[RFC PATCH] drivers: Raspbery Pi Sense Hat

Peter Robinson pbrobinson at gmail.com
Thu Apr 8 10:21:21 BST 2021


 " Hi Joel,

> This is a forward port of the Rapsberry Pi Sense Hat driver from the
> downstream Raspberry Pi kernel tree.

Please copy/reference the original author of the driver that is being
forward ported if it's not you.

> 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.
>
> 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.

Without reviewing the actual drivers I would suggest:
1) split each driver out into a separate patch with a cover letter for
the series
2) Each of the drivers will also need to have their subsystem mailing
lists copied. Something like "./scripts/get_maintainer.pl -f
drivers/input/Kconfig" should give you this information
3) I suspect each of the drivers will also need a DT bindings added to
Documentation/devicetree/bindings/ as a separate patch

Peter

> 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;
> +static unsigned char keymap[5] = {KEY_DOWN, KEY_RIGHT, KEY_UP, KEY_ENTER, KEY_LEFT,};
> +
> +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,
> +       },
> +};
> +
> +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;
> +       } 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);
> +               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
> +        * 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,
> +       },
> +       .probe = rpisense_probe,
> +       .remove = rpisense_remove,
> +       .id_table = rpisense_i2c_id,
> +};
> +
> +module_i2c_driver(rpisense_driver);
> +
> +MODULE_DESCRIPTION("Raspberry Pi Sense HAT core driver");
> +MODULE_AUTHOR("Serge Schneider <serge at raspberrypi.org>");
> +MODULE_LICENSE("GPL");
> +
> diff --git a/drivers/video/fbdev/Kconfig b/drivers/video/fbdev/Kconfig
> index 4f02db65dede..2238e36e71e4 100644
> --- a/drivers/video/fbdev/Kconfig
> +++ b/drivers/video/fbdev/Kconfig
> @@ -2236,6 +2236,19 @@ config FB_SM712
>           called sm712fb. If you want to compile it as a module, say M
>           here and read <file:Documentation/kbuild/modules.rst>.
>
> +config FB_RPISENSE
> +        tristate "Raspberry Pi Sense HAT framebuffer"
> +        depends on FB
> +        select MFD_RPISENSE_CORE
> +        select FB_SYS_FOPS
> +        select FB_SYS_FILLRECT
> +        select FB_SYS_COPYAREA
> +        select FB_SYS_IMAGEBLIT
> +        select FB_DEFERRED_IO
> +
> +        help
> +          This is the framebuffer driver for the Raspberry Pi Sense HAT
> +
>  source "drivers/video/fbdev/omap/Kconfig"
>  source "drivers/video/fbdev/omap2/Kconfig"
>  source "drivers/video/fbdev/mmp/Kconfig"
> diff --git a/drivers/video/fbdev/Makefile b/drivers/video/fbdev/Makefile
> index 477b9624b703..5b17203b7e43 100644
> --- a/drivers/video/fbdev/Makefile
> +++ b/drivers/video/fbdev/Makefile
> @@ -129,6 +129,7 @@ obj-$(CONFIG_FB_MX3)                  += mx3fb.o
>  obj-$(CONFIG_FB_DA8XX)           += da8xx-fb.o
>  obj-$(CONFIG_FB_SSD1307)         += ssd1307fb.o
>  obj-$(CONFIG_FB_SIMPLE)           += simplefb.o
> +obj-$(CONFIG_FB_RPISENSE)         += rpisense-fb.o
>
>  # the test framebuffer is last
>  obj-$(CONFIG_FB_VIRTUAL)          += vfb.o
> diff --git a/drivers/video/fbdev/rpisense-fb.c b/drivers/video/fbdev/rpisense-fb.c
> new file mode 100644
> index 000000000000..a90a5ec51fd7
> --- /dev/null
> +++ b/drivers/video/fbdev/rpisense-fb.c
> @@ -0,0 +1,291 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Raspberry Pi Sense HAT framebuffer 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/kernel.h>
> +#include <linux/errno.h>
> +#include <linux/string.h>
> +#include <linux/mm.h>
