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Message-ID: <52AC8857.8070504@roeck-us.net>
Date: Sat, 14 Dec 2013 08:33:27 -0800
From: Guenter Roeck <linux@...ck-us.net>
To: Mike Turquette <mturquette@...aro.org>,
Sören Brinkmann
<soren.brinkmann@...inx.com>,
Rob Herring <rob.herring@...xeda.com>,
Pawel Moll <pawel.moll@....com>,
Mark Rutland <mark.rutland@....com>,
Stephen Warren <swarren@...dotorg.org>
CC: devicetree@...r.kernel.org, linux-doc@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
Hyun Kwon <hyunk@...inx.com>
Subject: Re: [PATCH v5] clk: si570: Add a driver for SI570 oscillators
On 10/02/2013 04:17 PM, Mike Turquette wrote:
> Quoting Sören Brinkmann (2013-10-02 10:20:38)
>> Hi Mike,
>>
>> could you please comment on this/apply it to clk-next?
>
> It looks good and is in the queue. Will show up in clk-next in a few
> days.
>
Hi Mike,
trying again ... what happened with this driver ? Any reason for not pushing it after all ?
Thanks,
Guenter
> Thanks,
> Mike
>
>>
>> Thanks,
>> Sören
>>
>> On Sat, Sep 21, 2013 at 04:40:39PM -0700, Soren Brinkmann wrote:
>>> Add a driver for SILabs 570, 571, 598, 599 programmable oscillators.
>>> The devices generate low-jitter clock signals and are reprogrammable via
>>> an I2C interface.
>>>
>>> Cc: Guenter Roeck <linux@...ck-us.net>
>>> Signed-off-by: Soren Brinkmann <soren.brinkmann@...inx.com>
>>> ---
>>> v5:
>>> - fix typo in bindings documentation
>>> - mention the unit for the 'temperature-stability' property
>>> - remove calls to clk_unregister() (the device managed code takes care
>>> of it)
>>>
>>> v4:
>>> - actually check and handle error on clk_set_rate() call
>>>
>>> v3:
>>> - add delay in the path for small frequency changes, which can take up
>>> to 100us according to the data sheet
>>> - use real range for usleep_range() argument
>>> - use dev_err() over dev_warn() in set_rate()
>>> - add list of applicable devices for 7ppm DT prop
>>> - remove comments regarding platform data
>>> - ignore 7ppm DT prop for incompatible devices
>>> - replace raw numbers with #defines
>>> - convert DT prop 'temperature-stability' from boolean to u32
>>> - make 'temperature-stability' DT prop required (actually not fully
>>> true, for 59x it is ignored and the driver does not require its
>>> presence)
>>>
>>> v2:
>>> - document clock-output-names in bindings documentation
>>> - don't use wildcards in compatibility string
>>> - change Kconfig entry to "... 570 and compatible devices"
>>> - change some indentation flaws
>>> - use 10000 as MIN and MAX value in usleep_range
>>> - fail probe() if 'factory-fout' is not provided in DT
>>> - default factory fout #defines removed
>>> - use i2c driver_data instead of OF data
>>> - remove some related structs and data
>>> - rename DT property 'initial-fout' => 'clock-frequency' (like si5351
>>> driver)
>>> - add some more details regarding the 'factory-fout' DT property
>>> ---
>>> .../devicetree/bindings/clock/silabs,si570.txt | 39 ++
>>> drivers/clk/Kconfig | 10 +
>>> drivers/clk/Makefile | 1 +
>>> drivers/clk/clk-si570.c | 531 +++++++++++++++++++++
>>> 4 files changed, 581 insertions(+)
>>> create mode 100644 Documentation/devicetree/bindings/clock/silabs,si570.txt
>>> create mode 100644 drivers/clk/clk-si570.c
>>>
>>> diff --git a/Documentation/devicetree/bindings/clock/silabs,si570.txt b/Documentation/devicetree/bindings/clock/silabs,si570.txt
>>> new file mode 100644
>>> index 0000000..c09f21e
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/clock/silabs,si570.txt
>>> @@ -0,0 +1,39 @@
>>> +Binding for Silicon Labs 570, 571, 598 and 599 programmable
>>> +I2C clock generators.
>>> +
>>> +Reference
>>> +This binding uses the common clock binding[1]. Details about the devices can be
>>> +found in the data sheets[2][3].
