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linux/drivers/i2c/busses/i2c-designware-platdrv.c
Ard Biesheuvel 9d64084330 i2c: designware: don't infer timings described by ACPI from clock rate 
Commit bd698d24b1b57 ("i2c: designware: Get selected speed mode
sda-hold-time via ACPI") updated the logic that reads the timing
parameters for various I2C bus rates from the DSDT, to only read
the timing parameters for the currently selected mode.

This causes a WARN_ON() splat on platforms that legally omit the clock
frequency from the ACPI description, because in the new situation, the
core I2C designware driver still accesses the fields in the driver
struct that we no longer populate, and proceeds to calculate them from
the clock frequency. Since the clock frequency is unspecified, the
driver complains loudly using a WARN_ON().

So revert back to the old situation, where the struct fields for all
timings are populated, but retain the new logic which chooses the SDA
hold time from the timing mode that is currently in use.

Fixes: bd698d24b1b57 ("i2c: designware: Get selected speed mode ...")
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reported-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2017-05-19 14:36:24 +02:00

455 lines
12 KiB
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/*
* Synopsys DesignWare I2C adapter driver (master only).
*
* Based on the TI DAVINCI I2C adapter driver.
*
* Copyright (C) 2006 Texas Instruments.
* Copyright (C) 2007 MontaVista Software Inc.
* Copyright (C) 2009 Provigent Ltd.
*
* ----------------------------------------------------------------------------
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* ----------------------------------------------------------------------------
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/dmi.h>
#include <linux/i2c.h>
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/pm_runtime.h>
#include <linux/property.h>
#include <linux/io.h>
#include <linux/reset.h>
#include <linux/slab.h>
#include <linux/acpi.h>
#include <linux/platform_data/i2c-designware.h>
#include "i2c-designware-core.h"
static u32 i2c_dw_get_clk_rate_khz(struct dw_i2c_dev *dev)
{
return clk_get_rate(dev->clk)/1000;
}
#ifdef CONFIG_ACPI
/*
* The HCNT/LCNT information coming from ACPI should be the most accurate
* for given platform. However, some systems get it wrong. On such systems
* we get better results by calculating those based on the input clock.
*/
static const struct dmi_system_id dw_i2c_no_acpi_params[] = {
{
.ident = "Dell Inspiron 7348",
.matches = {
DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 7348"),
},
},
{ }
};
static void dw_i2c_acpi_params(struct platform_device *pdev, char method[],
u16 *hcnt, u16 *lcnt, u32 *sda_hold)
{
struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
acpi_handle handle = ACPI_HANDLE(&pdev->dev);
union acpi_object *obj;
if (dmi_check_system(dw_i2c_no_acpi_params))
return;
if (ACPI_FAILURE(acpi_evaluate_object(handle, method, NULL, &buf)))
return;
obj = (union acpi_object *)buf.pointer;
if (obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 3) {
const union acpi_object *objs = obj->package.elements;
*hcnt = (u16)objs[0].integer.value;
*lcnt = (u16)objs[1].integer.value;
*sda_hold = (u32)objs[2].integer.value;
}
kfree(buf.pointer);
}
static int dw_i2c_acpi_configure(struct platform_device *pdev)
{
struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
acpi_handle handle = ACPI_HANDLE(&pdev->dev);
const struct acpi_device_id *id;
u32 ss_ht, fp_ht, hs_ht, fs_ht;
struct acpi_device *adev;
const char *uid;
dev->adapter.nr = -1;
dev->tx_fifo_depth = 32;
dev->rx_fifo_depth = 32;
/*
* Try to get SDA hold time and *CNT values from an ACPI method for
* selected speed modes.
*/
dw_i2c_acpi_params(pdev, "SSCN", &dev->ss_hcnt, &dev->ss_lcnt, &ss_ht);
dw_i2c_acpi_params(pdev, "FPCN", &dev->fp_hcnt, &dev->fp_lcnt, &fp_ht);
dw_i2c_acpi_params(pdev, "HSCN", &dev->hs_hcnt, &dev->hs_lcnt, &hs_ht);
dw_i2c_acpi_params(pdev, "FMCN", &dev->fs_hcnt, &dev->fs_lcnt, &fs_ht);
switch (dev->clk_freq) {
case 100000:
dev->sda_hold_time = ss_ht;
break;
case 1000000:
dev->sda_hold_time = fp_ht;
break;
case 3400000:
dev->sda_hold_time = hs_ht;
break;
case 400000:
default:
dev->sda_hold_time = fs_ht;
break;
}
id = acpi_match_device(pdev->dev.driver->acpi_match_table, &pdev->dev);
if (id && id->driver_data)
dev->flags |= (u32)id->driver_data;
if (acpi_bus_get_device(handle, &adev))
return -ENODEV;
/*
* Cherrytrail I2C7 gets used for the PMIC which gets accessed
* through ACPI opregions during late suspend / early resume
* disable pm for it.
