linux/drivers/clk/clk-si514.c
Thomas Gleixner c942fddf87 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157
Based on 3 normalized pattern(s):

  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

  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 [author] [kishon] [vijay] [abraham]
  [i] [kishon]@[ti] [com] 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

  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 [author] [graeme] [gregory]
  [gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i]
  [kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema]
  [hk] [hemahk]@[ti] [com] 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

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1105 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:37 -07:00

406 lines
9.5 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Driver for Silicon Labs Si514 Programmable Oscillator
*
* Copyright (C) 2015 Topic Embedded Products
*
* Author: Mike Looijmans <mike.looijmans@topic.nl>
*/
#include <linux/clk-provider.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/regmap.h>
#include <linux/slab.h>
/* I2C registers */
#define SI514_REG_LP 0
#define SI514_REG_M_FRAC1 5
#define SI514_REG_M_FRAC2 6
#define SI514_REG_M_FRAC3 7
#define SI514_REG_M_INT_FRAC 8
#define SI514_REG_M_INT 9
#define SI514_REG_HS_DIV 10
#define SI514_REG_LS_HS_DIV 11
#define SI514_REG_OE_STATE 14
#define SI514_REG_RESET 128
#define SI514_REG_CONTROL 132
/* Register values */
#define SI514_RESET_RST BIT(7)
#define SI514_CONTROL_FCAL BIT(0)
#define SI514_CONTROL_OE BIT(2)
#define SI514_MIN_FREQ 100000U
#define SI514_MAX_FREQ 250000000U
#define FXO 31980000U
#define FVCO_MIN 2080000000U
#define FVCO_MAX 2500000000U
#define HS_DIV_MAX 1022
struct clk_si514 {
struct clk_hw hw;
struct regmap *regmap;
struct i2c_client *i2c_client;
};
#define to_clk_si514(_hw) container_of(_hw, struct clk_si514, hw)
/* Multiplier/divider settings */
struct clk_si514_muldiv {
u32 m_frac; /* 29-bit Fractional part of multiplier M */
u8 m_int; /* Integer part of multiplier M, 65..78 */
u8 ls_div_bits; /* 2nd divider, as 2^x */
u16 hs_div; /* 1st divider, must be even and 10<=x<=1022 */
};
/* Enables or disables the output driver */
static int si514_enable_output(struct clk_si514 *data, bool enable)
{
return regmap_update_bits(data->regmap, SI514_REG_CONTROL,
SI514_CONTROL_OE, enable ? SI514_CONTROL_OE : 0);
}
static int si514_prepare(struct clk_hw *hw)
{
struct clk_si514 *data = to_clk_si514(hw);
return si514_enable_output(data, true);
}
static void si514_unprepare(struct clk_hw *hw)
{
struct clk_si514 *data = to_clk_si514(hw);
si514_enable_output(data, false);
}
static int si514_is_prepared(struct clk_hw *hw)
{
struct clk_si514 *data = to_clk_si514(hw);
unsigned int val;
int err;
err = regmap_read(data->regmap, SI514_REG_CONTROL, &val);
if (err < 0)
return err;
return !!(val & SI514_CONTROL_OE);
}
/* Retrieve clock multiplier and dividers from hardware */
static int si514_get_muldiv(struct clk_si514 *data,
struct clk_si514_muldiv *settings)
{
int err;
u8 reg[7];
err = regmap_bulk_read(data->regmap, SI514_REG_M_FRAC1,
reg, ARRAY_SIZE(reg));
if (err)
return err;
settings->m_frac = reg[0] | reg[1] << 8 | reg[2] << 16 |
(reg[3] & 0x1F) << 24;
settings->m_int = (reg[4] & 0x3f) << 3 | reg[3] >> 5;
settings->ls_div_bits = (reg[6] >> 4) & 0x07;
