This driver adds support for Si570, Si571, Si598, and Si599 programmable XO/VCXO. Signed-off-by: Guenter Roeck <guenter.roeck@xxxxxxxxxxxx> --- v2: - Fixed checkpatch errors and warnings - Moved si570.h platform data include file to include/linux/platform_data - Documented reset sysfs attribute - Added Documentation/ABI/testing/sysfs-bus-i2c-si570 Documentation/ABI/testing/sysfs-bus-i2c-si570 | 21 ++ Documentation/misc-devices/si570 | 62 ++++ MAINTAINERS | 7 + drivers/misc/Kconfig | 10 + drivers/misc/Makefile | 1 + drivers/misc/si570.c | 398 +++++++++++++++++++++++++ include/linux/platform_data/si570.h | 23 ++ 7 files changed, 522 insertions(+), 0 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-bus-i2c-si570 create mode 100644 Documentation/misc-devices/si570 create mode 100644 drivers/misc/si570.c create mode 100644 include/linux/platform_data/si570.h diff --git a/Documentation/ABI/testing/sysfs-bus-i2c-si570 b/Documentation/ABI/testing/sysfs-bus-i2c-si570 new file mode 100644 index 0000000..78c43f7 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-i2c-si570 @@ -0,0 +1,21 @@ +What: /sys/bus/i2c/devices/<busnum>-<devaddr>/frequency +Date: April 2011 +Kernel version: 2.6.40 ? +Contact: Guenter Roeck <guenter.roeck@xxxxxxxxxxxx> +Description: + Read or write XO/VCXO frequency of the device in Hz. + + Accepted values: 10 MHz to 1400 MHz for Si570 and Si571, + 10 MHz to 525 MHz for Si598 and Si599. +Users: + Userspace applications interested in knowing or changing the + device frequency. + +What: /sys/bus/i2c/devices/<busnum>-<devaddr>/reset +Date: April 2011 +Kernel Version: 2.6.40 ? +Contact: Guenter Roeck <guenter.roeck@xxxxxxxxxxxx> +Description: Writing a value other than 0 resets the device. + Reading always returns 0 and has no effect. +Users: + Userspace applications interested in resetting the device. diff --git a/Documentation/misc-devices/si570 b/Documentation/misc-devices/si570 new file mode 100644 index 0000000..54e32f7 --- /dev/null +++ b/Documentation/misc-devices/si570 @@ -0,0 +1,62 @@ +Kernel driver si570 +===================== + +Supported chips: + * Silicon Labs Si570/Si571 + Prefix: 'si570' + Addresses scanned: None (see below) + Datasheets: + http://www.silabs.com/Support%20Documents/TechnicalDocs/si570.pdf + * Silicon Labs Si598/Si599 + Prefix: 'si598' + Addresses scanned: None (see below) + Datasheets: + http://www.silabs.com/Support%20Documents/TechnicalDocs/si598-99.pdf + +Author: Guenter Roeck <guenter.roeck@xxxxxxxxxxxx> + + +Description +----------- + +The Si570/Si598 XO and Si571/Si599 VCXO provide a low-jitter clock at any +frequency. + +The Si570/Si571 are user-programmable to any output frequency from 10 to 945 MHz +and select frequencies to 1400 MHz with <1 ppb resolution. + +The Si598/Si599 are user programmable to any output frequency from 10 to 525 MHz +with 28 parts per trillion (ppt) resolution. + +See the datasheets for more information. + + +Sysfs entries +------------- + +frequency - Selected frequency +reset - Writing a value other than 0 resets the device + + +General Remarks +--------------- + +The chips support all valid 7-bit I2C addresses. I2C addresses are assigned +during the ordering process. + +This driver does not auto-detect devices. You will have to instantiate the +devices explicitly. Please see Documentation/i2c/instantiating-devices for +details. + + +Platform data +------------- + +The devices can be provided with platform data to select the factory default +output frequency. If platform data is not specified, the driver will assume a +default factory output frequency of 125 MHz for Si570/Si571 and 10 MHz for +Si598/Si599. + +struct si570_platform_data { + unsigned long fout; /* Factory default output frequency */ +}; diff --git a/MAINTAINERS b/MAINTAINERS index ec36003..4c339ea 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -5406,6 +5406,13 @@ L: linux-serial@xxxxxxxxxxxxxxx S: Maintained F: drivers/tty/serial +SI570 DRIVER +M: Guenter Roeck <guenter.roeck@xxxxxxxxxxxx> +L: linux-kernel@xxxxxxxxxxxxxxx +S: Maintained +F: drivers/misc/si570.c +F: include/linux/platform_data/si570.h + TIMEKEEPING, NTP M: John Stultz <johnstul@xxxxxxxxxx> M: Thomas Gleixner <tglx@xxxxxxxxxxxxx> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index 4e007c6..c7041c9 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -475,6 +475,16 @@ config PCH_PHUB To compile this driver as a module, choose M here: the module will be called pch_phub. +config SI570 + tristate "Silicon Labs Si570/Si571/Si598/Si599" + depends on I2C && SYSFS && EXPERIMENTAL + help + This is a driver for Silicon Labs Si570/Si571/Si598/Si599 programmable + XO/VCXO. + + To compile this driver as a module, choose M here: the module will + be called si570. + source "drivers/misc/c2port/Kconfig" source "drivers/misc/eeprom/Kconfig" source "drivers/misc/cb710/Kconfig" diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile index f546860..a2397c6 100644 --- a/drivers/misc/Makefile +++ b/drivers/misc/Makefile @@ -41,6 +41,7 @@ obj-$(CONFIG_SPEAR13XX_PCIE_GADGET) += spear13xx_pcie_gadget.o obj-$(CONFIG_VMWARE_BALLOON) += vmw_balloon.o obj-$(CONFIG_ARM_CHARLCD) += arm-charlcd.o obj-$(CONFIG_PCH_PHUB) += pch_phub.o +obj-$(CONFIG_SI570) += si570.o obj-y += ti-st/ obj-$(CONFIG_AB8500_PWM) += ab8500-pwm.o obj-y += lis3lv02d/ diff --git a/drivers/misc/si570.c b/drivers/misc/si570.c new file mode 100644 index 0000000..69a3806 --- /dev/null +++ b/drivers/misc/si570.c @@ -0,0 +1,398 @@ +/* + * Driver for Silicon Labs Si570/Si571 Programmable XO/VCXO + * + * Copyright (C) 2011 Ericsson AB. + * + * Author: Guenter Roeck <guenter.roeck@xxxxxxxxxxxx> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/module.h> +#include <linux/jiffies.h> +#include <linux/i2c.h> +#include <linux/err.h> +#include <linux/mutex.h> +#include <linux/delay.h> +#include <linux/log2.h> +#include <linux/slab.h> +#include <linux/platform_data/si570.h> + +/* Si570 registers */ +#define SI570_REG_HS_N1 7 +#define SI570_REG_N1_RFREQ0 8 +#define SI570_REG_RFREQ1 9 +#define SI570_REG_RFREQ2 10 +#define SI570_REG_RFREQ3 11 +#define SI570_REG_RFREQ4 12 +#define SI570_REG_CONTROL 135 +#define SI570_REG_FREEZE_DCO 137 + +#define HS_DIV_SHIFT 5 +#define HS_DIV_MASK 0xe0 +#define HS_DIV_OFFSET 4 +#define N1_6_2_MASK 0x1f +#define N1_1_0_MASK 0xc0 +#define