing useful is read try it in a shorter grid
+ *
+ * polling for not more than 20 ms should be enough
+ */
+ waittime = 1 + data->range_mm / 172;
+ msleep(waittime);
+ for (i = 0; i < 4; i++) {
+ ret = i2c_smbus_read_byte_data(data->client,
+ SRF08_READ_SW_REVISION);
+
+ /* check if a valid version number is read */
+ if (ret < 255 && ret > 0)
+ break;
+ msleep(5);
+ }
+
+ if (ret >= 255 || ret <= 0) {
+ dev_err(&client->dev, "device not ready\n");
+ mutex_unlock(&data->lock);
+ return -EIO;
+ }
+
+ ret = i2c_smbus_read_word_swapped(data->client,
+ SRF08_READ_ECHO_1_HIGH);
+ if (ret < 0) {
+ dev_err(&client->dev, "cannot read distance: ret=%d\n", ret);
+ mutex_unlock(&data->lock);
+ return ret;
+ }
+
+ mutex_unlock(&data->lock);
+
+ return ret;
+}
+
+static int srf08_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *channel, int *val,
+ int *val2, long mask)
+{
+ struct srf08_data *data = iio_priv(indio_dev);
+ int ret;
+
+ if (channel->type != IIO_DISTANCE)
+ return -EINVAL;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ ret = srf08_read_ranging(data);
+ if (ret < 0)
+ return ret;
+ *val = ret;
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ /* 1 LSB is 1 cm */
+ *val = 0;
+ *val2 = 10000;
+ return IIO_VAL_INT_PLUS_MICRO;
+ default:
+ return -EINVAL;
+ }
+}
+
+static ssize_t srf08_show_range_mm_available(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ int i, len = 0;
+
+ for (i = 0; i < 256; i++)
+ len += scnprintf(buf + len, PAGE_SIZE - len,
+ "%d ", (i + 1) * 43);
+
+ buf[len - 1] = '\n';
+
+ return len;
+}
+
+static IIO_DEVICE_ATTR(sensor_max_range_available, S_IRUGO,
+ srf08_show_range_mm_available, NULL, 0);
+
+static ssize_t srf08_show_range_mm(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct srf08_data *data = iio_priv(indio_dev);
+
+ return sprintf(buf, "%d\n", data->range_mm);
+}
+
+/*
+ * set the range of the sensor to an even multiple of 43 mm
+ * which corresponds to 1 LSB in the register
+ *
+ * register value corresponding range
+ * 0x00 43 mm
+ * 0x01 86 mm
+ * 0x02 129 mm
+ * ...
+ * 0xFF 11008 mm
+ */
+static ssize_t srf08_write_range_mm(struct srf08_data *data, unsigned int val)
+{
+ int ret;
+ struct i2c_client *client = data->client;
+ unsigned int mod;
+ u8 regval;
+
+ ret = val / 43 - 1;
+ mod = val % 43;
+
+ if (mod || (ret < 0) || (ret > 255))
+ return -EINVAL;
+
+ regval = ret;
+
+ mutex_lock(&data->lock);
+
+ ret = i2c_smbus_write_byte_data(client, SRF08_WRITE_RANGE, regval);
+ if (ret < 0) {
+ dev_err(&client->dev, "write_range - err: %d\n", ret);
+ mutex_unlock(&data->lock);
+ return ret;
+ }
+
+ data->range_mm = val;
+
+ mutex_unlock(&data->lock);
+
+ return 0;
+}
+
+static ssize_t srf08_store_range_mm(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct srf08_data *data = iio_priv(indio_dev);
+ int ret;
+ unsigned int val;
+
+ ret = kstrtouint(buf, 10, &val);
+ if (ret)
+ return ret;
+
+ ret = srf08_write_range_mm(data, val);
+ if (ret < 0)
+ return ret;
+
+ return len;
+}
+
+static IIO_DEVICE_ATTR(sensor_max_range, S_IRUGO | S_IWUSR,
+ srf08_show_range_mm, srf08_store_range_mm, 0);
+
+static ssize_t srf08_show_sensitivity_available(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ int i, len = 0;
+
+ for (i = 0; i < ARRAY_SIZE(srf08_sensitivity); i++)
+ len += sprintf(buf + len, "%d ", srf08_sensitivity[i]);
+
+ len += sprintf(buf + len, "\n");
+
+ return len;
+}
+
+static IIO_DEVICE_ATTR(sensor_sensitivity_available, S_IRUGO,
+ srf08_show_sensitivity_available, NULL, 0);
+
+static ssize_t srf08_show_sensitivity(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct srf08_data *data = iio_priv(indio_dev);
+ int len;
+
+ len = sprintf(buf, "%d\n", data->sensitivity);
+
+ return len;
+}
+
+static ssize_t srf08_write_sensitivity(struct srf08_data *data,
+ unsigned int val)
+{
+ struct i2c_client *client = data->client;
+ int ret, i;
+ u8 regval;
+
+ for (i = 0; i < ARRAY_SIZE(srf08_sensitivity); i++)
+ if (val == srf08_sensitivity[i]) {
+ regval = i;
+ break;
+ }
+
+ if (i >= ARRAY_SIZE(srf08_sensitivity))
+ return -EINVAL;
+
+ mutex_lock(&data->lock);
+
+ ret = i2c_smbus_write_byte_data(client,
+ SRF08_WRITE_MAX_GAIN, regval);
+ if (ret < 0) {
+ dev_err(&client->dev, "write_sensitivity - err: %d\n", ret);
+ mutex_unlock(&data->lock);
+ return ret;
+ }
+
+ data->sensitivity = val;
+
+ mutex_unlock(&data->lock);
+
+ return 0;
+}
+
+static ssize_t srf08_store_sensitivity(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct srf08_data *data = iio_priv(indio_dev);
+ int ret;
+ unsigned int val;
+
+ ret = kstrtouint(buf, 10, &val);
+ if (ret)
+ return ret;
+
+ ret = srf08_write_sensitivity(data, val);
+ if (ret < 0)
+ return ret;
+
+ return len;
+}
+
+static IIO_DEVICE_ATTR(sensor_sensitivity, S_IRUGO | S_IWUSR,
+ srf08_show_sensitivity, srf08_store_sensitivity, 0);
+
+static struct attribute *srf08_attributes[] = {
+ &iio_dev_attr_sensor_max_range.dev_attr.attr,
+ &iio_dev_attr_sensor_max_range_available.dev_attr.attr,
+ &iio_dev_attr_sensor_sensitivity.dev_attr.attr,
+ &iio_dev_attr_sensor_sensitivity_available.dev_attr.attr,
+ NULL,
+};
+
+static const struct attribute_group srf08_attribute_group = {
+ .attrs = srf08_attributes,
+};
+
+static const struct iio_chan_spec srf08_channels[] = {
+ {
+ .type = IIO_DISTANCE,
+ .info_mask_separate =
+ BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ },
+};
+
+static const struct iio_info srf08_info = {
+ .read_raw = srf08_read_raw,
+ .attrs = &srf08_attribute_group,
+ .driver_module = THIS_MODULE,
+};
+
+static int srf08_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct iio_dev *indio_dev;
+ struct srf08_data *data;
+ int ret;
+
+ if (!i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_READ_BYTE_DATA |
+ I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
+ I2C_FUNC_SMBUS_READ_WORD_DATA))
+ return -ENODEV;
+
+ indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ data = iio_priv(indio_dev);
+ i2c_set_clientdata(client, indio_dev);
+ data->client = client;
+
+ indio_dev->name = "srf08";
+ indio_dev->dev.parent = &client->dev;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->info = &srf08_info;
+ indio_dev->channels = srf08_channels;
+ indio_dev->num_channels = ARRAY_SIZE(srf08_channels);
+
+ mutex_init(&data->lock);
+
+ /*
+ * set default values of device here
+ * these register values cannot be read from the hardware
+ * therefore set driver specific default values
+ */
+ ret = srf08_write_sensitivity(data, SRF08_DEFAULT_GAIN);
+ if (ret < 0)
+ return ret;
+
+ ret = srf08_write_range_mm(data, SRF08_DEFAULT_RANGE);
+ if (ret < 0)
+ return ret;
+
+ return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct i2c_device_id srf08_id[] = {
+ { "srf08", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, srf08_id);
+
+static struct i2c_driver srf08_driver = {
+ .driver = {
+ .name = "srf08",
+ },
+ .probe = srf08_probe,
+ .id_table = srf08_id,
+};
+module_i2c_driver(srf08_driver);
+
+MODULE_AUTHOR("Andreas Klinger <ak-n176/SwNRljddJNmlsFzeA@public.gmane.org>");
+MODULE_DESCRIPTION("Devantech SRF08 ultrasonic ranger driver");
+MODULE_LICENSE("GPL");
--
2.1.4
--
^ permalink raw reply related
* [PATCH v3 3/3] iio: distance: srf08: add driver ABI documentation
From: Andreas Klinger @ 2017-01-17 13:50 UTC (permalink / raw)
To: jic23-DgEjT+Ai2ygdnm+yROfE0A, knaack.h-Mmb7MZpHnFY,
lars-Qo5EllUWu/uELgA04lAiVw, pmeerw-jW+XmwGofnusTnJN9+BGXg,
linux-iio-u79uwXL29TY76Z2rM5mHXA,
linux-kernel-u79uwXL29TY76Z2rM5mHXA, ktsai-GubuWUlQtMwciDkP5Hr2oA,
wsa-z923LK4zBo2bacvFa/9K2g, robh+dt-DgEjT+Ai2ygdnm+yROfE0A,
pawel.moll-5wv7dgnIgG8, mark.rutland-5wv7dgnIgG8,
ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg,
galak-sgV2jX0FEOL9JmXXK+q4OQ, trivial-DgEjT+Ai2ygdnm+yROfE0A,
mranostay-Re5JQEeQqe8AvxtiuMwx3w,
linux-i2c-u79uwXL29TY76Z2rM5mHXA,
devicetree-u79uwXL29TY76Z2rM5mHXA
Cc: ak-n176/SwNRljddJNmlsFzeA
Add sysfs-bus-iio-distance-srf08 for individual attributes of the driver,
especially:
- sensitivity which the device documentation calls gain for amplifying the
signal
- max_range for limiting the maximum distance for expected echos and
therefore limiting the time waiting for telegrams
Signed-off-by: Andreas Klinger <ak-n176/SwNRljddJNmlsFzeA@public.gmane.org>
---
.../ABI/testing/sysfs-bus-iio-distance-srf08 | 27 ++++++++++++++++++++++
1 file changed, 27 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-distance-srf08
diff --git a/Documentation/ABI/testing/sysfs-bus-iio-distance-srf08 b/Documentation/ABI/testing/sysfs-bus-iio-distance-srf08
new file mode 100644
index 000000000000..e96c28064748
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-iio-distance-srf08
@@ -0,0 +1,27 @@
+What /sys/bus/iio/devices/iio:deviceX/in_distance_raw
+Date: January 2017
+KernelVersion: 4.11
+Contact: linux-iio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
+Description:
+ Get the current distance in meters between the sensor and
+ the first object recognized
+
+What /sys/bus/iio/devices/iio:deviceX/sensor_sensitivity
+Date: January 2017
+KernelVersion: 4.11
+Contact: linux-iio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
+Description:
+ Show or set the gain boost of the amp, from 0-31 range.
+ default 31
+
+What /sys/bus/iio/devices/iio:deviceX/sensor_max_range
+Date: January 2017
+KernelVersion: 4.11
+Contact: linux-iio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
+Description:
+ Show or set the maximum range between the sensor and the
+ first object echoed in millimeters.
+ This setting limits the time the driver is waiting for a
+ echo.
+ Can be set between 43 and 11008 in a grid of 43 mm.
+ default 6020
--
2.1.4
--
--
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^ permalink raw reply related
* [PATCH v3] i2c: core: helper function to detect slave mode
From: Luis Oliveira @ 2017-01-17 14:33 UTC (permalink / raw)
To: wsa, robh+dt, mark.rutland, jarkko.nikula, andriy.shevchenko,
mika.westerberg, linux-i2c, devicetree, linux-kernel, vz
Cc: Luis.Oliveira, Ramiro.Oliveira, Joao.Pinto, CARLOS.PALMINHA
This function has the purpose of mode detection by checking the
device nodes for a reg matching with the I2C_OWN_SLAVE_ADDREESS flag.
Currently only checks using OF functions (ACPI slave not supported yet).
Signed-off-by: Luis Oliveira <lolivei@synopsys.com>
Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
---
Changes V2->V3: (@Vladimir)
- Bug Fix: «of_node_put(child)» added.
drivers/i2c/i2c-core.c | 30 ++++++++++++++++++++++++++++++
include/linux/i2c.h | 1 +
2 files changed, 31 insertions(+)
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 583e95042a21..30aa7b50b5bc 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -3690,6 +3690,36 @@ int i2c_slave_unregister(struct i2c_client *client)
return ret;
}
EXPORT_SYMBOL_GPL(i2c_slave_unregister);
+
+/**
+ * i2c_slave_mode_detect - detect operation mode
+ * @dev: The device owning the bus
+ *
+ * This checks the device nodes for an I2C slave by checking the address
+ * used.
+ *
+ * Returns true if an I2C slave is detected, otherwise returns false.
+ */
+bool i2c_slave_mode_detect(struct device *dev)
+{
+ if (IS_BUILTIN(CONFIG_OF) && dev->of_node) {
+ struct device_node *child;
+ u32 reg;
+
+ for_each_child_of_node(dev->of_node, child) {
+ of_property_read_u32(child, "reg", ®);
+ if (reg & I2C_OWN_SLAVE_ADDRESS) {
+ of_node_put(child);
+ return true;
+ }
+ }
+ } else if (IS_BUILTIN(CONFIG_ACPI) && ACPI_HANDLE(dev)) {
+ dev_dbg(dev, "ACPI slave is not supported yet\n");
+ }
+ return false;
+}
+EXPORT_SYMBOL_GPL(i2c_slave_mode_detect);
+
#endif
MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 4b45ec46161f..2e72e157826c 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -282,6 +282,7 @@ enum i2c_slave_event {
extern int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb);
extern int i2c_slave_unregister(struct i2c_client *client);
+extern bool i2c_slave_mode_detect(struct device *dev);
static inline int i2c_slave_event(struct i2c_client *client,
enum i2c_slave_event event, u8 *val)
--
2.11.0
^ permalink raw reply related
* [PATCH v9 0/5] Add support for the STM32F4 I2C
From: M'boumba Cedric Madianga @ 2017-01-17 15:26 UTC (permalink / raw)
To: wsa, robh+dt, mcoquelin.stm32, alexandre.torgue, linus.walleij,
patrice.chotard, linux, linux-i2c, devicetree, linux-arm-kernel,
linux-kernel, u.kleine-koenig
Cc: M'boumba Cedric Madianga
This patchset adds support for the I2C controller embedded in STM32F4xx SoC.
It enables I2C transfer in interrupt mode with Standard-mode and Fast-mode bus
speed.
Changes since v8:
- Rework I2C Clock Control Register computation (Uwe)
- Save register accesses as often as possible (Uwe)
- Don't use mask before saving rx buffer (Uwe)
- Add more comments to explain hardware way of working (Uwe)
- Rename stm32f4_i2c_handle_rx_btf function by stm32f4_i2c_handle_rx_done (Uwe)
- Set/Clear Ack position bit during address match phase
M'boumba Cedric Madianga (5):
dt-bindings: Document the STM32 I2C bindings
i2c: Add STM32F4 I2C driver
ARM: dts: stm32: Add I2C1 support for STM32F429 SoC
ARM: dts: stm32: Add I2C1 support for STM32429 eval board
ARM: configs: stm32: Add I2C support for STM32 defconfig
.../devicetree/bindings/i2c/i2c-stm32.txt | 33 +
arch/arm/boot/dts/stm32429i-eval.dts | 6 +
arch/arm/boot/dts/stm32f429.dtsi | 23 +
arch/arm/configs/stm32_defconfig | 3 +
drivers/i2c/busses/Kconfig | 10 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-stm32f4.c | 883 +++++++++++++++++++++
7 files changed, 959 insertions(+)
create mode 100644 Documentation/devicetree/bindings/i2c/i2c-stm32.txt
create mode 100644 drivers/i2c/busses/i2c-stm32f4.c
--
1.9.1
^ permalink raw reply
* [PATCH v9 1/5] dt-bindings: Document the STM32 I2C bindings
From: M'boumba Cedric Madianga @ 2017-01-17 15:26 UTC (permalink / raw)
To: wsa, robh+dt, mcoquelin.stm32, alexandre.torgue, linus.walleij,
patrice.chotard, linux, linux-i2c, devicetree, linux-arm-kernel,
linux-kernel, u.kleine-koenig
Cc: M'boumba Cedric Madianga
In-Reply-To: <1484666821-20551-1-git-send-email-cedric.madianga@gmail.com>
This patch adds documentation of device tree bindings for the STM32 I2C
controller.