settings->hs_div = (reg[6] & 0x03) << 8 | reg[5];
return 0;
}
static int si514_set_muldiv(struct clk_si514 *data,
struct clk_si514_muldiv *settings)
{
u8 lp;
u8 reg[7];
int err;
/* Calculate LP1/LP2 according to table 13 in the datasheet */
/* 65.259980246 */
if (settings->m_int < 65 ||
(settings->m_int == 65 && settings->m_frac <= 139575831))
lp = 0x22;
/* 67.859763463 */
else if (settings->m_int < 67 ||
(settings->m_int == 67 && settings->m_frac <= 461581994))
lp = 0x23;
/* 72.937624981 */
else if (settings->m_int < 72 ||
(settings->m_int == 72 && settings->m_frac <= 503383578))
lp = 0x33;
/* 75.843265046 */
else if (settings->m_int < 75 ||
(settings->m_int == 75 && settings->m_frac <= 452724474))
lp = 0x34;
else
lp = 0x44;
err = regmap_write(data->regmap, SI514_REG_LP, lp);
if (err < 0)
return err;
reg[0] = settings->m_frac;
reg[1] = settings->m_frac >> 8;
reg[2] = settings->m_frac >> 16;
reg[3] = settings->m_frac >> 24 | settings->m_int << 5;
reg[4] = settings->m_int >> 3;
reg[5] = settings->hs_div;
reg[6] = (settings->hs_div >> 8) | (settings->ls_div_bits << 4);
err = regmap_bulk_write(data->regmap, SI514_REG_HS_DIV, reg + 5, 2);
if (err < 0)
return err;
/*
* Writing to SI514_REG_M_INT_FRAC triggers the clock change, so that
* must be written last
*/
return regmap_bulk_write(data->regmap, SI514_REG_M_FRAC1, reg, 5);
}
/* Calculate divider settings for a given frequency */
static int si514_calc_muldiv(struct clk_si514_muldiv *settings,
unsigned long frequency)
{
u64 m;
u32 ls_freq;
u32 tmp;
u8 res;
if ((frequency < SI514_MIN_FREQ) || (frequency > SI514_MAX_FREQ))
return -EINVAL;
/* Determine the minimum value of LS_DIV and resulting target freq. */
ls_freq = frequency;
if (frequency >= (FVCO_MIN / HS_DIV_MAX))
settings->ls_div_bits = 0;
else {
res = 1;
tmp = 2 * HS_DIV_MAX;
while (tmp <= (HS_DIV_MAX * 32)) {
if ((frequency * tmp) >= FVCO_MIN)
break;
++res;
tmp <<= 1;
}
settings->ls_div_bits = res;
ls_freq = frequency << res;
}
/* Determine minimum HS_DIV, round up to even number */
settings->hs_div = DIV_ROUND_UP(FVCO_MIN >> 1, ls_freq) << 1;
/* M = LS_DIV x HS_DIV x frequency / F_XO (in fixed-point) */
m = ((u64)(ls_freq * settings->hs_div) << 29) + (FXO / 2);
do_div(m, FXO);
settings->m_frac = (u32)m & (BIT(29) - 1);
settings->m_int = (u32)(m >> 29);
return 0;
}
/* Calculate resulting frequency given the register settings */
static unsigned long si514_calc_rate(struct clk_si514_muldiv *settings)
{
u64 m = settings->m_frac | ((u64)settings->m_int << 29);
u32 d = settings->hs_div * BIT(settings->ls_div_bits);
return ((u32)(((m * FXO) + (FXO / 2)) >> 29)) / d;
}
static unsigned long si514_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct clk_si514 *data = to_clk_si514(hw);
struct clk_si514_muldiv settings;
int err;
err = si514_get_muldiv(data, &settings);
if (err) {
dev_err(&data->i2c_client->dev, "unable to retrieve settings\n");
return 0;
}
return si514_calc_rate(&settings);
}
static long si514_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *parent_rate)
{
struct clk_si514_muldiv settings;
int err;
if (!rate)
return 0;
err = si514_calc_muldiv(&settings, rate);
if (err)
return err;
return si514_calc_rate(&settings);
}
/*
* Update output frequency for big frequency changes (> 1000 ppm).
* The chip supports <1000ppm changes "on the fly", we haven't implemented
* that here.
*/
