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linux-next/drivers/phy/phy-exynos-mipi-video.c
Arnd Bergmann 06061dc63b phy: exynos-mipi-video: avoid uninitialized variable use 
A rework of the exynos-mipi-video driver caused a warning
about the new __set_phy_state function potentially accessing
a variable before its initialization:

drivers/phy/phy-exynos-mipi-video.c: In function '__set_phy_state':
drivers/phy/phy-exynos-mipi-video.c:238:13: error: 'val' may be used uninitialized in this function [-Werror=maybe-uninitialized]
  return val & data->resetn_val;
         ~~~~^~~~~~~~~~~~~~~~~~
drivers/phy/phy-exynos-mipi-video.c:235:6: note: 'val' was declared here
  u32 val;

The failure scenario here is the offset passed into a the
stub regmap_read() function that does not modify its output,
however regmap_read() can also fail for other reasons, so
adding error handling (in this case, returning zero from
is_running) seems the best solution.

Note that this warning showed up with the ARM s5pv210_defconfig,
indicating that we most likely want to either enable CONFIG_REGMAP
in that defconfig as well, or disable the phy-exynos-mipi-video
driver.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Fixes: 97a3042f76 ("phy: exynos-mipi-video: Rewrite handling of phy registers")
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
2016-05-30 18:21:37 +05:30

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/*
* Samsung S5P/EXYNOS SoC series MIPI CSIS/DSIM DPHY driver
*
* Copyright (C) 2013,2016 Samsung Electronics Co., Ltd.
* Author: Sylwester Nawrocki <s.nawrocki@samsung.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/err.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon/exynos4-pmu.h>
#include <linux/mfd/syscon/exynos5-pmu.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/phy/phy.h>
#include <linux/regmap.h>
#include <linux/spinlock.h>
#include <linux/mfd/syscon.h>
enum exynos_mipi_phy_id {
EXYNOS_MIPI_PHY_ID_NONE = -1,
EXYNOS_MIPI_PHY_ID_CSIS0,
EXYNOS_MIPI_PHY_ID_DSIM0,
EXYNOS_MIPI_PHY_ID_CSIS1,
EXYNOS_MIPI_PHY_ID_DSIM1,
EXYNOS_MIPI_PHY_ID_CSIS2,
EXYNOS_MIPI_PHYS_NUM
};
enum exynos_mipi_phy_regmap_id {
EXYNOS_MIPI_REGMAP_PMU,
EXYNOS_MIPI_REGMAP_DISP,
EXYNOS_MIPI_REGMAP_CAM0,
EXYNOS_MIPI_REGMAP_CAM1,
EXYNOS_MIPI_REGMAPS_NUM
};
struct mipi_phy_device_desc {
int num_phys;
int num_regmaps;
const char *regmap_names[EXYNOS_MIPI_REGMAPS_NUM];
struct exynos_mipi_phy_desc {
enum exynos_mipi_phy_id coupled_phy_id;
u32 enable_val;
unsigned int enable_reg;
enum exynos_mipi_phy_regmap_id enable_map;
u32 resetn_val;
unsigned int resetn_reg;
enum exynos_mipi_phy_regmap_id resetn_map;
} phys[EXYNOS_MIPI_PHYS_NUM];
};
static const struct mipi_phy_device_desc s5pv210_mipi_phy = {
.num_regmaps = 1,
.regmap_names = {"syscon"},
.num_phys = 4,
.phys = {
{
/* EXYNOS_MIPI_PHY_ID_CSIS0 */
.coupled_phy_id = EXYNOS_MIPI_PHY_ID_DSIM0,
.enable_val = EXYNOS4_MIPI_PHY_ENABLE,
.enable_reg = EXYNOS4_MIPI_PHY_CONTROL(0),
.enable_map = EXYNOS_MIPI_REGMAP_PMU,
.resetn_val = EXYNOS4_MIPI_PHY_SRESETN,
.resetn_reg = EXYNOS4_MIPI_PHY_CONTROL(0),
