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|
/*
* Arche Platform driver to enable Unipro link.
*
* Copyright 2014-2015 Google Inc.
* Copyright 2014-2015 Linaro Ltd.
*
* Released under the GPLv2 only.
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/of_gpio.h>
#include <linux/of_platform.h>
#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include "arche_platform.h"
struct arche_platform_drvdata {
/* Control GPIO signals to and from AP <=> SVC */
int svc_reset_gpio;
bool is_reset_act_hi;
int svc_sysboot_gpio;
int wake_detect_gpio; /* bi-dir,maps to WAKE_MOD & WAKE_FRAME signals */
unsigned int svc_refclk_req;
struct clk *svc_ref_clk;
struct pinctrl *pinctrl;
struct pinctrl_state *pin_default;
int num_apbs;
struct delayed_work delayed_work;
struct device *dev;
};
static inline void svc_reset_onoff(unsigned int gpio, bool onoff)
{
gpio_set_value(gpio, onoff);
}
/**
* svc_delayed_work - Time to give SVC to boot.
*/
static void svc_delayed_work(struct work_struct *work)
{
struct arche_platform_drvdata *arche_pdata =
container_of(work, struct arche_platform_drvdata, delayed_work.work);
struct device *dev = arche_pdata->dev;
struct device_node *np = dev->of_node;
int timeout = 50;
int ret;
/*
* 1. SVC and AP boot independently, with AP<-->SVC wake/detect pin
* deasserted (LOW in this case)
* 2.1. SVC allows 360 milliseconds to elapse after switch boots to work
* around bug described in ENG-330.
* 2.2. AP asserts wake/detect pin (HIGH) (this can proceed in parallel with 2.1)
* 3. SVC detects assertion of wake/detect pin, and sends "wake out" signal to AP
* 4. AP receives "wake out" signal, takes AP Bridges through their power
* on reset sequence as defined in the bridge ASIC reference manuals
* 5. AP takes USB3613 through its power on reset sequence
* 6. AP enumerates AP Bridges
*/
gpio_set_value(arche_pdata->wake_detect_gpio, 1);
gpio_direction_input(arche_pdata->wake_detect_gpio);
do {
/* Read the wake_detect GPIO, for WAKE_OUT event from SVC */
if (gpio_get_value(arche_pdata->wake_detect_gpio) == 0)
break;
msleep(100);
} while(timeout--);
if (timeout >= 0) {
ret = of_platform_populate(np, NULL, NULL, dev);
if (!ret) {
/* re-assert wake_detect to confirm SVC WAKE_OUT */
gpio_direction_output(arche_pdata->wake_detect_gpio, 1);
return;
}
}
/* FIXME: We may want to limit retries here */
gpio_direction_output(arche_pdata->wake_detect_gpio, 0);
schedule_delayed_work(&arche_pdata->delayed_work, msecs_to_jiffies(2000));
}
/* Export gpio's to user space */
static void export_gpios(struct arche_platform_drvdata *arche_pdata)
{
gpio_export(arche_pdata->svc_reset_gpio, false);
gpio_export(arche_pdata->svc_sysboot_gpio, false);
}
static void unexport_gpios(struct arche_platform_drvdata *arche_pdata)
{
gpio_unexport(arche_pdata->svc_reset_gpio);
gpio_unexport(arche_pdata->svc_sysboot_gpio);
}
static void arche_platform_cleanup(struct arche_platform_drvdata *arche_pdata)
{
clk_disable_unprepare(arche_pdata->svc_ref_clk);
/* As part of exit, put APB back in reset state */
svc_reset_onoff(arche_pdata->svc_reset_gpio,
arche_pdata->is_reset_act_hi);
}
static int arche_platform_probe(struct platform_device *pdev)
{
struct arche_platform_drvdata *arche_pdata;
struct device *dev = &pdev->dev;
struct device_node *np = dev->of_node;
int ret;
arche_pdata = devm_kzalloc(&pdev->dev, sizeof(*arche_pdata), GFP_KERNEL);
if (!arche_pdata)
return -ENOMEM;
/* setup svc reset gpio */
arche_pdata->is_reset_act_hi = of_property_read_bool(np,
"svc,reset-active-high");
arche_pdata->svc_reset_gpio = of_get_named_gpio(np, "svc,reset-gpio", 0);
if (arche_pdata->svc_reset_gpio < 0) {
dev_err(dev, "failed to get reset-gpio\n");
return arche_pdata->svc_reset_gpio;
}
ret = devm_gpio_request(dev, arche_pdata->svc_reset_gpio, "svc-reset");
if (ret) {
dev_err(dev, "failed to request svc-reset gpio:%d\n", ret);
return ret;
}
ret = gpio_direction_output(arche_pdata->svc_reset_gpio,
arche_pdata->is_reset_act_hi);
if (ret) {