RFREQ_37_32_MASK 0x3f + +#define SI570_FOUT_FACTORY_DFLT 125000000LL +#define SI598_FOUT_FACTORY_DFLT 10000000LL + +#define SI570_MIN_FREQ 10000000L +#define SI570_MAX_FREQ 1417500000L +#define SI598_MAX_FREQ 525000000L + +#define FDCO_MIN 4850000000LL +#define FDCO_MAX 5670000000LL +#define FDCO_CENTER ((FDCO_MIN + FDCO_MAX) / 2) + +#define SI570_CNTRL_RECALL (1 << 0) +#define SI570_CNTRL_FREEZE_ADC (1 << 4) +#define SI570_CNTRL_FREEZE_M (1 << 5) +#define SI570_CNTRL_NEWFREQ (1 << 6) +#define SI570_CNTRL_RESET (1 << 7) + +#define SI570_FREEZE_DCO (1 << 4) + +struct si570_data { + struct attribute_group attrs; + struct mutex lock; + u64 max_freq; + u64 fout; /* Factory default frequency */ + u64 fxtal; /* Factory xtal frequency */ + unsigned int n1; + unsigned int hs_div; + u64 rfreq; + u64 frequency; +}; + +static int si570_get_defaults(struct i2c_client *client) +{ + struct si570_data *data = i2c_get_clientdata(client); + int reg1, reg2, reg3, reg4, reg5, reg6; + u64 fdco; + + i2c_smbus_write_byte_data(client, SI570_REG_CONTROL, + SI570_CNTRL_RECALL); + + reg1 = i2c_smbus_read_byte_data(client, SI570_REG_HS_N1); + if (reg1 < 0) + return reg1; + reg2 = i2c_smbus_read_byte_data(client, SI570_REG_N1_RFREQ0); + if (reg2 < 0) + return reg2; + reg3 = i2c_smbus_read_byte_data(client, SI570_REG_RFREQ1); + if (reg3 < 0) + return reg3; + reg4 = i2c_smbus_read_byte_data(client, SI570_REG_RFREQ2); + if (reg4 < 0) + return reg4; + reg5 = i2c_smbus_read_byte_data(client, SI570_REG_RFREQ3); + if (reg5 < 0) + return reg5; + reg6 = i2c_smbus_read_byte_data(client, SI570_REG_RFREQ4); + if (reg6 < 0) + return reg6; + + data->hs_div = ((reg1 & HS_DIV_MASK) >> HS_DIV_SHIFT) + HS_DIV_OFFSET; + data->n1 = ((reg1 & N1_6_2_MASK) << 2) + ((reg2 & N1_1_0_MASK) >> 6) + + 1; + /* Handle invalid cases */ + if (data->n1 > 1) + data->n1 &= ~1; + + data->rfreq = reg2 & RFREQ_37_32_MASK; + data->rfreq = (data->rfreq << 8) + reg3; + data->rfreq = (data->rfreq << 8) + reg4; + data->rfreq = (data->rfreq << 8) + reg5; + data->rfreq = (data->rfreq << 8) + reg6; + + /* + * Accept optional precision loss to avoid arithmetic overflows. + * Acceptable per Silicon Labs Application Note AN334. + */ + fdco = data->fout * data->n1 * data->hs_div; + if (fdco >= (1LL << 36)) + data->fxtal = (fdco << 24) / (data->rfreq >> 4); + else + data->fxtal = (fdco << 28) / data->rfreq; + + data->frequency = data->fout; + + return 0; +} + +/* + * Update rfreq registers + * This function must be called with update mutex lock held. + */ +static void si570_update_rfreq(struct i2c_client *client, + struct si570_data *data) +{ + i2c_smbus_write_byte_data(client, SI570_REG_N1_RFREQ0, + ((data->n1 - 1) << 6) + | ((data->rfreq >> 32) & RFREQ_37_32_MASK)); + i2c_smbus_write_byte_data(client, SI570_REG_RFREQ1, + (data->rfreq >> 24) & 0xff); + i2c_smbus_write_byte_data(client, SI570_REG_RFREQ2, + (data->rfreq >> 16) & 0xff); + i2c_smbus_write_byte_data(client, SI570_REG_RFREQ3, + (data->rfreq >> 8) & 0xff); + i2c_smbus_write_byte_data(client, SI570_REG_RFREQ4, + data->rfreq & 0xff); +} + +/* + * Update si570 frequency for small frequency changes (< 3,500 ppm) + * This function must be called