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bus.c
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bus.c
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// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
// Copyright(c) 2015-17 Intel Corporation.
#include <linux/acpi.h>
#include <linux/delay.h>
#include <linux/mod_devicetable.h>
#include <linux/pm_runtime.h>
#include <linux/soundwire/sdw_registers.h>
#include <linux/soundwire/sdw.h>
#include "bus.h"
/**
* sdw_add_bus_master() - add a bus Master instance
* @bus: bus instance
*
* Initializes the bus instance, read properties and create child
* devices.
*/
int sdw_add_bus_master(struct sdw_bus *bus)
{
struct sdw_master_prop *prop = NULL;
int ret;
if (!bus->dev) {
pr_err("SoundWire bus has no device\n");
return -ENODEV;
}
if (!bus->ops) {
dev_err(bus->dev, "SoundWire Bus ops are not set\n");
return -EINVAL;
}
if (!bus->compute_params) {
dev_err(bus->dev,
"Bandwidth allocation not configured, compute_parems no set\n");
return -EINVAL;
}
mutex_init(&bus->msg_lock);
mutex_init(&bus->bus_lock);
INIT_LIST_HEAD(&bus->slaves);
INIT_LIST_HEAD(&bus->m_rt_list);
/*
* Initialize multi_link flag
* TODO: populate this flag by reading property from FW node
*/
bus->multi_link = false;
if (bus->ops->read_prop) {
ret = bus->ops->read_prop(bus);
if (ret < 0) {
dev_err(bus->dev,
"Bus read properties failed:%d\n", ret);
return ret;
}
}
sdw_bus_debugfs_init(bus);
/*
* Device numbers in SoundWire are 0 through 15. Enumeration device
* number (0), Broadcast device number (15), Group numbers (12 and
* 13) and Master device number (14) are not used for assignment so
* mask these and other higher bits.
*/
/* Set higher order bits */
*bus->assigned = ~GENMASK(SDW_BROADCAST_DEV_NUM, SDW_ENUM_DEV_NUM);
/* Set enumuration device number and broadcast device number */
set_bit(SDW_ENUM_DEV_NUM, bus->assigned);
set_bit(SDW_BROADCAST_DEV_NUM, bus->assigned);
/* Set group device numbers and master device number */
set_bit(SDW_GROUP12_DEV_NUM, bus->assigned);
set_bit(SDW_GROUP13_DEV_NUM, bus->assigned);
set_bit(SDW_MASTER_DEV_NUM, bus->assigned);
/*
* SDW is an enumerable bus, but devices can be powered off. So,
* they won't be able to report as present.
*
* Create Slave devices based on Slaves described in
* the respective firmware (ACPI/DT)
*/
if (IS_ENABLED(CONFIG_ACPI) && ACPI_HANDLE(bus->dev))
ret = sdw_acpi_find_slaves(bus);
else if (IS_ENABLED(CONFIG_OF) && bus->dev->of_node)
ret = sdw_of_find_slaves(bus);
else
ret = -ENOTSUPP; /* No ACPI/DT so error out */
if (ret) {
dev_err(bus->dev, "Finding slaves failed:%d\n", ret);
return ret;
}
/*
* Initialize clock values based on Master properties. The max
* frequency is read from max_clk_freq property. Current assumption
* is that the bus will start at highest clock frequency when
* powered on.
*
* Default active bank will be 0 as out of reset the Slaves have
* to start with bank 0 (Table 40 of Spec)
*/
prop = &bus->prop;
bus->params.max_dr_freq = prop->max_clk_freq * SDW_DOUBLE_RATE_FACTOR;
bus->params.curr_dr_freq = bus->params.max_dr_freq;
bus->params.curr_bank = SDW_BANK0;
bus->params.next_bank = SDW_BANK1;
return 0;
}
EXPORT_SYMBOL(sdw_add_bus_master);
static int sdw_delete_slave(struct device *dev, void *data)
{
struct sdw_slave *slave = to_sdw_slave_device(dev);
struct sdw_bus *bus = slave->bus;
pm_runtime_disable(dev);
sdw_slave_debugfs_exit(slave);
mutex_lock(&bus->bus_lock);
if (slave->dev_num) /* clear dev_num if assigned */
clear_bit(slave->dev_num, bus->assigned);
list_del_init(&slave->node);
mutex_unlock(&bus->bus_lock);
device_unregister(dev);
return 0;
}
/**
* sdw_delete_bus_master() - delete the bus master instance
* @bus: bus to be deleted
*
* Remove the instance, delete the child devices.
