[RFC PATCH] drivers: Raspbery Pi Sense Hat
Stefan Wahren
stefan.wahren at i2se.com
Thu Apr 8 20:29:06 BST 2021
Hi Joel,
Am 08.04.21 um 02:03 schrieb Joel Savitz:
> From: Joel Savitz <joelsavitz at gmail.com>
>
> This is a forward port of the Rapsberry Pi Sense Hat driver from the
> downstream Raspberry Pi kernel tree.
>
> I have slightly consolidated things and done some quick testing of this
> driver on Fedora (which comes with the device tree blobs), and I want to
> do a bit more testing before submiting the driver for inclusion in
> mainline Linux.
at first some general comments:
- keep in mind that the drivers shouldn't make any assumption of the
target platform
- always run scripts/checkpatch.pl before submission
>
> I would like to get some feedback from the community on what may need to
> be improved, fixed, or changed as early as possible, so this is a request
> for comments.
>
> Signed-off-by: Joel Savitz <joelsavitz at gmail.com>
> ---
> drivers/input/joystick/Kconfig | 8 +
> drivers/input/joystick/Makefile | 1 +
> drivers/input/joystick/rpisense-js.c | 147 ++++++++++++++
> drivers/mfd/Kconfig | 8 +
> drivers/mfd/Makefile | 1 +
> drivers/mfd/rpisense-core.c | 162 +++++++++++++++
> drivers/video/fbdev/Kconfig | 13 ++
> drivers/video/fbdev/Makefile | 1 +
> drivers/video/fbdev/rpisense-fb.c | 291 +++++++++++++++++++++++++++
> include/linux/mfd/rpisense.h | 66 ++++++
> 10 files changed, 698 insertions(+)
> create mode 100644 drivers/input/joystick/rpisense-js.c
> create mode 100644 drivers/mfd/rpisense-core.c
> create mode 100644 drivers/video/fbdev/rpisense-fb.c
> create mode 100644 include/linux/mfd/rpisense.h
>
> diff --git a/drivers/input/joystick/Kconfig b/drivers/input/joystick/Kconfig
> index 5e38899058c1..1c0025c22bf4 100644
> --- a/drivers/input/joystick/Kconfig
> +++ b/drivers/input/joystick/Kconfig
> @@ -389,4 +389,12 @@ config JOYSTICK_N64
> Say Y here if you want enable support for the four
> built-in controller ports on the Nintendo 64 console.
>
> +config JOYSTICK_RPISENSE
> + tristate "Raspberry Pi Sense HAT joystick"
> + depends on GPIOLIB && INPUT
> + select MFD_RPISENSE_CORE
> +
> + help
> + This is the joystick driver for the Raspberry Pi Sense HAT
> +
> endif
> diff --git a/drivers/input/joystick/Makefile b/drivers/input/joystick/Makefile
> index 31d720c9e493..b227e98cd179 100644
> --- a/drivers/input/joystick/Makefile
> +++ b/drivers/input/joystick/Makefile
> @@ -27,6 +27,7 @@ obj-$(CONFIG_JOYSTICK_MAPLE) += maplecontrol.o
> obj-$(CONFIG_JOYSTICK_N64) += n64joy.o
> obj-$(CONFIG_JOYSTICK_PSXPAD_SPI) += psxpad-spi.o
> obj-$(CONFIG_JOYSTICK_PXRC) += pxrc.o
> +obj-$(CONFIG_JOYSTICK_RPISENSE) += rpisense-js.o
> obj-$(CONFIG_JOYSTICK_SIDEWINDER) += sidewinder.o
> obj-$(CONFIG_JOYSTICK_SPACEBALL) += spaceball.o
> obj-$(CONFIG_JOYSTICK_SPACEORB) += spaceorb.o
> diff --git a/drivers/input/joystick/rpisense-js.c b/drivers/input/joystick/rpisense-js.c
> new file mode 100644
> index 000000000000..41d4bd1fed46
> --- /dev/null
> +++ b/drivers/input/joystick/rpisense-js.c
> @@ -0,0 +1,147 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Raspberry Pi Sense HAT joystick driver
> + * http://raspberrypi.org
> + *
> + * Copyright (C) 2015 Raspberry Pi
> + *
> + * Author: Serge Schneider
> + * Adapted for mainline Linux by: Joel Savitz
> + */
> +
> +#include <linux/module.h>
> +#include <linux/mfd/rpisense.h>
> +
> +static struct rpisense *rpisense;
please try to avoid such limitation. It's preferred to allow multiple
instances of input drivers.
