The hardware has two current sources ISRC0 and ISRC1 to allow measuring
resistors without additional circuitry. This commit makes them available
as regulators.
Tested on an imx233-olinuxino board.
Signed-off-by: Harald Geyer <harald@xxxxxxxxx>
---
The current regulator API doesn't fit this type of device very well: Typically
consumers will want to set a defined current, ie. min_uA == max_uA, but they
can't without help from configuration data, because the valid values aren't
reported by the API for current regulators. I have been thinking about
extending the API, but currently AFAIK no such consumers exist and most
users, like myself, will force the regulator to a defined value in
devicetree anyway.
.../bindings/staging/iio/adc/mxs-lradc.txt | 29 ++++
drivers/iio/adc/Kconfig | 1 +
drivers/iio/adc/mxs-lradc.c | 152 +++++++++++++++++++++
3 files changed, 182 insertions(+)
diff --git a/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt b/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt
index 555fb11..983952c 100644
--- a/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt
+++ b/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt
@@ -19,6 +19,15 @@ Optional properties:
- fsl,settling: delay between plate switch to next sample. Allowed value is
1 ... 2047. It counts at 2 kHz and its default is
10 (= 5 ms)
+- ISRC0: A node describing the regulator of internal current source 0
+- ISRC1: A node describing the regulator of internal current source 1
+
+Required properties for the ISRCx sub-nodes:
+- regulator-max-microamp: See standard regulator binding documentation.
+ Valid values are from 0 to 300 in steps of 20.
+
+Optional properties for the ISRCx sub-nodes:
+Any standard regulator properties that apply to current regulators.
Example for i.MX23 SoC:
@@ -31,6 +40,16 @@ Example for i.MX23 SoC:
fsl,ave-ctrl = <4>;
fsl,ave-delay = <2>;
fsl,settling = <10>;
+
+ isrc_lradc0: ISRC0 {
+ regulator-max-microamp = <300>;
+ };
+
+ isrc_lradc1: ISRC1 {
+ regulator-max-microamp = <120>;
+ regulator-min-microamp = <120>;
+ regulator-always-on;
+ };
};
Example for i.MX28 SoC:
@@ -44,4 +63,14 @@ Example for i.MX28 SoC:
fsl,ave-ctrl = <4>;
fsl,ave-delay = <2>;
fsl,settling = <10>;
+
+ isrc_lradc0: ISRC0 {
+ regulator-max-microamp = <300>;
+ };
+
+ isrc_lradc6: ISRC1 {
+ regulator-max-microamp = <120>;
+ regulator-min-microamp = <120>;
+ regulator-always-on;
+ };
};
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 5937030..1968d1c 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -319,6 +319,7 @@ config MXS_LRADC
tristate "Freescale i.MX23/i.MX28 LRADC"
depends on (ARCH_MXS || COMPILE_TEST) && HAS_IOMEM
depends on INPUT
+ depends on REGULATOR
select STMP_DEVICE
select IIO_BUFFER
select IIO_TRIGGERED_BUFFER
diff --git a/drivers/iio/adc/mxs-lradc.c b/drivers/iio/adc/mxs-lradc.c
index 33051b8..f22f339 100644
--- a/drivers/iio/adc/mxs-lradc.c
+++ b/drivers/iio/adc/mxs-lradc.c
