[02/12] i2c: si570: merge support for si570 clock generator

Message ID	1387865711-23124-3-git-send-email-daniel.sangorrin@toshiba.co.jp (mailing list archive)
State	New, archived
Headers	show Return-Path: <ltsi-dev-bounces@lists.linuxfoundation.org> From: Daniel Sangorrin <daniel.sangorrin@toshiba.co.jp> To: ltsi-dev@lists.linuxfoundation.org Date: Tue, 24 Dec 2013 15:15:01 +0900 Message-Id: <1387865711-23124-3-git-send-email-daniel.sangorrin@toshiba.co.jp> In-Reply-To: <1387865711-23124-1-git-send-email-daniel.sangorrin@toshiba.co.jp> References: <1387865711-23124-1-git-send-email-daniel.sangorrin@toshiba.co.jp> Cc: michal.simek@xilinx.com Subject: [LTSI-dev] [PATCH 02/12] i2c: si570: merge support for si570 clock generator Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: ltsi-dev-bounces@lists.linuxfoundation.org Errors-To: ltsi-dev-bounces@lists.linuxfoundation.org

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index c002d86..1c9fd72 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -507,6 +507,16 @@ config USB_SWITCH_FSA9480 stereo and mono audio, video, microphone and UART data to use a common connector port. +config SI570 + tristate "Silicon Labs Si570 Clock Generator" + depends on I2C && SYSFS + help + If you say yes here you get support for the Silicon Labs Si570 + digital clock generator. + + To compile this driver as a module, choose M here: the module + will be called si570 + config LATTICE_ECP3_CONFIG tristate "Lattice ECP3 FPGA bitstream configuration via SPI" depends on SPI && SYSFS diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile index c235d5b..e84bcaa 100644 --- a/drivers/misc/Makefile +++ b/drivers/misc/Makefile @@ -50,6 +50,7 @@ obj-y += carma/ obj-$(CONFIG_USB_SWITCH_FSA9480) += fsa9480.o obj-$(CONFIG_ALTERA_STAPL) +=altera-stapl/ obj-$(CONFIG_INTEL_MEI) += mei/ +obj-$(CONFIG_SI570) += si570.o obj-$(CONFIG_VMWARE_VMCI) += vmw_vmci/ obj-$(CONFIG_LATTICE_ECP3_CONFIG) += lattice-ecp3-config.o obj-$(CONFIG_SRAM) += sram.o diff --git a/drivers/misc/si570.c b/drivers/misc/si570.c new file mode 100644 index 0000000..30d8288 --- /dev/null +++ b/drivers/misc/si570.c @@ -0,0 +1,576 @@ +/* + * Driver for Silicon Labs Si570/Si571 Programmable XO/VCXO + * + * Copyright (C) 2010, 2011 Ericsson AB. + * Copyright (C) 2011 Guenter Roeck. + * + * Author: Guenter Roeck <guenter.roeck@ericsson.com> + * + * 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/of_i2c.h> +#include <linux/i2c/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 156250000LL +#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) +#define SI570_UNFREEZE_DCO 0xEF + +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 struct i2c_client *si570_client; + + +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 = div64_u64((fdco << 24), (data->rfreq >> 4)); + else + data->fxtal = div64_u64((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) +{ + int status; + status = i2c_smbus_write_byte_data(client, SI570_REG_N1_RFREQ0, + ((data->n1 - 1) << 6) + | ((data->rfreq >> 32) & RFREQ_37_32_MASK)); + if (status < 0) + dev_err(&client->dev, + "unable to write 0x%llX to REG_N1_RFREQ0: %d\n", + (((data->n1 - 1) << 6) | ((data->rfreq >> 32) & + RFREQ_37_32_MASK)) & 0xff, status); + status = i2c_smbus_write_byte_data(client, SI570_REG_RFREQ1, + (data->rfreq >> 24) & 0xff); + if (status < 0) + dev_err(&client->dev, + "unable to write 0x%llX to REG_RFREQ1: %d\n", + (data->rfreq >> 24) & 0xff, status); + status = i2c_smbus_write_byte_data(client, SI570_REG_RFREQ2, + (data->rfreq >> 16) & 0xff); + if (status < 0) + dev_err(&client->dev, + "unable to write 0x%llX to REG_RFREQ2: %d\n", + (data->rfreq >> 16) & 0xff, status); + status = i2c_smbus_write_byte_data(client, SI570_REG_RFREQ3, + (data->rfreq >> 8) & 0xff); + if (status < 0) + dev_err(&client->dev, + "unable to write 0x%llX to REG_RFREQ3: %d\n", + (data->rfreq >> 8) & 0xff, status); + status = i2c_smbus_write_byte_data(client, SI570_REG_RFREQ4, + data->rfreq & 0xff); + if (status < 0) + dev_err(&client->dev, + "unable to write 0x%llX to REG_RFREQ4: %d\n", + data->rfreq & 0xff, status); +} + +/* + * 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; + /* This is a re-implementation of DIV_ROUND_CLOSEST + * using the div64_u64 function lieu of letting the compiler + * insert EABI calls + */ + data->rfreq = div64_u64((data->rfreq * frequency) + + div64_u64(data->frequency, 2), 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; +} + +static 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 = div64_u64(div64_u64(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 = div64_u64((fdco << 28), + data->fxtal); + best_fdco = fdco; + } + n1 += (n1 == 1 ? 