*/
void sdw_delete_bus_master(struct sdw_bus *bus)
{
device_for_each_child(bus->dev, NULL, sdw_delete_slave);
sdw_bus_debugfs_exit(bus);
}
EXPORT_SYMBOL(sdw_delete_bus_master);
/*
* SDW IO Calls
*/
static inline int find_response_code(enum sdw_command_response resp)
{
switch (resp) {
case SDW_CMD_OK:
return 0;
case SDW_CMD_IGNORED:
return -ENODATA;
case SDW_CMD_TIMEOUT:
return -ETIMEDOUT;
default:
return -EIO;
}
}
static inline int do_transfer(struct sdw_bus *bus, struct sdw_msg *msg)
{
int retry = bus->prop.err_threshold;
enum sdw_command_response resp;
int ret = 0, i;
for (i = 0; i <= retry; i++) {
resp = bus->ops->xfer_msg(bus, msg);
ret = find_response_code(resp);
/* if cmd is ok or ignored return */
if (ret == 0 || ret == -ENODATA)
return ret;
}
return ret;
}
static inline int do_transfer_defer(struct sdw_bus *bus,
struct sdw_msg *msg,
struct sdw_defer *defer)
{
int retry = bus->prop.err_threshold;
enum sdw_command_response resp;
int ret = 0, i;
defer->msg = msg;
defer->length = msg->len;
init_completion(&defer->complete);
for (i = 0; i <= retry; i++) {
resp = bus->ops->xfer_msg_defer(bus, msg, defer);
ret = find_response_code(resp);
/* if cmd is ok or ignored return */
if (ret == 0 || ret == -ENODATA)
return ret;
}
return ret;
}
static int sdw_reset_page(struct sdw_bus *bus, u16 dev_num)
{
int retry = bus->prop.err_threshold;
enum sdw_command_response resp;
int ret = 0, i;
for (i = 0; i <= retry; i++) {
resp = bus->ops->reset_page_addr(bus, dev_num);
ret = find_response_code(resp);
/* if cmd is ok or ignored return */
if (ret == 0 || ret == -ENODATA)
return ret;
}
return ret;
}
/**
* sdw_transfer() - Synchronous transfer message to a SDW Slave device
* @bus: SDW bus
* @msg: SDW message to be xfered
*/
int sdw_transfer(struct sdw_bus *bus, struct sdw_msg *msg)
{
int ret;
mutex_lock(&bus->msg_lock);
ret = do_transfer(bus, msg);
if (ret != 0 && ret != -ENODATA)
dev_err(bus->dev, "trf on Slave %d failed:%d\n",
msg->dev_num, ret);
if (msg->page)
sdw_reset_page(bus, msg->dev_num);
mutex_unlock(&bus->msg_lock);
return ret;
}
/**
* sdw_transfer_defer() - Asynchronously transfer message to a SDW Slave device
* @bus: SDW bus
* @msg: SDW message to be xfered
* @defer: Defer block for signal completion
*
* Caller needs to hold the msg_lock lock while calling this
*/
int sdw_transfer_defer(struct sdw_bus *bus, struct sdw_msg *msg,
struct sdw_defer *defer)
{
int ret;
if (!bus->ops->xfer_msg_defer)
return -ENOTSUPP;
ret = do_transfer_defer(bus, msg, defer);
if (ret != 0 && ret != -ENODATA)
dev_err(bus->dev, "Defer trf on Slave %d failed:%d\n",
msg->dev_num, ret);
if (msg->page)
sdw_reset_page(bus, msg->dev_num);
return ret;
}
int sdw_fill_msg(struct sdw_msg *msg, struct sdw_slave *slave,
u32 addr, size_t count, u16 dev_num, u8 flags, u8 *buf)
{
memset(msg, 0, sizeof(*msg));
msg->addr = addr; /* addr is 16 bit and truncated here */
