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misc: qpnp-misc: add support for clients to read register from misc device

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On certain PMICs, PMIC peripheral drivers like haptics need to
read MISC peripheral register. Add support for clients to read
it by using qpnp_misc_read_reg().

Change-Id: Id5dfd9e440a8861b56572dab50839d1583535882
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>
This commit is contained in:
Subbaraman Narayanamurthy 2017-03-07 19:26:14 -08:00
parent b8b4bc2271
commit 0ed3b2e19d
2 changed files with 61 additions and 2 deletions
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41
drivers/misc/qpnp-misc.c
View file

@ -130,6 +130,47 @@ static bool __misc_irqs_available(struct qpnp_misc_dev *dev)
return 1;
}
int qpnp_misc_read_reg(struct device_node *node, u16 addr, u8 *val)
{
struct qpnp_misc_dev *mdev = NULL;
struct qpnp_misc_dev *mdev_found = NULL;
int rc;
u8 temp;
if (IS_ERR_OR_NULL(node)) {
pr_err("Invalid device node pointer\n");
return -EINVAL;
}
mutex_lock(&qpnp_misc_dev_list_mutex);
list_for_each_entry(mdev, &qpnp_misc_dev_list, list) {
if (mdev->dev->of_node == node) {
mdev_found = mdev;
break;
}
}
mutex_unlock(&qpnp_misc_dev_list_mutex);
if (!mdev_found) {
/*
* No MISC device was found. This API should only
* be called by drivers which have specified the
* misc phandle in their device tree node.
*/
pr_err("no probed misc device found\n");
return -EPROBE_DEFER;
}
rc = qpnp_read_byte(mdev, addr, &temp);
if (rc < 0) {
dev_err(mdev->dev, "Failed to read addr %x, rc=%d\n", addr, rc);
return rc;
}
*val = temp;
return 0;
}
int qpnp_misc_irqs_available(struct device *consumer_dev)
{
struct device_node *misc_node = NULL;

22
include/linux/qpnp-misc.h
View file

@ -1,4 +1,4 @@
/* Copyright (c) 2013-2014, The Linux Foundation. All rights reserved.
/* Copyright (c) 2013-2014, 2017, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
@ -29,8 +29,26 @@
*/
int qpnp_misc_irqs_available(struct device *consumer_dev);
/**
* qpnp_misc_read_reg - read register from misc device
*
* @node: device node pointer
* @address: address offset in misc peripheral to be read
* @val: data read from register
*
* This function returns zero if reading the MISC register succeeds.
*
*/
int qpnp_misc_read_reg(struct device_node *node, u16 addr, u8 *val);
#else
static int qpnp_misc_irqs_available(struct device *consumer_dev)
static inline int qpnp_misc_irqs_available(struct device *consumer_dev)
{
return 0;
}
static inline int qpnp_misc_read_reg(struct device_node *node, u16 addr,
u8 *val)
{
return 0;
}