> +static unsigned char keymap[5] = {KEY_DOWN, KEY_RIGHT, KEY_UP, KEY_ENTER, KEY_LEFT,};
please try to avoid magic numbers
> +
> +static void keys_work_fn(struct work_struct *work)
> +{
> + int i;
> + static s32 prev_keys;
> + struct rpisense_js *rpisense_js = &rpisense->joystick;
> + s32 keys = rpisense_reg_read(rpisense, RPISENSE_KEYS);
> + s32 changes = keys ^ prev_keys;
> +
> + prev_keys = keys;
> + for (i = 0; i < 5; i++) {
> + if (changes & 1) {
> + input_report_key(rpisense_js->keys_dev,
> + keymap[i], keys & 1);
> + }
> + changes >>= 1;
> + keys >>= 1;
> + }
> + input_sync(rpisense_js->keys_dev);
> +}
> +
> +static irqreturn_t keys_irq_handler(int irq, void *pdev)
> +{
> + struct rpisense_js *rpisense_js = &rpisense->joystick;
> +
> + schedule_work(&rpisense_js->keys_work_s);
> + return IRQ_HANDLED;
> +}
> +
> +static int rpisense_js_probe(struct platform_device *pdev)
> +{
> + int ret;
> + int i;
> + struct rpisense_js *rpisense_js;
> +
> + rpisense = rpisense_get_dev();
> + rpisense_js = &rpisense->joystick;
> +
> + INIT_WORK(&rpisense_js->keys_work_s, keys_work_fn);
> +
> + rpisense_js->keys_dev = input_allocate_device();
> + if (!rpisense_js->keys_dev) {
> + dev_err(&pdev->dev, "Could not allocate input device.\n");
> + return -ENOMEM;
> + }
> +
> + rpisense_js->keys_dev->evbit[0] = BIT_MASK(EV_KEY);
> + for (i = 0; i < ARRAY_SIZE(keymap); i++) {
> + set_bit(keymap[i],
> + rpisense_js->keys_dev->keybit);
> + }
> +
> + rpisense_js->keys_dev->name = "Raspberry Pi Sense HAT Joystick";
> + rpisense_js->keys_dev->phys = "rpi-sense-joy/input0";
> + rpisense_js->keys_dev->id.bustype = BUS_I2C;
> + rpisense_js->keys_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REP);
> + rpisense_js->keys_dev->keycode = keymap;
> + rpisense_js->keys_dev->keycodesize = sizeof(unsigned char);
> + rpisense_js->keys_dev->keycodemax = ARRAY_SIZE(keymap);
> +
> + ret = input_register_device(rpisense_js->keys_dev);
> + if (ret) {
> + dev_err(&pdev->dev, "Could not register input device.\n");
> + goto err_keys_alloc;
> + }
> +
> + ret = gpiod_direction_input(rpisense_js->keys_desc);
> + if (ret) {
> + dev_err(&pdev->dev, "Could not set keys-int direction.\n");
> + goto err_keys_reg;
> + }
> +
> + rpisense_js->keys_irq = gpiod_to_irq(rpisense_js->keys_desc);
> + if (rpisense_js->keys_irq < 0) {
> + dev_err(&pdev->dev, "Could not determine keys-int IRQ.\n");
> + ret = rpisense_js->keys_irq;
> + goto err_keys_reg;
> + }
> +
> + ret = devm_request_irq(&pdev->dev, rpisense_js->keys_irq,
> + keys_irq_handler, IRQF_TRIGGER_RISING,
> + "keys", &pdev->dev);
> + if (ret) {
> + dev_err(&pdev->dev, "IRQ request failed.\n");
> + goto err_keys_reg;
> + }
> + return 0;
> +err_keys_reg:
> + input_unregister_device(rpisense_js->keys_dev);
> +err_keys_alloc:
> + input_free_device(rpisense_js->keys_dev);
> + return ret;
> +}
> +
> +static int rpisense_js_remove(struct platform_device *pdev)
> +{
> + struct rpisense_js *rpisense_js = &rpisense->joystick;
> +
> + input_unregister_device(rpisense_js->keys_dev);
> + input_free_device(rpisense_js->keys_dev);
> + return 0;
> +}
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id rpisense_js_id[] = {