msg->len = count;
msg->dev_num = dev_num;
msg->flags = flags;
msg->buf = buf;
if (addr < SDW_REG_NO_PAGE) { /* no paging area */
return 0;
} else if (addr >= SDW_REG_MAX) { /* illegal addr */
pr_err("SDW: Invalid address %x passed\n", addr);
return -EINVAL;
}
if (addr < SDW_REG_OPTIONAL_PAGE) { /* 32k but no page */
if (slave && !slave->prop.paging_support)
return 0;
/* no need for else as that will fall-through to paging */
}
/* paging mandatory */
if (dev_num == SDW_ENUM_DEV_NUM || dev_num == SDW_BROADCAST_DEV_NUM) {
pr_err("SDW: Invalid device for paging :%d\n", dev_num);
return -EINVAL;
}
if (!slave) {
pr_err("SDW: No slave for paging addr\n");
return -EINVAL;
} else if (!slave->prop.paging_support) {
dev_err(&slave->dev,
"address %x needs paging but no support\n", addr);
return -EINVAL;
}
msg->addr_page1 = (addr >> SDW_REG_SHIFT(SDW_SCP_ADDRPAGE1_MASK));
msg->addr_page2 = (addr >> SDW_REG_SHIFT(SDW_SCP_ADDRPAGE2_MASK));
msg->addr |= BIT(15);
msg->page = true;
return 0;
}
/*
* Read/Write IO functions.
* no_pm versions can only be called by the bus, e.g. while enumerating or
* handling suspend-resume sequences.
* all clients need to use the pm versions
*/
static int
sdw_nread_no_pm(struct sdw_slave *slave, u32 addr, size_t count, u8 *val)
{
struct sdw_msg msg;
int ret;
ret = sdw_fill_msg(&msg, slave, addr, count,
slave->dev_num, SDW_MSG_FLAG_READ, val);
if (ret < 0)
return ret;
return sdw_transfer(slave->bus, &msg);
}
static int
sdw_nwrite_no_pm(struct sdw_slave *slave, u32 addr, size_t count, u8 *val)
{
struct sdw_msg msg;
int ret;
ret = sdw_fill_msg(&msg, slave, addr, count,
slave->dev_num, SDW_MSG_FLAG_WRITE, val);
if (ret < 0)
return ret;
return sdw_transfer(slave->bus, &msg);
}
static int sdw_write_no_pm(struct sdw_slave *slave, u32 addr, u8 value)
{
return sdw_nwrite_no_pm(slave, addr, 1, &value);
}
static int
sdw_bread_no_pm(struct sdw_bus *bus, u16 dev_num, u32 addr)
{
struct sdw_msg msg;
u8 buf;
int ret;
ret = sdw_fill_msg(&msg, NULL, addr, 1, dev_num,
SDW_MSG_FLAG_READ, &buf);
if (ret)
return ret;
ret = sdw_transfer(bus, &msg);
if (ret < 0)
return ret;
else
return buf;
}
static int
sdw_bwrite_no_pm(struct sdw_bus *bus, u16 dev_num, u32 addr, u8 value)
{
struct sdw_msg msg;
int ret;
ret = sdw_fill_msg(&msg, NULL, addr, 1, dev_num,
SDW_MSG_FLAG_WRITE, &value);
if (ret)
return ret;
return sdw_transfer(bus, &msg);
}
static int
sdw_read_no_pm(struct sdw_slave *slave, u32 addr)
{
u8 buf;
int ret;
ret = sdw_nread_no_pm(slave, addr, 1, &buf);
if (ret < 0)
return ret;
else
return buf;
}
/**
* sdw_nread() - Read "n" contiguous SDW Slave registers
* @slave: SDW Slave
* @addr: Register address
* @count: length
* @val: Buffer for values to be read
*/
int sdw_nread(struct sdw_slave *slave, u32 addr, size_t count, u8 *val)
{
int ret;
ret = pm_runtime_get_sync(slave->bus->dev);
if (ret < 0 && ret != -EACCES) {
