OpenCloudOS-Kernel/drivers/iio/trigger/stm32-timer-trigger.c

343 lines
8.3 KiB
C

/*
* Copyright (C) STMicroelectronics 2016
*
* Author: Benjamin Gaignard <benjamin.gaignard@st.com>
*
* License terms: GNU General Public License (GPL), version 2
*/
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/timer/stm32-timer-trigger.h>
#include <linux/iio/trigger.h>
#include <linux/mfd/stm32-timers.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#define MAX_TRIGGERS 6
/* List the triggers created by each timer */
static const void *triggers_table[][MAX_TRIGGERS] = {
{ TIM1_TRGO, TIM1_CH1, TIM1_CH2, TIM1_CH3, TIM1_CH4,},
{ TIM2_TRGO, TIM2_CH1, TIM2_CH2, TIM2_CH3, TIM2_CH4,},
{ TIM3_TRGO, TIM3_CH1, TIM3_CH2, TIM3_CH3, TIM3_CH4,},
{ TIM4_TRGO, TIM4_CH1, TIM4_CH2, TIM4_CH3, TIM4_CH4,},
{ TIM5_TRGO, TIM5_CH1, TIM5_CH2, TIM5_CH3, TIM5_CH4,},
{ TIM6_TRGO,},
{ TIM7_TRGO,},
{ TIM8_TRGO, TIM8_CH1, TIM8_CH2, TIM8_CH3, TIM8_CH4,},
{ TIM9_TRGO, TIM9_CH1, TIM9_CH2,},
{ }, /* timer 10 */
{ }, /* timer 11 */
{ TIM12_TRGO, TIM12_CH1, TIM12_CH2,},
};
struct stm32_timer_trigger {
struct device *dev;
struct regmap *regmap;
struct clk *clk;
u32 max_arr;
const void *triggers;
};
static int stm32_timer_start(struct stm32_timer_trigger *priv,
unsigned int frequency)
{
unsigned long long prd, div;
int prescaler = 0;
u32 ccer, cr1;
/* Period and prescaler values depends of clock rate */
div = (unsigned long long)clk_get_rate(priv->clk);
do_div(div, frequency);
prd = div;
/*
* Increase prescaler value until we get a result that fit
* with auto reload register maximum value.
*/
while (div > priv->max_arr) {
prescaler++;
div = prd;
do_div(div, (prescaler + 1));
}
prd = div;
if (prescaler > MAX_TIM_PSC) {
dev_err(priv->dev, "prescaler exceeds the maximum value\n");
return -EINVAL;
}
/* Check if nobody else use the timer */
regmap_read(priv->regmap, TIM_CCER, &ccer);
if (ccer & TIM_CCER_CCXE)
return -EBUSY;
regmap_read(priv->regmap, TIM_CR1, &cr1);
if (!(cr1 & TIM_CR1_CEN))
clk_enable(priv->clk);
regmap_write(priv->regmap, TIM_PSC, prescaler);
regmap_write(priv->regmap, TIM_ARR, prd - 1);
regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, TIM_CR1_ARPE);
/* Force master mode to update mode */
regmap_update_bits(priv->regmap, TIM_CR2, TIM_CR2_MMS, 0x20);
/* Make sure that registers are updated */
regmap_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG);
/* Enable controller */
regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, TIM_CR1_CEN);
return 0;
}
static void stm32_timer_stop(struct stm32_timer_trigger *priv)
{
u32 ccer, cr1;
regmap_read(priv->regmap, TIM_CCER, &ccer);
if (ccer & TIM_CCER_CCXE)
return;
regmap_read(priv->regmap, TIM_CR1, &cr1);
if (cr1 & TIM_CR1_CEN)
clk_disable(priv->clk);
/* Stop timer */
regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
regmap_write(priv->regmap, TIM_PSC, 0);
regmap_write(priv->regmap, TIM_ARR, 0);
/* Make sure that registers are updated */
regmap_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG);
}
static ssize_t stm32_tt_store_frequency(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
struct iio_trigger *trig = to_iio_trigger(dev);
struct stm32_timer_trigger *priv = iio_trigger_get_drvdata(trig);
unsigned int freq;
int ret;
ret = kstrtouint(buf, 10, &freq);
if (ret)
return ret;
if (freq == 0) {
stm32_timer_stop(priv);
} else {
ret = stm32_timer_start(priv, freq);
if (ret)
return ret;
}
return len;
}
static ssize_t stm32_tt_read_frequency(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct iio_trigger *trig = to_iio_trigger(dev);
struct stm32_timer_trigger *priv = iio_trigger_get_drvdata(trig);
u32 psc, arr, cr1;
unsigned long long freq = 0;
regmap_read(priv->regmap, TIM_CR1, &cr1);
regmap_read(priv->regmap, TIM_PSC, &psc);
regmap_read(priv->regmap, TIM_ARR, &arr);
if (psc && arr && (cr1 & TIM_CR1_CEN)) {
freq = (unsigned long long)clk_get_rate(priv->clk);
do_div(freq, psc);
do_div(freq, arr);
}
