linux/drivers/misc/atmel-ssc.c
Michał Mirosław b037d60a3b misc: atmel-ssc: lock with mutex instead of spinlock
Uninterruptible context is not needed in the driver and causes lockdep
warning because of mutex taken in of_alias_get_id(). Convert the lock to
mutex to avoid the issue.

Cc: stable@vger.kernel.org
Fixes: 099343c64e ("ARM: at91: atmel-ssc: add device tree support")
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Link: https://lore.kernel.org/r/50f0d7fa107f318296afb49477c3571e4d6978c5.1592998403.git.mirq-linux@rere.qmqm.pl
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-29 19:10:51 +02:00

283 lines
5.9 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Atmel SSC driver
*
* Copyright (C) 2007 Atmel Corporation
*/
#include <linux/platform_device.h>
#include <linux/list.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/mutex.h>
#include <linux/atmel-ssc.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/of.h>
#include "../../sound/soc/atmel/atmel_ssc_dai.h"
/* Serialize access to ssc_list and user count */
static DEFINE_MUTEX(user_lock);
static LIST_HEAD(ssc_list);
struct ssc_device *ssc_request(unsigned int ssc_num)
{
int ssc_valid = 0;
struct ssc_device *ssc;
mutex_lock(&user_lock);
list_for_each_entry(ssc, &ssc_list, list) {
if (ssc->pdev->dev.of_node) {
if (of_alias_get_id(ssc->pdev->dev.of_node, "ssc")
== ssc_num) {
ssc->pdev->id = ssc_num;
ssc_valid = 1;
break;
}
} else if (ssc->pdev->id == ssc_num) {
ssc_valid = 1;
break;
}
}
if (!ssc_valid) {
mutex_unlock(&user_lock);
pr_err("ssc: ssc%d platform device is missing\n", ssc_num);
return ERR_PTR(-ENODEV);
}
if (ssc->user) {
mutex_unlock(&user_lock);
dev_dbg(&ssc->pdev->dev, "module busy\n");
return ERR_PTR(-EBUSY);
}
ssc->user++;
mutex_unlock(&user_lock);
clk_prepare(ssc->clk);
return ssc;
}
EXPORT_SYMBOL(ssc_request);
void ssc_free(struct ssc_device *ssc)
{
bool disable_clk = true;
mutex_lock(&user_lock);
if (ssc->user)
ssc->user--;
else {
disable_clk = false;
dev_dbg(&ssc->pdev->dev, "device already free\n");
}
mutex_unlock(&user_lock);
if (disable_clk)
clk_unprepare(ssc->clk);
}
EXPORT_SYMBOL(ssc_free);
static struct atmel_ssc_platform_data at91rm9200_config = {
.use_dma = 0,
.has_fslen_ext = 0,
};
static struct atmel_ssc_platform_data at91sam9rl_config = {
.use_dma = 0,
.has_fslen_ext = 1,
};
static struct atmel_ssc_platform_data at91sam9g45_config = {
.use_dma = 1,
.has_fslen_ext = 1,
};
static const struct platform_device_id atmel_ssc_devtypes[] = {
{
.name = "at91rm9200_ssc",
.driver_data = (unsigned long) &at91rm9200_config,
}, {
.name = "at91sam9rl_ssc",
.driver_data = (unsigned long) &at91sam9rl_config,
}, {
.name = "at91sam9g45_ssc",
.driver_data = (unsigned long) &at91sam9g45_config,
}, {
/* sentinel */
}
};
#ifdef CONFIG_OF
static const struct of_device_id atmel_ssc_dt_ids[] = {
{
.compatible = "atmel,at91rm9200-ssc",
.data = &at91rm9200_config,
}, {
.compatible = "atmel,at91sam9rl-ssc",
.data = &at91sam9rl_config,
}, {
.compatible = "atmel,at91sam9g45-ssc",
.data = &at91sam9g45_config,
}, {
/* sentinel */
}
};
MODULE_DEVICE_TABLE(of, atmel_ssc_dt_ids);
#endif
static inline const struct atmel_ssc_platform_data *
