summaryrefslogtreecommitdiff
path: root/drivers/iio/adc/spear_adc.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/iio/adc/spear_adc.c')
-rw-r--r--drivers/iio/adc/spear_adc.c114
1 files changed, 44 insertions, 70 deletions
diff --git a/drivers/iio/adc/spear_adc.c b/drivers/iio/adc/spear_adc.c
index 0ad536494e8f..50b0a607baeb 100644
--- a/drivers/iio/adc/spear_adc.c
+++ b/drivers/iio/adc/spear_adc.c
@@ -5,18 +5,19 @@
* Copyright 2012 Stefan Roese <sr@denx.de>
*/
+#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
+#include <linux/property.h>
#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/io.h>
+#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/completion.h>
-#include <linux/of.h>
-#include <linux/of_address.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
@@ -29,9 +30,9 @@
/* Bit definitions for SPEAR_ADC_STATUS */
#define SPEAR_ADC_STATUS_START_CONVERSION BIT(0)
-#define SPEAR_ADC_STATUS_CHANNEL_NUM(x) ((x) << 1)
+#define SPEAR_ADC_STATUS_CHANNEL_NUM_MASK GENMASK(3, 1)
#define SPEAR_ADC_STATUS_ADC_ENABLE BIT(4)
-#define SPEAR_ADC_STATUS_AVG_SAMPLE(x) ((x) << 5)
+#define SPEAR_ADC_STATUS_AVG_SAMPLE_MASK GENMASK(8, 5)
#define SPEAR_ADC_STATUS_VREF_INTERNAL BIT(9)
#define SPEAR_ADC_DATA_MASK 0x03ff
@@ -70,11 +71,20 @@ struct adc_regs_spear6xx {
};
struct spear_adc_state {
- struct device_node *np;
+ struct device *dev;
struct adc_regs_spear3xx __iomem *adc_base_spear3xx;
struct adc_regs_spear6xx __iomem *adc_base_spear6xx;
struct clk *clk;
struct completion completion;
+ /*
+ * Lock to protect the device state during a potential concurrent
+ * read access from userspace. Reading a raw value requires a sequence
+ * of register writes, then a wait for a completion callback,
+ * and finally a register read, during which userspace could issue
+ * another read request. This lock protects a read access from
+ * ocurring before another one has finished.
+ */
+ struct mutex lock;
u32 current_clk;
u32 sampling_freq;
u32 avg_samples;
@@ -114,7 +124,7 @@ static void spear_adc_set_ctrl(struct spear_adc_state *st, int n,
static u32 spear_adc_get_average(struct spear_adc_state *st)
{
- if (of_device_is_compatible(st->np, "st,spear600-adc")) {
+ if (device_is_compatible(st->dev, "st,spear600-adc")) {
return __raw_readl(&st->adc_base_spear6xx->average.msb) &
SPEAR_ADC_DATA_MASK;
} else {
@@ -125,7 +135,7 @@ static u32 spear_adc_get_average(struct spear_adc_state *st)
static void spear_adc_set_scanrate(struct spear_adc_state *st, u32 rate)
{
- if (of_device_is_compatible(st->np, "st,spear600-adc")) {
+ if (device_is_compatible(st->dev, "st,spear600-adc")) {
__raw_writel(SPEAR600_ADC_SCAN_RATE_LO(rate),
&st->adc_base_spear6xx->scan_rate_lo);
__raw_writel(SPEAR600_ADC_SCAN_RATE_HI(rate),
@@ -146,10 +156,10 @@ static int spear_adc_read_raw(struct iio_dev *indio_dev,
switch (mask) {
case IIO_CHAN_INFO_RAW:
- mutex_lock(&indio_dev->mlock);
+ mutex_lock(&st->lock);
- status = SPEAR_ADC_STATUS_CHANNEL_NUM(chan->channel) |
- SPEAR_ADC_STATUS_AVG_SAMPLE(st->avg_samples) |
+ status = FIELD_PREP(SPEAR_ADC_STATUS_CHANNEL_NUM_MASK, chan->channel) |
+ FIELD_PREP(SPEAR_ADC_STATUS_AVG_SAMPLE_MASK, st->avg_samples) |
SPEAR_ADC_STATUS_START_CONVERSION |
SPEAR_ADC_STATUS_ADC_ENABLE;
if (st->vref_external == 0)
@@ -159,7 +169,7 @@ static int spear_adc_read_raw(struct iio_dev *indio_dev,
wait_for_completion(&st->completion); /* set by ISR */
*val = st->value;
- mutex_unlock(&indio_dev->mlock);
+ mutex_unlock(&st->lock);
return IIO_VAL_INT;
@@ -187,7 +197,7 @@ static int spear_adc_write_raw(struct iio_dev *indio_dev,
if (mask != IIO_CHAN_INFO_SAMP_FREQ)
return -EINVAL;
- mutex_lock(&indio_dev->mlock);
+ mutex_lock(&st->lock);
if ((val < SPEAR_ADC_CLK_MIN) ||
(val > SPEAR_ADC_CLK_MAX) ||
@@ -199,7 +209,7 @@ static int spear_adc_write_raw(struct iio_dev *indio_dev,