>>> +
>>> +[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
>>> +[2] Si570/571 Data Sheet
>>> + http://www.silabs.com/Support%20Documents/TechnicalDocs/si570.pdf
>>> +[3] Si598/599 Data Sheet
>>> + http://www.silabs.com/Support%20Documents/TechnicalDocs/si598-99.pdf
>>> +
>>> +Required properties:
>>> + - compatible: Shall be one of "silabs,si570", "silabs,si571",
>>> + "silabs,si598", "silabs,si599"
>>> + - reg: I2C device address.
>>> + - #clock-cells: From common clock bindings: Shall be 0.
>>> + - factory-fout: Factory set default frequency. This frequency is part specific.
>>> + The correct frequency for the part used has to be provided in
>>> + order to generate the correct output frequencies. For more
>>> + details, please refer to the data sheet.
>>> + - temperature-stability: Temperature stability of the device in PPM. Should be
>>> + one of: 7, 20, 50 or 100.
>>> +
>>> +Optional properties:
>>> + - clock-output-names: From common clock bindings. Recommended to be "si570".
>>> + - clock-frequency: Output frequency to generate. This defines the output
>>> + frequency set during boot. It can be reprogrammed during
>>> + runtime through the common clock framework.
>>> +
>>> +Example:
>>> + si570: clock-generator@5d {
>>> + #clock-cells = <0>;
>>> + compatible = "silabs,si570";
>>> + temperature-stability = <50>;
>>> + reg = <0x5d>;
>>> + factory-fout = <156250000>;
>>> + };
>>> diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
>>> index 279407a..349b88a 100644
>>> --- a/drivers/clk/Kconfig
>>> +++ b/drivers/clk/Kconfig
>>> @@ -64,6 +64,16 @@ config COMMON_CLK_SI5351
>>> This driver supports Silicon Labs 5351A/B/C programmable clock
>>> generators.
>>>
>>> +config COMMON_CLK_SI570
>>> + tristate "Clock driver for SiLabs 570 and compatible devices"
>>> + depends on I2C
>>> + depends on OF
>>> + select REGMAP_I2C
>>> + help
>>> + ---help---
>>> + This driver supports Silicon Labs 570/571/598/599 programmable
>>> + clock generators.
>>> +
>>> config COMMON_CLK_S2MPS11
>>> tristate "Clock driver for S2MPS11 MFD"
>>> depends on MFD_SEC_CORE
>>> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
>>> index 7b11106..c0e94b3 100644
>>> --- a/drivers/clk/Makefile
>>> +++ b/drivers/clk/Makefile
>>> @@ -40,6 +40,7 @@ obj-$(CONFIG_COMMON_CLK_AXI_CLKGEN) += clk-axi-clkgen.o
>>> obj-$(CONFIG_COMMON_CLK_WM831X) += clk-wm831x.o
>>> obj-$(CONFIG_COMMON_CLK_MAX77686) += clk-max77686.o
>>> obj-$(CONFIG_COMMON_CLK_SI5351) += clk-si5351.o
>>> +obj-$(CONFIG_COMMON_CLK_SI570) += clk-si570.o
>>> obj-$(CONFIG_COMMON_CLK_S2MPS11) += clk-s2mps11.o
>>> obj-$(CONFIG_CLK_TWL6040) += clk-twl6040.o
>>> obj-$(CONFIG_CLK_PPC_CORENET) += clk-ppc-corenet.o
>>> diff --git a/drivers/clk/clk-si570.c b/drivers/clk/clk-si570.c
>>> new file mode 100644
>>> index 0000000..5d0ac9f
>>> --- /dev/null
>>> +++ b/drivers/clk/clk-si570.c
>>> @@ -0,0 +1,531 @@
>>> +/*
>>> + * Driver for Silicon Labs Si570/Si571 Programmable XO/VCXO
>>> + *
>>> + * Copyright (C) 2010, 2011 Ericsson AB.
>>> + * Copyright (C) 2011 Guenter Roeck.
>>> + * Copyright (C) 2011 - 2013 Xilinx Inc.