@@ -40,6 +40,10 @@
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/sysfs.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/regulator/of_regulator.h>
+
#define DRIVER_NAME "mxs-lradc"
#define LRADC_MAX_DELAY_CHANS 4
@@ -261,6 +265,9 @@ struct mxs_lradc {
unsigned over_sample_delay;
/* time in clocks to wait after the plates where switched */
unsigned settling_delay;
+
+ struct regulator_desc isrc0;
+ struct regulator_desc isrc1;
};
#define LRADC_CTRL0 0x00
@@ -305,6 +312,11 @@ struct mxs_lradc {
#define LRADC_CTRL2 0x20
#define LRADC_CTRL2_DIVIDE_BY_TWO_OFFSET 24
#define LRADC_CTRL2_TEMPSENSE_PWD BIT(15)
+#define LRADC_CTRL2_TEMP_SENSOR_IENABLE1 BIT(9)
+#define LRADC_CTRL2_TEMP_SENSOR_IENABLE0 BIT(8)
+#define LRADC_CTRL2_TEMP_ISRC1_OFFSET 4
+#define LRADC_CTRL2_TEMP_ISRC0_OFFSET 0
+#define LRADC_CTRL2_TEMP_ISRC_MASK 0x0f
#define LRADC_STATUS 0x40
#define LRADC_STATUS_TOUCH_DETECT_RAW BIT(0)
@@ -1383,6 +1395,109 @@ static const struct iio_buffer_setup_ops mxs_lradc_buffer_ops = {
.validate_scan_mask = &mxs_lradc_validate_scan_mask,
};
+static int mxs_lradc_regulator_is_enabled(struct regulator_dev *dev)
+{
+ struct mxs_lradc *lradc = rdev_get_drvdata(dev);
+ int reg = readl(lradc->base + LRADC_CTRL2);
+
+ if (dev->desc == &lradc->isrc0)
+ return reg & LRADC_CTRL2_TEMP_SENSOR_IENABLE0;
+ else if (dev->desc == &lradc->isrc1)
+ return reg & LRADC_CTRL2_TEMP_SENSOR_IENABLE1;
+
+ /* This should never happen */
+ return -ENODEV;
+}
+
+#define LRADC_REGVALUE2uA(regval, offset) \
+ (20 * ((regval >> offset) & LRADC_CTRL2_TEMP_ISRC_MASK))
+
+static int mxs_lradc_regulator_get_current_limit(struct regulator_dev *dev)
+{
+ struct mxs_lradc *lradc = rdev_get_drvdata(dev);
+ int reg = readl(lradc->base + LRADC_CTRL2);
+
+ if (dev->desc == &lradc->isrc0)
+ return LRADC_REGVALUE2uA(reg, LRADC_CTRL2_TEMP_ISRC0_OFFSET);
+ else if (dev->desc == &lradc->isrc1)
+ return LRADC_REGVALUE2uA(reg, LRADC_CTRL2_TEMP_ISRC1_OFFSET);
+
+ /* This should never happen */
+ return -ENODEV;
+}
+
+static int mxs_lradc_regulator_enable(struct regulator_dev *dev)
+{
+ struct mxs_lradc *lradc = rdev_get_drvdata(dev);
+
+ if (dev->desc == &lradc->isrc0)
+ mxs_lradc_reg_set(lradc, LRADC_CTRL2_TEMP_SENSOR_IENABLE0,
+ LRADC_CTRL2);
+ else if (dev->desc == &lradc->isrc1)
+ mxs_lradc_reg_set(lradc, LRADC_CTRL2_TEMP_SENSOR_IENABLE1,
+ LRADC_CTRL2);
+ else
+ /* This should never happen */
+ return -ENODEV;
+
+ return 0;
+}
+
+static int mxs_lradc_regulator_disable(struct regulator_dev *dev)
+{
+ struct mxs_lradc *lradc = rdev_get_drvdata(dev);
+
+ if (dev->desc == &lradc->isrc0)
+ mxs_lradc_reg_clear(lradc, LRADC_CTRL2_TEMP_SENSOR_IENABLE0,
+ LRADC_CTRL2);
+ else if (dev->desc == &lradc->isrc1)
+ mxs_lradc_reg_clear(lradc, LRADC_CTRL2_TEMP_SENSOR_IENABLE1,
+ LRADC_CTRL2);
+ else
+ /* This should never happen */
+ return -ENODEV;
+
+ return 0;
+}
+
+static int mxs_lradc_regulator_set_current_limit(struct regulator_dev *dev,
