On Tue, 26 Mar 2019 15:33:32 +0900
Shinji Kanematsu <kanematsu.shinji@xxxxxxxxxxxxx> wrote:
> Add support for Milbeaut Updown Counter, that can be used as counter
> or quadrature encoder.
>
> Signed-off-by: Shinji Kanematsu <kanematsu.shinji@xxxxxxxxxxxxx>
A few minor comments inline. The counter subsystem will provide a cleaner
way of describing this. Please look to that for v2.
Hopefully William will give some feedback as well.
Jonathan
> ---
> drivers/iio/counter/Kconfig | 12 +
> drivers/iio/counter/Makefile | 1 +
> drivers/iio/counter/milbeaut-updown.h | 38 +++
> drivers/iio/counter/milbeaut-updown_cnt.c | 385 ++++++++++++++++++++++++++++++
> 4 files changed, 436 insertions(+)
> create mode 100644 drivers/iio/counter/milbeaut-updown.h
> create mode 100644 drivers/iio/counter/milbeaut-updown_cnt.c
>
> diff --git a/drivers/iio/counter/Kconfig b/drivers/iio/counter/Kconfig
> index bf1e559..a665f61 100644
> --- a/drivers/iio/counter/Kconfig
> +++ b/drivers/iio/counter/Kconfig
> @@ -31,4 +31,16 @@ config STM32_LPTIMER_CNT
>
> To compile this driver as a module, choose M here: the
> module will be called stm32-lptimer-cnt.
> +
> +config MILBEAUT_UPDOWN_CNT
> + tristate "Milbeaut Updown Counter driver"
> + depends on OF
> + depends on ARCH_MILBEAUT || COMPILE_TEST
> + help
> + Select this option to enable Milbeaut Updown Counter quadrature encoder
> + and counter driver.
> +
> + To compile this driver as a module, choose M here: the
> + module will be called milbeaut-updown-cnt.
> +
> endmenu
> diff --git a/drivers/iio/counter/Makefile b/drivers/iio/counter/Makefile
> index 1b9a896..0cb708b 100644
> --- a/drivers/iio/counter/Makefile
> +++ b/drivers/iio/counter/Makefile
> @@ -6,3 +6,4 @@
>
> obj-$(CONFIG_104_QUAD_8) += 104-quad-8.o
> obj-$(CONFIG_STM32_LPTIMER_CNT) += stm32-lptimer-cnt.o
> +obj-$(CONFIG_MILBEAUT_UPDOWN_CNT) += milbeaut-updown_cnt.o
> diff --git a/drivers/iio/counter/milbeaut-updown.h b/drivers/iio/counter/milbeaut-updown.h
> new file mode 100644
> index 0000000..9a038ad
> --- /dev/null
> +++ b/drivers/iio/counter/milbeaut-updown.h
> @@ -0,0 +1,38 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Milbeaut Updown parent driver
> + * Copyright (C) 2019 Socionext Inc.
> + */
> +
> +#ifndef _LINUX_MILBEAUT_UPDOWN_H_
> +#define _LINUX_MILBEAUT_UPDOWN_H_
> +
> +#define MLB_UPDOWN_UDCR 0x0 /* Updown Count Reg */
> +#define MLB_UPDOWN_RCR 0x4 /* Reload Compare Reg */
> +#define MLB_UPDOWN_CSR 0xC /* Counter Status Reg */
> +#define MLB_UPDOWN_CCR 0x14 /* Counter Control Reg */
> +
> +/* MLB_UPDOWN_CSR - bit fields */
> +#define MLB_UPDOWN_CSTR BIT(7)
> +#define MLB_UPDOWN_UDIE BIT(5)
> +#define MLB_UPDOWN_CMPF BIT(4)
> +#define MLB_UPDOWN_OVFF BIT(3)
> +#define MLB_UPDOWN_UDFF BIT(2)
> +
> +/* MLB_UPDOWN_CCR - bit fields */
> +#define MLB_UPDOWN_FIXED BIT(15)
> +#define MLB_UPDOWN_CMS GENMASK(11, 10)
> +#define MLB_UPDOWN_CES GENMASK(9, 8)
> +#define MLB_UPDOWN_CTUT BIT(6)
> +#define MLB_UPDOWN_RLDE BIT(4)
> +
> +/* MLB_UPDOWN max count value */
> +#define MLB_UPDOWN_MAX_COUNT 0xFFFF
> +
> +/* MLB_UPDOWN rising edge detection */
> +#define MLB_UPDOWN_RISING_EDGE BIT(9)
> +
> +/* MLB_UPDOWN mode */
> +#define MLB_UPDOWN_MODE 1
> +
> +#endif
> diff --git a/drivers/iio/counter/milbeaut-updown_cnt.c b/drivers/iio/counter/milbeaut-updown_cnt.c
> new file mode 100644
> index 0000000..a58709a
> --- /dev/null
> +++ b/drivers/iio/counter/milbeaut-updown_cnt.c
> @@ -0,0 +1,385 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Milbeaut Updown counter driver
> + *
> + * Copyright (C) 2019 Socionext Inc.