>>> + *
>>> + * Author: Guenter Roeck <guenter.roeck@...csson.com>
>>> + * Sören Brinkmann <soren.brinkmann@...inx.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/clk-provider.h>
>>> +#include <linux/delay.h>
>>> +#include <linux/module.h>
>>> +#include <linux/i2c.h>
>>> +#include <linux/regmap.h>
>>> +#include <linux/slab.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 SI570_DIV_OFFSET_7PPM 6
>>> +
>>> +#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_MIN_FREQ 10000000L
>>> +#define SI570_MAX_FREQ 1417500000L
>>> +#define SI598_MAX_FREQ 525000000L
>>> +
>>> +#define FDCO_MIN 4850000000LL
>>> +#define FDCO_MAX 5670000000LL
>>> +
>>> +#define SI570_CNTRL_RECALL (1 << 0)
>>> +#define SI570_CNTRL_FREEZE_M (1 << 5)
>>> +#define SI570_CNTRL_NEWFREQ (1 << 6)
>>> +
>>> +#define SI570_FREEZE_DCO (1 << 4)
>>> +
>>> +/**
>>> + * struct clk_si570:
>>> + * @hw: Clock hw struct
>>> + * @regmap: Device's regmap
>>> + * @div_offset: Rgister offset for dividers
>>> + * @max_freq: Maximum frequency for this device
>>> + * @fxtal: Factory xtal frequency
>>> + * @n1: Clock divider N1
>>> + * @hs_div: Clock divider HSDIV
>>> + * @rfreq: Clock multiplier RFREQ
>>> + * @frequency: Current output frequency
>>> + * @i2c_client: I2C client pointer
>>> + */
>>> +struct clk_si570 {
>>> + struct clk_hw hw;
>>> + struct regmap *regmap;
>>> + unsigned int div_offset;
>>> + u64 max_freq;
>>> + u64 fxtal;
>>> + unsigned int n1;
>>> + unsigned int hs_div;
>>> + u64 rfreq;
>>> + u64 frequency;
>>> + struct i2c_client *i2c_client;
>>> +};
>>> +#define to_clk_si570(_hw) container_of(_hw, struct clk_si570, hw)
>>> +
>>> +enum clk_si570_variant {
>>> + si57x,
>>> + si59x
>>> +};
>>> +
>>> +/**
>>> + * si570_get_divs() - Read clock dividers from HW
>>> + * @data: Pointer to struct clk_si570
>>> + * @rfreq: Fractional multiplier (output)
>>> + * @n1: Divider N1 (output)
>>> + * @hs_div: Divider HSDIV (output)
>>> + * Returns 0 on success, negative errno otherwise.
>>> + *
>>> + * Retrieve clock dividers and multipliers from the HW.
>>> + */
>>> +static int si570_get_divs(struct clk_si570 *data, u64 *rfreq,
>>> + unsigned int *n1, unsigned int *hs_div)
>>> +{
>>> + int err;
>>> + u8 reg[6];
>>> + u64 tmp;
>>> +
>>> + err = regmap_bulk_read(data->regmap, SI570_REG_HS_N1 + data->div_offset,
>>> + reg, ARRAY_SIZE(reg));
>>> + if (err)
>>> + return err;
>>> +
>>> + *hs_div = ((reg[0] & HS_DIV_MASK) >> HS_DIV_SHIFT) + HS_DIV_OFFSET;
>>> + *n1 = ((reg[0] & N1_6_2_MASK) << 2) + ((reg[1] & N1_1_0_MASK) >> 6) + 1;
>>> + /* Handle invalid cases */
>>> + if (*n1 > 1)
>>> + *n1 &= ~1;
>>> +
>>> + tmp = reg[1] & RFREQ_37_32_MASK;
>>> + tmp = (tmp << 8) + reg[2];
>>> + tmp = (tmp << 8) + reg[3];
>>> + tmp = (tmp << 8) + reg[4];
>>> + tmp = (tmp << 8) + reg[5];
>>> + *rfreq = tmp;
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +/**
>>> + * si570_get_defaults() - Get default values
>>> + * @data: Driver data structure
>>> + * @fout: Factory frequency output
>>> + * Returns 0 on success, negative errno otherwise.
>>> + */
>>> +static int si570_get_defaults(struct clk_si570 *data, u64 fout)
>>> +{
>>> + int err;
>>> + u64 fdco;
>>> +
>>> + regmap_write(data->regmap, SI570_REG_CONTROL, SI570_CNTRL_RECALL);
>>> +
>>> + err = si570_get_divs(data, &data->rfreq, &data->n1, &data->hs_div);
>>> + if (err)
>>> + return err;
>>> +
>>> + /*
>>> + * Accept optional precision loss to avoid arithmetic overflows.
>>> + * Acceptable per Silicon Labs Application Note AN334.
>>> + */
>>> + fdco = 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 = fout;
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +/**
>>> + * si570_update_rfreq() - Update clock multiplier
>>> + * @data: Driver data structure
>>> + * Passes on regmap_bulk_write() return value.