*/
uid = adev->pnp.unique_id;
if ((dev->flags & MODEL_CHERRYTRAIL) && !strcmp(uid, "7"))
dev->pm_disabled = true;
return 0;
}
static const struct acpi_device_id dw_i2c_acpi_match[] = {
{ "INT33C2", 0 },
{ "INT33C3", 0 },
{ "INT3432", 0 },
{ "INT3433", 0 },
{ "80860F41", 0 },
{ "808622C1", MODEL_CHERRYTRAIL },
{ "AMD0010", ACCESS_INTR_MASK },
{ "AMDI0010", ACCESS_INTR_MASK },
{ "AMDI0510", 0 },
{ "APMC0D0F", 0 },
{ "HISI02A1", 0 },
{ "HISI02A2", 0 },
{ }
};
MODULE_DEVICE_TABLE(acpi, dw_i2c_acpi_match);
#else
static inline int dw_i2c_acpi_configure(struct platform_device *pdev)
{
return -ENODEV;
}
#endif
static int i2c_dw_plat_prepare_clk(struct dw_i2c_dev *i_dev, bool prepare)
{
if (IS_ERR(i_dev->clk))
return PTR_ERR(i_dev->clk);
if (prepare)
return clk_prepare_enable(i_dev->clk);
clk_disable_unprepare(i_dev->clk);
return 0;
}
static void dw_i2c_set_fifo_size(struct dw_i2c_dev *dev, int id)
{
u32 param, tx_fifo_depth, rx_fifo_depth;
/*
* Try to detect the FIFO depth if not set by interface driver,
* the depth could be from 2 to 256 from HW spec.
*/
param = i2c_dw_read_comp_param(dev);
tx_fifo_depth = ((param >> 16) & 0xff) + 1;
rx_fifo_depth = ((param >> 8) & 0xff) + 1;
if (!dev->tx_fifo_depth) {
dev->tx_fifo_depth = tx_fifo_depth;
dev->rx_fifo_depth = rx_fifo_depth;
dev->adapter.nr = id;
} else if (tx_fifo_depth >= 2) {
dev->tx_fifo_depth = min_t(u32, dev->tx_fifo_depth,
tx_fifo_depth);
dev->rx_fifo_depth = min_t(u32, dev->rx_fifo_depth,
rx_fifo_depth);
}
}
static int dw_i2c_plat_probe(struct platform_device *pdev)
{
struct dw_i2c_platform_data *pdata = dev_get_platdata(&pdev->dev);
struct dw_i2c_dev *dev;
struct i2c_adapter *adap;
struct resource *mem;
int irq, r;
u32 acpi_speed, ht = 0;
irq = platform_get_irq(pdev, 0);
if (irq < 0)
return irq;
dev = devm_kzalloc(&pdev->dev, sizeof(struct dw_i2c_dev), GFP_KERNEL);
if (!dev)
return -ENOMEM;
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
dev->base = devm_ioremap_resource(&pdev->dev, mem);
if (IS_ERR(dev->base))
return PTR_ERR(dev->base);
dev->dev = &pdev->dev;
dev->irq = irq;
platform_set_drvdata(pdev, dev);
dev->rst = devm_reset_control_get_optional_exclusive(&pdev->dev, NULL);
if (IS_ERR(dev->rst)) {
if (PTR_ERR(dev->rst) == -EPROBE_DEFER)
return -EPROBE_DEFER;
} else {
reset_control_deassert(dev->rst);
}
if (pdata) {
dev->clk_freq = pdata->i2c_scl_freq;
} else {
device_property_read_u32(&pdev->dev, "i2c-sda-hold-time-ns",
&ht);
device_property_read_u32(&pdev->dev, "i2c-sda-falling-time-ns",
&dev->sda_falling_time);
device_property_read_u32(&pdev->dev, "i2c-scl-falling-time-ns",
&dev->scl_falling_time);
device_property_read_u32(&pdev->dev, "clock-frequency",
&dev->clk_freq);
}
acpi_speed = i2c_acpi_find_bus_speed(&pdev->dev);
/*
* Find bus speed from the "clock-frequency" device property, ACPI
* or by using fast mode if neither is set.
*/
if (acpi_speed && dev->clk_freq)
dev->clk_freq = min(dev->clk_freq, acpi_speed);
else if (acpi_speed || dev->clk_freq)
dev->clk_freq = max(dev->clk_freq, acpi_speed);
else
dev->clk_freq = 400000;
if (has_acpi_companion(&pdev->dev))
dw_i2c_acpi_configure(pdev);
/*
* Only standard mode at 100kHz, fast mode at 400kHz,
* fast mode plus at 1MHz and high speed mode at 3.4MHz are supported.