spear_adc_set_clk(st, val);
out:
- mutex_unlock(&indio_dev->mlock);
+ mutex_unlock(&st->lock);
return ret;
}
@@ -257,7 +267,6 @@ static const struct iio_info spear_adc_info = {
static int spear_adc_probe(struct platform_device *pdev)
{
- struct device_node *np = pdev->dev.of_node;
struct device *dev = &pdev->dev;
struct spear_adc_state *st;
struct iio_dev *indio_dev = NULL;
@@ -265,13 +274,13 @@ static int spear_adc_probe(struct platform_device *pdev)
int irq;
indio_dev = devm_iio_device_alloc(dev, sizeof(struct spear_adc_state));
- if (!indio_dev) {
- dev_err(dev, "failed allocating iio device\n");
+ if (!indio_dev)
return -ENOMEM;
- }
st = iio_priv(indio_dev);
- st->np = np;
+ st->dev = dev;
+
+ mutex_init(&st->lock);
/*
* SPEAr600 has a different register layout than other SPEAr SoC's
@@ -285,101 +294,66 @@ static int spear_adc_probe(struct platform_device *pdev)
st->adc_base_spear3xx =
(struct adc_regs_spear3xx __iomem *)st->adc_base_spear6xx;
- st->clk = devm_clk_get(dev, NULL);
- if (IS_ERR(st->clk)) {
- dev_err(dev, "failed getting clock\n");
- return PTR_ERR(st->clk);
- }
-
- ret = clk_prepare_enable(st->clk);
- if (ret) {
- dev_err(dev, "failed enabling clock\n");
- return ret;
- }
+ st->clk = devm_clk_get_enabled(dev, NULL);
+ if (IS_ERR(st->clk))
+ return dev_err_probe(dev, PTR_ERR(st->clk),
+ "failed enabling clock\n");
irq = platform_get_irq(pdev, 0);
- if (irq <= 0) {
- ret = -EINVAL;
- goto errout2;
- }
+ if (irq < 0)
+ return irq;
ret = devm_request_irq(dev, irq, spear_adc_isr, 0, SPEAR_ADC_MOD_NAME,
st);
- if (ret < 0) {
- dev_err(dev, "failed requesting interrupt\n");
- goto errout2;
- }
+ if (ret < 0)
+ return dev_err_probe(dev, ret, "failed requesting interrupt\n");
- if (of_property_read_u32(np, "sampling-frequency",
- &st->sampling_freq)) {
- dev_err(dev, "sampling-frequency missing in DT\n");
- ret = -EINVAL;
- goto errout2;
- }
+ if (device_property_read_u32(dev, "sampling-frequency", &st->sampling_freq))
+ return dev_err_probe(dev, -EINVAL,
+ "sampling-frequency missing in DT\n");
/*
* Optional avg_samples defaults to 0, resulting in single data
* conversion
*/
- of_property_read_u32(np, "average-samples", &st->avg_samples);
+ device_property_read_u32(dev, "average-samples", &st->avg_samples);
/*
* Optional vref_external defaults to 0, resulting in internal vref
* selection
*/
- of_property_read_u32(np, "vref-external", &st->vref_external);
+ device_property_read_u32(dev, "vref-external", &st->vref_external);
spear_adc_configure(st);
- platform_set_drvdata(pdev, indio_dev);
-
init_completion(&st->completion);
indio_dev->name = SPEAR_ADC_MOD_NAME;
- indio_dev->dev.parent = dev;
indio_dev->info = &spear_adc_info;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = spear_adc_iio_channels;
indio_dev->num_channels = ARRAY_SIZE(spear_adc_iio_channels);
- ret = iio_device_register(indio_dev);
+ ret = devm_iio_device_register(dev, indio_dev);
if (ret)
- goto errout2;
+ return ret;
dev_info(dev, "SPEAR ADC driver loaded, IRQ %d\n", irq);
return 0;
-
-errout2:
- clk_disable_unprepare(st->clk);
- return ret;
-}
-
-static int spear_adc_remove(struct platform_device *pdev)
-{
- struct iio_dev *indio_dev = platform_get_drvdata(pdev);
- struct spear_adc_state *st = iio_priv(indio_dev);
-
- iio_device_unregister(indio_dev);
- clk_disable_unprepare(st->clk);
-
- return 0;
}
-#ifdef CONFIG_OF
static const struct of_device_id spear_adc_dt_ids[] = {
{ .compatible = "st,spear600-adc", },
- { /* sentinel */ }
+ { }
};
MODULE_DEVICE_TABLE(of, spear_adc_dt_ids);
-#endif
static struct platform_driver spear_adc_driver = {
.probe = spear_adc_probe,
- .remove = spear_adc_remove,
.driver = {
.name = SPEAR_ADC_MOD_NAME,
- .of_match_table = of_match_ptr(spear_adc_dt_ids),
+ .of_match_table = spear_adc_dt_ids,
},
};
generated by cgit (git 2.34.1) at 2025-12-26 04:54:39 +0000