>>> + */
>>> +static int si570_update_rfreq(struct clk_si570 *data)
>>> +{
>>> + u8 reg[5];
>>> +
>>> + reg[0] = ((data->n1 - 1) << 6) |
>>> + ((data->rfreq >> 32) & RFREQ_37_32_MASK);
>>> + reg[1] = (data->rfreq >> 24) & 0xff;
>>> + reg[2] = (data->rfreq >> 16) & 0xff;
>>> + reg[3] = (data->rfreq >> 8) & 0xff;
>>> + reg[4] = data->rfreq & 0xff;
>>> +
>>> + return regmap_bulk_write(data->regmap, SI570_REG_N1_RFREQ0 +
>>> + data->div_offset, reg, ARRAY_SIZE(reg));
>>> +}
>>> +
>>> +/**
>>> + * si570_calc_divs() - Caluclate clock dividers
>>> + * @frequency: Target frequency
>>> + * @data: Driver data structure
>>> + * @out_rfreq: RFREG fractional multiplier (output)
>>> + * @out_n1: Clock divider N1 (output)
>>> + * @out_hs_div: Clock divider HSDIV (output)
>>> + * Returns 0 on success, negative errno otherwise.
>>> + *
>>> + * Calculate the clock dividers (@out_hs_div, @out_n1) and clock multiplier
>>> + * (@out_rfreq) for a given target @frequency.
>>> + */
>>> +static int si570_calc_divs(unsigned long frequency, struct clk_si570 *data,
>>> + u64 *out_rfreq, unsigned int *out_n1, unsigned int *out_hs_div)
>>> +{
>>> + int i;
>>> + unsigned int n1, hs_div;
>>> + u64 fdco, best_fdco = ULLONG_MAX;
>>> + static const uint8_t si570_hs_div_values[] = { 11, 9, 7, 6, 5, 4 };
>>> +
>>> + 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 = div_u64(div_u64(FDCO_MIN, hs_div), 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) {
>>> + *out_n1 = n1;
>>> + *out_hs_div = hs_div;
>>> + *out_rfreq = div64_u64(fdco << 28, data->fxtal);
>>> + best_fdco = fdco;
>>> + }
>>> + n1 += (n1 == 1 ? 1 : 2);
>>> + }
>>> + }
>>> +
>>> + if (best_fdco == ULLONG_MAX)
>>> + return -EINVAL;
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static unsigned long si570_recalc_rate(struct clk_hw *hw,
>>> + unsigned long parent_rate)
>>> +{
>>> + int err;
>>> + u64 rfreq, rate;
>>> + unsigned int n1, hs_div;
>>> + struct clk_si570 *data = to_clk_si570(hw);
>>> +
>>> + err = si570_get_divs(data, &rfreq, &n1, &hs_div);
>>> + if (err) {
>>> + dev_err(&data->i2c_client->dev, "unable to recalc rate\n");
>>> + return data->frequency;
>>> + }
>>> +
>>> + rfreq = div_u64(rfreq, hs_div * n1);
>>> + rate = (data->fxtal * rfreq) >> 28;
>>> +
>>> + return rate;
>>> +}
>>> +
>>> +static long si570_round_rate(struct clk_hw *hw, unsigned long rate,
>>> + unsigned long *parent_rate)
>>> +{
>>> + int err;
>>> + u64 rfreq;
>>> + unsigned int n1, hs_div;
>>> + struct clk_si570 *data = to_clk_si570(hw);
>>> +
>>> + if (!rate)
>>> + return 0;
>>> +
>>> + if (div64_u64(abs(rate - data->frequency) * 10000LL,
>>> + data->frequency) < 35) {
>>> + rfreq = div64_u64((data->rfreq * rate) +
>>> + div64_u64(data->frequency, 2), data->frequency);
>>> + n1 = data->n1;
>>> + hs_div = data->hs_div;
>>> +
>>> + } else {
>>> + err = si570_calc_divs(rate, data, &rfreq, &n1, &hs_div);
>>> + if (err) {
>>> + dev_err(&data->i2c_client->dev,
>>> + "unable to round rate\n");
>>> + return 0;
>>> + }
>>> + }
>>> +
>>> + return rate;
>>> +}
>>> +
>>> +/**
>>> + * si570_set_frequency() - Adjust output frequency
>>> + * @data: Driver data structure
>>> + * @frequency: Target frequency
>>> + * Returns 0 on success.
>>> + *
>>> + * Update output frequency for big frequency changes (> 3,500 ppm).