.resetn_map = EXYNOS_MIPI_REGMAP_PMU,
}, {
/* EXYNOS_MIPI_PHY_ID_DSIM0 */
.coupled_phy_id = EXYNOS_MIPI_PHY_ID_CSIS0,
.enable_val = EXYNOS4_MIPI_PHY_ENABLE,
.enable_reg = EXYNOS4_MIPI_PHY_CONTROL(0),
.enable_map = EXYNOS_MIPI_REGMAP_PMU,
.resetn_val = EXYNOS4_MIPI_PHY_MRESETN,
.resetn_reg = EXYNOS4_MIPI_PHY_CONTROL(0),
.resetn_map = EXYNOS_MIPI_REGMAP_PMU,
}, {
/* EXYNOS_MIPI_PHY_ID_CSIS1 */
.coupled_phy_id = EXYNOS_MIPI_PHY_ID_DSIM1,
.enable_val = EXYNOS4_MIPI_PHY_ENABLE,
.enable_reg = EXYNOS4_MIPI_PHY_CONTROL(1),
.enable_map = EXYNOS_MIPI_REGMAP_PMU,
.resetn_val = EXYNOS4_MIPI_PHY_SRESETN,
.resetn_reg = EXYNOS4_MIPI_PHY_CONTROL(1),
.resetn_map = EXYNOS_MIPI_REGMAP_PMU,
}, {
/* EXYNOS_MIPI_PHY_ID_DSIM1 */
.coupled_phy_id = EXYNOS_MIPI_PHY_ID_CSIS1,
.enable_val = EXYNOS4_MIPI_PHY_ENABLE,
.enable_reg = EXYNOS4_MIPI_PHY_CONTROL(1),
.enable_map = EXYNOS_MIPI_REGMAP_PMU,
.resetn_val = EXYNOS4_MIPI_PHY_MRESETN,
.resetn_reg = EXYNOS4_MIPI_PHY_CONTROL(1),
.resetn_map = EXYNOS_MIPI_REGMAP_PMU,
},
},
};
static const struct mipi_phy_device_desc exynos5420_mipi_phy = {
.num_regmaps = 1,
.regmap_names = {"syscon"},
.num_phys = 5,
.phys = {
{
/* EXYNOS_MIPI_PHY_ID_CSIS0 */
.coupled_phy_id = EXYNOS_MIPI_PHY_ID_DSIM0,
.enable_val = EXYNOS5_PHY_ENABLE,
.enable_reg = EXYNOS5420_MIPI_PHY0_CONTROL,
.enable_map = EXYNOS_MIPI_REGMAP_PMU,
.resetn_val = EXYNOS5_MIPI_PHY_S_RESETN,
.resetn_reg = EXYNOS5420_MIPI_PHY0_CONTROL,
.resetn_map = EXYNOS_MIPI_REGMAP_PMU,
}, {
/* EXYNOS_MIPI_PHY_ID_DSIM0 */
.coupled_phy_id = EXYNOS_MIPI_PHY_ID_CSIS0,
.enable_val = EXYNOS5_PHY_ENABLE,
.enable_reg = EXYNOS5420_MIPI_PHY0_CONTROL,
.enable_map = EXYNOS_MIPI_REGMAP_PMU,
.resetn_val = EXYNOS5_MIPI_PHY_M_RESETN,
.resetn_reg = EXYNOS5420_MIPI_PHY0_CONTROL,
.resetn_map = EXYNOS_MIPI_REGMAP_PMU,
}, {
/* EXYNOS_MIPI_PHY_ID_CSIS1 */
.coupled_phy_id = EXYNOS_MIPI_PHY_ID_DSIM1,
.enable_val = EXYNOS5_PHY_ENABLE,
.enable_reg = EXYNOS5420_MIPI_PHY1_CONTROL,
.enable_map = EXYNOS_MIPI_REGMAP_PMU,
.resetn_val = EXYNOS5_MIPI_PHY_S_RESETN,
.resetn_reg = EXYNOS5420_MIPI_PHY1_CONTROL,
.resetn_map = EXYNOS_MIPI_REGMAP_PMU,
}, {
/* EXYNOS_MIPI_PHY_ID_DSIM1 */
.coupled_phy_id = EXYNOS_MIPI_PHY_ID_CSIS1,
.enable_val = EXYNOS5_PHY_ENABLE,
.enable_reg = EXYNOS5420_MIPI_PHY1_CONTROL,
.enable_map = EXYNOS_MIPI_REGMAP_PMU,
.resetn_val = EXYNOS5_MIPI_PHY_M_RESETN,
.resetn_reg = EXYNOS5420_MIPI_PHY1_CONTROL,
.resetn_map = EXYNOS_MIPI_REGMAP_PMU,
}, {
/* EXYNOS_MIPI_PHY_ID_CSIS2 */
.coupled_phy_id = EXYNOS_MIPI_PHY_ID_NONE,
.enable_val = EXYNOS5_PHY_ENABLE,
.enable_reg = EXYNOS5420_MIPI_PHY2_CONTROL,
.enable_map = EXYNOS_MIPI_REGMAP_PMU,
.resetn_val = EXYNOS5_MIPI_PHY_S_RESETN,
.resetn_reg = EXYNOS5420_MIPI_PHY2_CONTROL,
.resetn_map = EXYNOS_MIPI_REGMAP_PMU,
},
},
};
#define EXYNOS5433_SYSREG_DISP_MIPI_PHY 0x100C
#define EXYNOS5433_SYSREG_CAM0_MIPI_DPHY_CON 0x1014
#define EXYNOS5433_SYSREG_CAM1_MIPI_DPHY_CON 0x1020
static const struct mipi_phy_device_desc exynos5433_mipi_phy = {
.num_regmaps = 4,
.regmap_names = {
"samsung,pmu-syscon",
"samsung,disp-sysreg",