1 : 2); + } + } + if (best_fdco == ULLONG_MAX) { + dev_err(&client->dev, "error - best FDCO is out of range\n"); + return -EINVAL; + } + + /* The DCO reg should be accessed with a read-modify-write operation + * per AN334 + */ + 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_attr(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); +} + +int get_frequency_si570(struct device *dev, unsigned long *freq) +{ + int err; + char buf[10+1]; + + if ((!dev) || (to_i2c_client(dev) != si570_client)) + return -EINVAL; + + show_frequency_attr(dev, NULL, buf); + + err = kstrtoul(buf, 10, freq); + if (err) + return err; + + return 0; +} +EXPORT_SYMBOL(get_frequency_si570); + +static ssize_t set_frequency_attr(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 = kstrtoul(buf, 10, &val); + if (err) + return err; + + if (val < SI570_MIN_FREQ || val > data->max_freq) { + dev_err(&client->dev, + "requested frequency %lu Hz is out of range\n", val); + return -EINVAL; + } + + mutex_lock(&data->lock); + + if (div64_u64(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) { + dev_warn(&client->dev, + "unable to set output frequency %lu Hz: %d\n", + val, err); + return err; + } + + dev_info(&client->dev, + "set new output frequency %lu Hz\n", val); + + return count; +} + +int set_frequency_si570(struct device *dev, unsigned long freq) +{ + char buf[10+1]; + + if ((!dev) || (to_i2c_client(dev) != si570_client)) + return -EINVAL; + + sprintf(buf, "%lu", freq); + + return set_frequency_attr(dev, NULL, buf, 0); +} +EXPORT_SYMBOL(set_frequency_si570); + +static ssize_t show_reset_attr(struct device *dev, + struct device_attribute *devattr, + char *buf) +{ + return sprintf(buf, "%d\n", 0); +} + +static ssize_t set_reset_attr(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 = kstrtoul(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; +} + +int reset_si570(struct device *dev, int id) +{ + char buf[4]; + + if ((!dev) || (to_i2c_client(dev) != si570_client)) + return -EINVAL; + + sprintf(buf, "%lu", (unsigned long)id); + return set_reset_attr(dev, NULL, buf, 0); +} +EXPORT_SYMBOL(reset_si570); + +struct i2c_client *get_i2c_client_si570(void) +{ + return si570_client; +} +EXPORT_SYMBOL(get_i2c_client_si570); + +static DEVICE_ATTR(frequency, S_IWUSR | S_IRUGO, show_frequency_attr, + set_frequency_attr); +static DEVICE_ATTR(reset, S_IWUSR | S_IRUGO, show_reset_attr, set_reset_attr); + +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; + unsigned long initial_fout; + u32 tmp = SI570_FOUT_FACTORY_DFLT; + + 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->factory_fout) + data->fout = pdata->factory_fout; + + if (client->dev.of_node && + (of_property_read_u32(client->dev.of_node, "factory-fout", + &tmp) < 0)) + dev_warn(&client->dev, + "DTS does not contain factory-fout, using default\n"); + else + data->fout = tmp; + + 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; + + /* Display a message indicating that we've successfully registered */ + dev_info(&client->dev, + "registered %s with default frequency %llu Hz\n", + id->name, data->fout); + + /* Read the requested initial fout from either platform data or the + * device tree + */ + initial_fout = 0; + if (pdata && pdata->initial_fout) + initial_fout = pdata->initial_fout; + if (client->dev.of_node) { + of_property_read_u32(client->dev.of_node, "initial-fout", + (u32 *)&initial_fout); + if (pdata && pdata->initial_fout && + (pdata->initial_fout != initial_fout)) { + dev_warn(&client->dev, + "OF initial fout %lu overrides platform data fout %lu\n", + initial_fout, + pdata->initial_fout); + } + } + + if (initial_fout != 0) { + if (initial_fout < SI570_MIN_FREQ || + initial_fout > data->max_freq) { + dev_err(&client->dev, + "requested initial frequency %lu is out of range, using default\n", + initial_fout); + return 0; + } + + mutex_lock(&data->lock); + + if (div64_u64(abs(initial_fout - data->frequency) * + 10000LL, data->frequency) < 35) + err = si570_set_frequency_small(client, data, + initial_fout); + else + err = si570_set_frequency(client, data, + initial_fout); + mutex_unlock(&data->lock); + if (err) { + dev_warn(&client->dev, + "unable to set initial output frequency %lu: %d\n", + initial_fout, err); + return err; + } + + dev_info(&client->dev, + "set initial output frequency %lu Hz\n", + initial_fout); + } + + si570_client = client; + + 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; +} + +#ifdef CONFIG_OF +static const struct of_device_id i2c_si570_of_match[] = { + { .compatible = "si570" }, + { }, +}; +MODULE_DEVICE_TABLE(of, i2c_si570_of_match); +#endif + +static struct i2c_driver si570_driver = { + .driver = { + .name = "si570", + .of_match_table = of_match_ptr(i2c_si570_of_match), + }, + .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@ericsson.com>"); +MODULE_DESCRIPTION("Si570 driver"); +MODULE_LICENSE("GPL"); + +module_init(si570_init); +module_exit(si570_exit); diff --git a/include/linux/i2c/si570.h b/include/linux/i2c/si570.h new file mode 100644 index 0000000..f2cf285 --- /dev/null +++ b/include/linux/i2c/si570.h @@ -0,0 +1,31 @@ +/* + * 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> +#include <linux/device.h> +#include <linux/i2c.h> + +struct si570_platform_data { + u64 factory_fout; /* Factory default output frequency */ + unsigned long initial_fout; /* Requested initial frequency */ +}; + +int get_frequency_si570(struct device *dev, unsigned long *freq); +int set_frequency_si570(struct device *dev, unsigned long freq); +int reset_si570(struct device *dev, int id); +struct i2c_client *get_i2c_client_si570(void); + +#endif /* __LINUX_SI570_H */

[02/12] i2c: si570: merge support for si570 clock generator

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