>>> + */
>>> +static int si570_set_frequency(struct clk_si570 *data, unsigned long frequency)
>>> +{
>>> + int err;
>>> +
>>> + err = si570_calc_divs(frequency, data, &data->rfreq, &data->n1,
>>> + &data->hs_div);
>>> + if (err)
>>> + return err;
>>> +
>>> + /*
>>> + * The DCO reg should be accessed with a read-modify-write operation
>>> + * per AN334
>>> + */
>>> + regmap_write(data->regmap, SI570_REG_FREEZE_DCO, SI570_FREEZE_DCO);
>>> + regmap_write(data->regmap, SI570_REG_HS_N1 + data->div_offset,
>>> + ((data->hs_div - HS_DIV_OFFSET) << HS_DIV_SHIFT) |
>>> + (((data->n1 - 1) >> 2) & N1_6_2_MASK));
>>> + si570_update_rfreq(data);
>>> + regmap_write(data->regmap, SI570_REG_FREEZE_DCO, 0);
>>> + regmap_write(data->regmap, SI570_REG_CONTROL, SI570_CNTRL_NEWFREQ);
>>> +
>>> + /* Applying a new frequency can take up to 10ms */
>>> + usleep_range(10000, 12000);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +/**
>>> + * si570_set_frequency_small() - Adjust output frequency
>>> + * @data: Driver data structure
>>> + * @frequency: Target frequency
>>> + * Returns 0 on success.
>>> + *
>>> + * Update output frequency for small frequency changes (< 3,500 ppm).
>>> + */
>>> +static int si570_set_frequency_small(struct clk_si570 *data,
>>> + unsigned long 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) +
>>> + div_u64(data->frequency, 2), data->frequency);
>>> + regmap_write(data->regmap, SI570_REG_CONTROL, SI570_CNTRL_FREEZE_M);
>>> + si570_update_rfreq(data);
>>> + regmap_write(data->regmap, SI570_REG_CONTROL, 0);
>>> +
>>> + /* Applying a new frequency (small change) can take up to 100us */
>>> + usleep_range(100, 200);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int si570_set_rate(struct clk_hw *hw, unsigned long rate,
>>> + unsigned long parent_rate)
>>> +{
>>> + struct clk_si570 *data = to_clk_si570(hw);
>>> + struct i2c_client *client = data->i2c_client;
>>> + int err;
>>> +
>>> + if (rate < SI570_MIN_FREQ || rate > data->max_freq) {
>>> + dev_err(&client->dev,
>>> + "requested frequency %lu Hz is out of range\n", rate);
>>> + return -EINVAL;
>>> + }
>>> +
>>> + if (div64_u64(abs(rate - data->frequency) * 10000LL,
>>> + data->frequency) < 35)
>>> + err = si570_set_frequency_small(data, rate);
>>> + else
>>> + err = si570_set_frequency(data, rate);
>>> +
>>> + if (err)
>>> + return err;
>>> +
>>> + data->frequency = rate;
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static const struct clk_ops si570_clk_ops = {
>>> + .recalc_rate = si570_recalc_rate,
>>> + .round_rate = si570_round_rate,
>>> + .set_rate = si570_set_rate,
>>> +};
>>> +
>>> +static bool si570_regmap_is_volatile(struct device *dev, unsigned int reg)
>>> +{
>>> + switch (reg) {
>>> + case SI570_REG_CONTROL:
>>> + return true;
>>> + default:
>>> + return false;
>>> + }
>>> +}
>>> +
>>> +static bool si570_regmap_is_writeable(struct device *dev, unsigned int reg)
>>> +{
>>> + switch (reg) {
>>> + case SI570_REG_HS_N1 ... (SI570_REG_RFREQ4 + SI570_DIV_OFFSET_7PPM):
>>> + case SI570_REG_CONTROL:
>>> + case SI570_REG_FREEZE_DCO:
>>> + return true;
>>> + default:
>>> + return false;
>>> + }
>>> +}
>>> +
>>> +static struct regmap_config si570_regmap_config = {
>>> + .reg_bits = 8,
>>> + .val_bits = 8,
>>> + .cache_type = REGCACHE_RBTREE,
>>> + .max_register = 137,
>>> + .writeable_reg = si570_regmap_is_writeable,
>>> + .volatile_reg = si570_regmap_is_volatile,
>>> +};
>>> +
>>> +static int si570_probe(struct i2c_client *client,
>>> + const struct i2c_device_id *id)
>>> +{
>>> + struct clk_si570 *data;
>>> + struct clk_init_data init;