Signed-off-by: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
---
.../devicetree/bindings/i2c/i2c-stm32.txt | 33 ++++++++++++++++++++++
1 file changed, 33 insertions(+)
create mode 100644 Documentation/devicetree/bindings/i2c/i2c-stm32.txt
diff --git a/Documentation/devicetree/bindings/i2c/i2c-stm32.txt b/Documentation/devicetree/bindings/i2c/i2c-stm32.txt
new file mode 100644
index 0000000..78eaf7b
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-stm32.txt
@@ -0,0 +1,33 @@
+* I2C controller embedded in STMicroelectronics STM32 I2C platform
+
+Required properties :
+- compatible : Must be "st,stm32f4-i2c"
+- reg : Offset and length of the register set for the device
+- interrupts : Must contain the interrupt id for I2C event and then the
+ interrupt id for I2C error.
+- resets: Must contain the phandle to the reset controller.
+- clocks: Must contain the input clock of the I2C instance.
+- A pinctrl state named "default" must be defined to set pins in mode of
+ operation for I2C transfer
+- #address-cells = <1>;
+- #size-cells = <0>;
+
+Optional properties :
+- clock-frequency : Desired I2C bus clock frequency in Hz. If not specified,
+ the default 100 kHz frequency will be used. As only Normal and Fast modes
+ are supported, possible values are 100000 and 400000.
+
+Example :
+
+ i2c@40005400 {
+ compatible = "st,stm32f4-i2c";
+ #address-cells = <1>;
+ #size-cells = <0>;
+ reg = <0x40005400 0x400>;
+ interrupts = <31>,
+ <32>;
+ resets = <&rcc 277>;
+ clocks = <&rcc 0 149>;
+ pinctrl-0 = <&i2c1_sda_pin>, <&i2c1_scl_pin>;
+ pinctrl-names = "default";
+ };
--
1.9.1
^ permalink raw reply related
* [PATCH v9 2/5] i2c: Add STM32F4 I2C driver
From: M'boumba Cedric Madianga @ 2017-01-17 15:26 UTC (permalink / raw)
To: wsa, robh+dt, mcoquelin.stm32, alexandre.torgue, linus.walleij,
patrice.chotard, linux, linux-i2c, devicetree, linux-arm-kernel,
linux-kernel, u.kleine-koenig
Cc: M'boumba Cedric Madianga
In-Reply-To: <1484666821-20551-1-git-send-email-cedric.madianga@gmail.com>
This patch adds support for the STM32F4 I2C controller.
Signed-off-by: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
---
drivers/i2c/busses/Kconfig | 10 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-stm32f4.c | 883 +++++++++++++++++++++++++++++++++++++++
3 files changed, 894 insertions(+)
create mode 100644 drivers/i2c/busses/i2c-stm32f4.c
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 0cdc844..2719208 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -886,6 +886,16 @@ config I2C_ST
This driver can also be built as module. If so, the module
will be called i2c-st.
+config I2C_STM32F4
+ tristate "STMicroelectronics STM32F4 I2C support"
+ depends on ARCH_STM32 || COMPILE_TEST
+ help
+ Enable this option to add support for STM32 I2C controller embedded
+ in STM32F4 SoCs.
+
+ This driver can also be built as module. If so, the module
+ will be called i2c-stm32f4.
+
config I2C_STU300
tristate "ST Microelectronics DDC I2C interface"
depends on MACH_U300
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 1c1bac8..a2c6ff5 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -85,6 +85,7 @@ obj-$(CONFIG_I2C_SH_MOBILE) += i2c-sh_mobile.o
obj-$(CONFIG_I2C_SIMTEC) += i2c-simtec.o
obj-$(CONFIG_I2C_SIRF) += i2c-sirf.o
obj-$(CONFIG_I2C_ST) += i2c-st.o
+obj-$(CONFIG_I2C_STM32F4) += i2c-stm32f4.o
obj-$(CONFIG_I2C_STU300) += i2c-stu300.o
obj-$(CONFIG_I2C_SUN6I_P2WI) += i2c-sun6i-p2wi.o
obj-$(CONFIG_I2C_TEGRA) += i2c-tegra.o
diff --git a/drivers/i2c/busses/i2c-stm32f4.c b/drivers/i2c/busses/i2c-stm32f4.c
new file mode 100644
index 0000000..7733a96
--- /dev/null
+++ b/drivers/i2c/busses/i2c-stm32f4.c
@@ -0,0 +1,883 @@
+/*
+ * Driver for STMicroelectronics STM32 I2C controller
+ *
+ * This I2C controller is described in the STM32F429/439 Soc reference manual.
+ * Please see below a link to the documentation:
+ * http://www.st.com/resource/en/reference_manual/DM00031020.pdf
+ *
+ * Copyright (C) M'boumba Cedric Madianga 2016
+ * Author: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
+ *
+ * This driver is based on i2c-st.c
+ *
+ * License terms: GNU General Public License (GPL), version 2
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+
+/* STM32F4 I2C offset registers */
+#define STM32F4_I2C_CR1 0x00
+#define STM32F4_I2C_CR2 0x04
+#define STM32F4_I2C_DR 0x10
+#define STM32F4_I2C_SR1 0x14
+#define STM32F4_I2C_SR2 0x18
+#define STM32F4_I2C_CCR 0x1C
+#define STM32F4_I2C_TRISE 0x20
+#define STM32F4_I2C_FLTR 0x24
+
+/* STM32F4 I2C control 1*/
+#define STM32F4_I2C_CR1_POS BIT(11)
+#define STM32F4_I2C_CR1_ACK BIT(10)
+#define STM32F4_I2C_CR1_STOP BIT(9)
+#define STM32F4_I2C_CR1_START BIT(8)
+#define STM32F4_I2C_CR1_PE BIT(0)
+
+/* STM32F4 I2C control 2 */
+#define STM32F4_I2C_CR2_FREQ_MASK GENMASK(5, 0)
+#define STM32F4_I2C_CR2_FREQ(n) ((n) & STM32F4_I2C_CR2_FREQ_MASK)
+#define STM32F4_I2C_CR2_ITBUFEN BIT(10)
+#define STM32F4_I2C_CR2_ITEVTEN BIT(9)
+#define STM32F4_I2C_CR2_ITERREN BIT(8)
+#define STM32F4_I2C_CR2_IRQ_MASK (STM32F4_I2C_CR2_ITBUFEN | \
+ STM32F4_I2C_CR2_ITEVTEN | \
+ STM32F4_I2C_CR2_ITERREN)
+
+/* STM32F4 I2C Status 1 */
+#define STM32F4_I2C_SR1_AF BIT(10)
+#define STM32F4_I2C_SR1_ARLO BIT(9)
+#define STM32F4_I2C_SR1_BERR BIT(8)
+#define STM32F4_I2C_SR1_TXE BIT(7)
+#define STM32F4_I2C_SR1_RXNE BIT(6)
+#define STM32F4_I2C_SR1_BTF BIT(2)
+#define STM32F4_I2C_SR1_ADDR BIT(1)
+#define STM32F4_I2C_SR1_SB BIT(0)
+#define STM32F4_I2C_SR1_ITEVTEN_MASK (STM32F4_I2C_SR1_BTF | \
+ STM32F4_I2C_SR1_ADDR | \
+ STM32F4_I2C_SR1_SB)
+#define STM32F4_I2C_SR1_ITBUFEN_MASK (STM32F4_I2C_SR1_TXE | \
+ STM32F4_I2C_SR1_RXNE)
+#define STM32F4_I2C_SR1_ITERREN_MASK (STM32F4_I2C_SR1_AF | \
+ STM32F4_I2C_SR1_ARLO | \
+ STM32F4_I2C_SR1_BERR)
+
+/* STM32F4 I2C Status 2 */
+#define STM32F4_I2C_SR2_BUSY BIT(1)
+
+/* STM32F4 I2C Control Clock */
+#define STM32F4_I2C_CCR_CCR_MASK GENMASK(11, 0)
+#define STM32F4_I2C_CCR_CCR(n) ((n) & STM32F4_I2C_CCR_CCR_MASK)
+#define STM32F4_I2C_CCR_FS BIT(15)
+#define STM32F4_I2C_CCR_DUTY BIT(14)
+
+/* STM32F4 I2C Trise */
+#define STM32F4_I2C_TRISE_VALUE_MASK GENMASK(5, 0)
+#define STM32F4_I2C_TRISE_VALUE(n) ((n) & STM32F4_I2C_TRISE_VALUE_MASK)
+
+#define STM32F4_I2C_MIN_STANDARD_FREQ 2U
+#define STM32F4_I2C_MIN_FAST_FREQ 6U
+#define STM32F4_I2C_MAX_FREQ 46U
+#define HZ_TO_MHZ 1000000
+
+enum stm32f4_i2c_speed {
+ STM32F4_I2C_SPEED_STANDARD, /* 100 kHz */
+ STM32F4_I2C_SPEED_FAST, /* 400 kHz */
+ STM32F4_I2C_SPEED_END,
+};
+
+/**
+ * struct stm32f4_i2c_msg - client specific data
+ * @addr: 8-bit slave addr, including r/w bit
+ * @count: number of bytes to be transferred
+ * @buf: data buffer
+ * @result: result of the transfer
+ * @stop: last I2C msg to be sent, i.e. STOP to be generated
+ */
+struct stm32f4_i2c_msg {
+ u8 addr;
+ u32 count;
+ u8 *buf;
+ int result;
+ bool stop;
+};
+
+/**
+ * struct stm32f4_i2c_dev - private data of the controller
+ * @adap: I2C adapter for this controller
+ * @dev: device for this controller
+ * @base: virtual memory area
+ * @complete: completion of I2C message
+ * @clk: hw i2c clock
+ * @speed: I2C clock frequency of the controller. Standard or Fast are supported
+ * @parent_rate: I2C clock parent rate in MHz
+ * @msg: I2C transfer information
+ */
+struct stm32f4_i2c_dev {
+ struct i2c_adapter adap;
+ struct device *dev;
+ void __iomem *base;
+ struct completion complete;
+ struct clk *clk;
+ int speed;
+ int parent_rate;
+ struct stm32f4_i2c_msg msg;
+};
+
+static inline void stm32f4_i2c_set_bits(void __iomem *reg, u32 mask)
+{
+ writel_relaxed(readl_relaxed(reg) | mask, reg);
+}
+
+static inline void stm32f4_i2c_clr_bits(void __iomem *reg, u32 mask)
+{
+ writel_relaxed(readl_relaxed(reg) & ~mask, reg);
+}
+
+static void stm32f4_i2c_disable_irq(struct stm32f4_i2c_dev *i2c_dev)
+{
+ void __iomem *reg = i2c_dev->base + STM32F4_I2C_CR2;
+
+ stm32f4_i2c_clr_bits(reg, STM32F4_I2C_CR2_IRQ_MASK);
+}
+
+static int stm32f4_i2c_set_periph_clk_freq(struct stm32f4_i2c_dev *i2c_dev)
+{
+ u32 freq;
+ u32 cr2 = 0;
+
+ i2c_dev->parent_rate = clk_get_rate(i2c_dev->clk);
+ freq = DIV_ROUND_UP(i2c_dev->parent_rate, HZ_TO_MHZ);
+
+ if (i2c_dev->speed == STM32F4_I2C_SPEED_STANDARD) {
+ /*
+ * To reach 100 kHz, the parent clk frequency should be between
+ * a minimum value of 2 MHz and a maximum value of 46 MHz due
+ * to hardware limitation
+ */
+ if (freq < STM32F4_I2C_MIN_STANDARD_FREQ ||
+ freq > STM32F4_I2C_MAX_FREQ) {
+ dev_err(i2c_dev->dev,
+ "bad parent clk freq for standard mode\n");
+ return -EINVAL;
+ }
+ } else {
+ /*
+ * To be as close as possible to 400 kHz, the parent clk
+ * frequency should be between a minimum value of 6 MHz and a
+ * maximum value of 46 MHz due to hardware limitation
+ */
+ if (freq < STM32F4_I2C_MIN_FAST_FREQ ||
+ freq > STM32F4_I2C_MAX_FREQ) {
+ dev_err(i2c_dev->dev,
+ "bad parent clk freq for fast mode\n");
+ return -EINVAL;
+ }
+ }
+
+ cr2 |= STM32F4_I2C_CR2_FREQ(freq);
+ writel_relaxed(cr2, i2c_dev->base + STM32F4_I2C_CR2);
+
+ return 0;
+}
+
+static void stm32f4_i2c_set_rise_time(struct stm32f4_i2c_dev *i2c_dev)
+{
+ u32 freq = DIV_ROUND_UP(i2c_dev->parent_rate, HZ_TO_MHZ);
+ u32 trise;
+
+ /*
+ * These bits must be programmed with the maximum SCL rise time given in
+ * the I2C bus specification, incremented by 1.
+ *
+ * In standard mode, the maximum allowed SCL rise time is 1000 ns.
+ * If, in the I2C_CR2 register, the value of FREQ[5:0] bits is equal to
+ * 0x08 so period = 125 ns therefore the TRISE[5:0] bits must be
+ * programmed with 09h.(1000 ns / 125 ns = 8 + 1)
+ * So, for I2C standard mode TRISE = FREQ[5:0] + 1
+ *
+ * In fast mode, the maximum allowed SCL rise time is 300 ns.
+ * If, in the I2C_CR2 register, the value of FREQ[5:0] bits is equal to
+ * 0x08 so period = 125 ns therefore the TRISE[5:0] bits must be
+ * programmed with 03h.(300 ns / 125 ns = 2 + 1)
+ * So, for I2C fast mode TRISE = FREQ[5:0] * 300 / 1000 + 1
+ */
+ if (i2c_dev->speed == STM32F4_I2C_SPEED_STANDARD)
+ trise = freq + 1;
+ else
+ trise = freq * 300 / 1000 + 1;
+
+ writel_relaxed(STM32F4_I2C_TRISE_VALUE(trise),
+ i2c_dev->base + STM32F4_I2C_TRISE);
+}
+
+static void stm32f4_i2c_set_speed_mode(struct stm32f4_i2c_dev *i2c_dev)
+{
+ u32 val;
+ u32 ccr = 0;
+
+ if (i2c_dev->speed == STM32F4_I2C_SPEED_STANDARD) {
+ /*
+ * In standard mode:
+ * t_scl_high = t_scl_low = CCR * I2C parent clk period
+ * So to reach 100 kHz, we have:
+ * CCR = I2C parent rate / 100 kHz >> 1
+ *
+ * For example with parent rate = 2 MHz:
+ * CCR = 2000000 / (100000 << 1) = 10
+ * t_scl_high = t_scl_low = 10 * (1 / 2000000) = 5000 ns
+ * t_scl_high + t_scl_low = 10000 ns so 100 kHz is reached
+ */
+ val = i2c_dev->parent_rate / (100000 << 1);
+ } else {
+ /*
+ * In fast mode, we compute CCR with duty = 0 as with low
+ * frequencies we are not able to reach 400 kHz.