pm_runtime_put_noidle(slave->bus->dev);
return ret;
}
ret = sdw_nread_no_pm(slave, addr, count, val);
pm_runtime_mark_last_busy(slave->bus->dev);
pm_runtime_put(slave->bus->dev);
return ret;
}
EXPORT_SYMBOL(sdw_nread);
/**
* sdw_nwrite() - Write "n" contiguous SDW Slave registers
* @slave: SDW Slave
* @addr: Register address
* @count: length
* @val: Buffer for values to be read
*/
int sdw_nwrite(struct sdw_slave *slave, u32 addr, size_t count, u8 *val)
{
int ret;
ret = pm_runtime_get_sync(slave->bus->dev);
if (ret < 0 && ret != -EACCES) {
pm_runtime_put_noidle(slave->bus->dev);
return ret;
}
ret = sdw_nwrite_no_pm(slave, addr, count, val);
pm_runtime_mark_last_busy(slave->bus->dev);
pm_runtime_put(slave->bus->dev);
return ret;
}
EXPORT_SYMBOL(sdw_nwrite);
/**
* sdw_read() - Read a SDW Slave register
* @slave: SDW Slave
* @addr: Register address
*/
int sdw_read(struct sdw_slave *slave, u32 addr)
{
u8 buf;
int ret;
ret = sdw_nread(slave, addr, 1, &buf);
if (ret < 0)
return ret;
else
return buf;
}
EXPORT_SYMBOL(sdw_read);
/**
* sdw_write() - Write a SDW Slave register
* @slave: SDW Slave
* @addr: Register address
* @value: Register value
*/
int sdw_write(struct sdw_slave *slave, u32 addr, u8 value)
{
return sdw_nwrite(slave, addr, 1, &value);
}
EXPORT_SYMBOL(sdw_write);
/*
* SDW alert handling
*/
/* called with bus_lock held */
static struct sdw_slave *sdw_get_slave(struct sdw_bus *bus, int i)
{
struct sdw_slave *slave = NULL;
list_for_each_entry(slave, &bus->slaves, node) {
if (slave->dev_num == i)
return slave;
}
return NULL;
}
static int sdw_compare_devid(struct sdw_slave *slave, struct sdw_slave_id id)
{
if (slave->id.mfg_id != id.mfg_id ||
slave->id.part_id != id.part_id ||
slave->id.class_id != id.class_id ||
(slave->id.unique_id != SDW_IGNORED_UNIQUE_ID &&
slave->id.unique_id != id.unique_id))
return -ENODEV;
return 0;
}
/* called with bus_lock held */
static int sdw_get_device_num(struct sdw_slave *slave)
{
int bit;
bit = find_first_zero_bit(slave->bus->assigned, SDW_MAX_DEVICES);
if (bit == SDW_MAX_DEVICES) {
bit = -ENODEV;
goto err;
}
/*
* Do not update dev_num in Slave data structure here,
* Update once program dev_num is successful
*/
set_bit(bit, slave->bus->assigned);
err:
return bit;
}
static int sdw_assign_device_num(struct sdw_slave *slave)
{
int ret, dev_num;
bool new_device = false;
dev_dbg(slave->bus->dev, "in %s\n", __func__);
dev_dbg(slave->bus->dev, "in %s\n", __func__);
/* check first if device number is assigned, if so reuse that */
if (!slave->dev_num) {
if (!slave->dev_num_sticky) {
mutex_lock(&slave->bus->bus_lock);
dev_num = sdw_get_device_num(slave);
mutex_unlock(&slave->bus->bus_lock);
if (dev_num < 0) {
dev_err(slave->bus->dev, "Get dev_num failed: %d\n",
dev_num);
return dev_num;
}
slave->dev_num = dev_num;
slave->dev_num_sticky = dev_num;
new_device = true;
} else {
slave->dev_num = slave->dev_num_sticky;
}