with update mutex lock held. + */ +static int si570_set_frequency_small(struct i2c_client *client, + struct si570_data *data, + unsigned long frequency) +{ + data->frequency = frequency; + data->rfreq = DIV_ROUND_CLOSEST(data->rfreq * frequency, + data->frequency); + i2c_smbus_write_byte_data(client, SI570_REG_CONTROL, + SI570_CNTRL_FREEZE_M); + si570_update_rfreq(client, data); + i2c_smbus_write_byte_data(client, SI570_REG_CONTROL, 0); + + return 0; +} + +const uint8_t si570_hs_div_values[] = { 11, 9, 7, 6, 5, 4 }; + +/* + * Set si570 frequency. + * This function must be called with update mutex lock held. + */ +static int si570_set_frequency(struct i2c_client *client, + struct si570_data *data, + unsigned long frequency) +{ + int i, n1, hs_div; + u64 fdco, best_fdco = ULLONG_MAX; + + for (i = 0; i < ARRAY_SIZE(si570_hs_div_values); i++) { + hs_div = si570_hs_div_values[i]; + /* Calculate lowest possible value for n1 */ + n1 = FDCO_MIN / (u64)hs_div / (u64)frequency; + if (!n1 || (n1 & 1)) + n1++; + while (n1 <= 128) { + fdco = (u64)frequency * (u64)hs_div * (u64)n1; + if (fdco > FDCO_MAX) + break; + if (fdco >= FDCO_MIN && fdco < best_fdco) { + data->n1 = n1; + data->hs_div = hs_div; + data->frequency = frequency; + data->rfreq = (fdco << 28) / data->fxtal; + best_fdco = fdco; + } + n1 += (n1 == 1 ? 1 : 2); + } + } + if (best_fdco == ULLONG_MAX) + return -EINVAL; + + i2c_smbus_write_byte_data(client, SI570_REG_FREEZE_DCO, + SI570_FREEZE_DCO); + i2c_smbus_write_byte_data(client, SI570_REG_HS_N1, + ((data->hs_div - HS_DIV_OFFSET) << + HS_DIV_SHIFT) + | (((data->n1 - 1) >> 2) & N1_6_2_MASK)); + si570_update_rfreq(client, data); + i2c_smbus_write_byte_data(client, SI570_REG_FREEZE_DCO, + 0); + i2c_smbus_write_byte_data(client, SI570_REG_CONTROL, + SI570_CNTRL_NEWFREQ); + return 0; +} + +/* + * Reset chip. + * This function must be called with update mutex lock held. + */ +static int si570_reset(struct i2c_client *client, struct si570_data *data) +{ + i2c_smbus_write_byte_data(client, SI570_REG_CONTROL, + SI570_CNTRL_RESET); + usleep_range(1000, 5000); + return si570_set_frequency(client, data, data->frequency); +} + +static ssize_t show_frequency(struct device *dev, + struct device_attribute *devattr, + char *buf) +{ + struct i2c_client *client = to_i2c_client(dev); + struct si570_data *data = i2c_get_clientdata(client); + + return sprintf(buf, "%llu\n", data->frequency); +} + +static ssize_t set_frequency(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct i2c_client *client = to_i2c_client(dev); + struct si570_data *data = i2c_get_clientdata(client); + unsigned long val; + int err; + + err = strict_strtoul(buf, 10, &val); + if (err) + return err; + + if (val < SI570_MIN_FREQ || val > data->max_freq) + return -EINVAL; + + mutex_lock(&data->lock); + if (abs(val - data->frequency) * 10000LL / data->frequency < 35) + err = si570_set_frequency_small(client, data, val); + else + err = si570_set_frequency(client, data, val); + mutex_unlock(&data->lock); + if (err) + return err; + + return count; +} +static ssize_t show_reset(struct device *dev, + struct device_attribute *devattr, + char *buf) +{ + return sprintf(buf, "%d\n", 