"samsung,cam0-sysreg",
"samsung,cam1-sysreg"
},
.num_phys = 5,
.phys = {
{
/* EXYNOS_MIPI_PHY_ID_CSIS0 */
.coupled_phy_id = EXYNOS_MIPI_PHY_ID_DSIM0,
.enable_val = EXYNOS5_PHY_ENABLE,
.enable_reg = EXYNOS5433_MIPI_PHY0_CONTROL,
.enable_map = EXYNOS_MIPI_REGMAP_PMU,
.resetn_val = BIT(0),
.resetn_reg = EXYNOS5433_SYSREG_CAM0_MIPI_DPHY_CON,
.resetn_map = EXYNOS_MIPI_REGMAP_CAM0,
}, {
/* EXYNOS_MIPI_PHY_ID_DSIM0 */
.coupled_phy_id = EXYNOS_MIPI_PHY_ID_CSIS0,
.enable_val = EXYNOS5_PHY_ENABLE,
.enable_reg = EXYNOS5433_MIPI_PHY0_CONTROL,
.enable_map = EXYNOS_MIPI_REGMAP_PMU,
.resetn_val = BIT(0),
.resetn_reg = EXYNOS5433_SYSREG_DISP_MIPI_PHY,
.resetn_map = EXYNOS_MIPI_REGMAP_DISP,
}, {
/* EXYNOS_MIPI_PHY_ID_CSIS1 */
.coupled_phy_id = EXYNOS_MIPI_PHY_ID_NONE,
.enable_val = EXYNOS5_PHY_ENABLE,
.enable_reg = EXYNOS5433_MIPI_PHY1_CONTROL,
.enable_map = EXYNOS_MIPI_REGMAP_PMU,
.resetn_val = BIT(1),
.resetn_reg = EXYNOS5433_SYSREG_CAM0_MIPI_DPHY_CON,
.resetn_map = EXYNOS_MIPI_REGMAP_CAM0,
}, {
/* EXYNOS_MIPI_PHY_ID_DSIM1 */
.coupled_phy_id = EXYNOS_MIPI_PHY_ID_NONE,
.enable_val = EXYNOS5_PHY_ENABLE,
.enable_reg = EXYNOS5433_MIPI_PHY1_CONTROL,
.enable_map = EXYNOS_MIPI_REGMAP_PMU,
.resetn_val = BIT(1),
.resetn_reg = EXYNOS5433_SYSREG_DISP_MIPI_PHY,
.resetn_map = EXYNOS_MIPI_REGMAP_DISP,
}, {
/* EXYNOS_MIPI_PHY_ID_CSIS2 */
.coupled_phy_id = EXYNOS_MIPI_PHY_ID_NONE,
.enable_val = EXYNOS5_PHY_ENABLE,
.enable_reg = EXYNOS5433_MIPI_PHY2_CONTROL,
.enable_map = EXYNOS_MIPI_REGMAP_PMU,
.resetn_val = BIT(0),
.resetn_reg = EXYNOS5433_SYSREG_CAM1_MIPI_DPHY_CON,
.resetn_map = EXYNOS_MIPI_REGMAP_CAM1,
},
},
};
struct exynos_mipi_video_phy {
struct regmap *regmaps[EXYNOS_MIPI_REGMAPS_NUM];
int num_phys;
struct video_phy_desc {
struct phy *phy;
unsigned int index;
const struct exynos_mipi_phy_desc *data;
} phys[EXYNOS_MIPI_PHYS_NUM];
spinlock_t slock;
};
static inline int __is_running(const struct exynos_mipi_phy_desc *data,
struct exynos_mipi_video_phy *state)
{
u32 val;
int ret;
ret = regmap_read(state->regmaps[data->resetn_map], data->resetn_reg, &val);
if (ret)
return 0;
return val & data->resetn_val;
}
static int __set_phy_state(const struct exynos_mipi_phy_desc *data,
struct exynos_mipi_video_phy *state, unsigned int on)
{
u32 val;
spin_lock(&state->slock);
/* disable in PMU sysreg */
if (!on && data->coupled_phy_id >= 0 &&
!__is_running(state->phys[data->coupled_phy_id].data, state)) {
regmap_read(state->regmaps[data->enable_map], data->enable_reg,
&val);
val &= ~data->enable_val;
regmap_write(state->regmaps[data->enable_map], data->enable_reg,
val);
}
/* PHY reset */
regmap_read(state->regmaps[data->resetn_map], data->resetn_reg, &val);
val = on ? (val | data->resetn_val) : (val & ~data->resetn_val);
regmap_write(state->regmaps[data->resetn_map], data->resetn_reg, val);
/* enable in PMU sysreg */
if (on) {
regmap_read(state->regmaps[data->enable_map], data->enable_reg,
&val);
val |= data->enable_val;
regmap_write(state->regmaps[data->enable_map], data->enable_reg,
val);
}
spin_unlock(&state->slock);
return 0;
}
#define to_mipi_video_phy(desc) \