}
if (!new_device)
dev_info(slave->bus->dev,
"Slave already registered, reusing dev_num:%d\n",
slave->dev_num);
/* Clear the slave->dev_num to transfer message on device 0 */
dev_num = slave->dev_num;
slave->dev_num = 0;
dev_dbg(slave->bus->dev, "in %s, writing dev_num %d\n", __func__, dev_num);
ret = sdw_write_no_pm(slave, SDW_SCP_DEVNUMBER, dev_num);
if (ret < 0) {
dev_err(&slave->dev, "Program device_num %d failed: %d\n",
dev_num, ret);
return ret;
}
/* After xfer of msg, restore dev_num */
slave->dev_num = slave->dev_num_sticky;
return 0;
}
void sdw_extract_slave_id(struct sdw_bus *bus,
u64 addr, struct sdw_slave_id *id)
{
dev_dbg(bus->dev, "SDW Slave Addr: %llx\n", addr);
/*
* Spec definition
* Register Bit Contents
* DevId_0 [7:4] 47:44 sdw_version
* DevId_0 [3:0] 43:40 unique_id
* DevId_1 39:32 mfg_id [15:8]
* DevId_2 31:24 mfg_id [7:0]
* DevId_3 23:16 part_id [15:8]
* DevId_4 15:08 part_id [7:0]
* DevId_5 07:00 class_id
*/
id->sdw_version = (addr >> 44) & GENMASK(3, 0);
id->unique_id = (addr >> 40) & GENMASK(3, 0);
id->mfg_id = (addr >> 24) & GENMASK(15, 0);
id->part_id = (addr >> 8) & GENMASK(15, 0);
id->class_id = addr & GENMASK(7, 0);
dev_dbg(bus->dev,
"SDW Slave class_id %x, part_id %x, mfg_id %x, unique_id %x, version %x\n",
id->class_id, id->part_id, id->mfg_id,
id->unique_id, id->sdw_version);
}
static int sdw_program_device_num(struct sdw_bus *bus)
{
u8 buf[SDW_NUM_DEV_ID_REGISTERS] = {0};
struct sdw_slave *slave, *_s;
struct sdw_slave_id id;
struct sdw_msg msg;
bool found = false;
int count = 0, ret;
u64 addr;
/* No Slave, so use raw xfer api */
ret = sdw_fill_msg(&msg, NULL, SDW_SCP_DEVID_0,
SDW_NUM_DEV_ID_REGISTERS, 0, SDW_MSG_FLAG_READ, buf);
if (ret < 0)
return ret;
do {
ret = sdw_transfer(bus, &msg);
if (ret == -ENODATA) { /* end of device id reads */
dev_dbg(bus->dev, "No more devices to enumerate\n");
ret = 0;
break;
}
if (ret < 0) {
dev_err(bus->dev, "DEVID read fail:%d\n", ret);
break;
}
/*
* Construct the addr and extract. Cast the higher shift
* bits to avoid truncation due to size limit.
*/
addr = buf[5] | (buf[4] << 8) | (buf[3] << 16) |
((u64)buf[2] << 24) | ((u64)buf[1] << 32) |
((u64)buf[0] << 40);
sdw_extract_slave_id(bus, addr, &id);
/* Now compare with entries */
list_for_each_entry_safe(slave, _s, &bus->slaves, node) {
if (sdw_compare_devid(slave, id) == 0) {
found = true;
/*
* Assign a new dev_num to this Slave and
* not mark it present. It will be marked
* present after it reports ATTACHED on new
* dev_num
*/
ret = sdw_assign_device_num(slave);
if (ret) {
dev_err(slave->bus->dev,
"Assign dev_num failed:%d\n",
ret);
return ret;
}
break;
}
}
if (!found) {
/* TODO: Park this device in Group 13 */
dev_err(bus->dev, "Slave Entry not found\n");
}
count++;
/*
* Check till error out or retry (count) exhausts.
* Device can drop off and rejoin during enumeration
* so count till twice the bound.