return sprintf(buf, "%d\n", (unsigned int)freq);
}
static IIO_DEV_ATTR_SAMP_FREQ(0660,
stm32_tt_read_frequency,
stm32_tt_store_frequency);
static char *master_mode_table[] = {
"reset",
"enable",
"update",
"compare_pulse",
"OC1REF",
"OC2REF",
"OC3REF",
"OC4REF"
};
static ssize_t stm32_tt_show_master_mode(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct stm32_timer_trigger *priv = iio_priv(indio_dev);
u32 cr2;
regmap_read(priv->regmap, TIM_CR2, &cr2);
cr2 = (cr2 & TIM_CR2_MMS) >> TIM_CR2_MMS_SHIFT;
return snprintf(buf, PAGE_SIZE, "%s\n", master_mode_table[cr2]);
}
static ssize_t stm32_tt_store_master_mode(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct stm32_timer_trigger *priv = iio_priv(indio_dev);
int i;
for (i = 0; i < ARRAY_SIZE(master_mode_table); i++) {
if (!strncmp(master_mode_table[i], buf,
strlen(master_mode_table[i]))) {
regmap_update_bits(priv->regmap, TIM_CR2,
TIM_CR2_MMS, i << TIM_CR2_MMS_SHIFT);
/* Make sure that registers are updated */
regmap_update_bits(priv->regmap, TIM_EGR,
TIM_EGR_UG, TIM_EGR_UG);
return len;
}
}
return -EINVAL;
}
static IIO_CONST_ATTR(master_mode_available,
"reset enable update compare_pulse OC1REF OC2REF OC3REF OC4REF");
static IIO_DEVICE_ATTR(master_mode, 0660,
stm32_tt_show_master_mode,
stm32_tt_store_master_mode,
0);
static struct attribute *stm32_trigger_attrs[] = {
&iio_dev_attr_sampling_frequency.dev_attr.attr,
&iio_dev_attr_master_mode.dev_attr.attr,
&iio_const_attr_master_mode_available.dev_attr.attr,
NULL,
};
static const struct attribute_group stm32_trigger_attr_group = {
.attrs = stm32_trigger_attrs,
};
static const struct attribute_group *stm32_trigger_attr_groups[] = {
&stm32_trigger_attr_group,
NULL,
};
static const struct iio_trigger_ops timer_trigger_ops = {
.owner = THIS_MODULE,
};
static int stm32_setup_iio_triggers(struct stm32_timer_trigger *priv)
{
int ret;
const char * const *cur = priv->triggers;
while (cur && *cur) {
struct iio_trigger *trig;
trig = devm_iio_trigger_alloc(priv->dev, "%s", *cur);
if (!trig)
return -ENOMEM;
trig->dev.parent = priv->dev->parent;
trig->ops = &timer_trigger_ops;
/*
* sampling frequency and master mode attributes
* should only be available on trgo trigger which
* is always the first in the list.
*/
if (cur == priv->triggers)
trig->dev.groups = stm32_trigger_attr_groups;
iio_trigger_set_drvdata(trig, priv);
ret = devm_iio_trigger_register(priv->dev, trig);
if (ret)
return ret;
cur++;
}
return 0;
}
/**
* is_stm32_timer_trigger
* @trig: trigger to be checked
*
* return true if the trigger is a valid stm32 iio timer trigger
* either return false
*/
bool is_stm32_timer_trigger(struct iio_trigger *trig)
{
return (trig->ops == &timer_trigger_ops);
}
EXPORT_SYMBOL(is_stm32_timer_trigger);
static int stm32_timer_trigger_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct stm32_timer_trigger *priv;
struct stm32_timers *ddata = dev_get_drvdata(pdev->dev.parent);
unsigned int index;
int ret;
if (of_property_read_u32(dev->of_node, "reg", &index))
return -EINVAL;
if (index >= ARRAY_SIZE(triggers_table))
return -EINVAL;
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->dev = dev;
priv->regmap = ddata->regmap;
priv->clk = ddata->clk;
priv->max_arr = ddata->max_arr;
priv->triggers = triggers_table[index];
ret = stm32_setup_iio_triggers(priv);
if (ret)
return ret;
platform_set_drvdata(pdev, priv);
return 0;
}
static const struct of_device_id stm32_trig_of_match[] = {
{ .compatible = "st,stm32-timer-trigger", },
{ /* end node */ },
};
MODULE_DEVICE_TABLE(of, stm32_trig_of_match);
static struct platform_driver stm32_timer_trigger_driver = {
.probe = stm32_timer_trigger_probe,
.driver = {
.name = "stm32-timer-trigger",
.of_match_table = stm32_trig_of_match,
},
};
module_platform_driver(stm32_timer_trigger_driver);
MODULE_ALIAS("platform: stm32-timer-trigger");
MODULE_DESCRIPTION("STMicroelectronics STM32 Timer Trigger driver");
MODULE_LICENSE("GPL v2");