container_of((desc), struct exynos_mipi_video_phy, phys[(desc)->index])
static int exynos_mipi_video_phy_power_on(struct phy *phy)
{
struct video_phy_desc *phy_desc = phy_get_drvdata(phy);
struct exynos_mipi_video_phy *state = to_mipi_video_phy(phy_desc);
return __set_phy_state(phy_desc->data, state, 1);
}
static int exynos_mipi_video_phy_power_off(struct phy *phy)
{
struct video_phy_desc *phy_desc = phy_get_drvdata(phy);
struct exynos_mipi_video_phy *state = to_mipi_video_phy(phy_desc);
return __set_phy_state(phy_desc->data, state, 0);
}
static struct phy *exynos_mipi_video_phy_xlate(struct device *dev,
struct of_phandle_args *args)
{
struct exynos_mipi_video_phy *state = dev_get_drvdata(dev);
if (WARN_ON(args->args[0] >= state->num_phys))
return ERR_PTR(-ENODEV);
return state->phys[args->args[0]].phy;
}
static const struct phy_ops exynos_mipi_video_phy_ops = {
.power_on = exynos_mipi_video_phy_power_on,
.power_off = exynos_mipi_video_phy_power_off,
.owner = THIS_MODULE,
};
static int exynos_mipi_video_phy_probe(struct platform_device *pdev)
{
const struct mipi_phy_device_desc *phy_dev;
struct exynos_mipi_video_phy *state;
struct device *dev = &pdev->dev;
struct device_node *np = dev->of_node;
struct phy_provider *phy_provider;
unsigned int i;
phy_dev = of_device_get_match_data(dev);
if (!phy_dev)
return -ENODEV;
state = devm_kzalloc(dev, sizeof(*state), GFP_KERNEL);
if (!state)
return -ENOMEM;
for (i = 0; i < phy_dev->num_regmaps; i++) {
state->regmaps[i] = syscon_regmap_lookup_by_phandle(np,
phy_dev->regmap_names[i]);
if (IS_ERR(state->regmaps[i]))
return PTR_ERR(state->regmaps[i]);
}
state->num_phys = phy_dev->num_phys;
spin_lock_init(&state->slock);
dev_set_drvdata(dev, state);
for (i = 0; i < state->num_phys; i++) {
struct phy *phy = devm_phy_create(dev, NULL,
&exynos_mipi_video_phy_ops);
if (IS_ERR(phy)) {
dev_err(dev, "failed to create PHY %d\n", i);
return PTR_ERR(phy);
}
state->phys[i].phy = phy;
state->phys[i].index = i;
state->phys[i].data = &phy_dev->phys[i];
phy_set_drvdata(phy, &state->phys[i]);
}
phy_provider = devm_of_phy_provider_register(dev,
exynos_mipi_video_phy_xlate);
return PTR_ERR_OR_ZERO(phy_provider);
}
static const struct of_device_id exynos_mipi_video_phy_of_match[] = {
{
.compatible = "samsung,s5pv210-mipi-video-phy",
.data = &s5pv210_mipi_phy,
}, {
.compatible = "samsung,exynos5420-mipi-video-phy",
.data = &exynos5420_mipi_phy,
}, {
.compatible = "samsung,exynos5433-mipi-video-phy",
.data = &exynos5433_mipi_phy,
},
{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, exynos_mipi_video_phy_of_match);
static struct platform_driver exynos_mipi_video_phy_driver = {
.probe = exynos_mipi_video_phy_probe,
.driver = {
.of_match_table = exynos_mipi_video_phy_of_match,
.name = "exynos-mipi-video-phy",
}
};
module_platform_driver(exynos_mipi_video_phy_driver);
MODULE_DESCRIPTION("Samsung S5P/EXYNOS SoC MIPI CSI-2/DSI PHY driver");
MODULE_AUTHOR("Sylwester Nawrocki <s.nawrocki@samsung.com>");
MODULE_LICENSE("GPL v2");
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