> + { .compatible = "raspberrypi,rpi-sense-js" },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, rpisense_js_id);
> +#endif
> +
> +static struct platform_device_id rpisense_js_device_id[] = {
> + { .name = "rpi-sense-js" },
> + { },
> +};
> +MODULE_DEVICE_TABLE(platform, rpisense_js_device_id);
> +
> +static struct platform_driver rpisense_js_driver = {
> + .probe = rpisense_js_probe,
> + .remove = rpisense_js_remove,
> + .driver = {
> + .name = "rpi-sense-js",
> + .owner = THIS_MODULE,
please drop this line
> + },
> +};
> +
> +module_platform_driver(rpisense_js_driver);
> +
> +MODULE_DESCRIPTION("Raspberry Pi Sense HAT joystick driver");
> +MODULE_AUTHOR("Serge Schneider <serge at raspberrypi.org>");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index b74efa469e90..8c309e389359 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -11,6 +11,14 @@ config MFD_CORE
> select IRQ_DOMAIN
> default n
>
> +config MFD_RPISENSE_CORE
> + tristate "Raspberry Pi Sense HAT core functions"
> + depends on I2C
> + select MFD_CORE
> + help
> + This is the core driver for the Raspberry Pi Sense HAT. This provides
> + the necessary functions to communicate with the hardware.
> +
> config MFD_CS5535
> tristate "AMD CS5535 and CS5536 southbridge core functions"
> select MFD_CORE
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index 834f5463af28..7140a8fc36ee 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -263,6 +263,7 @@ obj-$(CONFIG_MFD_ROHM_BD71828) += rohm-bd71828.o
> obj-$(CONFIG_MFD_ROHM_BD718XX) += rohm-bd718x7.o
> obj-$(CONFIG_MFD_STMFX) += stmfx.o
> obj-$(CONFIG_MFD_KHADAS_MCU) += khadas-mcu.o
> +obj-$(CONFIG_MFD_RPISENSE_CORE) += rpisense-core.o
> obj-$(CONFIG_MFD_ACER_A500_EC) += acer-ec-a500.o
>
> obj-$(CONFIG_SGI_MFD_IOC3) += ioc3.o
> diff --git a/drivers/mfd/rpisense-core.c b/drivers/mfd/rpisense-core.c
> new file mode 100644
> index 000000000000..aa2c394c5e67
> --- /dev/null
> +++ b/drivers/mfd/rpisense-core.c
> @@ -0,0 +1,162 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Raspberry Pi Sense HAT core driver
> + * http://raspberrypi.org
> + *
> + * Copyright (C) 2015 Raspberry Pi
> + *
> + * Author: Serge Schneider
> + * Adapted for mainline Linux by: Joel Savitz
> + *
> + * This driver is based on wm8350 implementation.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/moduleparam.h>
> +#include <linux/err.h>
> +#include <linux/init.h>
> +#include <linux/i2c.h>
> +#include <linux/slab.h>
> +
> +#include <linux/mfd/rpisense.h>
> +
> +static struct rpisense *rpisense;
> +
> +static void rpisense_client_dev_register(struct rpisense *rpisense,
> + const char *name,
> + struct platform_device **pdev)
> +{
> + int ret;
> +
> + *pdev = platform_device_alloc(name, -1);
> + if (*pdev == NULL) {
> + dev_err(rpisense->dev, "Failed to allocate %s\n", name);
> + return;
> + }
> +
> + (*pdev)->dev.parent = rpisense->dev;
> + platform_set_drvdata(*pdev, rpisense);
> + ret = platform_device_add(*pdev);
> + if (ret != 0) {
> + dev_err(rpisense->dev, "Failed to register %s: %d\n",
> + name, ret);
> + platform_device_put(*pdev);
> + *pdev = NULL;
> + }
> +}
> +