*/
} while (ret == 0 && count < (SDW_MAX_DEVICES * 2));
dev_err(bus->dev, "End of %s ret %d\n", __func__, ret);
return ret;
}
static void sdw_modify_slave_status(struct sdw_slave *slave,
enum sdw_slave_status status)
{
mutex_lock(&slave->bus->bus_lock);
dev_dbg(&slave->dev,
"%s: changing status slave %d status %d new status %d\n",
__func__, slave->dev_num, slave->status, status);
if (status == SDW_SLAVE_UNATTACHED) {
dev_dbg(&slave->dev,
"%s: initializing completion for Slave %d\n",
__func__, slave->dev_num);
init_completion(&slave->enumeration_complete);
init_completion(&slave->initialization_complete);
} else if ((status == SDW_SLAVE_ATTACHED) &&
(slave->status == SDW_SLAVE_UNATTACHED)) {
dev_dbg(&slave->dev,
"%s: signaling completion for Slave %d\n",
__func__, slave->dev_num);
complete(&slave->enumeration_complete);
}
slave->status = status;
mutex_unlock(&slave->bus->bus_lock);
}
static enum sdw_clk_stop_mode sdw_get_clk_stop_mode(struct sdw_slave *slave)
{
enum sdw_clk_stop_mode mode;
/*
* Query for clock stop mode if Slave implements
* ops->get_clk_stop_mode, else read from property.
*/
if (slave->ops && slave->ops->get_clk_stop_mode) {
mode = slave->ops->get_clk_stop_mode(slave);
} else {
if (slave->prop.clk_stop_mode1)
mode = SDW_CLK_STOP_MODE1;
else
mode = SDW_CLK_STOP_MODE0;
}
return mode;
}
static int sdw_slave_clk_stop_callback(struct sdw_slave *slave,
enum sdw_clk_stop_mode mode,
enum sdw_clk_stop_type type)
{
int ret;
if (slave->ops && slave->ops->clk_stop) {
ret = slave->ops->clk_stop(slave, mode, type);
if (ret < 0) {
dev_err(&slave->dev,
"Clk Stop type =%d failed: %d\n", type, ret);
return ret;
}
}
return 0;
}
static int sdw_slave_clk_stop_prepare(struct sdw_slave *slave,
enum sdw_clk_stop_mode mode,
bool prepare)
{
bool wake_en;
u32 val = 0;
int ret;
wake_en = slave->prop.wake_capable;
if (prepare) {
val = SDW_SCP_SYSTEMCTRL_CLK_STP_PREP;
if (mode == SDW_CLK_STOP_MODE1)
val |= SDW_SCP_SYSTEMCTRL_CLK_STP_MODE1;
if (wake_en)
val |= SDW_SCP_SYSTEMCTRL_WAKE_UP_EN;
} else {
val = sdw_read_no_pm(slave, SDW_SCP_SYSTEMCTRL);
val &= ~(SDW_SCP_SYSTEMCTRL_CLK_STP_PREP);
}
ret = sdw_write_no_pm(slave, SDW_SCP_SYSTEMCTRL, val);
if (ret != 0)
dev_err(&slave->dev,
"Clock Stop prepare failed for slave: %d", ret);
return ret;
}
static int sdw_bus_wait_for_clk_prep_deprep(struct sdw_bus *bus, u16 dev_num)
{
int retry = bus->clk_stop_timeout;
int val;
do {
val = sdw_bread_no_pm(bus, dev_num, SDW_SCP_STAT) &
SDW_SCP_STAT_CLK_STP_NF;
if (!val) {
dev_info(bus->dev, "clock stop prep/de-prep done slave:%d",
dev_num);
return 0;
}
usleep_range(1000, 1500);
retry--;
} while (retry);
dev_err(bus->dev, "clock stop prep/de-prep failed slave:%d",
dev_num);
return -ETIMEDOUT;
}
/**
* sdw_bus_prep_clk_stop: prepare Slave(s) for clock stop
*
* @bus: SDW bus instance
*
* Query Slave for clock stop mode and prepare for that mode.
*/
int sdw_bus_prep_clk_stop(struct sdw_bus *bus)
{
enum sdw_clk_stop_mode slave_mode;
bool simple_clk_stop = true;
struct sdw_slave *slave;
bool is_slave = false;
int ret = 0;
/*
* In order to save on transition time, prepare
* each Slave and then wait for all Slave(s) to be
* prepared for clock stop.
