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linux/drivers/bus/tegra-gmi.c
Uwe Kleine-König 812c0c38a8 bus: tegra-gmi: Convert to platform remove callback returning void 
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Link: https://lore.kernel.org/r/20231109202830.4124591-10-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2023-11-28 18:43:26 +01:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Driver for NVIDIA Generic Memory Interface
*
* Copyright (C) 2016 Host Mobility AB. All rights reserved.
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/reset.h>
#include <soc/tegra/common.h>
#define TEGRA_GMI_CONFIG 0x00
#define TEGRA_GMI_CONFIG_GO BIT(31)
#define TEGRA_GMI_BUS_WIDTH_32BIT BIT(30)
#define TEGRA_GMI_MUX_MODE BIT(28)
#define TEGRA_GMI_RDY_BEFORE_DATA BIT(24)
#define TEGRA_GMI_RDY_ACTIVE_HIGH BIT(23)
#define TEGRA_GMI_ADV_ACTIVE_HIGH BIT(22)
#define TEGRA_GMI_OE_ACTIVE_HIGH BIT(21)
#define TEGRA_GMI_CS_ACTIVE_HIGH BIT(20)
#define TEGRA_GMI_CS_SELECT(x) ((x & 0x7) << 4)
#define TEGRA_GMI_TIMING0 0x10
#define TEGRA_GMI_MUXED_WIDTH(x) ((x & 0xf) << 12)
#define TEGRA_GMI_HOLD_WIDTH(x) ((x & 0xf) << 8)
#define TEGRA_GMI_ADV_WIDTH(x) ((x & 0xf) << 4)
#define TEGRA_GMI_CE_WIDTH(x) (x & 0xf)
#define TEGRA_GMI_TIMING1 0x14
#define TEGRA_GMI_WE_WIDTH(x) ((x & 0xff) << 16)
#define TEGRA_GMI_OE_WIDTH(x) ((x & 0xff) << 8)
#define TEGRA_GMI_WAIT_WIDTH(x) (x & 0xff)
#define TEGRA_GMI_MAX_CHIP_SELECT 8
struct tegra_gmi {
struct device *dev;
void __iomem *base;
struct clk *clk;
struct reset_control *rst;
u32 snor_config;
u32 snor_timing0;
u32 snor_timing1;
};
static int tegra_gmi_enable(struct tegra_gmi *gmi)
{
int err;
pm_runtime_enable(gmi->dev);
err = pm_runtime_resume_and_get(gmi->dev);
if (err) {
pm_runtime_disable(gmi->dev);
return err;
}
reset_control_assert(gmi->rst);
usleep_range(2000, 4000);
reset_control_deassert(gmi->rst);
writel(gmi->snor_timing0, gmi->base + TEGRA_GMI_TIMING0);
writel(gmi->snor_timing1, gmi->base + TEGRA_GMI_TIMING1);
gmi->snor_config |= TEGRA_GMI_CONFIG_GO;
writel(gmi->snor_config, gmi->base + TEGRA_GMI_CONFIG);
return 0;
}
static void tegra_gmi_disable(struct tegra_gmi *gmi)
{
u32 config;
/* stop GMI operation */
config = readl(gmi->base + TEGRA_GMI_CONFIG);
config &= ~TEGRA_GMI_CONFIG_GO;
writel(config, gmi->base + TEGRA_GMI_CONFIG);
reset_control_assert(gmi->rst);
pm_runtime_put_sync_suspend(gmi->dev);
pm_runtime_force_suspend(gmi->dev);
}
static int tegra_gmi_parse_dt(struct tegra_gmi *gmi)
{
struct device_node *child;
u32 property, ranges[4];
int err;
child = of_get_next_available_child(gmi->dev->of_node, NULL);
if (!child) {
dev_err(gmi->dev, "no child nodes found\n");
return -ENODEV;
}
/*
* We currently only support one child device due to lack of
* chip-select address decoding. Which means that we only have one
* chip-select line from the GMI controller.
*/
if (of_get_child_count(gmi->dev->of_node) > 1)
dev_warn(gmi->dev, "only one child device is supported.");
if (of_property_read_bool(child, "nvidia,snor-data-width-32bit"))
gmi->snor_config |= TEGRA_GMI_BUS_WIDTH_32BIT;
if (of_property_read_bool(child, "nvidia,snor-mux-mode"))
gmi->snor_config |= TEGRA_GMI_MUX_MODE;
if (of_property_read_bool(child, "nvidia,snor-rdy-active-before-data"))
gmi->snor_config |= TEGRA_GMI_RDY_BEFORE_DATA;
if (of_property_read_bool(child, "nvidia,snor-rdy-active-high"))
gmi->snor_config |= TEGRA_GMI_RDY_ACTIVE_HIGH;
if (of_property_read_bool(child, "nvidia,snor-adv-active-high"))
gmi->snor_config |= TEGRA_GMI_ADV_ACTIVE_HIGH;
if (of_property_read_bool(child, "nvidia,snor-oe-active-high"))
gmi->snor_config |= TEGRA_GMI_OE_ACTIVE_HIGH;
if (of_property_read_bool(child, "nvidia,snor-cs-active-high"))
gmi->snor_config |= TEGRA_GMI_CS_ACTIVE_HIGH;
/* Decode the CS# */
err = of_property_read_u32_array(child, "ranges", ranges, 4);
if (err < 0) {
/* Invalid binding */
if (err == -EOVERFLOW) {
dev_err(gmi->dev,
"failed to decode CS: invalid ranges length\n");
goto error_cs;
}
/*
* If we reach here it means that the child node has an empty
* ranges or it does not exist at all. Attempt to decode the
* CS# from the reg property instead.