+ * In that case:
+ * t_scl_high = CCR * I2C parent clk period
+ * t_scl_low = 2 * CCR * I2C parent clk period
+ * So, CCR = I2C parent rate / (400 kHz * 3)
+ *
+ * For example with parent rate = 6 MHz:
+ * CCR = 6000000 / (400000 * 3) = 5
+ * t_scl_high = 5 * (1 / 6000000) = 833 ns > 600 ns
+ * t_scl_low = 2 * 5 * (1 / 6000000) = 1667 ns > 1300 ns
+ * t_scl_high + t_scl_low = 2500 ns so 400 kHz is reached
+ */
+ val = DIV_ROUND_UP(i2c_dev->parent_rate, 400000 * 3);
+ ccr |= STM32F4_I2C_CCR_FS;
+ }
+
+ ccr |= STM32F4_I2C_CCR_CCR(val);
+ writel_relaxed(ccr, i2c_dev->base + STM32F4_I2C_CCR);
+}
+
+/**
+ * stm32f4_i2c_hw_config() - Prepare I2C block
+ * @i2c_dev: Controller's private data
+ */
+static int stm32f4_i2c_hw_config(struct stm32f4_i2c_dev *i2c_dev)
+{
+ int ret;
+
+ ret = stm32f4_i2c_set_periph_clk_freq(i2c_dev);
+ if (ret)
+ return ret;
+
+ stm32f4_i2c_set_rise_time(i2c_dev);
+
+ stm32f4_i2c_set_speed_mode(i2c_dev);
+
+ /* Enable I2C */
+ writel_relaxed(STM32F4_I2C_CR1_PE, i2c_dev->base + STM32F4_I2C_CR1);
+
+ return 0;
+}
+
+static int stm32f4_i2c_wait_free_bus(struct stm32f4_i2c_dev *i2c_dev)
+{
+ u32 status;
+ int ret;
+
+ ret = readl_relaxed_poll_timeout(i2c_dev->base + STM32F4_I2C_SR2,
+ status,
+ !(status & STM32F4_I2C_SR2_BUSY),
+ 10, 1000);
+ if (ret) {
+ dev_dbg(i2c_dev->dev, "bus not free\n");
+ ret = -EBUSY;
+ }
+
+ return ret;
+}
+
+/**
+ * stm32f4_i2c_write_ byte() - Write a byte in the data register
+ * @i2c_dev: Controller's private data
+ * @byte: Data to write in the register
+ */
+static void stm32f4_i2c_write_byte(struct stm32f4_i2c_dev *i2c_dev, u8 byte)
+{
+ writel_relaxed(byte, i2c_dev->base + STM32F4_I2C_DR);
+}
+
+/**
+ * stm32f4_i2c_write_msg() - Fill the data register in write mode
+ * @i2c_dev: Controller's private data
+ *
+ * This function fills the data register with I2C transfer buffer
+ */
+static void stm32f4_i2c_write_msg(struct stm32f4_i2c_dev *i2c_dev)
+{
+ struct stm32f4_i2c_msg *msg = &i2c_dev->msg;
+
+ stm32f4_i2c_write_byte(i2c_dev, *msg->buf++);
+ msg->count--;
+}
+
+static void stm32f4_i2c_read_msg(struct stm32f4_i2c_dev *i2c_dev)
+{
+ struct stm32f4_i2c_msg *msg = &i2c_dev->msg;
+ u32 rbuf;
+
+ rbuf = readl_relaxed(i2c_dev->base + STM32F4_I2C_DR);
+ *msg->buf++ = rbuf;
+ msg->count--;
+}
+
+static void stm32f4_i2c_terminate_xfer(struct stm32f4_i2c_dev *i2c_dev)
+{
+ struct stm32f4_i2c_msg *msg = &i2c_dev->msg;
+ void __iomem *reg = i2c_dev->base + STM32F4_I2C_CR2;
+
+ stm32f4_i2c_disable_irq(i2c_dev);
+
+ reg = i2c_dev->base + STM32F4_I2C_CR1;
+ if (msg->stop)
+ stm32f4_i2c_set_bits(reg, STM32F4_I2C_CR1_STOP);
+ else
+ stm32f4_i2c_set_bits(reg, STM32F4_I2C_CR1_START);
+
+ complete(&i2c_dev->complete);
+}
+
+/**
+ * stm32f4_i2c_handle_write() - Handle FIFO empty interrupt in case of write
+ * @i2c_dev: Controller's private data
+ */
+static void stm32f4_i2c_handle_write(struct stm32f4_i2c_dev *i2c_dev)
+{
+ struct stm32f4_i2c_msg *msg = &i2c_dev->msg;
+ void __iomem *reg = i2c_dev->base + STM32F4_I2C_CR2;
+
+ if (msg->count) {
+ stm32f4_i2c_write_msg(i2c_dev);
+ if (!msg->count) {
+ /*
+ * Disable buffer interrupts for RX not empty and TX
+ * empty events
+ */
+ stm32f4_i2c_clr_bits(reg, STM32F4_I2C_CR2_ITBUFEN);
+ }
+ } else {
+ stm32f4_i2c_terminate_xfer(i2c_dev);
+ }
+}
+
+/**
+ * stm32f4_i2c_handle_read() - Handle FIFO empty interrupt in case of read
+ * @i2c_dev: Controller's private data
+ *
+ * This function is called when a new data is received in data register
+ */
+static void stm32f4_i2c_handle_read(struct stm32f4_i2c_dev *i2c_dev)
+{
+ struct stm32f4_i2c_msg *msg = &i2c_dev->msg;
+ void __iomem *reg = i2c_dev->base + STM32F4_I2C_CR2;
+
+ switch (msg->count) {
+ case 1:
+ stm32f4_i2c_disable_irq(i2c_dev);
+ stm32f4_i2c_read_msg(i2c_dev);
+ complete(&i2c_dev->complete);
+ break;
+ /*
+ * For 2-byte reception, 3-byte reception and for Data N-2, N-1 and N
+ * for N-byte reception with N > 3, we do not have to read the data
+ * register when RX not empty event occurs as we have to wait for byte
+ * transferred finished event before reading data.
+ * So, here we just disable buffer interrupt in order to avoid another
+ * system preemption due to RX not empty event.
+ */
+ case 2:
+ case 3:
+ stm32f4_i2c_clr_bits(reg, STM32F4_I2C_CR2_ITBUFEN);
+ break;
+ /*
+ * For N byte reception with N > 3 we directly read data register
+ * until N-2 data.
+ */
+ default:
+ stm32f4_i2c_read_msg(i2c_dev);
+ }
+}
+
+/**
+ * stm32f4_i2c_handle_rx_done() - Handle byte transfer finished interrupt
+ * in case of read
+ * @i2c_dev: Controller's private data
+ *
+ * This function is called when a new data is received in the shift register
+ * but data register has not been read yet.
+ */
+static void stm32f4_i2c_handle_rx_done(struct stm32f4_i2c_dev *i2c_dev)
+{
+ struct stm32f4_i2c_msg *msg = &i2c_dev->msg;
+ void __iomem *reg;
+ u32 mask;
+ int i;
+
+ switch (msg->count) {
+ case 2:
+ /*
+ * In order to correctly send the Stop or Repeated Start
+ * condition on the I2C bus, the STOP/START bit has to be set
+ * before reading the last two bytes (data N-1 and N).
+ * After that, we could read the last two bytes, disable
+ * remaining interrupts and notify the end of xfer to the
+ * client
+ */
+ reg = i2c_dev->base + STM32F4_I2C_CR1;
+ if (msg->stop)
+ stm32f4_i2c_set_bits(reg, STM32F4_I2C_CR1_STOP);
+ else
+ stm32f4_i2c_set_bits(reg, STM32F4_I2C_CR1_START);
+
+ for (i = 2; i > 0; i--)
+ stm32f4_i2c_read_msg(i2c_dev);
+
+ reg = i2c_dev->base + STM32F4_I2C_CR2;
+ mask = STM32F4_I2C_CR2_ITEVTEN | STM32F4_I2C_CR2_ITERREN;
+ stm32f4_i2c_clr_bits(reg, mask);
+
+ complete(&i2c_dev->complete);
+ break;
+ case 3:
+ /*
+ * In order to correctly generate the NACK pulse after the last
+ * received data byte, we have to enable NACK before reading N-2
+ * data
+ */
+ reg = i2c_dev->base + STM32F4_I2C_CR1;
+ stm32f4_i2c_clr_bits(reg, STM32F4_I2C_CR1_ACK);
+ stm32f4_i2c_read_msg(i2c_dev);
+ break;
+ default:
+ stm32f4_i2c_read_msg(i2c_dev);
+ }
+}
+
+/**
+ * stm32f4_i2c_handle_rx_addr() - Handle address matched interrupt in case of
+ * master receiver
+ * @i2c_dev: Controller's private data
+ */
+static void stm32f4_i2c_handle_rx_addr(struct stm32f4_i2c_dev *i2c_dev)
+{
+ struct stm32f4_i2c_msg *msg = &i2c_dev->msg;
+ u32 cr1;
+
+ switch (msg->count) {
+ case 0:
+ stm32f4_i2c_terminate_xfer(i2c_dev);
+
+ /* Clear ADDR flag */
+ readl_relaxed(i2c_dev->base + STM32F4_I2C_SR2);
+ break;
+ case 1:
+ /*
+ * Single byte reception:
+ * Enable NACK and reset POS (Acknowledge position).
+ * Then, clear ADDR flag and set STOP or RepSTART.
+ * In that way, the NACK and STOP or RepStart pulses will be
+ * sent as soon as the byte will be received in shift register
+ */
+ cr1 = readl_relaxed(i2c_dev->base + STM32F4_I2C_CR1);
+ cr1 &= ~(STM32F4_I2C_CR1_ACK | STM32F4_I2C_CR1_POS);
+ writel_relaxed(cr1, i2c_dev->base + STM32F4_I2C_CR1);
+
+ readl_relaxed(i2c_dev->base + STM32F4_I2C_SR2);
+
+ if (msg->stop)
+ cr1 |= STM32F4_I2C_CR1_STOP;
+ else
+ cr1 |= STM32F4_I2C_CR1_START;
+ writel_relaxed(cr1, i2c_dev->base + STM32F4_I2C_CR1);
+ break;
+ case 2:
+ /*
+ * 2-byte reception:
+ * Enable NACK, set POS (NACK position) and clear ADDR flag.
+ * In that way, NACK will be sent for the next byte which will
+ * be received in the shift register instead of the current
+ * one.
+ */
+ cr1 = readl_relaxed(i2c_dev->base + STM32F4_I2C_CR1);
+ cr1 &= ~STM32F4_I2C_CR1_ACK;
+ cr1 |= STM32F4_I2C_CR1_POS;
+ writel_relaxed(cr1, i2c_dev->base + STM32F4_I2C_CR1);
+
+ readl_relaxed(i2c_dev->base + STM32F4_I2C_SR2);
+ break;
+
+ default:
+ /*
+ * N-byte reception:
+ * Enable ACK, reset POS (ACK postion) and clear ADDR flag.
+ * In that way, ACK will be sent as soon as the current byte
+ * will be received in the shift register
+ */
+ cr1 = readl_relaxed(i2c_dev->base + STM32F4_I2C_CR1);
+ cr1 |= STM32F4_I2C_CR1_ACK;
+ cr1 &= ~STM32F4_I2C_CR1_POS;
+ writel_relaxed(cr1, i2c_dev->base + STM32F4_I2C_CR1);
+
+ readl_relaxed(i2c_dev->base + STM32F4_I2C_SR2);
+ break;
+ }
+}
+
+/**
+ * stm32f4_i2c_isr_event() - Interrupt routine for I2C bus event
+ * @irq: interrupt number
+ * @data: Controller's private data
+ */
+static irqreturn_t stm32f4_i2c_isr_event(int irq, void *data)
+{
+ struct stm32f4_i2c_dev *i2c_dev = data;
+ struct stm32f4_i2c_msg *msg = &i2c_dev->msg;
+ u32 possible_status = STM32F4_I2C_SR1_ITEVTEN_MASK;
+ u32 status, ien, event, cr2;
+
+ cr2 = readl_relaxed(i2c_dev->base + STM32F4_I2C_CR2);
+ ien = cr2 & STM32F4_I2C_CR2_IRQ_MASK;
+
+ /* Update possible_status if buffer interrupt is enabled */
+ if (ien & STM32F4_I2C_CR2_ITBUFEN)
+ possible_status |= STM32F4_I2C_SR1_ITBUFEN_MASK;
+
+ status = readl_relaxed(i2c_dev->base + STM32F4_I2C_SR1);
+ event = status & possible_status;
+ if (!event) {
+ dev_dbg(i2c_dev->dev,
+ "spurious evt irq (status=0x%08x, ien=0x%08x)\n",
+ status, ien);
+ return IRQ_NONE;
+ }
+
+ /* Start condition generated */
+ if (event & STM32F4_I2C_SR1_SB)
+ stm32f4_i2c_write_byte(i2c_dev, msg->addr);
+
+ /* I2C Address sent */
+ if (event & STM32F4_I2C_SR1_ADDR) {
+ if (msg->addr & I2C_M_RD)
+ stm32f4_i2c_handle_rx_addr(i2c_dev);
+ else
+ readl_relaxed(i2c_dev->base + STM32F4_I2C_SR2);
+
+ /*
+ * Enable buffer interrupts for RX not empty and TX empty
+ * events
+ */
+ cr2 |= STM32F4_I2C_CR2_ITBUFEN;
+ writel_relaxed(cr2, i2c_dev->base + STM32F4_I2C_CR2);
+ }
+
+ /* TX empty */
+ if ((event & STM32F4_I2C_SR1_TXE) && !(msg->addr & I2C_M_RD))
+ stm32f4_i2c_handle_write(i2c_dev);
+
+ /* RX not empty */
+ if ((event & STM32F4_I2C_SR1_RXNE) && (msg->addr & I2C_M_RD))
+ stm32f4_i2c_handle_read(i2c_dev);
+
+ /*
+ * The BTF (Byte Transfer finished) event occurs when:
+ * - in reception : a new byte is received in the shift register
+ * but the previous byte has not been read yet from data register
+ * - in transmission: a new byte should be sent but the data register
+ * has not been written yet
+ */
+ if (event & STM32F4_I2C_SR1_BTF) {
+ if (msg->addr & I2C_M_RD)
+ stm32f4_i2c_handle_rx_done(i2c_dev);
+ else
+ stm32f4_i2c_handle_write(i2c_dev);
+ }
+
+ return IRQ_HANDLED;
+}
+
+/**
+ * stm32f4_i2c_isr_error() - Interrupt routine for I2C bus error
+ * @irq: interrupt number
+ * @data: Controller's private data
+ */
+static irqreturn_t stm32f4_i2c_isr_error(int irq, void *data)
+{
+ struct stm32f4_i2c_dev *i2c_dev = data;
+ struct stm32f4_i2c_msg *msg = &i2c_dev->msg;
+ void __iomem *reg;
+ u32 status;
+
+ status = readl_relaxed(i2c_dev->base + STM32F4_I2C_SR1);
+
+ /* Arbitration lost */
+ if (status & STM32F4_I2C_SR1_ARLO) {
+ status &= ~STM32F4_I2C_SR1_ARLO;
+ writel_relaxed(status, i2c_dev->base + STM32F4_I2C_SR1);
+ msg->result = -EAGAIN;
+ }
+
+ /*
+ * Acknowledge failure:
+ * In master transmitter mode a Stop must be generated by software
+ */
+ if (status & STM32F4_I2C_SR1_AF) {
+ if (!(msg->addr & I2C_M_RD)) {
+ reg = i2c_dev->base + STM32F4_I2C_CR1;
+ stm32f4_i2c_set_bits(reg, STM32F4_I2C_CR1_STOP);
+ }
+ status &= ~STM32F4_I2C_SR1_AF;
+ writel_relaxed(status, i2c_dev->base + STM32F4_I2C_SR1);
+ msg->result = -EIO;
+ }
+
+ /* Bus error */
+ if (status & STM32F4_I2C_SR1_BERR) {
+ status &= ~STM32F4_I2C_SR1_BERR;
+ writel_relaxed(status, i2c_dev->base + STM32F4_I2C_SR1);
+ msg->result = -EIO;
+ }
+
+ stm32f4_i2c_disable_irq(i2c_dev);
+ complete(&i2c_dev->complete);
+
+ return IRQ_HANDLED;
+}
+
+/**
+ * stm32f4_i2c_xfer_msg() - Transfer a single I2C message
+ * @i2c_dev: Controller's private data
+ * @msg: I2C message to transfer
+ * @is_first: first message of the sequence
+ * @is_last: last message of the sequence
+ */
+static int stm32f4_i2c_xfer_msg(struct stm32f4_i2c_dev *i2c_dev,
+ struct i2c_msg *msg, bool is_first,
+ bool is_last)
+{
+ struct stm32f4_i2c_msg *f4_msg = &i2c_dev->msg;
+ void __iomem *reg = i2c_dev->base + STM32F4_I2C_CR1;
+ unsigned long timeout;
+ u32 mask;
+ int ret;
+
+ f4_msg->addr = i2c_8bit_addr_from_msg(msg);
+ f4_msg->buf = msg->buf;
+ f4_msg->count = msg->len;
+ f4_msg->result = 0;
+ f4_msg->stop = is_last;
+
+ reinit_completion(&i2c_dev->complete);
+
+ /* Enable events and errors interrupts */
+ mask = STM32F4_I2C_CR2_ITEVTEN | STM32F4_I2C_CR2_ITERREN;
+ stm32f4_i2c_set_bits(i2c_dev->base + STM32F4_I2C_CR2, mask);
+
+ if (is_first) {
+ ret = stm32f4_i2c_wait_free_bus(i2c_dev);
+ if (ret)
+ return ret;
+
+ /* START generation */
+ stm32f4_i2c_set_bits(reg, STM32F4_I2C_CR1_START);
+ }
+
+ timeout = wait_for_completion_timeout(&i2c_dev->complete,
+ i2c_dev->adap.timeout);
+ ret = f4_msg->result;
+
+ if (!timeout)
+ ret = -ETIMEDOUT;
+
+ return ret;
+}
+
+/**
+ * stm32f4_i2c_xfer() - Transfer combined I2C message
+ * @i2c_adap: Adapter pointer to the controller
+ * @msgs: Pointer to data to be written.
