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alistair23-linux/drivers/i2c/busses/i2c-designware-platdrv.c
David Box 894acb2f82 i2c: designware: Add Intel Baytrail PMIC I2C bus support 
This patch implements an I2C bus sharing mechanism between the host and platform
hardware on select Intel BayTrail SoC platforms using the X-Powers AXP288 PMIC.

On these platforms access to the PMIC must be shared with platform hardware. The
hardware unit assumes full control of the I2C bus and the host must request
access through a special semaphore. Hardware control of the bus also makes it
necessary to disable runtime pm to avoid interfering with hardware transactions.

Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-01-26 12:26:25 +01:00

361 lines
9.2 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/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/io.h>
#include <linux/slab.h>
#include <linux/acpi.h>
#include <linux/platform_data/i2c-designware.h>
#include "i2c-designware-core.h"
static struct i2c_algorithm i2c_dw_algo = {
.master_xfer = i2c_dw_xfer,
.functionality = i2c_dw_func,
};
static u32 i2c_dw_get_clk_rate_khz(struct dw_i2c_dev *dev)
{
return clk_get_rate(dev->clk)/1000;
}
#ifdef CONFIG_ACPI
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 (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;
if (sda_hold)
*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);
const struct acpi_device_id *id;
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 if
* it exists for both supported speed modes.
*/
dw_i2c_acpi_params(pdev, "SSCN", &dev->ss_hcnt, &dev->ss_lcnt, NULL);
dw_i2c_acpi_params(pdev, "FMCN", &dev->fs_hcnt, &dev->fs_lcnt,
&dev->sda_hold_time);
/*
* Provide a way for Designware I2C host controllers that are not
* based on Intel LPSS to specify their input clock frequency via
* id->driver_data.
*/
id = acpi_match_device(pdev->dev.driver->acpi_match_table, &pdev->dev);
if (id && id->driver_data)
clk_register_fixed_rate(&pdev->dev, dev_name(&pdev->dev), NULL,
CLK_IS_ROOT, id->driver_data);
return 0;
}
static void dw_i2c_acpi_unconfigure(struct platform_device *pdev)
{
struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
const struct acpi_device_id *id;
id = acpi_match_device(pdev->dev.driver->acpi_match_table, &pdev->dev);
if (id && id->driver_data)
clk_unregister(dev->clk);
}
static const struct acpi_device_id dw_i2c_acpi_match[] = {
{ "INT33C2", 0 },
{ "INT33C3", 0 },
{ "INT3432", 0 },
{ "INT3433", 0 },
{ "80860F41", 0 },
{ "808622C1", 0 },
{ "AMD0010", 133 * 1000 * 1000 },
{ }
};
MODULE_DEVICE_TABLE(acpi, dw_i2c_acpi_match);
#else
static inline int dw_i2c_acpi_configure(struct platform_device *pdev)
{
return -ENODEV;
}
static inline void dw_i2c_acpi_unconfigure(struct platform_device *pdev) { }
#endif
static int dw_i2c_probe(struct platform_device *pdev)
{
struct dw_i2c_dev *dev;
struct i2c_adapter *adap;
struct resource *mem;
struct dw_i2c_platform_data *pdata;
int irq, r;
u32 clk_freq, ht = 0;
irq = platform_get_irq(pdev, 0);
if (irq < 0) {
dev_err(&pdev->dev, "no irq resource?\n");
return irq; /* -ENXIO */
}
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);
init_completion(&dev->cmd_complete);
mutex_init(&dev->lock);
dev->dev = &pdev->dev;
dev->irq = irq;
platform_set_drvdata(pdev, dev);
/* fast mode by default because of legacy reasons */
clk_freq = 400000;
if (ACPI_COMPANION(&pdev->dev)) {