I'm fussy about pointless lines. The one below doesn't add anything ;)
> + *
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/clk.h>
> +#include <linux/iio/events.h>
> +#include <linux/iio/iio.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +
> +#include "milbeaut-updown.h"
> +
> +#define MILBEAUT_UPDOWN_IRQ_NAME "milbeaut_updown_event"
> +#define MILBEAUT_UPDOWN_MAX_REGISTER 0x1f
> +
> +static const struct regmap_config milbeaut_updown_regmap_cfg = {
> + .reg_bits = 32,
> + .val_bits = 32,
> + .reg_stride = sizeof(u32),
> + .max_register = MILBEAUT_UPDOWN_MAX_REGISTER,
> +};
> +struct milbeaut_updown_cnt {
> + struct device *dev;
> + struct regmap *regmap;
> + struct clk *clk;
> + u32 preset;
> + u32 polarity;
> + u32 quadrature_mode;
> +};
> +
> +static int milbeaut_updown_is_enabled(struct milbeaut_updown_cnt *priv)
> +{
> + u32 val;
> + int ret;
> +
> + ret = regmap_read(priv->regmap, MLB_UPDOWN_CSR, &val);
> + if (ret)
> + return ret;
> +
> + return FIELD_GET(MLB_UPDOWN_CSTR, val);
> +}
> +
> +static int milbeaut_updown_setup(struct milbeaut_updown_cnt *priv,
> + int val)
> +{
> + int ret;
> +
> + if (val) {
> + ret = regmap_update_bits(priv->regmap, MLB_UPDOWN_CCR,
> + MLB_UPDOWN_CMS | MLB_UPDOWN_RLDE,
> + FIELD_PREP(MLB_UPDOWN_CMS, priv->quadrature_mode) |
> + MLB_UPDOWN_RLDE);
> + if (ret)
> + return ret;
> +
> + if (priv->quadrature_mode == MLB_UPDOWN_MODE) {
> + ret = regmap_update_bits(priv->regmap, MLB_UPDOWN_CCR,
> + MLB_UPDOWN_CES, MLB_UPDOWN_RISING_EDGE);
> + if (ret)
> + return ret;
> + }
> +
> + ret = regmap_write(priv->regmap, MLB_UPDOWN_RCR, priv->preset);
> + if (ret)
> + return ret;
> +
> + /* interrupt */
> + ret = regmap_update_bits(priv->regmap, MLB_UPDOWN_CSR,
> + MLB_UPDOWN_UDIE, MLB_UPDOWN_UDIE);
> + if (ret)
> + return ret;
> +
> + ret = regmap_update_bits(priv->regmap, MLB_UPDOWN_CCR,
> + MLB_UPDOWN_CTUT | MLB_UPDOWN_FIXED,
> + MLB_UPDOWN_CTUT | MLB_UPDOWN_FIXED);
> + if (ret)
> + return ret;
> +
> + val = MLB_UPDOWN_CSTR;
> + }
> +
> + return regmap_update_bits(priv->regmap, MLB_UPDOWN_CSR,
> + MLB_UPDOWN_CSTR, val);
> +}
> +
> +static int milbeaut_updown_write_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int val, int val2, long mask)
> +{
> + struct milbeaut_updown_cnt *priv = iio_priv(indio_dev);
> + int ret;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_ENABLE:
> + if (val < 0 || val > 1)
> + return -EINVAL;
> +
> + ret = milbeaut_updown_is_enabled(priv);
> + if (val && ret)
> + return -EBUSY;
> +
> + ret = milbeaut_updown_setup(priv, val);
> +
> + break;
> +
> + default:
> + return -EINVAL;
> + }
> +
> + return ret;
> +}
> +
> +static int milbeaut_updown_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int *val, int *val2, long mask)
> +{
> + struct milbeaut_updown_cnt *priv = iio_priv(indio_dev);
> + u32 dat;
> + int ret;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_RAW:
> + ret = regmap_read(priv->regmap, MLB_UPDOWN_UDCR, &dat);
> + if (ret)
> + return ret;
> + *val = dat;
> + return IIO_VAL_INT;
> +
> + case IIO_CHAN_INFO_ENABLE:
> + ret = milbeaut_updown_is_enabled(priv);