static int si514_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct clk_si514 *data = to_clk_si514(hw);
struct clk_si514_muldiv settings;
unsigned int old_oe_state;
int err;
err = si514_calc_muldiv(&settings, rate);
if (err)
return err;
err = regmap_read(data->regmap, SI514_REG_CONTROL, &old_oe_state);
if (err)
return err;
si514_enable_output(data, false);
err = si514_set_muldiv(data, &settings);
if (err < 0)
return err; /* Undefined state now, best to leave disabled */
/* Trigger calibration */
err = regmap_write(data->regmap, SI514_REG_CONTROL, SI514_CONTROL_FCAL);
if (err < 0)
return err;
/* Applying a new frequency can take up to 10ms */
usleep_range(10000, 12000);
if (old_oe_state & SI514_CONTROL_OE)
si514_enable_output(data, true);
return err;
}
static const struct clk_ops si514_clk_ops = {
.prepare = si514_prepare,
.unprepare = si514_unprepare,
.is_prepared = si514_is_prepared,
.recalc_rate = si514_recalc_rate,
.round_rate = si514_round_rate,
.set_rate = si514_set_rate,
};
static bool si514_regmap_is_volatile(struct device *dev, unsigned int reg)
{
switch (reg) {
case SI514_REG_CONTROL:
case SI514_REG_RESET:
return true;
default:
return false;
}
}
static bool si514_regmap_is_writeable(struct device *dev, unsigned int reg)
{
switch (reg) {
case SI514_REG_LP:
case SI514_REG_M_FRAC1 ... SI514_REG_LS_HS_DIV:
case SI514_REG_OE_STATE:
case SI514_REG_RESET:
case SI514_REG_CONTROL:
return true;
default:
return false;
}
}
static const struct regmap_config si514_regmap_config = {
.reg_bits = 8,
.val_bits = 8,
.cache_type = REGCACHE_RBTREE,
.max_register = SI514_REG_CONTROL,
.writeable_reg = si514_regmap_is_writeable,
.volatile_reg = si514_regmap_is_volatile,
};
static int si514_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct clk_si514 *data;
struct clk_init_data init;
int err;
data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
init.ops = &si514_clk_ops;
init.flags = 0;
init.num_parents = 0;
data->hw.init = &init;
data->i2c_client = client;
if (of_property_read_string(client->dev.of_node, "clock-output-names",
&init.name))
init.name = client->dev.of_node->name;
data->regmap = devm_regmap_init_i2c(client, &si514_regmap_config);
if (IS_ERR(data->regmap)) {
dev_err(&client->dev, "failed to allocate register map\n");
return PTR_ERR(data->regmap);
}
i2c_set_clientdata(client, data);
err = devm_clk_hw_register(&client->dev, &data->hw);
if (err) {
dev_err(&client->dev, "clock registration failed\n");
return err;
}
err = of_clk_add_hw_provider(client->dev.of_node, of_clk_hw_simple_get,
&data->hw);
if (err) {
dev_err(&client->dev, "unable to add clk provider\n");
return err;
}
return 0;
}
static int si514_remove(struct i2c_client *client)
{
of_clk_del_provider(client->dev.of_node);
return 0;
}
static const struct i2c_device_id si514_id[] = {
{ "si514", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, si514_id);
static const struct of_device_id clk_si514_of_match[] = {
{ .compatible = "silabs,si514" },
{ },
};
MODULE_DEVICE_TABLE(of, clk_si514_of_match);
static struct i2c_driver si514_driver = {
.driver = {
.name = "si514",
.of_match_table = clk_si514_of_match,
},
.probe = si514_probe,
.remove = si514_remove,
.id_table = si514_id,
};
module_i2c_driver(si514_driver);
MODULE_AUTHOR("Mike Looijmans <mike.looijmans@topic.nl>");
MODULE_DESCRIPTION("Si514 driver");
MODULE_LICENSE("GPL");