atmel_ssc_get_driver_data(struct platform_device *pdev)
{
if (pdev->dev.of_node) {
const struct of_device_id *match;
match = of_match_node(atmel_ssc_dt_ids, pdev->dev.of_node);
if (match == NULL)
return NULL;
return match->data;
}
return (struct atmel_ssc_platform_data *)
platform_get_device_id(pdev)->driver_data;
}
#ifdef CONFIG_SND_ATMEL_SOC_SSC
static int ssc_sound_dai_probe(struct ssc_device *ssc)
{
struct device_node *np = ssc->pdev->dev.of_node;
int ret;
int id;
ssc->sound_dai = false;
if (!of_property_read_bool(np, "#sound-dai-cells"))
return 0;
id = of_alias_get_id(np, "ssc");
if (id < 0)
return id;
ret = atmel_ssc_set_audio(id);
ssc->sound_dai = !ret;
return ret;
}
static void ssc_sound_dai_remove(struct ssc_device *ssc)
{
if (!ssc->sound_dai)
return;
atmel_ssc_put_audio(of_alias_get_id(ssc->pdev->dev.of_node, "ssc"));
}
#else
static inline int ssc_sound_dai_probe(struct ssc_device *ssc)
{
if (of_property_read_bool(ssc->pdev->dev.of_node, "#sound-dai-cells"))
return -ENOTSUPP;
return 0;
}
static inline void ssc_sound_dai_remove(struct ssc_device *ssc)
{
}
#endif
static int ssc_probe(struct platform_device *pdev)
{
struct resource *regs;
struct ssc_device *ssc;
const struct atmel_ssc_platform_data *plat_dat;
ssc = devm_kzalloc(&pdev->dev, sizeof(struct ssc_device), GFP_KERNEL);
if (!ssc) {
dev_dbg(&pdev->dev, "out of memory\n");
return -ENOMEM;
}
ssc->pdev = pdev;
plat_dat = atmel_ssc_get_driver_data(pdev);
if (!plat_dat)
return -ENODEV;
ssc->pdata = (struct atmel_ssc_platform_data *)plat_dat;
if (pdev->dev.of_node) {
struct device_node *np = pdev->dev.of_node;
ssc->clk_from_rk_pin =
of_property_read_bool(np, "atmel,clk-from-rk-pin");
}
regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
ssc->regs = devm_ioremap_resource(&pdev->dev, regs);
if (IS_ERR(ssc->regs))
return PTR_ERR(ssc->regs);
ssc->phybase = regs->start;
ssc->clk = devm_clk_get(&pdev->dev, "pclk");
if (IS_ERR(ssc->clk)) {
dev_dbg(&pdev->dev, "no pclk clock defined\n");
return -ENXIO;
}
/* disable all interrupts */
clk_prepare_enable(ssc->clk);
ssc_writel(ssc->regs, IDR, -1);
ssc_readl(ssc->regs, SR);
clk_disable_unprepare(ssc->clk);
ssc->irq = platform_get_irq(pdev, 0);
if (!ssc->irq) {
dev_dbg(&pdev->dev, "could not get irq\n");
return -ENXIO;
}
mutex_lock(&user_lock);
list_add_tail(&ssc->list, &ssc_list);
mutex_unlock(&user_lock);
platform_set_drvdata(pdev, ssc);
dev_info(&pdev->dev, "Atmel SSC device at 0x%p (irq %d)\n",
ssc->regs, ssc->irq);
if (ssc_sound_dai_probe(ssc))
dev_err(&pdev->dev, "failed to auto-setup ssc for audio\n");
return 0;
}
static int ssc_remove(struct platform_device *pdev)
{
struct ssc_device *ssc = platform_get_drvdata(pdev);
ssc_sound_dai_remove(ssc);
mutex_lock(&user_lock);
list_del(&ssc->list);
mutex_unlock(&user_lock);
return 0;
}
static struct platform_driver ssc_driver = {
.driver = {
.name = "ssc",
.of_match_table = of_match_ptr(atmel_ssc_dt_ids),
},
.id_table = atmel_ssc_devtypes,
.probe = ssc_probe,
.remove = ssc_remove,
};
module_platform_driver(ssc_driver);
MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
MODULE_DESCRIPTION("SSC driver for Atmel AVR32 and AT91");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:ssc");