> + if (ret < 0)
> + return ret;
> + *val = ret;
> + return IIO_VAL_INT;
> +
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +static const struct iio_info milbeaut_updown_cnt_iio_info = {
> + .read_raw = milbeaut_updown_read_raw,
> + .write_raw = milbeaut_updown_write_raw,
> +};
> +
> +static const char *const milbeaut_updown_quadrature_modes[] = {
> + "non-quadrature",
> + "quadrature",
> +};
> +
> +static int milbeaut_updown_get_quadrature_mode(struct iio_dev *indio_dev,
> + const struct iio_chan_spec *chan)
> +{
> + struct milbeaut_updown_cnt *priv = iio_priv(indio_dev);
> +
> + return priv->quadrature_mode;
> +}
> +
> +static int milbeaut_updown_set_quadrature_mode(struct iio_dev *indio_dev,
> + const struct iio_chan_spec *chan,
> + unsigned int type)
> +{
> + struct milbeaut_updown_cnt *priv = iio_priv(indio_dev);
> +
> + if (milbeaut_updown_is_enabled(priv))
> + return -EBUSY;
> +
> + priv->quadrature_mode = type;
> +
> + return 0;
> +}
> +
> +static const struct iio_enum milbeaut_updown_quadrature_mode_en = {
> + .items = milbeaut_updown_quadrature_modes,
> + .num_items = ARRAY_SIZE(milbeaut_updown_quadrature_modes),
> + .get = milbeaut_updown_get_quadrature_mode,
> + .set = milbeaut_updown_set_quadrature_mode,
> +};
> +
> +static const char * const milbeaut_updown_cnt_polarity[] = {
> + "rising-edge", "falling-edge", "both-edges",
> +};
> +
> +static int milbeaut_updown_cnt_get_polarity(struct iio_dev *indio_dev,
> + const struct iio_chan_spec *chan)
> +{
> + struct milbeaut_updown_cnt *priv = iio_priv(indio_dev);
> +
> + return priv->polarity;
> +}
> +
> +static int milbeaut_updown_cnt_set_polarity(struct iio_dev *indio_dev,
> + const struct iio_chan_spec *chan,
> + unsigned int type)
> +{
> + struct milbeaut_updown_cnt *priv = iio_priv(indio_dev);
> +
> + if (milbeaut_updown_is_enabled(priv))
> + return -EBUSY;
> +
> + priv->polarity = type;
> +
> + return 0;
> +}
> +
> +static const struct iio_enum milbeaut_updown_cnt_polarity_en = {
> + .items = milbeaut_updown_cnt_polarity,
> + .num_items = ARRAY_SIZE(milbeaut_updown_cnt_polarity),
> + .get = milbeaut_updown_cnt_get_polarity,
> + .set = milbeaut_updown_cnt_set_polarity,
> +};
> +
> +static ssize_t milbeaut_updown_cnt_get_preset(struct iio_dev *indio_dev,
> + uintptr_t private,
> + const struct iio_chan_spec *chan,
> + char *buf)
> +{
> + struct milbeaut_updown_cnt *priv = iio_priv(indio_dev);
> +
> + return snprintf(buf, PAGE_SIZE, "%u\n", priv->preset);
> +}
> +
> +static ssize_t milbeaut_updown_cnt_set_preset(struct iio_dev *indio_dev,
> + uintptr_t private,
> + const struct iio_chan_spec *chan,
> + const char *buf, size_t len)
> +{
> + struct milbeaut_updown_cnt *priv = iio_priv(indio_dev);
> + u32 check_preset;
> + int ret;
> +
> + if (milbeaut_updown_is_enabled(priv))
> + return -EBUSY;
> +
> + ret = kstrtouint(buf, 0, &check_preset);
> + if (ret)
> + return ret;
> +
> + if (check_preset > MLB_UPDOWN_MAX_COUNT)
> + return -EINVAL;
> +
> + ret = kstrtouint(buf, 0, &priv->preset);
This structure is a little unusual.
priv->preset = check_preset and that can't result
in an error.