dw_i2c_acpi_configure(pdev);
} else if (pdev->dev.of_node) {
of_property_read_u32(pdev->dev.of_node,
"i2c-sda-hold-time-ns", &ht);
of_property_read_u32(pdev->dev.of_node,
"i2c-sda-falling-time-ns",
&dev->sda_falling_time);
of_property_read_u32(pdev->dev.of_node,
"i2c-scl-falling-time-ns",
&dev->scl_falling_time);
of_property_read_u32(pdev->dev.of_node, "clock-frequency",
&clk_freq);
/* Only standard mode at 100kHz and fast mode at 400kHz
* are supported.
*/
if (clk_freq != 100000 && clk_freq != 400000) {
dev_err(&pdev->dev, "Only 100kHz and 400kHz supported");
return -EINVAL;
}
} else {
pdata = dev_get_platdata(&pdev->dev);
if (pdata)
clk_freq = pdata->i2c_scl_freq;
}
r = i2c_dw_eval_lock_support(dev);
if (r)
return r;
dev->functionality =
I2C_FUNC_I2C |
I2C_FUNC_10BIT_ADDR |
I2C_FUNC_SMBUS_BYTE |
I2C_FUNC_SMBUS_BYTE_DATA |
I2C_FUNC_SMBUS_WORD_DATA |
I2C_FUNC_SMBUS_I2C_BLOCK;
if (clk_freq == 100000)
dev->master_cfg = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE |
DW_IC_CON_RESTART_EN | DW_IC_CON_SPEED_STD;
else
dev->master_cfg = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE |
DW_IC_CON_RESTART_EN | DW_IC_CON_SPEED_FAST;
dev->clk = devm_clk_get(&pdev->dev, NULL);
dev->get_clk_rate_khz = i2c_dw_get_clk_rate_khz;
if (IS_ERR(dev->clk))
return PTR_ERR(dev->clk);
clk_prepare_enable(dev->clk);
if (!dev->sda_hold_time && ht) {
u32 ic_clk = dev->get_clk_rate_khz(dev);
dev->sda_hold_time = div_u64((u64)ic_clk * ht + 500000,
1000000);
}
if (!dev->tx_fifo_depth) {
u32 param1 = i2c_dw_read_comp_param(dev);
dev->tx_fifo_depth = ((param1 >> 16) & 0xff) + 1;
dev->rx_fifo_depth = ((param1 >> 8) & 0xff) + 1;
dev->adapter.nr = pdev->id;
}
r = i2c_dw_init(dev);
if (r)
return r;
i2c_dw_disable_int(dev);
r = devm_request_irq(&pdev->dev, dev->irq, i2c_dw_isr, IRQF_SHARED,
pdev->name, dev);
if (r) {
dev_err(&pdev->dev, "failure requesting irq %i\n", dev->irq);
return r;
}
adap = &dev->adapter;
i2c_set_adapdata(adap, dev);
adap->owner = THIS_MODULE;
adap->class = I2C_CLASS_DEPRECATED;
strlcpy(adap->name, "Synopsys DesignWare I2C adapter",
sizeof(adap->name));
adap->algo = &i2c_dw_algo;
adap->dev.parent = &pdev->dev;
adap->dev.of_node = pdev->dev.of_node;
r = i2c_add_numbered_adapter(adap);
if (r) {
dev_err(&pdev->dev, "failure adding adapter\n");
return r;
}
if (dev->pm_runtime_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);
}
return 0;
}
static int dw_i2c_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_put(&pdev->dev);
pm_runtime_disable(&pdev->dev);
if (ACPI_COMPANION(&pdev->dev))
dw_i2c_acpi_unconfigure(pdev);
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
static int dw_i2c_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);
clk_disable_unprepare(i_dev->clk);
return 0;
}
static int dw_i2c_resume(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct dw_i2c_dev *i_dev = platform_get_drvdata(pdev);
clk_prepare_enable(i_dev->clk);
if (!i_dev->pm_runtime_disabled)
i2c_dw_init(i_dev);
return 0;
}
#endif
static UNIVERSAL_DEV_PM_OPS(dw_i2c_dev_pm_ops, dw_i2c_suspend,
dw_i2c_resume, NULL);
/* work with hotplug and coldplug */
MODULE_ALIAS("platform:i2c_designware");
static struct platform_driver dw_i2c_driver = {
.probe = dw_i2c_probe,
.remove = dw_i2c_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_pm_ops,
},
};
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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