+ * @num: Number of messages to be executed
+ */
+static int stm32f4_i2c_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg msgs[],
+ int num)
+{
+ struct stm32f4_i2c_dev *i2c_dev = i2c_get_adapdata(i2c_adap);
+ int ret, i;
+
+ ret = clk_enable(i2c_dev->clk);
+ if (ret) {
+ dev_err(i2c_dev->dev, "Failed to enable clock\n");
+ return ret;
+ }
+
+ for (i = 0; i < num && !ret; i++)
+ ret = stm32f4_i2c_xfer_msg(i2c_dev, &msgs[i], i == 0,
+ i == num - 1);
+
+ clk_disable(i2c_dev->clk);
+
+ return (ret < 0) ? ret : num;
+}
+
+static u32 stm32f4_i2c_func(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static struct i2c_algorithm stm32f4_i2c_algo = {
+ .master_xfer = stm32f4_i2c_xfer,
+ .functionality = stm32f4_i2c_func,
+};
+
+static int stm32f4_i2c_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct stm32f4_i2c_dev *i2c_dev;
+ struct resource *res;
+ u32 irq_event, irq_error, clk_rate;
+ struct i2c_adapter *adap;
+ struct reset_control *rst;
+ int ret;
+
+ i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL);
+ if (!i2c_dev)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ i2c_dev->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(i2c_dev->base))
+ return PTR_ERR(i2c_dev->base);
+
+ irq_event = irq_of_parse_and_map(np, 0);
+ if (!irq_event) {
+ dev_err(&pdev->dev, "IRQ event missing or invalid\n");
+ return -EINVAL;
+ }
+
+ irq_error = irq_of_parse_and_map(np, 1);
+ if (!irq_error) {
+ dev_err(&pdev->dev, "IRQ error missing or invalid\n");
+ return -EINVAL;
+ }
+
+ i2c_dev->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(i2c_dev->clk)) {
+ dev_err(&pdev->dev, "Error: Missing controller clock\n");
+ return PTR_ERR(i2c_dev->clk);
+ }
+ ret = clk_prepare_enable(i2c_dev->clk);
+ if (ret) {
+ dev_err(i2c_dev->dev, "Failed to prepare_enable clock\n");
+ return ret;
+ }
+
+ rst = devm_reset_control_get(&pdev->dev, NULL);
+ if (IS_ERR(rst)) {
+ dev_err(&pdev->dev, "Error: Missing controller reset\n");
+ ret = PTR_ERR(rst);
+ goto clk_free;
+ }
+ reset_control_assert(rst);
+ udelay(2);
+ reset_control_deassert(rst);
+
+ i2c_dev->speed = STM32F4_I2C_SPEED_STANDARD;
+ ret = of_property_read_u32(np, "clock-frequency", &clk_rate);
+ if (!ret && clk_rate >= 400000)
+ i2c_dev->speed = STM32F4_I2C_SPEED_FAST;
+
+ i2c_dev->dev = &pdev->dev;
+
+ ret = devm_request_irq(&pdev->dev, irq_event, stm32f4_i2c_isr_event, 0,
+ pdev->name, i2c_dev);
+ if (ret) {
+ dev_err(&pdev->dev, "Failed to request irq event %i\n",
+ irq_event);
+ goto clk_free;
+ }
+
+ ret = devm_request_irq(&pdev->dev, irq_error, stm32f4_i2c_isr_error, 0,
+ pdev->name, i2c_dev);
+ if (ret) {
+ dev_err(&pdev->dev, "Failed to request irq error %i\n",
+ irq_error);
+ goto clk_free;
+ }
+
+ ret = stm32f4_i2c_hw_config(i2c_dev);
+ if (ret)
+ goto clk_free;
+
+ adap = &i2c_dev->adap;
+ i2c_set_adapdata(adap, i2c_dev);
+ snprintf(adap->name, sizeof(adap->name), "STM32 I2C(%pa)", &res->start);
+ adap->owner = THIS_MODULE;
+ adap->timeout = 2 * HZ;
+ adap->retries = 0;
+ adap->algo = &stm32f4_i2c_algo;
+ adap->dev.parent = &pdev->dev;
+ adap->dev.of_node = pdev->dev.of_node;
+
+ init_completion(&i2c_dev->complete);
+
+ ret = i2c_add_adapter(adap);
+ if (ret)
+ goto clk_free;
+
+ platform_set_drvdata(pdev, i2c_dev);
+
+ clk_disable(i2c_dev->clk);
+
+ dev_info(i2c_dev->dev, "STM32F4 I2C driver registered\n");
+
+ return 0;
+
+clk_free:
+ clk_disable_unprepare(i2c_dev->clk);
+ return ret;
+}
+
+static int stm32f4_i2c_remove(struct platform_device *pdev)
+{
+ struct stm32f4_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
+
+ i2c_del_adapter(&i2c_dev->adap);
+
+ clk_unprepare(i2c_dev->clk);
+
+ return 0;
+}
+
+static const struct of_device_id stm32f4_i2c_match[] = {
+ { .compatible = "st,stm32f4-i2c", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, stm32f4_i2c_match);
+
+static struct platform_driver stm32f4_i2c_driver = {
+ .driver = {
+ .name = "stm32f4-i2c",
+ .of_match_table = stm32f4_i2c_match,
+ },
+ .probe = stm32f4_i2c_probe,
+ .remove = stm32f4_i2c_remove,
+};
+
+module_platform_driver(stm32f4_i2c_driver);
+
+MODULE_AUTHOR("M'boumba Cedric Madianga <cedric.madianga@gmail.com>");
+MODULE_DESCRIPTION("STMicroelectronics STM32F4 I2C driver");
+MODULE_LICENSE("GPL v2");
--
1.9.1
^ permalink raw reply related
* [PATCH v9 3/5] ARM: dts: stm32: Add I2C1 support for STM32F429 SoC
From: M'boumba Cedric Madianga @ 2017-01-17 15:26 UTC (permalink / raw)
To: wsa, robh+dt, mcoquelin.stm32, alexandre.torgue, linus.walleij,
patrice.chotard, linux, linux-i2c, devicetree, linux-arm-kernel,
linux-kernel, u.kleine-koenig
Cc: M'boumba Cedric Madianga
In-Reply-To: <1484666821-20551-1-git-send-email-cedric.madianga@gmail.com>
This patch adds I2C1 support for STM32F429 SoC
Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Signed-off-by: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
---
arch/arm/boot/dts/stm32f429.dtsi | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
diff --git a/arch/arm/boot/dts/stm32f429.dtsi b/arch/arm/boot/dts/stm32f429.dtsi
index e4dae0e..5b063e9 100644
--- a/arch/arm/boot/dts/stm32f429.dtsi
+++ b/arch/arm/boot/dts/stm32f429.dtsi
@@ -48,6 +48,7 @@
#include "skeleton.dtsi"
#include "armv7-m.dtsi"
#include <dt-bindings/pinctrl/stm32f429-pinfunc.h>
+#include <dt-bindings/mfd/stm32f4-rcc.h>
/ {
clocks {
@@ -153,6 +154,18 @@
status = "disabled";
};
+ i2c1: i2c@40005400 {
+ compatible = "st,stm32f4-i2c";
+ reg = <0x40005400 0x400>;
+ interrupts = <31>,
+ <32>;
+ resets = <&rcc STM32F4_APB1_RESET(I2C1)>;
+ clocks = <&rcc 0 STM32F4_APB1_CLOCK(I2C1)>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+ status = "disabled";
+ };
+
usart7: serial@40007800 {
compatible = "st,stm32-usart", "st,stm32-uart";
reg = <0x40007800 0x400>;
@@ -355,6 +368,16 @@
slew-rate = <2>;
};
};
+
+ i2c1_pins_b: i2c1@0 {
+ pins {
+ pinmux = <STM32F429_PB9_FUNC_I2C1_SDA>,
+ <STM32F429_PB6_FUNC_I2C1_SCL>;
+ bias-disable;
+ drive-open-drain;
+ slew-rate = <3>;
+ };
+ };
};
rcc: rcc@40023810 {
--
1.9.1
^ permalink raw reply related
* [PATCH v9 5/5] ARM: configs: stm32: Add I2C support for STM32 defconfig
From: M'boumba Cedric Madianga @ 2017-01-17 15:27 UTC (permalink / raw)
To: wsa, robh+dt, mcoquelin.stm32, alexandre.torgue, linus.walleij,
patrice.chotard, linux, linux-i2c, devicetree, linux-arm-kernel,
linux-kernel, u.kleine-koenig
Cc: M'boumba Cedric Madianga
In-Reply-To: <1484666821-20551-1-git-send-email-cedric.madianga@gmail.com>
This patch adds I2C support for STM32 default configuration
Signed-off-by: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
---
arch/arm/configs/stm32_defconfig | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/arm/configs/stm32_defconfig b/arch/arm/configs/stm32_defconfig
index 5a72d69..323d2a3 100644
--- a/arch/arm/configs/stm32_defconfig
+++ b/arch/arm/configs/stm32_defconfig
@@ -47,6 +47,9 @@ CONFIG_SERIAL_NONSTANDARD=y
CONFIG_SERIAL_STM32=y
CONFIG_SERIAL_STM32_CONSOLE=y
# CONFIG_HW_RANDOM is not set
+CONFIG_I2C=y
+CONFIG_I2C_CHARDEV=y
+CONFIG_I2C_STM32F4=y
# CONFIG_HWMON is not set
# CONFIG_USB_SUPPORT is not set
CONFIG_NEW_LEDS=y
--
1.9.1
^ permalink raw reply related
* [PATCH v9 4/5] ARM: dts: stm32: Add I2C1 support for STM32429 eval board
From: M'boumba Cedric Madianga @ 2017-01-17 15:27 UTC (permalink / raw)
To: wsa, robh+dt, mcoquelin.stm32, alexandre.torgue, linus.walleij,
patrice.chotard, linux, linux-i2c, devicetree, linux-arm-kernel,
linux-kernel, u.kleine-koenig
Cc: M'boumba Cedric Madianga
In-Reply-To: <1484666821-20551-1-git-send-email-cedric.madianga@gmail.com>
This patch adds I2C1 instance support for STM32x9I-Eval board.
Signed-off-by: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
---
arch/arm/boot/dts/stm32429i-eval.dts | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/arm/boot/dts/stm32429i-eval.dts b/arch/arm/boot/dts/stm32429i-eval.dts
index 76f7206..c943539 100644
--- a/arch/arm/boot/dts/stm32429i-eval.dts
+++ b/arch/arm/boot/dts/stm32429i-eval.dts
@@ -146,3 +146,9 @@
pinctrl-names = "default";
status = "okay";
};
+
+&i2c1 {
+ pinctrl-0 = <&i2c1_pins_b>;
+ pinctrl-names = "default";
+ status = "okay";
+};
--
1.9.1
^ permalink raw reply related
* Peace Of The Lord Be With You And Your Family
From: reply388 @ 2017-01-17 16:23 UTC (permalink / raw)
Dear friend, I am Mrs Alice Banneth from Burkina Faso are you online? I
have important issue to discus with you.
Reply to my private email address : (mrsalicebanneth1@yahoo.com)
^ permalink raw reply
* Re: [PATCH v9 2/5] i2c: Add STM32F4 I2C driver
From: Uwe Kleine-König @ 2017-01-17 19:37 UTC (permalink / raw)
To: M'boumba Cedric Madianga
Cc: wsa, robh+dt, mcoquelin.stm32, alexandre.torgue, linus.walleij,
patrice.chotard, linux, linux-i2c, devicetree, linux-arm-kernel,
linux-kernel
In-Reply-To: <1484666821-20551-3-git-send-email-cedric.madianga@gmail.com>
Hello,
On Tue, Jan 17, 2017 at 04:26:58PM +0100, M'boumba Cedric Madianga wrote:
> +static void stm32f4_i2c_set_rise_time(struct stm32f4_i2c_dev *i2c_dev)
> +{
> + u32 freq = DIV_ROUND_UP(i2c_dev->parent_rate, HZ_TO_MHZ);
> + u32 trise;
> +
> + /*
> + * These bits must be programmed with the maximum SCL rise time given in
> + * the I2C bus specification, incremented by 1.
> + *
> + * In standard mode, the maximum allowed SCL rise time is 1000 ns.
> + * If, in the I2C_CR2 register, the value of FREQ[5:0] bits is equal to
> + * 0x08 so period = 125 ns therefore the TRISE[5:0] bits must be
> + * programmed with 09h.(1000 ns / 125 ns = 8 + 1)
* programmed with 0x9. (1000 ns / 125 ns = 8)
> + * So, for I2C standard mode TRISE = FREQ[5:0] + 1
> + *
> + * In fast mode, the maximum allowed SCL rise time is 300 ns.
> + * If, in the I2C_CR2 register, the value of FREQ[5:0] bits is equal to
> + * 0x08 so period = 125 ns therefore the TRISE[5:0] bits must be
> + * programmed with 03h.(300 ns / 125 ns = 2 + 1)
as above s/03h/0x3/; s/.(/. (/; s/+ 1//;
> + * So, for I2C fast mode TRISE = FREQ[5:0] * 300 / 1000 + 1
> + */
> + if (i2c_dev->speed == STM32F4_I2C_SPEED_STANDARD)
> + trise = freq + 1;
> + else
> + trise = freq * 300 / 1000 + 1;
I'd use
* 3 / 10
without downside and lesser chance to overflow.
> +
> + writel_relaxed(STM32F4_I2C_TRISE_VALUE(trise),
> + i2c_dev->base + STM32F4_I2C_TRISE);
> +}
> +
> +static void stm32f4_i2c_set_speed_mode(struct stm32f4_i2c_dev *i2c_dev)
> +{
> + u32 val;
> + u32 ccr = 0;
> +
> + if (i2c_dev->speed == STM32F4_I2C_SPEED_STANDARD) {
> + /*
> + * In standard mode:
> + * t_scl_high = t_scl_low = CCR * I2C parent clk period
> + * So to reach 100 kHz, we have:
> + * CCR = I2C parent rate / 100 kHz >> 1
> + *
> + * For example with parent rate = 2 MHz:
> + * CCR = 2000000 / (100000 << 1) = 10
> + * t_scl_high = t_scl_low = 10 * (1 / 2000000) = 5000 ns
> + * t_scl_high + t_scl_low = 10000 ns so 100 kHz is reached
> + */
> + val = i2c_dev->parent_rate / (100000 << 1);
> + } else {
> + /*
> + * In fast mode, we compute CCR with duty = 0 as with low
> + * frequencies we are not able to reach 400 kHz.
> + * In that case:
> + * t_scl_high = CCR * I2C parent clk period
> + * t_scl_low = 2 * CCR * I2C parent clk period
> + * So, CCR = I2C parent rate / (400 kHz * 3)
> + *
> + * For example with parent rate = 6 MHz:
> + * CCR = 6000000 / (400000 * 3) = 5
> + * t_scl_high = 5 * (1 / 6000000) = 833 ns > 600 ns
> + * t_scl_low = 2 * 5 * (1 / 6000000) = 1667 ns > 1300 ns
> + * t_scl_high + t_scl_low = 2500 ns so 400 kHz is reached
> + */
Huh, that's surprising. So you don't use DUTY any more. I found two
hints in the manual that contradict here:
f_{PCLK1} must be at least 2 MHz to achieve Sm mode I2C
frequencies. It must be at least 4 MHz to achieve Fm mode I2C
frequencies. It must be a multiple of 10MHz to reach the
400 kHz maximum I2C Fm mode clock.
and
[...]
If DUTY = 1: (to reach 400 kHz)
Strange.