*/
if (dev->clk_freq != 100000 && dev->clk_freq != 400000
&& dev->clk_freq != 1000000 && dev->clk_freq != 3400000) {
dev_err(&pdev->dev,
"Only 100kHz, 400kHz, 1MHz and 3.4MHz supported");
r = -EINVAL;
goto exit_reset;
}
r = i2c_dw_probe_lock_support(dev);
if (r)
goto exit_reset;
dev->functionality = I2C_FUNC_10BIT_ADDR | DW_IC_DEFAULT_FUNCTIONALITY;
dev->master_cfg = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE |
DW_IC_CON_RESTART_EN;
switch (dev->clk_freq) {
case 100000:
dev->master_cfg |= DW_IC_CON_SPEED_STD;
break;
case 3400000:
dev->master_cfg |= DW_IC_CON_SPEED_HIGH;
break;
default:
dev->master_cfg |= DW_IC_CON_SPEED_FAST;
}
dev->clk = devm_clk_get(&pdev->dev, NULL);
if (!i2c_dw_plat_prepare_clk(dev, true)) {
dev->get_clk_rate_khz = i2c_dw_get_clk_rate_khz;
if (!dev->sda_hold_time && ht)
dev->sda_hold_time = div_u64(
(u64)dev->get_clk_rate_khz(dev) * ht + 500000,
1000000);
}
dw_i2c_set_fifo_size(dev, pdev->id);
adap = &dev->adapter;
adap->owner = THIS_MODULE;
adap->class = I2C_CLASS_DEPRECATED;
ACPI_COMPANION_SET(&adap->dev, ACPI_COMPANION(&pdev->dev));
adap->dev.of_node = pdev->dev.of_node;
if (dev->pm_disabled) {
pm_runtime_forbid(&pdev->dev);
} else {
pm_runtime_set_autosuspend_delay(&pdev->dev, 1000);
pm_runtime_use_autosuspend(&pdev->dev);
pm_runtime_set_active(&pdev->dev);
pm_runtime_enable(&pdev->dev);
}
r = i2c_dw_probe(dev);
if (r)
goto exit_probe;
return r;
exit_probe:
if (!dev->pm_disabled)
pm_runtime_disable(&pdev->dev);
exit_reset:
if (!IS_ERR_OR_NULL(dev->rst))
reset_control_assert(dev->rst);
return r;
}
static int dw_i2c_plat_remove(struct platform_device *pdev)
{
struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
pm_runtime_get_sync(&pdev->dev);
i2c_del_adapter(&dev->adapter);
i2c_dw_disable(dev);
pm_runtime_dont_use_autosuspend(&pdev->dev);
pm_runtime_put_sync(&pdev->dev);
if (!dev->pm_disabled)
pm_runtime_disable(&pdev->dev);
if (!IS_ERR_OR_NULL(dev->rst))
reset_control_assert(dev->rst);
i2c_dw_remove_lock_support(dev);
return 0;
}
#ifdef CONFIG_OF
static const struct of_device_id dw_i2c_of_match[] = {
{ .compatible = "snps,designware-i2c", },
{},
};
MODULE_DEVICE_TABLE(of, dw_i2c_of_match);
#endif
#ifdef CONFIG_PM_SLEEP
static int dw_i2c_plat_prepare(struct device *dev)
{
return pm_runtime_suspended(dev);
}
static void dw_i2c_plat_complete(struct device *dev)
{
if (dev->power.direct_complete)
pm_request_resume(dev);
}
#else
#define dw_i2c_plat_prepare NULL
#define dw_i2c_plat_complete NULL
#endif
#ifdef CONFIG_PM
static int dw_i2c_plat_suspend(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct dw_i2c_dev *i_dev = platform_get_drvdata(pdev);
i2c_dw_disable(i_dev);
i2c_dw_plat_prepare_clk(i_dev, false);
return 0;
}
static int dw_i2c_plat_resume(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct dw_i2c_dev *i_dev = platform_get_drvdata(pdev);
i2c_dw_plat_prepare_clk(i_dev, true);
i2c_dw_init(i_dev);
return 0;
}
static const struct dev_pm_ops dw_i2c_dev_pm_ops = {
.prepare = dw_i2c_plat_prepare,
.complete = dw_i2c_plat_complete,
SET_SYSTEM_SLEEP_PM_OPS(dw_i2c_plat_suspend, dw_i2c_plat_resume)
SET_RUNTIME_PM_OPS(dw_i2c_plat_suspend, dw_i2c_plat_resume, NULL)
};
#define DW_I2C_DEV_PMOPS (&dw_i2c_dev_pm_ops)
#else
#define DW_I2C_DEV_PMOPS NULL
#endif
/* work with hotplug and coldplug */
MODULE_ALIAS("platform:i2c_designware");
static struct platform_driver dw_i2c_driver = {
.probe = dw_i2c_plat_probe,
.remove = dw_i2c_plat_remove,
.driver = {
.name = "i2c_designware",
.of_match_table = of_match_ptr(dw_i2c_of_match),
.acpi_match_table = ACPI_PTR(dw_i2c_acpi_match),
.pm = DW_I2C_DEV_PMOPS,
},
};
static int __init dw_i2c_init_driver(void)
{
return platform_driver_register(&dw_i2c_driver);
}
subsys_initcall(dw_i2c_init_driver);
static void __exit dw_i2c_exit_driver(void)
{
platform_driver_unregister(&dw_i2c_driver);
}
module_exit(dw_i2c_exit_driver);
MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>");
MODULE_DESCRIPTION("Synopsys DesignWare I2C bus adapter");
MODULE_LICENSE("GPL");
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