> +static int rpisense_probe(struct i2c_client *i2c,
> + const struct i2c_device_id *id)
> +{
> + int ret;
> + struct rpisense_js *rpisense_js;
> +
> + rpisense = devm_kzalloc(&i2c->dev, sizeof(struct rpisense), GFP_KERNEL);
> + if (rpisense == NULL)
> + return -ENOMEM;
> +
> + i2c_set_clientdata(i2c, rpisense);
> + rpisense->dev = &i2c->dev;
> + rpisense->i2c_client = i2c;
> +
> + ret = rpisense_reg_read(rpisense, RPISENSE_WAI);
> + if (ret > 0) {
> + if (ret != 's')
> + return -EINVAL;
this would be a good place for a error message like "Unable to detect
Raspberry Pi Sense HAT"
> + } else {
> + return ret;
> + }
> + ret = rpisense_reg_read(rpisense, RPISENSE_VER);
> + if (ret < 0)
> + return ret;
> +
> + dev_info(rpisense->dev,
> + "Raspberry Pi Sense HAT firmware version %i\n", ret);
> +
> + rpisense_js = &rpisense->joystick;
> + rpisense_js->keys_desc = devm_gpiod_get(&i2c->dev,
> + "keys-int", GPIOD_IN);
> + if (IS_ERR(rpisense_js->keys_desc)) {
> + dev_warn(&i2c->dev, "Failed to get keys-int descriptor.\n");
> + rpisense_js->keys_desc = gpio_to_desc(23);
Unfortunately we cannot keep this fallback, because it's platform dependent.
> + if (rpisense_js->keys_desc == NULL) {
> + dev_err(&i2c->dev, "GPIO23 fallback failed.\n");
> + return PTR_ERR(rpisense_js->keys_desc);
> + }
> + }
> + rpisense_client_dev_register(rpisense, "rpi-sense-js",
> + &(rpisense->joystick.pdev));
> + rpisense_client_dev_register(rpisense, "rpi-sense-fb",
> + &(rpisense->framebuffer.pdev));
> +
> + return 0;
> +}
> +
> +static int rpisense_remove(struct i2c_client *i2c)
> +{
> + struct rpisense *rpisense = i2c_get_clientdata(i2c);
> +
> + platform_device_unregister(rpisense->joystick.pdev);
> + return 0;
> +}
> +
> +struct rpisense *rpisense_get_dev(void)
> +{
> + return rpisense;
> +}
> +EXPORT_SYMBOL_GPL(rpisense_get_dev);
> +
> +s32 rpisense_reg_read(struct rpisense *rpisense, int reg)
> +{
> + int ret = i2c_smbus_read_byte_data(rpisense->i2c_client, reg);
> +
> + if (ret < 0)
> + dev_err(rpisense->dev, "Read from reg %d failed\n", reg);
> + /* Due to the BCM270x I2C clock stretching bug, some values
In upstream BCM283x is the more common naming for the SoC
> + * may have MSB set. Clear it to avoid incorrect values.
> + */
> + return ret & 0x7F;
> +}
> +EXPORT_SYMBOL_GPL(rpisense_reg_read);
> +
> +int rpisense_block_write(struct rpisense *rpisense, const char *buf, int count)
> +{
> + int ret = i2c_master_send(rpisense->i2c_client, buf, count);
> +
> + if (ret < 0)
> + dev_err(rpisense->dev, "Block write failed\n");
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(rpisense_block_write);
> +
> +static const struct i2c_device_id rpisense_i2c_id[] = {
> + { "rpi-sense", 0 },
> + { }
> +};
> +MODULE_DEVICE_TABLE(i2c, rpisense_i2c_id);
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id rpisense_core_id[] = {
> + { .compatible = "raspberrypi,rpi-sense" },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, rpisense_core_id);
> +#endif
> +
> +
> +static struct i2c_driver rpisense_driver = {
> + .driver = {
> + .name = "rpi-sense",
> + .owner = THIS_MODULE,
please drop this line
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