> + val = DIV_ROUND_UP(i2c_dev->parent_rate, 400000 * 3);
the manual reads:
The minimum allowed value is 0x04, except in FAST DUTY mode
where the minimum allowed value is 0x01
You don't check for that, right?
CCR is 11 bits wide. A comment confirming that this cannot overflow
would be nice.
+ /* select Fast Mode */
> + ccr |= STM32F4_I2C_CCR_FS;
I didn't check the rest of the code, so let's assume it's good :-)
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
^ permalink raw reply
* Re: [Patch V3] i2c: imx-lpi2c: add VLLS mode support
From: Vladimir Zapolskiy @ 2017-01-17 21:04 UTC (permalink / raw)
To: Gao Pan, wsa, wsa-dev; +Cc: linux-i2c, frank.li
In-Reply-To: <1484648455-5454-1-git-send-email-pandy.gao@nxp.com>
On 01/17/2017 12:20 PM, Gao Pan wrote:
> When system enters VLLS mode, module power is turned off. As a result,
> all registers are reset to HW default value. After exiting VLLS mode,
> registers are still in default mode. As a result, the pinctrl settings
> are incorrect, which will affect the module function.
>
> The patch recovers the pinctrl setting when exit VLLS mode.
>
> Signed-off-by: Gao Pan <pandy.gao@nxp.com>
> ---
> V2:
> -drop "#else branch" and IMX_LPI2C_PM completely
> -pm = &imx_lpi2c_pm
>
> V3:
> -remove unnecessary #ifdef
>
The change looks good, thank you for updates.
Reviewed-by: Vladimir Zapolskiy <vz@mleia.com>
--
With best wishes,
Vladimir
^ permalink raw reply
* Re: [PATCH] i2c: busses: constify dev_pm_ops structures
From: Tony Lindgren @ 2017-01-17 23:23 UTC (permalink / raw)
To: Bhumika Goyal; +Cc: julia.lawall, wsa, linux-omap, linux-i2c, linux-kernel
In-Reply-To: <1484474381-1064-1-git-send-email-bhumirks@gmail.com>
* Bhumika Goyal <bhumirks@gmail.com> [170115 02:00]:
> Declare dev_pm_ops structures as const as they are only stored in the pm
> field of a device_driver structure. This field is of type const, so
> dev_pm_ops structures having similar properties can be declared const
> too.
>
> File size before: drivers/i2c/busses/i2c-omap.o
> text data bss dec hex filename
> 6814 584 0 7398 1ce6 drivers/i2c/busses/i2c-omap.o
>
> File size after: drivers/i2c/busses/i2c-omap.o
> text data bss dec hex filename
> 7006 392 0 7398 1ce6 drivers/i2c/busses/i2c-omap.o
>
> Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Acked-by: Tony Lindgren <tony@atomide.com>
> ---
> drivers/i2c/busses/i2c-omap.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
> index c7da0c4..1ebb5e9 100644
> --- a/drivers/i2c/busses/i2c-omap.c
> +++ b/drivers/i2c/busses/i2c-omap.c
> @@ -1504,7 +1504,7 @@ static int omap_i2c_runtime_resume(struct device *dev)
> return 0;
> }
>
> -static struct dev_pm_ops omap_i2c_pm_ops = {
> +static const struct dev_pm_ops omap_i2c_pm_ops = {
> SET_RUNTIME_PM_OPS(omap_i2c_runtime_suspend,
> omap_i2c_runtime_resume, NULL)
> };
> --
> 1.9.1
>
^ permalink raw reply
* Re: [PATCH v5 4/5] dt: bindings: i2c-mux-pca954x: Add documentation for nxp,irq-mask-enable
From: Phil Reid @ 2017-01-18 9:00 UTC (permalink / raw)
To: Peter Rosin, wsa-z923LK4zBo2bacvFa/9K2g,
robh+dt-DgEjT+Ai2ygdnm+yROfE0A, mark.rutland-5wv7dgnIgG8,
linux-i2c-u79uwXL29TY76Z2rM5mHXA,
devicetree-u79uwXL29TY76Z2rM5mHXA
In-Reply-To: <1abf8327-9c3c-f390-fbc4-9eb142068a66-koto5C5qi+TLoDKTGw+V6w@public.gmane.org>
On 17/01/2017 18:14, Peter Rosin wrote:
> On 2017-01-17 10:43, Peter Rosin wrote:
>> On 2017-01-17 10:28, Phil Reid wrote:
>>> On 17/01/2017 16:57, Peter Rosin wrote:
>>>> On 2017-01-17 09:00, Phil Reid wrote:
>>>>> Unfortunately some hardware device will assert their irq line immediately
>>>>> on power on and provide no mechanism to mask the irq. As the i2c muxes
>>>>> provide no method to mask irq line this provides a work around by keeping
>>>>> the parent irq masked until enough device drivers have loaded to service
>>>>> all pending interrupts.
>>>>>
>>>>> For example the the ltc1760 assert its SMBALERT irq immediately on power
>>>>> on. With two ltc1760 attached to bus 0 & 1 on a pca954x mux when the first
>>>>> device is registered irq are enabled and fire continuously as the second
>>>>> device driver has not yet loaded. Setting this parameter to <1 1> will
>>>>> delay the irq being enabled until both devices are ready.
>>>>
>>> G'day Peter,
>>>
>>>
>>>> Hang on, does this suggestion I made make any sense at all? Maybe it does,
>>>> but does the pca954x driver even get notified of any but the first irq client
>>>> that unmasks interrupts on a mux segment? How can it count the number of
>>>> active irq clients if not?
>>>
>>> Good question.
>>>
>>> So what I did to test is setup my 2 ltc1760s to use the same irq on the pca954x.
>>> Using the latest patch series.
>>>
>>> Adding a log message into the irq_unmask function got the following.
>>> dev_err(&data->client->dev, "irq_unmask %d %x %d", pos, data->irq_mask, data->irq_enabled);
>>>
>>> dmesg | grep irq_unmask
>>> [ 4.392098] pca954x 4-0070: irq_unmask 0 1 1
>>>
>>>
>>> But Looks like both got registered ok to the same irq.
>>> cat /proc/interrupts
>>> 161: 0 0 i2c-mux-pca954x 0 Level 15-000a, 16-000a
>>>
>>> So from this testing, it doesn't look like it gets called multiple times.
>>
>> As I suspected, thanks for verifying!
>>
>>> So back to the bitmask for the dt do you think.
>>
>> Looking at kernel/irq/chip.c:irq_enable (and struct irq_chip docs), I get the
>> feeling that if you provide the irq_enable operation (and maybe irq_disable too?),
>> that might get us more info?
>
> No, I no longer think that. I think we need to get at the irq descriptor "depth".
> But that feels like poking at the wrong level. Crap.
>
> And to answer the question if I think we should go back to a dt bitmask, then
> no I do not think that. The array describes what we want to do, it's the linux
> implementation that gives us difficulties. Agreed?
G'day Peter,
Yes agreed, that makes sense.
I had a play with using the irq_enable call back.
But that doesn't seem to offer any more feedback then unmask.
Called just once on the first irq that registers.
The only way I can see to count the number of registered handlers on a
shared irq is to count the action handlers on the irq_desc.
The only irq_chip handler that seems guaranteed to be called on irq request is
irq_bus_lock, irq_bus_sync_unlock callbacks, but these are called elsewhere
at various times.
We have a dt spec that supports this future proofing of the irq count.
But as you say the kernel code prevents us at the moment.
The count of 1 bitmask implementation works for my particular situation at the moment.
Perhaps the > 1 case can be tackled in the future when someone has a use case?
Thoughts?
>
>>> I think the interrupt enablelogic is correct now.
>>>
>>>>
>>>> I'm truly sorry for the trouble I'm causing by not just saying how it should
>>>> be done from the start, but I feel like I've been thrown in at the deep end
>>>> when it comes to interrupt controllers...
>>>
>>> No problem. I'm learning a couple things as we go.
>>> Should help me out on other drivers :)
>>
>> Yes, I'm also picking up a few bits here and there...
--
Regards
Phil Reid
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply
* [RESEND PATCH 0/2] Add i2c DT binding and device node for Mediatek MT2701 Soc
From: Jun Gao @ 2017-01-18 9:40 UTC (permalink / raw)
To: Wolfram Sang, Matthias Brugger
Cc: devicetree, srv_heupstream, linux-kernel, linux-mediatek,
linux-i2c, linux-arm-kernel
This patch series based on v4.10-rc2, include MT2701 i2c DT binding and device node.
Dependent on "Add clock and power domain DT nodes for Mediatek MT2701"[1].
[1] http://lists.infradead.org/pipermail/linux-mediatek/2016-December/007637.html
Jun Gao (2):
Documentation: devicetree: Add i2c binding for mediatek MT2701 Soc
Platform
arm: dts: mt2701: Add i2c device node
.../devicetree/bindings/i2c/i2c-mt6577.txt | 11 ++---
arch/arm/boot/dts/mt2701-evb.dts | 44 ++++++++++++++++++++
arch/arm/boot/dts/mt2701.dtsi | 42 +++++++++++++++++++
3 files changed, 92 insertions(+), 5 deletions(-)
--
1.7.9.5
^ permalink raw reply
* [RESEND PATCH 1/2] Documentation: devicetree: Add i2c binding for mediatek MT2701 Soc Platform
From: Jun Gao @ 2017-01-18 9:41 UTC (permalink / raw)
To: Wolfram Sang, Matthias Brugger
Cc: devicetree, srv_heupstream, Jun Gao, linux-kernel, linux-mediatek,
linux-i2c, linux-arm-kernel
In-Reply-To: <1484732461-13594-1-git-send-email-jun.gao@mediatek.com>
From: Jun Gao <jun.gao@mediatek.com>
This add i2c DT binding to i2c-mt6577.txt for MT2701.
Signed-off-by: Jun Gao <jun.gao@mediatek.com>
---
.../devicetree/bindings/i2c/i2c-mt6577.txt | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/Documentation/devicetree/bindings/i2c/i2c-mt6577.txt b/Documentation/devicetree/bindings/i2c/i2c-mt6577.txt
index 0ce6fa3..ef22ecf 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-mt6577.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-mt6577.txt
@@ -4,11 +4,12 @@ The Mediatek's I2C controller is used to interface with I2C devices.
Required properties:
- compatible: value should be either of the following.
- (a) "mediatek,mt6577-i2c", for i2c compatible with mt6577 i2c.
- (b) "mediatek,mt6589-i2c", for i2c compatible with mt6589 i2c.
- (c) "mediatek,mt8127-i2c", for i2c compatible with mt8127 i2c.
- (d) "mediatek,mt8135-i2c", for i2c compatible with mt8135 i2c.
- (e) "mediatek,mt8173-i2c", for i2c compatible with mt8173 i2c.
+ "mediatek,mt2701-i2c", for i2c compatible with mt2701 i2c.
+ "mediatek,mt6577-i2c", for i2c compatible with mt6577 i2c.
+ "mediatek,mt6589-i2c", for i2c compatible with mt6589 i2c.
+ "mediatek,mt8127-i2c", for i2c compatible with mt8127 i2c.
+ "mediatek,mt8135-i2c", for i2c compatible with mt8135 i2c.
+ "mediatek,mt8173-i2c", for i2c compatible with mt8173 i2c.
- reg: physical base address of the controller and dma base, length of memory
mapped region.
- interrupts: interrupt number to the cpu.
--
1.7.9.5
^ permalink raw reply related
* [RESEND PATCH 2/2] arm: dts: mt2701: Add i2c device node
From: Jun Gao @ 2017-01-18 9:41 UTC (permalink / raw)
To: Wolfram Sang, Matthias Brugger
Cc: srv_heupstream, devicetree, linux-i2c, linux-arm-kernel,
linux-kernel, linux-mediatek, Jun Gao
In-Reply-To: <1484732461-13594-1-git-send-email-jun.gao@mediatek.com>
From: Jun Gao <jun.gao@mediatek.com>
Add i2c device node for MT2701.
Signed-off-by: Jun Gao <jun.gao@mediatek.com>
---
arch/arm/boot/dts/mt2701-evb.dts | 44 ++++++++++++++++++++++++++++++++++++++
arch/arm/boot/dts/mt2701.dtsi | 42 ++++++++++++++++++++++++++++++++++++
2 files changed, 86 insertions(+)
diff --git a/arch/arm/boot/dts/mt2701-evb.dts b/arch/arm/boot/dts/mt2701-evb.dts
index 082ca88..a908e94 100644
--- a/arch/arm/boot/dts/mt2701-evb.dts
+++ b/arch/arm/boot/dts/mt2701-evb.dts
@@ -24,6 +24,50 @@
};
};
+&i2c0 {
+ pinctrl-names = "default";
+ pinctrl-0 = <&i2c0_pins_a>;
+ status = "okay";
+};
+
+&i2c1 {
+ pinctrl-names = "default";
+ pinctrl-0 = <&i2c1_pins_a>;
+ status = "okay";
+};
+
+&i2c2 {
+ pinctrl-names = "default";
+ pinctrl-0 = <&i2c2_pins_a>;
+ status = "okay";
+};
+
+&pio {
+ i2c0_pins_a: i2c0@0 {
+ pins1 {
+ pinmux = <MT2701_PIN_75_SDA0__FUNC_SDA0>,
+ <MT2701_PIN_76_SCL0__FUNC_SCL0>;
+ bias-disable;
+ };
+ };
+
+ i2c1_pins_a: i2c1@0 {
+ pins1 {
+ pinmux = <MT2701_PIN_57_SDA1__FUNC_SDA1>,
+ <MT2701_PIN_58_SCL1__FUNC_SCL1>;
+ bias-disable;
+ };
+ };
+
+ i2c2_pins_a: i2c2@0 {
+ pins1 {
+ pinmux = <MT2701_PIN_77_SDA2__FUNC_SDA2>,
+ <MT2701_PIN_78_SCL2__FUNC_SCL2>;
+ bias-disable;
+ };
+ };
+};
+
&uart0 {
status = "okay";
};
diff --git a/arch/arm/boot/dts/mt2701.dtsi b/arch/arm/boot/dts/mt2701.dtsi
index bdf8954..0d1539f 100644
--- a/arch/arm/boot/dts/mt2701.dtsi
+++ b/arch/arm/boot/dts/mt2701.dtsi
@@ -227,6 +227,48 @@
status = "disabled";
};
+ i2c0: i2c@11007000 {
+ compatible = "mediatek,mt2701-i2c",
+ "mediatek,mt6577-i2c";
+ reg = <0 0x11007000 0 0x70>,
+ <0 0x11000200 0 0x80>;
+ interrupts = <GIC_SPI 44 IRQ_TYPE_LEVEL_LOW>;
+ clock-div = <16>;
+ clocks = <&pericfg CLK_PERI_I2C0>, <&pericfg CLK_PERI_AP_DMA>;
+ clock-names = "main", "dma";
+ #address-cells = <1>;
+ #size-cells = <0>;
+ status = "disabled";
+ };
+
+ i2c1: i2c@11008000 {
+ compatible = "mediatek,mt2701-i2c",
+ "mediatek,mt6577-i2c";
+ reg = <0 0x11008000 0 0x70>,
+ <0 0x11000280 0 0x80>;
+ interrupts = <GIC_SPI 45 IRQ_TYPE_LEVEL_LOW>;
+ clock-div = <16>;
+ clocks = <&pericfg CLK_PERI_I2C1>, <&pericfg CLK_PERI_AP_DMA>;
+ clock-names = "main", "dma";
+ #address-cells = <1>;
+ #size-cells = <0>;
+ status = "disabled";
+ };
+
+ i2c2: i2c@11009000 {
+ compatible = "mediatek,mt2701-i2c",
+ "mediatek,mt6577-i2c";
+ reg = <0 0x11009000 0 0x70>,
+ <0 0x11000300 0 0x80>;
+ interrupts = <GIC_SPI 46 IRQ_TYPE_LEVEL_LOW>;
+ clock-div = <16>;
+ clocks = <&pericfg CLK_PERI_I2C2>, <&pericfg CLK_PERI_AP_DMA>;
+ clock-names = "main", "dma";
+ #address-cells = <1>;
+ #size-cells = <0>;
+ status = "disabled";
+ };
+
mmsys: syscon@14000000 {
compatible = "mediatek,mt2701-mmsys", "syscon";
reg = <0 0x14000000 0 0x1000>;
--
1.7.9.5
^ permalink raw reply related
* Re: [PATCH] i2c: core: helper function to detect slave mode
From: Andy Shevchenko @ 2017-01-18 10:59 UTC (permalink / raw)
To: Vladimir Zapolskiy, Luis Oliveira, Andy Shevchenko
Cc: Wolfram Sang, Rob Herring, Mark Rutland, Jarkko Nikula,
Mika Westerberg, linux-i2c, devicetree,
linux-kernel@vger.kernel.org, Ramiro.Oliveira, Joao Pinto,
CARLOS.PALMINHA
In-Reply-To: <f751ffbe-f9f8-c5bd-3b1a-2edd91152a78@mleia.com>
On Tue, 2017-01-17 at 01:14 +0200, Vladimir Zapolskiy wrote:
> review comments then, for example it is not obvious that on a platform
> with both CONFIG_ACPI and CONFIG_OF enabled there should be an
> exclusive
> selection of only one of two possible branches as in your code etc.