*/
list_for_each_entry(slave, &bus->slaves, node) {
if (!slave->dev_num)
continue;
if (slave->status != SDW_SLAVE_ATTACHED &&
slave->status != SDW_SLAVE_ALERT)
continue;
/* Identify if Slave(s) are available on Bus */
is_slave = true;
slave_mode = sdw_get_clk_stop_mode(slave);
slave->curr_clk_stop_mode = slave_mode;
ret = sdw_slave_clk_stop_callback(slave, slave_mode,
SDW_CLK_PRE_PREPARE);
if (ret < 0) {
dev_err(&slave->dev,
"pre-prepare failed:%d", ret);
return ret;
}
ret = sdw_slave_clk_stop_prepare(slave,
slave_mode, true);
if (ret < 0) {
dev_err(&slave->dev,
"pre-prepare failed:%d", ret);
return ret;
}
if (slave_mode == SDW_CLK_STOP_MODE1)
simple_clk_stop = false;
}
if (is_slave && !simple_clk_stop) {
ret = sdw_bus_wait_for_clk_prep_deprep(bus,
SDW_BROADCAST_DEV_NUM);
if (ret < 0)
return ret;
}
/* Don't need to inform slaves if there is no slave attached */
if (!is_slave)
return ret;
/* Inform slaves that prep is done */
list_for_each_entry(slave, &bus->slaves, node) {
if (!slave->dev_num)
continue;
if (slave->status != SDW_SLAVE_ATTACHED &&
slave->status != SDW_SLAVE_ALERT)
continue;
slave_mode = slave->curr_clk_stop_mode;
if (slave_mode == SDW_CLK_STOP_MODE1) {
ret = sdw_slave_clk_stop_callback(slave,
slave_mode,
SDW_CLK_POST_PREPARE);
if (ret < 0) {
dev_err(&slave->dev,
"post-prepare failed:%d", ret);
}
}
}
return ret;
}
EXPORT_SYMBOL(sdw_bus_prep_clk_stop);
/**
* sdw_bus_clk_stop: stop bus clock
*
* @bus: SDW bus instance
*
* After preparing the Slaves for clock stop, stop the clock by broadcasting
* write to SCP_CTRL register.
*/
int sdw_bus_clk_stop(struct sdw_bus *bus)
{
int ret;
/*
* broadcast clock stop now, attached Slaves will ACK this,
* unattached will ignore
*/
ret = sdw_bwrite_no_pm(bus, SDW_BROADCAST_DEV_NUM,
SDW_SCP_CTRL, SDW_SCP_CTRL_CLK_STP_NOW);
if (ret < 0) {
if (ret == -ENODATA)
dev_dbg(bus->dev,
"ClockStopNow Broadcast msg ignored %d", ret);
else
dev_err(bus->dev,
"ClockStopNow Broadcast msg failed %d", ret);
return ret;
}
return 0;
}
EXPORT_SYMBOL(sdw_bus_clk_stop);
/**
* sdw_bus_exit_clk_stop: Exit clock stop mode
*
* @bus: SDW bus instance
*
* This De-prepares the Slaves by exiting Clock Stop Mode 0. For the Slaves
* exiting Clock Stop Mode 1, they will be de-prepared after they enumerate
* back.
*/
int sdw_bus_exit_clk_stop(struct sdw_bus *bus)
{
enum sdw_clk_stop_mode mode;
bool simple_clk_stop = true;
struct sdw_slave *slave;
bool is_slave = false;
int ret;
/*
* In order to save on transition time, de-prepare
* each Slave and then wait for all Slave(s) to be
* de-prepared after clock resume.
*/
list_for_each_entry(slave, &bus->slaves, node) {
if (!slave->dev_num)
continue;
if (slave->status != SDW_SLAVE_ATTACHED &&
slave->status != SDW_SLAVE_ALERT)
continue;
/* Identify if Slave(s) are available on Bus */
is_slave = true;
mode = slave->curr_clk_stop_mode;
if (mode == SDW_CLK_STOP_MODE1) {
simple_clk_stop = false;
continue;
}
ret = sdw_slave_clk_stop_callback(slave, mode,
SDW_CLK_PRE_DEPREPARE);
if (ret < 0)
dev_warn(&slave->dev,
"clk stop deprep failed:%d", ret);