dev_err(dev, "failed to set svc-reset gpio dir:%d\n", ret);
return ret;
}
arche_pdata->svc_sysboot_gpio = of_get_named_gpio(np,
"svc,sysboot-gpio", 0);
if (arche_pdata->svc_sysboot_gpio < 0) {
dev_err(dev, "failed to get sysboot gpio\n");
return arche_pdata->svc_sysboot_gpio;
}
ret = devm_gpio_request(dev, arche_pdata->svc_sysboot_gpio, "sysboot0");
if (ret) {
dev_err(dev, "failed to request sysboot0 gpio:%d\n", ret);
return ret;
}
ret = gpio_direction_output(arche_pdata->svc_sysboot_gpio, 0);
if (ret) {
dev_err(dev, "failed to set svc-reset gpio dir:%d\n", ret);
return ret;
}
/* setup the clock request gpio first */
arche_pdata->svc_refclk_req = of_get_named_gpio(np,
"svc,refclk-req-gpio", 0);
if (arche_pdata->svc_refclk_req < 0) {
dev_err(dev, "failed to get svc clock-req gpio\n");
return arche_pdata->svc_refclk_req;
}
ret = devm_gpio_request(dev, arche_pdata->svc_refclk_req, "svc-clk-req");
if (ret) {
dev_err(dev, "failed to request svc-clk-req gpio: %d\n", ret);
return ret;
}
ret = gpio_direction_input(arche_pdata->svc_refclk_req);
if (ret) {
dev_err(dev, "failed to set svc-clk-req gpio dir :%d\n", ret);
return ret;
}
/* setup refclk2 to follow the pin */
arche_pdata->svc_ref_clk = devm_clk_get(dev, "svc_ref_clk");
if (IS_ERR(arche_pdata->svc_ref_clk)) {
ret = PTR_ERR(arche_pdata->svc_ref_clk);
dev_err(dev, "failed to get svc_ref_clk: %d\n", ret);
return ret;
}
ret = clk_prepare_enable(arche_pdata->svc_ref_clk);
if (ret) {
dev_err(dev, "failed to enable svc_ref_clk: %d\n", ret);
return ret;
}
platform_set_drvdata(pdev, arche_pdata);
arche_pdata->num_apbs = of_get_child_count(np);
dev_dbg(dev, "Number of APB's available - %d\n", arche_pdata->num_apbs);
arche_pdata->wake_detect_gpio = of_get_named_gpio(np, "svc,wake-detect-gpio", 0);
if (arche_pdata->wake_detect_gpio < 0) {
dev_err(dev, "failed to get wake detect gpio\n");
ret = arche_pdata->wake_detect_gpio;
goto exit;
}
ret = devm_gpio_request(dev, arche_pdata->wake_detect_gpio, "wake detect");
if (ret) {
dev_err(dev, "Failed requesting wake_detect gpio %d\n",
arche_pdata->wake_detect_gpio);
goto exit;
}
/* deassert wake detect */
gpio_direction_output(arche_pdata->wake_detect_gpio, 0);
/* bring SVC out of reset */
svc_reset_onoff(arche_pdata->svc_reset_gpio,
!arche_pdata->is_reset_act_hi);
arche_pdata->dev = &pdev->dev;
INIT_DELAYED_WORK(&arche_pdata->delayed_work, svc_delayed_work);
schedule_delayed_work(&arche_pdata->delayed_work, msecs_to_jiffies(2000));
export_gpios(arche_pdata);
dev_info(dev, "Device registered successfully\n");
return 0;
exit:
arche_platform_cleanup(arche_pdata);
return ret;
}
static int arche_remove_child(struct device *dev, void *unused)
{
struct platform_device *pdev = to_platform_device(dev);
platform_device_unregister(pdev);
return 0;
}
static int arche_platform_remove(struct platform_device *pdev)
{
struct arche_platform_drvdata *arche_pdata = platform_get_drvdata(pdev);
device_for_each_child(&pdev->dev, NULL, arche_remove_child);
arche_platform_cleanup(arche_pdata);
platform_set_drvdata(pdev, NULL);
unexport_gpios(arche_pdata);
return 0;
}
static int arche_platform_suspend(struct device *dev)
{
/*
* If timing profile premits, we may shutdown bridge
* completely
*
* TODO: sequence ??
*
* Also, need to make sure we meet precondition for unipro suspend
* Precondition: Definition ???
*/
return 0;
}
static int arche_platform_resume(struct device *dev)
{
/*
* Atleast for ES2 we have to meet the delay requirement between
* unipro switch and AP bridge init, depending on whether bridge is in
* OFF state or standby state.
*
* Based on whether bridge is in standby or OFF state we may have to
* assert multiple signals. Please refer to WDM spec, for more info.
*
*/
return 0;
}
static SIMPLE_DEV_PM_OPS(arche_platform_pm_ops,
arche_platform_suspend,
arche_platform_resume);
static struct of_device_id arche_platform_of_match[] = {
{ .compatible = "google,arche-platform", }, /* Use PID/VID of SVC device */
{ },
};
static struct of_device_id
|