ACPI and DT approach differently to this property. Like I already said
to you check GPIO library where we have similarities.
--
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy
^ permalink raw reply
* Re: [PATCH v5 5/5] i2c: mux: pca954x: Add irq-mask-enable to delay enabling irqs
From: Peter Rosin @ 2017-01-18 12:19 UTC (permalink / raw)
To: Phil Reid, wsa-z923LK4zBo2bacvFa/9K2g,
robh+dt-DgEjT+Ai2ygdnm+yROfE0A, mark.rutland-5wv7dgnIgG8,
linux-i2c-u79uwXL29TY76Z2rM5mHXA,
devicetree-u79uwXL29TY76Z2rM5mHXA
In-Reply-To: <1484640029-22870-6-git-send-email-preid-qgqNFa1JUf/o2iN0hyhwsIdd74u8MsAO@public.gmane.org>
On 2017-01-17 09:00, Phil Reid wrote:
> Unfortunately some hardware device will assert their irq line immediately
> on power on and provide no mechanism to mask the irq. As the i2c muxes
> provide no method to mask irq line this provides a work around by keeping
> the parent irq masked until enough device drivers have loaded to service
> all pending interrupts.
>
> For example the the ltc1760 assert its SMBALERT irq immediately on power
> on. With two ltc1760 attached to bus 0 & 1 on a pca954x mux when the first
> device is registered irq are enabled and fire continuously as the second
> device driver has not yet loaded. Setting this parameter to <1 1> will
> delay the irq being enabled until both devices are ready.
>
> Signed-off-by: Phil Reid <preid-qgqNFa1JUf/o2iN0hyhwsIdd74u8MsAO@public.gmane.org>
> ---
> drivers/i2c/muxes/i2c-mux-pca954x.c | 33 ++++++++++++++++++++++++++++++---
> 1 file changed, 30 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c
> index f55da88..012b2ef 100644
> --- a/drivers/i2c/muxes/i2c-mux-pca954x.c
> +++ b/drivers/i2c/muxes/i2c-mux-pca954x.c
> @@ -76,6 +76,19 @@ struct chip_desc {
> } muxtype;
> };
>
> +/*
> + * irq_mask_enable: Provides a mechanism to work around hardware that asserts
> + * their irq immediately on power on. It allows the enabling of the irq to be
> + * delayed until the corresponding bits in the the irq_mask are set thru
> + * irq_unmask.
> + * For example the ltc1760 assert its SMBALERT irq immediately on power on.
> + * With two ltc1760 attached to bus 0 & 1 on a pca954x mux when the first
> + * device is registered irq are enabled and fire continuously as the second
> + * device driver has not yet loaded. Setting this parameter to 0x3 while
> + * delay the irq being enabled until both devices are ready.
> + * This workaround will not work if two devices share an interrupt on the
> + * same bus segment.
It will also not work if something shares the interrupt with the pca954x mux,
on the parent side of the mux, so to speak. Then that other driver may
potentially enable the irq "behind the back" of the pca954x driver.
> + */
> struct pca954x {
> const struct chip_desc *chip;
>
> @@ -84,7 +97,9 @@ struct pca954x {
> struct i2c_client *client;
>
> struct irq_domain *irq;
> + unsigned int irq_mask_enable;
> unsigned int irq_mask;
> + bool irq_enabled;
> spinlock_t lock;
> };
>
> @@ -266,8 +281,10 @@ static void pca954x_irq_mask(struct irq_data *idata)
> spin_lock_irqsave(&data->lock, flags);
>
> data->irq_mask &= ~BIT(pos);
> - if (!data->irq_mask)
> + if (data->irq_enabled && !data->irq_mask) {
> disable_irq(data->client->irq);
> + data->irq_enabled = false;
> + }
When irq_mask_enable is non-zero, I think the parent irq should be masked
when the first irq from the set in irq_mask_enable is masked. For symmetry.
Like so (untested):
if (data->irq_enabled) {
if (!data->irq_mask ||
(data->irq_mask & mask_enable) != mask_enable) {
disable_irq(data->client->irq);
data->irq_enabled = false;
}
}
Hmm, this whole thing is fiddly and while it solves your problem it doesn't
allow for solving the more general problem when there are "problematic"
devices mixed with other devices. At least, I don't see it. And the
limitations we are walking into with tracking number of enables etc suggests
that we are attacking this at the wrong level. Maybe you should try to work
around the hw limitations not in the pca954x driver, but in the irq core?
I.e. have the irq core check, for each irq, for a property that specifies
the depth at which each irq should be unmasked. This new property should
probably be located in the interrupt-controller node? Then the code can
unmask interrupts when the depth hits this mark, instead of always unmasking
the interrupt when the depth changes from zero to one. You are then adding
the workaround at a level where there is enough information to fix the
more general problem. I think?
But, once again, I'm no irq expert and would desperately like a second
opinion on this stuff...
>
> spin_unlock_irqrestore(&data->lock, flags);
> }
> @@ -275,14 +292,18 @@ static void pca954x_irq_mask(struct irq_data *idata)
> static void pca954x_irq_unmask(struct irq_data *idata)
> {
> struct pca954x *data = irq_data_get_irq_chip_data(idata);
> + unsigned int mask_enable = data->irq_mask_enable;
> unsigned int pos = idata->hwirq;
> unsigned long flags;
>
> spin_lock_irqsave(&data->lock, flags);
>
> - if (!data->irq_mask)
> - enable_irq(data->client->irq);
> data->irq_mask |= BIT(pos);
> + if (!data->irq_enabled
> + && (data->irq_mask & mask_enable) == mask_enable) {
I think the coding standard says that the && should be at the end of the
first line. Didn't checkpatch complain?
Cheers,
peda
> + enable_irq(data->client->irq);
> + data->irq_enabled = true;
> + }
>
> spin_unlock_irqrestore(&data->lock, flags);
> }
> @@ -305,6 +326,7 @@ static int pca954x_irq_setup(struct i2c_mux_core *muxc)
> {
> struct pca954x *data = i2c_mux_priv(muxc);
> struct i2c_client *client = data->client;
> + u32 irq_mask_enable[PCA954X_MAX_NCHANS] = { 0 };
> int c, err, irq;
>
> if (!data->chip->has_irq || client->irq <= 0)
> @@ -312,6 +334,9 @@ static int pca954x_irq_setup(struct i2c_mux_core *muxc)
>
> spin_lock_init(&data->lock);
>
> + of_property_read_u32_array(client->dev.of_node, "nxp,irq-mask-enable",
> + irq_mask_enable, data->chip->nchans);
> +
> data->irq = irq_domain_add_linear(client->dev.of_node,
> data->chip->nchans,
> &irq_domain_simple_ops, data);
> @@ -319,6 +344,8 @@ static int pca954x_irq_setup(struct i2c_mux_core *muxc)
> return -ENODEV;
>
> for (c = 0; c < data->chip->nchans; c++) {
> + data->irq_mask_enable |= irq_mask_enable[c] ? BIT(c) : 0;
> + WARN_ON(irq_mask_enable[c] > 1);
> irq = irq_create_mapping(data->irq, c);
> irq_set_chip_data(irq, data);
> irq_set_chip_and_handler(irq, &pca954x_irq_chip,
>
--
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^ permalink raw reply
* Re: [PATCH v9 2/5] i2c: Add STM32F4 I2C driver
From: M'boumba Cedric Madianga @ 2017-01-18 15:21 UTC (permalink / raw)
To: Uwe Kleine-König
Cc: Wolfram Sang, Rob Herring, Maxime Coquelin, Alexandre Torgue,
Linus Walleij, Patrice Chotard, Russell King,
linux-i2c-u79uwXL29TY76Z2rM5mHXA,
devicetree-u79uwXL29TY76Z2rM5mHXA,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r,
linux-kernel-u79uwXL29TY76Z2rM5mHXA
In-Reply-To: <20170117193752.e6hju25w74bb4i4z-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
Hello Uwe,
2017-01-17 20:37 GMT+01:00 Uwe Kleine-König <u.kleine-koenig@pengutronix.de>:
> Hello,
>
> On Tue, Jan 17, 2017 at 04:26:58PM +0100, M'boumba Cedric Madianga wrote:
>> +static void stm32f4_i2c_set_rise_time(struct stm32f4_i2c_dev *i2c_dev)
>> +{
>> + u32 freq = DIV_ROUND_UP(i2c_dev->parent_rate, HZ_TO_MHZ);
>> + u32 trise;
>> +
>> + /*
>> + * These bits must be programmed with the maximum SCL rise time given in
>> + * the I2C bus specification, incremented by 1.
>> + *
>> + * In standard mode, the maximum allowed SCL rise time is 1000 ns.
>> + * If, in the I2C_CR2 register, the value of FREQ[5:0] bits is equal to
>> + * 0x08 so period = 125 ns therefore the TRISE[5:0] bits must be
>> + * programmed with 09h.(1000 ns / 125 ns = 8 + 1)
>
> * programmed with 0x9.
> (1000 ns / 125 ns = 8)
>
>> + * So, for I2C standard mode TRISE = FREQ[5:0] + 1
>> + *
>> + * In fast mode, the maximum allowed SCL rise time is 300 ns.
>> + * If, in the I2C_CR2 register, the value of FREQ[5:0] bits is equal to
>> + * 0x08 so period = 125 ns therefore the TRISE[5:0] bits must be
>> + * programmed with 03h.(300 ns / 125 ns = 2 + 1)
>
> as above s/03h/0x3/;
ok
> s/.(/. (/;
ok
> s/+ 1//;
This formula is use to understand how we find the result 0x3
So, 0x3 => 300 ns / 125ns = 2 + 1
>
>> + * So, for I2C fast mode TRISE = FREQ[5:0] * 300 / 1000 + 1
>> + */
>> + if (i2c_dev->speed == STM32F4_I2C_SPEED_STANDARD)
>> + trise = freq + 1;
>> + else
>> + trise = freq * 300 / 1000 + 1;
>
> I'd use
>
> * 3 / 10
>
> without downside and lesser chance to overflow.
There is no chance of overflow as the max freq value allowed is 46
>
>> +
>> + writel_relaxed(STM32F4_I2C_TRISE_VALUE(trise),
>> + i2c_dev->base + STM32F4_I2C_TRISE);
>> +}
>> +
>> +static void stm32f4_i2c_set_speed_mode(struct stm32f4_i2c_dev *i2c_dev)
>> +{
>> + u32 val;
>> + u32 ccr = 0;
>> +
>> + if (i2c_dev->speed == STM32F4_I2C_SPEED_STANDARD) {
>> + /*
>> + * In standard mode:
>> + * t_scl_high = t_scl_low = CCR * I2C parent clk period
>> + * So to reach 100 kHz, we have:
>> + * CCR = I2C parent rate / 100 kHz >> 1
>> + *
>> + * For example with parent rate = 2 MHz:
>> + * CCR = 2000000 / (100000 << 1) = 10
>> + * t_scl_high = t_scl_low = 10 * (1 / 2000000) = 5000 ns
>> + * t_scl_high + t_scl_low = 10000 ns so 100 kHz is reached
>> + */
>> + val = i2c_dev->parent_rate / (100000 << 1);
>> + } else {
>> + /*
>> + * In fast mode, we compute CCR with duty = 0 as with low
>> + * frequencies we are not able to reach 400 kHz.
>> + * In that case:
>> + * t_scl_high = CCR * I2C parent clk period
>> + * t_scl_low = 2 * CCR * I2C parent clk period
>> + * So, CCR = I2C parent rate / (400 kHz * 3)
>> + *
>> + * For example with parent rate = 6 MHz:
>> + * CCR = 6000000 / (400000 * 3) = 5
>> + * t_scl_high = 5 * (1 / 6000000) = 833 ns > 600 ns
>> + * t_scl_low = 2 * 5 * (1 / 6000000) = 1667 ns > 1300 ns
>> + * t_scl_high + t_scl_low = 2500 ns so 400 kHz is reached
>> + */
>
> Huh, that's surprising. So you don't use DUTY any more. I found two
> hints in the manual that contradict here:
Yes with the above formula we could use duty = 0 by default
>
> f_{PCLK1} must be at least 2 MHz to achieve Sm mode I2C frequencies
STM32F4_I2C_MIN_STANDARD_FREQ = 2
> It must be at least 4 MHz to achieve Fm mode I2C frequencies.
STM32F4_I2C_MIN_FAST_FREQ = 6
> It must be a multiple of 10MHz to reach the 400 kHz maximum I2C Fm mode clock.
If we use this rule only 3 values are allowed 10 Mhz, 20 Mhz, 30 Mhz and 40 Mhz.
It is very restrictive.
So I don't take it into account in order to have more frequencies even
if 400 Khz is not reached.
Indeed, in many cases we are very close to 400 Khz.
For example, the default I2C parent clock in my board is 45 Mhz
I reach 395 kHz in theory and 390 kHz by testing.
I am in Fast mode but not with the max freq but very close.
>
> and
>
> [...]
> If DUTY = 1: (to reach 400 kHz)
>
> Strange.
>
>> + val = DIV_ROUND_UP(i2c_dev->parent_rate, 400000 * 3);
>
> the manual reads:
>
> The minimum allowed value is 0x04, except in FAST DUTY mode
> where the minimum allowed value is 0x01
>
> You don't check for that, right?
As the minimum freq value is 6 Mhz in fast mode the minimum CCR is 5
as described in the comment.
So I don't need to check that again as it is already done by checking
parent frequency.
> CCR is 11 bits wide. A comment confirming that this cannot overflow
> would be nice.
Again there is no chance of overflow thanks to parent frequency check
>
> + /* select Fast Mode */
>> + ccr |= STM32F4_I2C_CCR_FS;
ok
>
> I didn't check the rest of the code, so let's assume it's good :-)
ok Thanks
>
> Best regards
> Uwe
>
> --
> Pengutronix e.K. | Uwe Kleine-König |
> Industrial Linux Solutions | http://www.pengutronix.de/ |
--
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^ permalink raw reply
* [PATCH v8 01/12] devres: trivial whitespace fix
From: Peter Rosin @ 2017-01-18 15:57 UTC (permalink / raw)
To: linux-kernel
Cc: Peter Rosin, Wolfram Sang, Rob Herring, Mark Rutland,
Jonathan Cameron, Hartmut Knaack, Lars-Peter Clausen,
Peter Meerwald-Stadler, Jonathan Corbet, Andrew Morton, linux-i2c,
devicetree, linux-iio, linux-doc
In-Reply-To: <1484755035-25927-1-git-send-email-peda@axentia.se>
Everything else is indented with two spaces, so fix the odd one out.
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Peter Rosin <peda@axentia.se>
---
Documentation/driver-model/devres.txt | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt
index ca9d1eb46bc0..dc51fb024190 100644
--- a/Documentation/driver-model/devres.txt
+++ b/Documentation/driver-model/devres.txt
@@ -330,7 +330,7 @@ MEM
devm_kzalloc()
MFD
- devm_mfd_add_devices()
+ devm_mfd_add_devices()
PER-CPU MEM
devm_alloc_percpu()
--
2.1.4
^ permalink raw reply related
* [PATCH v8 02/12] dt-bindings: document devicetree bindings for mux-controllers and mux-gpio
From: Peter Rosin @ 2017-01-18 15:57 UTC (permalink / raw)
To: linux-kernel
Cc: Peter Rosin, Wolfram Sang, Rob Herring, Mark Rutland,
Jonathan Cameron, Hartmut Knaack, Lars-Peter Clausen,
Peter Meerwald-Stadler, Jonathan Corbet, Andrew Morton, linux-i2c,
devicetree, linux-iio, linux-doc
In-Reply-To: <1484755035-25927-1-git-send-email-peda@axentia.se>
Allow specifying that a single multiplexer controller can be used to control
several parallel multiplexers, thus enabling sharing of the multiplexer
controller by different consumers.