> + if (ret)
> + return ret;
> +
> + return len;
> +}
> +
> +static const struct iio_chan_spec_ext_info milbeaut_updown_cnt_ext_info[] = {
> + {
> + .name = "preset",
> + .shared = IIO_SEPARATE,
> + .read = milbeaut_updown_cnt_get_preset,
> + .write = milbeaut_updown_cnt_set_preset,
> + },
> + IIO_ENUM("polarity", IIO_SEPARATE, &milbeaut_updown_cnt_polarity_en),
> + IIO_ENUM_AVAILABLE("polarity", &milbeaut_updown_cnt_polarity_en),
> + {}
> +};
> +
> +static const struct iio_event_spec milbeaut_updown_cnt_event = {
> + .type = IIO_EV_TYPE_ROC,
> + .dir = IIO_EV_DIR_RISING,
> + .mask_separate = BIT(IIO_EV_INFO_ENABLE),
> + .mask_shared_by_type = BIT(IIO_EV_INFO_VALUE),
> +};
> +
> +static const struct iio_chan_spec milbeaut_updown_cnt_channels = {
> + .type = IIO_COUNT,
> + .channel = 0,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> + BIT(IIO_CHAN_INFO_ENABLE) |
> + BIT(IIO_CHAN_INFO_SCALE),
> + .ext_info = milbeaut_updown_cnt_ext_info,
> + .indexed = 1,
> + .event_spec = &milbeaut_updown_cnt_event,
> + .num_event_specs = 1,
> +};
> +
> +static irqreturn_t milbeaut_updown_event_handler(int irq, void *private)
> +{
> + struct iio_dev *indio_dev = private;
> + struct milbeaut_updown_cnt *priv;
> + int ret;
> +
> + priv = iio_priv(indio_dev);
> +
> + ret = regmap_update_bits(priv->regmap, MLB_UPDOWN_CSR,
> + MLB_UPDOWN_CMPF | MLB_UPDOWN_OVFF | MLB_UPDOWN_UDFF,
> + 0);
> + WARN_ON_ONCE(ret < 0);
> +
> + iio_push_event(indio_dev,
> + IIO_MOD_EVENT_CODE(IIO_INCLI, 0, 1,
> + IIO_EV_TYPE_ROC, IIO_EV_DIR_RISING),
> + iio_get_time_ns(indio_dev));
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int milbeaut_updown_cnt_probe(struct platform_device *pdev)
> +{
> + struct milbeaut_updown_cnt *priv;
> + struct iio_dev *indio_dev;
> + struct resource *res;
> + void __iomem *mmio;
> + int ret;
> + int irq;
> +
> + indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*priv));
> + if (!indio_dev)
> + return -ENOMEM;
> +
> + priv = iio_priv(indio_dev);
> + priv->dev = &pdev->dev;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + mmio = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(mmio))
> + return PTR_ERR(mmio);
> +
> + priv->regmap = devm_regmap_init_mmio_clk(&pdev->dev, "mux", mmio,
> + &milbeaut_updown_regmap_cfg);
> + if (IS_ERR(priv->regmap))
> + return PTR_ERR(priv->regmap);
> +
> + priv->clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(priv->clk))
> + return PTR_ERR(priv->clk);
> +
> + priv->preset = MLB_UPDOWN_MAX_COUNT;
> + ret = of_property_read_u32(priv->dev->of_node,
> + "cms_type", &priv->quadrature_mode);
> + if (ret)
> + return -ENODEV;
> +
> + indio_dev->name = dev_name(&pdev->dev);
> + indio_dev->dev.parent = &pdev->dev;
> + indio_dev->dev.of_node = pdev->dev.of_node;
Why set this. I don't think anything uses it?
> + indio_dev->info = &milbeaut_updown_cnt_iio_info;
> + indio_dev->channels = &milbeaut_updown_cnt_channels;
> + indio_dev->num_channels = 1;
> +
> + /* setting request irq */
The comment doesn't add anything not apparent directly from the code.
> + irq = platform_get_irq(pdev, 0);
> + ret = devm_request_threaded_irq(&pdev->dev, irq,
> + NULL, milbeaut_updown_event_handler,
> + IRQF_TRIGGER_RISING | IRQF_ONESHOT,
> + MILBEAUT_UPDOWN_IRQ_NAME, indio_dev);
> + if (ret < 0) {
> + pr_err("%s request irq failed\n", __func__);
> + return ret;
> + }
> +
> + platform_set_drvdata(pdev, priv);
Why? I'm not seeing calls to platform_get_drvdata.
> +
> + return devm_iio_device_register(&pdev->dev, indio_dev);
> +}
> +
> +static const struct of_device_id milbeaut_updown_cnt_of_match[] = {
> + { .compatible = "socionext,milbeaut-updown-counter", },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, milbeaut_updown_cnt_of_match);
> +
> +static struct platform_driver milbeaut_updown_cnt_driver = {
> + .probe = milbeaut_updown_cnt_probe,
> + .driver = {
> + .name = "milbeaut-updown-counter",
> + .of_match_table = milbeaut_updown_cnt_of_match,
> + },
> +};
> +module_platform_driver(milbeaut_updown_cnt_driver);
> +
> +MODULE_AUTHOR("Shinji Kanematsu <kanematsu.shinji@xxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Milbeaut Updown counter");
> +MODULE_ALIAS("platform:milbeaut_updown_counter");
> +MODULE_LICENSE("GPL v2");