*/
err = of_property_read_u32(child, "reg", &property);
if (err < 0) {
dev_err(gmi->dev,
"failed to decode CS: no reg property found\n");
goto error_cs;
}
} else {
property = ranges[1];
}
/* Valid chip selects are CS0-CS7 */
if (property >= TEGRA_GMI_MAX_CHIP_SELECT) {
dev_err(gmi->dev, "invalid chip select: %d", property);
err = -EINVAL;
goto error_cs;
}
gmi->snor_config |= TEGRA_GMI_CS_SELECT(property);
/* The default values that are provided below are reset values */
if (!of_property_read_u32(child, "nvidia,snor-muxed-width", &property))
gmi->snor_timing0 |= TEGRA_GMI_MUXED_WIDTH(property);
else
gmi->snor_timing0 |= TEGRA_GMI_MUXED_WIDTH(1);
if (!of_property_read_u32(child, "nvidia,snor-hold-width", &property))
gmi->snor_timing0 |= TEGRA_GMI_HOLD_WIDTH(property);
else
gmi->snor_timing0 |= TEGRA_GMI_HOLD_WIDTH(1);
if (!of_property_read_u32(child, "nvidia,snor-adv-width", &property))
gmi->snor_timing0 |= TEGRA_GMI_ADV_WIDTH(property);
else
gmi->snor_timing0 |= TEGRA_GMI_ADV_WIDTH(1);
if (!of_property_read_u32(child, "nvidia,snor-ce-width", &property))
gmi->snor_timing0 |= TEGRA_GMI_CE_WIDTH(property);
else
gmi->snor_timing0 |= TEGRA_GMI_CE_WIDTH(4);
if (!of_property_read_u32(child, "nvidia,snor-we-width", &property))
gmi->snor_timing1 |= TEGRA_GMI_WE_WIDTH(property);
else
gmi->snor_timing1 |= TEGRA_GMI_WE_WIDTH(1);
if (!of_property_read_u32(child, "nvidia,snor-oe-width", &property))
gmi->snor_timing1 |= TEGRA_GMI_OE_WIDTH(property);
else
gmi->snor_timing1 |= TEGRA_GMI_OE_WIDTH(1);
if (!of_property_read_u32(child, "nvidia,snor-wait-width", &property))
gmi->snor_timing1 |= TEGRA_GMI_WAIT_WIDTH(property);
else
gmi->snor_timing1 |= TEGRA_GMI_WAIT_WIDTH(3);
error_cs:
of_node_put(child);
return err;
}
static int tegra_gmi_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct tegra_gmi *gmi;
int err;
gmi = devm_kzalloc(dev, sizeof(*gmi), GFP_KERNEL);
if (!gmi)
return -ENOMEM;
platform_set_drvdata(pdev, gmi);
gmi->dev = dev;
gmi->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(gmi->base))
return PTR_ERR(gmi->base);
gmi->clk = devm_clk_get(dev, "gmi");
if (IS_ERR(gmi->clk)) {
dev_err(dev, "can not get clock\n");
return PTR_ERR(gmi->clk);
}
gmi->rst = devm_reset_control_get(dev, "gmi");
if (IS_ERR(gmi->rst)) {
dev_err(dev, "can not get reset\n");
return PTR_ERR(gmi->rst);
}
err = devm_tegra_core_dev_init_opp_table_common(&pdev->dev);
if (err)
return err;
err = tegra_gmi_parse_dt(gmi);
if (err)
return err;
err = tegra_gmi_enable(gmi);
if (err < 0)
return err;
err = of_platform_default_populate(dev->of_node, NULL, dev);
if (err < 0) {
dev_err(dev, "fail to create devices.\n");
tegra_gmi_disable(gmi);
return err;
}
return 0;
}
static void tegra_gmi_remove(struct platform_device *pdev)
{
struct tegra_gmi *gmi = platform_get_drvdata(pdev);
of_platform_depopulate(gmi->dev);
tegra_gmi_disable(gmi);
}
static int __maybe_unused tegra_gmi_runtime_resume(struct device *dev)
{
struct tegra_gmi *gmi = dev_get_drvdata(dev);
int err;
err = clk_prepare_enable(gmi->clk);
if (err < 0) {
dev_err(gmi->dev, "failed to enable clock: %d\n", err);
return err;
}
return 0;
}
static int __maybe_unused tegra_gmi_runtime_suspend(struct device *dev)
{
struct tegra_gmi *gmi = dev_get_drvdata(dev);
clk_disable_unprepare(gmi->clk);
return 0;
}
static const struct dev_pm_ops tegra_gmi_pm = {
SET_RUNTIME_PM_OPS(tegra_gmi_runtime_suspend, tegra_gmi_runtime_resume,
NULL)
};
static const struct of_device_id tegra_gmi_id_table[] = {
{ .compatible = "nvidia,tegra20-gmi", },
{ .compatible = "nvidia,tegra30-gmi", },
{ }
};
MODULE_DEVICE_TABLE(of, tegra_gmi_id_table);
static struct platform_driver tegra_gmi_driver = {
.probe = tegra_gmi_probe,
.remove_new = tegra_gmi_remove,
.driver = {
.name = "tegra-gmi",
.of_match_table = tegra_gmi_id_table,
.pm = &tegra_gmi_pm,
},
};
module_platform_driver(tegra_gmi_driver);
MODULE_AUTHOR("Mirza Krak <mirza.krak@gmail.com");
MODULE_DESCRIPTION("NVIDIA Tegra GMI Bus Driver");
MODULE_LICENSE("GPL v2");
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