>>> + struct clk *clk;
>>> + u32 initial_fout, factory_fout, stability;
>>> + int err;
>>> + enum clk_si570_variant variant = id->driver_data;
>>> +
>>> + data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
>>> + if (!data)
>>> + return -ENOMEM;
>>> +
>>> + init.ops = &si570_clk_ops;
>>> + init.flags = CLK_IS_ROOT;
>>> + init.num_parents = 0;
>>> + data->hw.init = &init;
>>> + data->i2c_client = client;
>>> +
>>> + if (variant == si57x) {
>>> + err = of_property_read_u32(client->dev.of_node,
>>> + "temperature-stability", &stability);
>>> + if (err) {
>>> + dev_err(&client->dev,
>>> + "'temperature-stability' property missing\n");
>>> + return err;
>>> + }
>>> + /* adjust register offsets for 7ppm devices */
>>> + if (stability == 7)
>>> + data->div_offset = SI570_DIV_OFFSET_7PPM;
>>> +
>>> + data->max_freq = SI570_MAX_FREQ;
>>> + } else {
>>> + data->max_freq = SI598_MAX_FREQ;
>>> + }
>>> +
>>> + if (of_property_read_string(client->dev.of_node, "clock-output-names",
>>> + &init.name))
>>> + init.name = client->dev.of_node->name;
>>> +
>>> + err = of_property_read_u32(client->dev.of_node, "factory-fout",
>>> + &factory_fout);
>>> + if (err) {
>>> + dev_err(&client->dev, "'factory-fout' property missing\n");
>>> + return err;
>>> + }
>>> +
>>> + data->regmap = devm_regmap_init_i2c(client, &si570_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 = si570_get_defaults(data, factory_fout);
>>> + if (err)
>>> + return err;
>>> +
>>> + clk = devm_clk_register(&client->dev, &data->hw);
>>> + if (IS_ERR(clk)) {
>>> + dev_err(&client->dev, "clock registration failed\n");
>>> + return PTR_ERR(clk);
>>> + }
>>> + err = of_clk_add_provider(client->dev.of_node, of_clk_src_simple_get,
>>> + clk);
>>> + if (err) {
>>> + dev_err(&client->dev, "unable to add clk provider\n");
>>> + return err;
>>> + }
>>> +
>>> + /* Read the requested initial output frequency from device tree */
>>> + if (!of_property_read_u32(client->dev.of_node, "clock-frequency",
>>> + &initial_fout)) {
>>> + err = clk_set_rate(clk, initial_fout);
>>> + if (err) {
>>> + of_clk_del_provider(client->dev.of_node);
>>> + return err;
>>> + }
>>> + }
>>> +
>>> + /* Display a message indicating that we've successfully registered */
>>> + dev_info(&client->dev, "registered, current frequency %llu Hz\n",
>>> + data->frequency);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int si570_remove(struct i2c_client *client)
>>> +{
>>> + of_clk_del_provider(client->dev.of_node);
>>> + return 0;
>>> +}
>>> +
>>> +static const struct i2c_device_id si570_id[] = {
>>> + { "si570", si57x },
>>> + { "si571", si57x },
>>> + { "si598", si59x },
>>> + { "si599", si59x },
>>> + { }
>>> +};
>>> +MODULE_DEVICE_TABLE(i2c, si570_id);
>>> +
>>> +static const struct of_device_id clk_si570_of_match[] = {
>>> + { .compatible = "silabs,si570" },
>>> + { .compatible = "silabs,si571" },
>>> + { .compatible = "silabs,si598" },
>>> + { .compatible = "silabs,si599" },
>>> + { },
>>> +};
>>> +MODULE_DEVICE_TABLE(of, clk_si570_of_match);
>>> +
>>> +static struct i2c_driver si570_driver = {
>>> + .driver = {
>>> + .name = "si570",
>>> + .of_match_table = of_match_ptr(clk_si570_of_match),
>>> + },
>>> + .probe = si570_probe,
>>> + .remove = si570_remove,
>>> + .id_table = si570_id,
>>> +};
>>> +module_i2c_driver(si570_driver);
>>> +
>>> +MODULE_AUTHOR("Guenter Roeck <guenter.roeck@...csson.com>");
>>> +MODULE_AUTHOR("Soeren Brinkmann <soren.brinkmann@...inx.com");
>>> +MODULE_DESCRIPTION("Si570 driver");
>>> +MODULE_LICENSE("GPL");
>>> --
>>> 1.8.4
>>>
>>>
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