Add a binding for a first mux controller in the form of a GPIO based mux
controlled.
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Peter Rosin <peda@axentia.se>
---
.../devicetree/bindings/mux/mux-controller.txt | 127 +++++++++++++++++++++
Documentation/devicetree/bindings/mux/mux-gpio.txt | 68 +++++++++++
MAINTAINERS | 5 +
3 files changed, 200 insertions(+)
create mode 100644 Documentation/devicetree/bindings/mux/mux-controller.txt
create mode 100644 Documentation/devicetree/bindings/mux/mux-gpio.txt
diff --git a/Documentation/devicetree/bindings/mux/mux-controller.txt b/Documentation/devicetree/bindings/mux/mux-controller.txt
new file mode 100644
index 000000000000..42b2177e5ae1
--- /dev/null
+++ b/Documentation/devicetree/bindings/mux/mux-controller.txt
@@ -0,0 +1,127 @@
+Common multiplexer controller bindings
+======================================
+
+A multiplexer (or mux) controller will have one, or several, consumer devices
+that uses the mux controller. Thus, a mux controller can possibly control
+several parallel multiplexers. Presumably there will be at least one
+multiplexer needed by each consumer, but a single mux controller can of course
+control several multiplexers for a single consumer.
+
+A mux controller provides a number of states to its consumers, and the state
+space is a simple zero-based enumeration. I.e. 0-1 for a 2-way multiplexer,
+0-7 for an 8-way multiplexer, etc.
+
+
+Consumers
+---------
+
+Mux controller consumers should specify a list of mux controllers that they
+want to use with a property containing a 'mux-ctrl-list':
+
+ mux-ctrl-list ::= <single-mux-ctrl> [mux-ctrl-list]
+ single-mux-ctrl ::= <mux-ctrl-phandle> [mux-ctrl-specifier]
+ mux-ctrl-phandle : phandle to mux controller node
+ mux-ctrl-specifier : array of #mux-control-cells specifying the
+ given mux controller (controller specific)
+
+Mux controller properties should be named "mux-controls". The exact meaning of
+each mux controller property must be documented in the device tree binding for
+each consumer. An optional property "mux-control-names" may contain a list of
+strings to label each of the mux controllers listed in the "mux-controls"
+property.
+
+Drivers for devices that use more than a single mux controller can use the
+"mux-control-names" property to map the name of the requested mux controller
+to an index into the list given by the "mux-controls" property.
+
+mux-ctrl-specifier typically encodes the chip-relative mux controller number.
+If the mux controller chip only provides a single mux controller, the
+mux-ctrl-specifier can typically be left out.
+
+Example:
+
+ /* One consumer of a 2-way mux controller (one GPIO-line) */
+ mux: mux-controller {
+ compatible = "mux-gpio";
+ #mux-control-cells = <0>;
+
+ mux-gpios = <&pioA 0 GPIO_ACTIVE_HIGH>;
+ };
+
+ adc-mux {
+ compatible = "io-channel-mux";
+ io-channels = <&adc 0>;
+ io-channel-names = "parent";
+ mux-controls = <&mux>;
+ mux-control-names = "adc";
+
+ channels = "sync", "in";
+ };
+
+Note that in the example above, specifying the "mux-control-names" is redundant
+because there is only one mux controller in the list.
+
+ /*
+ * Two consumers (one for an ADC line and one for an i2c bus) of
+ * parallel 4-way multiplexers controlled by the same two GPIO-lines.
+ */
+ mux: mux-controller {
+ compatible = "mux-gpio";
+ #mux-control-cells = <0>;
+
+ mux-gpios = <&pioA 0 GPIO_ACTIVE_HIGH>,
+ <&pioA 1 GPIO_ACTIVE_HIGH>;
+ };
+
+ adc-mux {
+ compatible = "io-channel-mux";
+ io-channels = <&adc 0>;
+ io-channel-names = "parent";
+ mux-controls = <&mux>;
+
+ channels = "sync-1", "in", "out", "sync-2";
+ };
+
+ i2c-mux {
+ compatible = "i2c-mux-simple,mux-locked";
+ i2c-parent = <&i2c1>;
+ mux-controls = <&mux>;
+
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ i2c@0 {
+ reg = <0>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ ssd1307: oled@3c {
+ /* ... */
+ };
+ };
+
+ i2c@3 {
+ reg = <3>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ pca9555: pca9555@20 {
+ /* ... */
+ };
+ };
+ };
+
+
+Mux controller nodes
+--------------------
+
+Mux controller nodes must specify the number of cells used for the
+specifier using the '#mux-control-cells' property.
+
+An example mux controller might look like this:
+
+ mux: adg792a@50 {
+ compatible = "adi,adg792a";
+ reg = <0x50>;
+ #mux-control-cells = <1>;
+ };
diff --git a/Documentation/devicetree/bindings/mux/mux-gpio.txt b/Documentation/devicetree/bindings/mux/mux-gpio.txt
new file mode 100644
index 000000000000..8f6bda6f9d78
--- /dev/null
+++ b/Documentation/devicetree/bindings/mux/mux-gpio.txt
@@ -0,0 +1,68 @@
+GPIO-based multiplexer controller bindings
+
+Define what GPIO pins are used to control a multiplexer. Or several
+multiplexers, if the same pins control more than one multiplexer.
+
+Required properties:
+- compatible : "mux-gpio"
+- mux-gpios : list of gpios used to control the multiplexer, least
+ significant bit first.
+- #mux-control-cells : <0>
+* Standard mux-controller bindings as decribed in mux-controller.txt
+
+Optional properties:
+- idle-state : if present, the state the mux will have when idle.
+
+The multiplexer state is defined as the number represented by the
+multiplexer GPIO pins, where the first pin is the least significant
+bit. An active pin is a binary 1, an inactive pin is a binary 0.
+
+Example:
+
+ mux: mux-controller {
+ compatible = "mux-gpio";
+ #mux-control-cells = <0>;
+
+ mux-gpios = <&pioA 0 GPIO_ACTIVE_HIGH>,
+ <&pioA 1 GPIO_ACTIVE_HIGH>;
+ };
+
+ adc-mux {
+ compatible = "io-channel-mux";
+ io-channels = <&adc 0>;
+ io-channel-names = "parent";
+
+ mux-controls = <&mux>;
+
+ channels = "sync-1", "in", "out", "sync-2";
+ };
+
+ i2c-mux {
+ compatible = "i2c-mux-simple,mux-locked";
+ i2c-parent = <&i2c1>;
+
+ mux-controls = <&mux>;
+
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ i2c@0 {
+ reg = <0>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ ssd1307: oled@3c {
+ /* ... */
+ };
+ };
+
+ i2c@3 {
+ reg = <3>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ pca9555: pca9555@20 {
+ /* ... */
+ };
+ };
+ };
diff --git a/MAINTAINERS b/MAINTAINERS
index 40de344ba0e6..be57f5b8f2c2 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8469,6 +8469,11 @@ S: Orphan
F: drivers/mmc/host/mmc_spi.c
F: include/linux/spi/mmc_spi.h
+MULTIPLEXER SUBSYSTEM
+M: Peter Rosin <peda@axentia.se>
+S: Maintained
+F: Documentation/devicetree/bindings/mux/
+
MULTISOUND SOUND DRIVER
M: Andrew Veliath <andrewtv@usa.net>
S: Maintained
--
2.1.4
^ permalink raw reply related
* [PATCH v8 04/12] iio: inkern: api for manipulating ext_info of iio channels
From: Peter Rosin @ 2017-01-18 15:57 UTC (permalink / raw)
To: linux-kernel
Cc: Peter Rosin, Wolfram Sang, Rob Herring, Mark Rutland,
Jonathan Cameron, Hartmut Knaack, Lars-Peter Clausen,
Peter Meerwald-Stadler, Jonathan Corbet, Andrew Morton, linux-i2c,
devicetree, linux-iio, linux-doc
In-Reply-To: <1484755035-25927-1-git-send-email-peda@axentia.se>
Extend the inkern api with functions for reading and writing ext_info
of iio channels.
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Peter Rosin <peda@axentia.se>
---
drivers/iio/inkern.c | 60 ++++++++++++++++++++++++++++++++++++++++++++
include/linux/iio/consumer.h | 37 +++++++++++++++++++++++++++
2 files changed, 97 insertions(+)
diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c
index b0f4630a163f..4848b8129e6c 100644
--- a/drivers/iio/inkern.c
+++ b/drivers/iio/inkern.c
@@ -863,3 +863,63 @@ int iio_write_channel_raw(struct iio_channel *chan, int val)
return ret;
}
EXPORT_SYMBOL_GPL(iio_write_channel_raw);
+
+unsigned int iio_get_channel_ext_info_count(struct iio_channel *chan)
+{
+ const struct iio_chan_spec_ext_info *ext_info;
+ unsigned int i = 0;
+
+ if (!chan->channel->ext_info)
+ return i;
+
+ for (ext_info = chan->channel->ext_info; ext_info->name; ext_info++)
+ ++i;
+
+ return i;
+}
+EXPORT_SYMBOL_GPL(iio_get_channel_ext_info_count);
+
+static const struct iio_chan_spec_ext_info *iio_lookup_ext_info(
+ const struct iio_channel *chan,
+ const char *attr)
+{
+ const struct iio_chan_spec_ext_info *ext_info;
+
+ if (!chan->channel->ext_info)
+ return NULL;
+
+ for (ext_info = chan->channel->ext_info; ext_info->name; ++ext_info) {
+ if (!strcmp(attr, ext_info->name))
+ return ext_info;
+ }
+
+ return NULL;
+}
+
+ssize_t iio_read_channel_ext_info(struct iio_channel *chan,
+ const char *attr, char *buf)
+{
+ const struct iio_chan_spec_ext_info *ext_info;
+
+ ext_info = iio_lookup_ext_info(chan, attr);
+ if (!ext_info)
+ return -EINVAL;
+
+ return ext_info->read(chan->indio_dev, ext_info->private,
+ chan->channel, buf);
+}
+EXPORT_SYMBOL_GPL(iio_read_channel_ext_info);
+
+ssize_t iio_write_channel_ext_info(struct iio_channel *chan, const char *attr,
+ const char *buf, size_t len)
+{
+ const struct iio_chan_spec_ext_info *ext_info;
+
+ ext_info = iio_lookup_ext_info(chan, attr);
+ if (!ext_info)
+ return -EINVAL;
+
+ return ext_info->write(chan->indio_dev, ext_info->private,
+ chan->channel, buf, len);
+}
+EXPORT_SYMBOL_GPL(iio_write_channel_ext_info);
diff --git a/include/linux/iio/consumer.h b/include/linux/iio/consumer.h
index 47eeec3218b5..5e347a9805fd 100644
--- a/include/linux/iio/consumer.h
+++ b/include/linux/iio/consumer.h
@@ -312,4 +312,41 @@ int iio_read_channel_scale(struct iio_channel *chan, int *val,
int iio_convert_raw_to_processed(struct iio_channel *chan, int raw,
int *processed, unsigned int scale);
+/**
+ * iio_get_channel_ext_info_count() - get number of ext_info attributes
+ * connected to the channel.
+ * @chan: The channel being queried
+ *
+ * Returns the number of ext_info attributes
+ */
+unsigned int iio_get_channel_ext_info_count(struct iio_channel *chan);
+
+/**
+ * iio_read_channel_ext_info() - read ext_info attribute from a given channel
+ * @chan: The channel being queried.
+ * @attr: The ext_info attribute to read.
+ * @buf: Where to store the attribute value. Assumed to hold
+ * at least PAGE_SIZE bytes.
+ *
+ * Returns the number of bytes written to buf (perhaps w/o zero termination;
+ * it need not even be a string), or an error code.
+ */
+ssize_t iio_read_channel_ext_info(struct iio_channel *chan,
+ const char *attr, char *buf);
+
+/**
+ * iio_write_channel_ext_info() - write ext_info attribute from a given channel
+ * @chan: The channel being queried.
+ * @attr: The ext_info attribute to read.
+ * @buf: The new attribute value. Strings needs to be zero-
+ * terminated, but the terminator should not be included
+ * in the below len.
+ * @len: The size of the new attribute value.
+ *
+ * Returns the number of accepted bytes, which should be the same as len.
+ * An error code can also be returned.
+ */
+ssize_t iio_write_channel_ext_info(struct iio_channel *chan, const char *attr,
+ const char *buf, size_t len);
+
#endif
--
2.1.4
^ permalink raw reply related
* [PATCH v8 05/12] dt-bindings: iio: io-channel-mux: document io-channel-mux bindings
From: Peter Rosin @ 2017-01-18 15:57 UTC (permalink / raw)
To: linux-kernel
Cc: Peter Rosin, Wolfram Sang, Rob Herring, Mark Rutland,
Jonathan Cameron, Hartmut Knaack, Lars-Peter Clausen,
Peter Meerwald-Stadler, Jonathan Corbet, Andrew Morton, linux-i2c,
devicetree, linux-iio, linux-doc
In-Reply-To: <1484755035-25927-1-git-send-email-peda@axentia.se>
Describe how a multiplexer can be used to select which signal is fed to
an io-channel.
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Peter Rosin <peda@axentia.se>
---
.../bindings/iio/multiplexer/io-channel-mux.txt | 39 ++++++++++++++++++++++
MAINTAINERS | 6 ++++
2 files changed, 45 insertions(+)
create mode 100644 Documentation/devicetree/bindings/iio/multiplexer/io-channel-mux.txt
diff --git a/Documentation/devicetree/bindings/iio/multiplexer/io-channel-mux.txt b/Documentation/devicetree/bindings/iio/multiplexer/io-channel-mux.txt
new file mode 100644
index 000000000000..c82794002595
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/multiplexer/io-channel-mux.txt
@@ -0,0 +1,39 @@
+I/O channel multiplexer bindings
+
+If a multiplexer is used to select which hardware signal is fed to
+e.g. an ADC channel, these bindings describe that situation.
+
+Required properties:
+- compatible : "io-channel-mux"
+- io-channels : Channel node of the parent channel that has multiplexed
+ input.
+- io-channel-names : Should be "parent".
+- #address-cells = <1>;
+- #size-cells = <0>;
+- mux-controls : Mux controller node to use for operating the mux
+- channels : List of strings, labeling the mux controller states.
+
+For each non-empty string in the channels property, an io-channel will
+be created. The number of this io-channel is the same as the index into
+the list of strings in the channels property, and also matches the mux
+controller state. The mux controller state is described in
+../mux/mux-controller.txt
+
+Example:
+ mux: mux-controller {
+ compatible = "mux-gpio";
+ #mux-control-cells = <0>;
+
+ mux-gpios = <&pioA 0 GPIO_ACTIVE_HIGH>,
+ <&pioA 1 GPIO_ACTIVE_HIGH>;
+ };
+
+ adc-mux {
+ compatible = "io-channel-mux";
+ io-channels = <&adc 0>;
+ io-channel-names = "parent";
+
+ mux-controls = <&mux>;
+
+ channels = "sync", "in", "system-regulator";
+ };
diff --git a/MAINTAINERS b/MAINTAINERS
index e4fac17e0fa4..35325a3d9ca4 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6289,6 +6289,12 @@ F: Documentation/ABI/testing/sysfs-bus-iio-adc-envelope-detector
F: Documentation/devicetree/bindings/iio/adc/envelope-detector.txt
F: drivers/iio/adc/envelope-detector.c
+IIO MULTIPLEXER
+M: Peter Rosin <peda@axentia.se>
+L: linux-iio@vger.kernel.org
+S: Maintained
+F: Documentation/devicetree/bindings/iio/multiplexer/iio-mux.txt
+
IIO SUBSYSTEM AND DRIVERS
M: Jonathan Cameron <jic23@kernel.org>
R: Hartmut Knaack <knaack.h@gmx.de>
--
2.1.4
^ permalink raw reply related
* [PATCH v8 06/12] iio: multiplexer: new iio category and iio-mux driver
From: Peter Rosin @ 2017-01-18 15:57 UTC (permalink / raw)
To: linux-kernel
Cc: Peter Rosin, Wolfram Sang, Rob Herring, Mark Rutland,
Jonathan Cameron, Hartmut Knaack, Lars-Peter Clausen,
Peter Meerwald-Stadler, Jonathan Corbet, Andrew Morton, linux-i2c,
devicetree, linux-iio, linux-doc
In-Reply-To: <1484755035-25927-1-git-send-email-peda@axentia.se>
When a multiplexer changes how an iio device behaves (for example
by feeding different signals to an ADC), this driver can be used
to create one virtual iio channel for each multiplexer state.