0); +} + +static ssize_t set_reset(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct i2c_client *client = to_i2c_client(dev); + struct si570_data *data = i2c_get_clientdata(client); + unsigned long val; + int err; + + err = strict_strtoul(buf, 10, &val); + if (err) + return err; + if (val == 0) + goto done; + + mutex_lock(&data->lock); + err = si570_reset(client, data); + mutex_unlock(&data->lock); + if (err) + return err; +done: + return count; +} + +static DEVICE_ATTR(frequency, S_IWUSR | S_IRUGO, show_frequency, set_frequency); +static DEVICE_ATTR(reset, S_IWUSR | S_IRUGO, show_reset, set_reset); + +static struct attribute *si570_attr[] = { + &dev_attr_frequency.attr, + &dev_attr_reset.attr, + NULL +}; + +static const struct i2c_device_id si570_id[] = { + { "si570", 0 }, + { "si571", 0 }, + { "si598", 1 }, + { "si599", 1 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, si570_id); + +static int si570_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct si570_platform_data *pdata = client->dev.platform_data; + struct si570_data *data; + int err; + + data = kzalloc(sizeof(struct si570_data), GFP_KERNEL); + if (!data) { + err = -ENOMEM; + goto exit; + } + + if (id->driver_data) { + data->fout = SI598_FOUT_FACTORY_DFLT; + data->max_freq = SI598_MAX_FREQ; + } else { + data->fout = SI570_FOUT_FACTORY_DFLT; + data->max_freq = SI570_MAX_FREQ; + } + + if (pdata && pdata->fout) + data->fout = pdata->fout; + + i2c_set_clientdata(client, data); + err = si570_get_defaults(client); + if (err < 0) + goto exit_free; + + mutex_init(&data->lock); + + /* Register sysfs hooks */ + data->attrs.attrs = si570_attr; + err = sysfs_create_group(&client->dev.kobj, &data->attrs); + if (err) + goto exit_free; + + return 0; + +exit_free: + kfree(data); +exit: + return err; +} + +static int si570_remove(struct i2c_client *client) +{ + struct si570_data *data = i2c_get_clientdata(client); + + sysfs_remove_group(&client->dev.kobj, &data->attrs); + kfree(data); + return 0; +} + +static struct i2c_driver si570_driver = { + .driver = { + .name = "si570", + }, + .probe = si570_probe, + .remove = si570_remove, + .id_table = si570_id, +}; + +static int __init si570_init(void) +{ + return i2c_add_driver(&si570_driver); +} + +static void __exit si570_exit(void) +{ + i2c_del_driver(&si570_driver); +} + +MODULE_AUTHOR("Guenter Roeck <guenter.roeck@xxxxxxxxxxxx>"); +MODULE_DESCRIPTION("Si570 driver"); +MODULE_LICENSE("GPL"); + +module_init(si570_init); +module_exit(si570_exit); diff --git a/include/linux/platform_data/si570.h b/include/linux/platform_data/si570.h new file mode 100644 index 0000000..22ec865 --- /dev/null +++ b/include/linux/platform_data/si570.h @@ -0,0 +1,23 @@ +/* + * si570.h - Configuration for si570 misc driver. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation (version 2 of the License only). + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#ifndef __LINUX_SI570_H +#define __LINUX_SI570_H + +#include <linux/types.h> + +struct si570_platform_data { + unsigned long fout; /* Factory default output frequency */ +}; + +#endif /* __LINUX_SI570_H */ -- 1.7.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