+ int min_uA, int max_uA)
+{
+ struct mxs_lradc *lradc = rdev_get_drvdata(dev);
+ int offset, value;
+
+ if (dev->desc == &lradc->isrc0)
+ offset = LRADC_CTRL2_TEMP_ISRC0_OFFSET;
+ else if (dev->desc == &lradc->isrc1)
+ offset = LRADC_CTRL2_TEMP_ISRC1_OFFSET;
+ else
+ /* This should never happen */
+ return -ENODEV;
+
+ value = min_uA / 20;
+ if (min_uA % 20)
+ value++;
+ if (value * 20 > max_uA)
+ return -EINVAL;
+ if (value & ~LRADC_CTRL2_TEMP_ISRC_MASK)
+ /* This should never happen */
+ return -EPERM;
+
+ mxs_lradc_reg_clear(lradc, LRADC_CTRL2_TEMP_ISRC_MASK << offset,
+ LRADC_CTRL2);
+ mxs_lradc_reg_set(lradc, value << offset, LRADC_CTRL2);
+
+ return 0;
+}
+
+static struct regulator_ops mxs_lradc_regulator_current_ops = {
+ .enable = mxs_lradc_regulator_enable,
+ .is_enabled = mxs_lradc_regulator_is_enabled,
+ .disable = mxs_lradc_regulator_disable,
+ .get_current_limit = mxs_lradc_regulator_get_current_limit,
+ .set_current_limit = mxs_lradc_regulator_set_current_limit,
+};
+
/*
* Driver initialization
*/
@@ -1519,6 +1634,10 @@ static void mxs_lradc_hw_stop(struct mxs_lradc *lradc)
for (i = 0; i < LRADC_MAX_DELAY_CHANS; i++)
mxs_lradc_reg_wrt(lradc, 0, LRADC_DELAY(i));
+
+ mxs_lradc_reg_clear(lradc, LRADC_CTRL2_TEMP_SENSOR_IENABLE0 |
+ LRADC_CTRL2_TEMP_SENSOR_IENABLE1,
+ LRADC_CTRL2);
}
static const struct of_device_id mxs_lradc_dt_ids[] = {
@@ -1592,6 +1711,32 @@ static int mxs_lradc_probe_touchscreen(struct mxs_lradc *lradc,
return 0;
}
+static void mxs_lradc_reg_helper(struct device_node *np, const char *name,
+ struct regulator_config *conf,
+ struct regulator_desc *desc)
+{
+ struct regulator_dev *ret;
+
+ conf->of_node = of_get_child_by_name(np, name);
+ if (!conf->of_node)
+ return;
+
+ desc->name = name;
+ desc->owner = THIS_MODULE;
+ desc->type = REGULATOR_CURRENT;
+ desc->ops = &mxs_lradc_regulator_current_ops;
+
+ conf->init_data = of_get_regulator_init_data(conf->dev, conf->of_node,
+ desc);
+ ret = devm_regulator_register(conf->dev, desc, conf);
+ if (IS_ERR(ret))
+ /* Just pretend the regulator isn't there */
+ dev_err(conf->dev, "Failed to register regulator %s: %ld\n",
+ desc->name, PTR_ERR(ret));
+
+ of_node_put(conf->of_node);
+}
+
static int mxs_lradc_probe(struct platform_device *pdev)
{
const struct of_device_id *of_id =
@@ -1603,6 +1748,7 @@ static int mxs_lradc_probe(struct platform_device *pdev)
struct mxs_lradc *lradc;
struct iio_dev *iio;
struct resource *iores;
+ struct regulator_config regconf;
int ret = 0, touch_ret;
int i, s;
u64 scale_uv;
@@ -1727,6 +1873,12 @@ static int mxs_lradc_probe(struct platform_device *pdev)
goto err_ts;
}
+ /* Setup regulator devices for current source. */
+ regconf.dev = dev;
+ regconf.driver_data = lradc;
+ mxs_lradc_reg_helper(node, "ISRC0", ®conf, &lradc->isrc0);
+ mxs_lradc_reg_helper(node, "ISRC1", ®conf, &lradc->isrc1);
+
return 0;
err_ts:
--
2.1.4
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