Depends on the generic multiplexer subsystem.
Cache any ext_info values from the parent iio channel, creating a private
copy of the ext_info attributes for each multiplexer state/channel.
Reviewed-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Peter Rosin <peda@axentia.se>
---
MAINTAINERS | 1 +
drivers/iio/Kconfig | 1 +
drivers/iio/Makefile | 1 +
drivers/iio/multiplexer/Kconfig | 18 ++
drivers/iio/multiplexer/Makefile | 6 +
drivers/iio/multiplexer/iio-mux.c | 456 ++++++++++++++++++++++++++++++++++++++
6 files changed, 483 insertions(+)
create mode 100644 drivers/iio/multiplexer/Kconfig
create mode 100644 drivers/iio/multiplexer/Makefile
create mode 100644 drivers/iio/multiplexer/iio-mux.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 35325a3d9ca4..bfbc1a9dd3fe 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6294,6 +6294,7 @@ M: Peter Rosin <peda@axentia.se>
L: linux-iio@vger.kernel.org
S: Maintained
F: Documentation/devicetree/bindings/iio/multiplexer/iio-mux.txt
+F: drivers/iio/multiplexer/iio-mux.c
IIO SUBSYSTEM AND DRIVERS
M: Jonathan Cameron <jic23@kernel.org>
diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
index a918270d6f54..b3c8c6ef0dff 100644
--- a/drivers/iio/Kconfig
+++ b/drivers/iio/Kconfig
@@ -83,6 +83,7 @@ source "drivers/iio/humidity/Kconfig"
source "drivers/iio/imu/Kconfig"
source "drivers/iio/light/Kconfig"
source "drivers/iio/magnetometer/Kconfig"
+source "drivers/iio/multiplexer/Kconfig"
source "drivers/iio/orientation/Kconfig"
if IIO_TRIGGER
source "drivers/iio/trigger/Kconfig"
diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
index 33fa4026f92c..93c769cd99bf 100644
--- a/drivers/iio/Makefile
+++ b/drivers/iio/Makefile
@@ -28,6 +28,7 @@ obj-y += humidity/
obj-y += imu/
obj-y += light/
obj-y += magnetometer/
+obj-y += multiplexer/
obj-y += orientation/
obj-y += potentiometer/
obj-y += potentiostat/
diff --git a/drivers/iio/multiplexer/Kconfig b/drivers/iio/multiplexer/Kconfig
new file mode 100644
index 000000000000..70a044510686
--- /dev/null
+++ b/drivers/iio/multiplexer/Kconfig
@@ -0,0 +1,18 @@
+#
+# Multiplexer drivers
+#
+# When adding new entries keep the list in alphabetical order
+
+menu "Multiplexers"
+
+config IIO_MUX
+ tristate "IIO multiplexer driver"
+ select MULTIPLEXER
+ depends on OF
+ help
+ Say yes here to build support for the IIO multiplexer.
+
+ To compile this driver as a module, choose M here: the
+ module will be called iio-mux.
+
+endmenu
diff --git a/drivers/iio/multiplexer/Makefile b/drivers/iio/multiplexer/Makefile
new file mode 100644
index 000000000000..68be3c4abd07
--- /dev/null
+++ b/drivers/iio/multiplexer/Makefile
@@ -0,0 +1,6 @@
+#
+# Makefile for industrial I/O multiplexer drivers
+#
+
+# When adding new entries keep the list in alphabetical order
+obj-$(CONFIG_IIO_MUX) += iio-mux.o
diff --git a/drivers/iio/multiplexer/iio-mux.c b/drivers/iio/multiplexer/iio-mux.c
new file mode 100644
index 000000000000..94d40f9bef4c
--- /dev/null
+++ b/drivers/iio/multiplexer/iio-mux.c
@@ -0,0 +1,456 @@
+/*
+ * IIO multiplexer driver
+ *
+ * Copyright (C) 2017 Axentia Technologies AB
+ *
+ * Author: Peter Rosin <peda@axentia.se>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/err.h>
+#include <linux/iio/consumer.h>
+#include <linux/iio/iio.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/mux.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
+struct mux_ext_info_cache {
+ char *data;
+ size_t size;
+};
+
+struct mux_child {
+ struct mux_ext_info_cache *ext_info_cache;
+};
+
+struct mux {
+ int cached_state;
+ struct mux_control *control;
+ struct iio_channel *parent;
+ struct iio_dev *indio_dev;
+ struct iio_chan_spec *chan;
+ struct iio_chan_spec_ext_info *ext_info;
+ struct mux_child *child;
+};
+
+static int iio_mux_select(struct mux *mux, int idx)
+{
+ struct mux_child *child = &mux->child[idx];
+ struct iio_chan_spec const *chan = &mux->chan[idx];
+ int ret;
+ int i;
+
+ ret = mux_control_select(mux->control, chan->channel);
+ if (ret < 0) {
+ mux->cached_state = -1;
+ return ret;
+ }
+
+ if (mux->cached_state == chan->channel)
+ return 0;
+
+ if (chan->ext_info) {
+ for (i = 0; chan->ext_info[i].name; ++i) {
+ const char *attr = chan->ext_info[i].name;
+ struct mux_ext_info_cache *cache;
+
+ cache = &child->ext_info_cache[i];
+
+ if (cache->size < 0)
+ continue;
+
+ ret = iio_write_channel_ext_info(mux->parent, attr,
+ cache->data,
+ cache->size);
+
+ if (ret < 0) {
+ mux_control_deselect(mux->control);
+ mux->cached_state = -1;
+ return ret;
+ }
+ }
+ }
+ mux->cached_state = chan->channel;
+
+ return 0;
+}
+
+static void iio_mux_deselect(struct mux *mux)
+{
+ mux_control_deselect(mux->control);
+}
+
+static int mux_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct mux *mux = iio_priv(indio_dev);
+ int idx = chan - mux->chan;
+ int ret;
+
+ ret = iio_mux_select(mux, idx);
+ if (ret < 0)
+ return ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ ret = iio_read_channel_raw(mux->parent, val);
+ break;
+
+ case IIO_CHAN_INFO_SCALE:
+ ret = iio_read_channel_scale(mux->parent, val, val2);
+ break;
+
+ default:
+ ret = -EINVAL;
+ }
+
+ iio_mux_deselect(mux);
+
+ return ret;
+}
+
+static int mux_read_avail(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ const int **vals, int *type, int *length,
+ long mask)
+{
+ struct mux *mux = iio_priv(indio_dev);
+ int idx = chan - mux->chan;
+ int ret;
+
+ ret = iio_mux_select(mux, idx);
+ if (ret < 0)
+ return ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ *type = IIO_VAL_INT;
+ ret = iio_read_avail_channel_raw(mux->parent, vals, length);
+ break;
+
+ default:
+ ret = -EINVAL;
+ }
+
+ iio_mux_deselect(mux);
+
+ return ret;
+}
+
+static int mux_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int val, int val2, long mask)
+{
+ struct mux *mux = iio_priv(indio_dev);
+ int idx = chan - mux->chan;
+ int ret;
+
+ ret = iio_mux_select(mux, idx);
+ if (ret < 0)
+ return ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ ret = iio_write_channel_raw(mux->parent, val);
+ break;
+
+ default:
+ ret = -EINVAL;
+ }
+
+ iio_mux_deselect(mux);
+
+ return ret;
+}
+
+static const struct iio_info mux_info = {
+ .read_raw = mux_read_raw,
+ .read_avail = mux_read_avail,
+ .write_raw = mux_write_raw,
+ .driver_module = THIS_MODULE,
+};
+
+static ssize_t mux_read_ext_info(struct iio_dev *indio_dev, uintptr_t private,
+ struct iio_chan_spec const *chan, char *buf)
+{
+ struct mux *mux = iio_priv(indio_dev);
+ int idx = chan - mux->chan;
+ ssize_t ret;
+
+ ret = iio_mux_select(mux, idx);
+ if (ret < 0)
+ return ret;
+
+ ret = iio_read_channel_ext_info(mux->parent,
+ mux->ext_info[private].name,
+ buf);
+
+ iio_mux_deselect(mux);
+
+ return ret;
+}
+
+static ssize_t mux_write_ext_info(struct iio_dev *indio_dev, uintptr_t private,
+ struct iio_chan_spec const *chan,
+ const char *buf, size_t len)
+{
+ struct device *dev = indio_dev->dev.parent;
+ struct mux *mux = iio_priv(indio_dev);
+ int idx = chan - mux->chan;
+ char *new;
+ ssize_t ret;
+
+ ret = iio_mux_select(mux, idx);
+ if (ret < 0)
+ return ret;
+
+ new = devm_kmemdup(dev, buf, len + 1, GFP_KERNEL);
+ if (!new) {
+ iio_mux_deselect(mux);
+ return -ENOMEM;
+ }
+
+ new[len] = 0;
+
+ ret = iio_write_channel_ext_info(mux->parent,
+ mux->ext_info[private].name,
+ buf, len);
+ if (ret < 0) {
+ iio_mux_deselect(mux);
+ devm_kfree(dev, new);
+ return ret;
+ }
+
+ devm_kfree(dev, mux->child[idx].ext_info_cache[private].data);
+ mux->child[idx].ext_info_cache[private].data = new;
+ mux->child[idx].ext_info_cache[private].size = len;
+
+ iio_mux_deselect(mux);
+
+ return ret;
+}
+
+static int mux_configure_channel(struct device *dev, struct mux *mux,
+ u32 state, const char *label, int idx)
+{
+ struct mux_child *child = &mux->child[idx];
+ struct iio_chan_spec *chan = &mux->chan[idx];
+ struct iio_chan_spec const *pchan = mux->parent->channel;
+ char *page = NULL;
+ int num_ext_info;
+ int i;
+ int ret;
+
+ chan->indexed = 1;
+ chan->output = pchan->output;
+ chan->datasheet_name = label;
+ chan->ext_info = mux->ext_info;
+
+ ret = iio_get_channel_type(mux->parent, &chan->type);
+ if (ret < 0) {
+ dev_err(dev, "failed to get parent channel type\n");
+ return ret;
+ }
+
+ if (iio_channel_has_info(pchan, IIO_CHAN_INFO_RAW))
+ chan->info_mask_separate |= BIT(IIO_CHAN_INFO_RAW);
+ if (iio_channel_has_info(pchan, IIO_CHAN_INFO_SCALE))
+ chan->info_mask_separate |= BIT(IIO_CHAN_INFO_SCALE);
+
+ if (iio_channel_has_available(pchan, IIO_CHAN_INFO_RAW))
+ chan->info_mask_separate_available |= BIT(IIO_CHAN_INFO_RAW);
+
+ if (state >= mux->control->states) {
+ dev_err(dev, "too many channels\n");
+ return -EINVAL;
+ }
+
+ chan->channel = state;
+
+ num_ext_info = iio_get_channel_ext_info_count(mux->parent);
+ if (num_ext_info) {
+ page = devm_kzalloc(dev, PAGE_SIZE, GFP_KERNEL);
+ if (!page)
+ return -ENOMEM;
+ }
+ child->ext_info_cache = devm_kzalloc(dev,
+ sizeof(*child->ext_info_cache) *
+ num_ext_info, GFP_KERNEL);
+ for (i = 0; i < num_ext_info; ++i) {
+ child->ext_info_cache[i].size = -1;
+
+ if (!pchan->ext_info[i].write)
+ continue;
+ if (!pchan->ext_info[i].read)
+ continue;
+
+ ret = iio_read_channel_ext_info(mux->parent,
+ mux->ext_info[i].name,
+ page);
+ if (ret < 0) {
+ dev_err(dev, "failed to get ext_info '%s'\n",
+ pchan->ext_info[i].name);
+ return ret;
+ }
+ if (ret >= PAGE_SIZE) {
+ dev_err(dev, "too large ext_info '%s'\n",
+ pchan->ext_info[i].name);
+ return -EINVAL;
+ }
+
+ child->ext_info_cache[i].data = devm_kmemdup(dev, page, ret + 1,
+ GFP_KERNEL);
+ child->ext_info_cache[i].data[ret] = 0;
+ child->ext_info_cache[i].size = ret;
+ }
+
+ if (page)
+ devm_kfree(dev, page);
+
+ return 0;
+}
+
+/*
+ * Same as of_property_for_each_string(), but also keeps track of the
+ * index of each string.
+ */
+#define of_property_for_each_string_index(np, propname, prop, s, i) \
+ for (prop = of_find_property(np, propname, NULL), \
+ s = of_prop_next_string(prop, NULL), \
+ i = 0; \
+ s; \
+ s = of_prop_next_string(prop, s), \
+ i++)
+
+static int mux_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *np = pdev->dev.of_node;
+ struct iio_dev *indio_dev;
+ struct iio_channel *parent;
+ struct mux *mux;
+ struct property *prop;
+ const char *label;
+ u32 state;
+ int sizeof_ext_info;
+ int children;
+ int sizeof_priv;
+ int i;
+ int ret;
+
+ if (!np)
+ return -ENODEV;
+
+ parent = devm_iio_channel_get(dev, "parent");
+ if (IS_ERR(parent)) {
+ if (PTR_ERR(parent) != -EPROBE_DEFER)
+ dev_err(dev, "failed to get parent channel\n");
+ return PTR_ERR(parent);
+ }
+
+ sizeof_ext_info = iio_get_channel_ext_info_count(parent);
+ if (sizeof_ext_info) {
+ sizeof_ext_info += 1; /* one extra entry for the sentinel */
+ sizeof_ext_info *= sizeof(*mux->ext_info);
+ }
+
+ children = 0;
+ of_property_for_each_string(np, "channels", prop, label) {
+ if (*label)
+ children++;
+ }
+ if (children <= 0) {
+ dev_err(dev, "not even a single child\n");
+ return -EINVAL;
+ }
+
+ sizeof_priv = sizeof(*mux);
+ sizeof_priv += sizeof(*mux->child) * children;
+ sizeof_priv += sizeof(*mux->chan) * children;
+ sizeof_priv += sizeof_ext_info;
+
+ indio_dev = devm_iio_device_alloc(dev, sizeof_priv);
+ if (!indio_dev)
+ return -ENOMEM;
+
+ mux = iio_priv(indio_dev);
+ mux->child = (struct mux_child *)(mux + 1);
+ mux->chan = (struct iio_chan_spec *)(mux->child + children);
+
+ platform_set_drvdata(pdev, indio_dev);
+
+ mux->parent = parent;
+ mux->cached_state = -1;
+
+ indio_dev->name = dev_name(dev);
+ indio_dev->dev.parent = dev;
+ indio_dev->info = &mux_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = mux->chan;
+ indio_dev->num_channels = children;
+ if (sizeof_ext_info) {
+ mux->ext_info = devm_kmemdup(dev,
+ parent->channel->ext_info,
+ sizeof_ext_info, GFP_KERNEL);
+ if (!mux->ext_info)
+ return -ENOMEM;
+
+ for (i = 0; mux->ext_info[i].name; ++i) {
+ if (parent->channel->ext_info[i].read)
+ mux->ext_info[i].read = mux_read_ext_info;
+ if (parent->channel->ext_info[i].write)
+ mux->ext_info[i].write = mux_write_ext_info;
+ mux->ext_info[i].private = i;
+ }
+ }
+
+ mux->control = devm_mux_control_get(dev, NULL);
+ if (IS_ERR(mux->control)) {
+ if (PTR_ERR(mux->control) != -EPROBE_DEFER)
+ dev_err(dev, "failed to get control-mux\n");
+ return PTR_ERR(mux->control);
+ }
+
+ i = 0;
+ of_property_for_each_string_index(np, "channels", prop, label, state) {
+ if (!*label)
+ continue;
+
+ ret = mux_configure_channel(dev, mux, state, label, i++);
+ if (ret < 0)
+ return ret;
+ }
+
+ ret = devm_iio_device_register(dev, indio_dev);
+ if (ret) {
+ dev_err(dev, "failed to register iio device\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+static const struct of_device_id mux_match[] = {
+ { .compatible = "io-channel-mux" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mux_match);
+
+static struct platform_driver mux_driver = {
+ .probe = mux_probe,
+ .driver = {
+ .name = "iio-mux",
+ .of_match_table = mux_match,
+ },
+};
+module_platform_driver(mux_driver);
+
+MODULE_DESCRIPTION("IIO multiplexer driver");
+MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
+MODULE_LICENSE("GPL v2");
--
2.1.4
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