> +#include <linux/slab.h>
> +#include <linux/uaccess.h>
> +#include <linux/delay.h>
> +#include <linux/fb.h>
> +#include <linux/init.h>
> +
> +#include <linux/mfd/rpisense.h>
> +
> +static bool lowlight;
> +module_param(lowlight, bool, 0);
> +MODULE_PARM_DESC(lowlight, "Reduce LED matrix brightness to one third");
> +
> +static struct rpisense *rpisense;
> +
> +struct rpisense_fb_param {
> +       char __iomem *vmem;
> +       u8 *vmem_work;
> +       u32 vmemsize;
> +       u8 *gamma;
> +};
> +
> +static u8 gamma_default[32] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x01,
> +                              0x02, 0x02, 0x03, 0x03, 0x04, 0x05, 0x06, 0x07,
> +                              0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0E, 0x0F, 0x11,
> +                              0x12, 0x14, 0x15, 0x17, 0x19, 0x1B, 0x1D, 0x1F,};
> +
> +static u8 gamma_low[32] = {0x00, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
> +                          0x01, 0x01, 0x01, 0x01, 0x01, 0x02, 0x02, 0x02,
> +                          0x03, 0x03, 0x03, 0x04, 0x04, 0x05, 0x05, 0x06,
> +                          0x06, 0x07, 0x07, 0x08, 0x08, 0x09, 0x0A, 0x0A,};
> +
> +static u8 gamma_user[32];
> +
> +static u32 pseudo_palette[16];
> +
> +static struct rpisense_fb_param rpisense_fb_param = {
> +       .vmem = NULL,
> +       .vmemsize = 128,
> +       .gamma = gamma_default,
> +};
> +
> +static struct fb_deferred_io rpisense_fb_defio;
> +
> +static struct fb_fix_screeninfo rpisense_fb_fix = {
> +       .id =           "RPi-Sense FB",
> +       .type =         FB_TYPE_PACKED_PIXELS,
> +       .visual =       FB_VISUAL_TRUECOLOR,
> +       .xpanstep =     0,
> +       .ypanstep =     0,
> +       .ywrapstep =    0,
> +       .accel =        FB_ACCEL_NONE,
> +       .line_length =  16,
> +};
> +
> +static struct fb_var_screeninfo rpisense_fb_var = {
> +       .xres           = 8,
> +       .yres           = 8,
> +       .xres_virtual   = 8,
> +       .yres_virtual   = 8,
> +       .bits_per_pixel = 16,
> +       .red            = {11, 5, 0},
> +       .green          = {5, 6, 0},
> +       .blue           = {0, 5, 0},
> +};
> +
> +static ssize_t rpisense_fb_write(struct fb_info *info,
> +                                const char __user *buf, size_t count,
> +                                loff_t *ppos)
> +{
> +       ssize_t res = fb_sys_write(info, buf, count, ppos);
> +
> +       schedule_delayed_work(&info->deferred_work, rpisense_fb_defio.delay);
> +       return res;
> +}
> +
> +static void rpisense_fb_fillrect(struct fb_info *info,
> +                                const struct fb_fillrect *rect)
> +{
> +       sys_fillrect(info, rect);
> +       schedule_delayed_work(&info->deferred_work, rpisense_fb_defio.delay);
> +}
> +
> +static void rpisense_fb_copyarea(struct fb_info *info,
> +                                const struct fb_copyarea *area)
> +{
> +       sys_copyarea(info, area);
> +       schedule_delayed_work(&info->deferred_work, rpisense_fb_defio.delay);
> +}
> +
> +static void rpisense_fb_imageblit(struct fb_info *info,
> +                                 const struct fb_image *image)
> +{
> +       sys_imageblit(info, image);
> +       schedule_delayed_work(&info->deferred_work, rpisense_fb_defio.delay);
> +}
> +
> +static void rpisense_fb_deferred_io(struct fb_info *info,
> +                               struct list_head *pagelist)
> +{
> +       int i;
> +       int j;
> +       u8 *vmem_work = rpisense_fb_param.vmem_work;
> +       u16 *mem = (u16 *)rpisense_fb_param.vmem;
> +       u8 *gamma = rpisense_fb_param.gamma;
> +
> +       vmem_work[0] = 0;
> +       for (j = 0; j < 8; j++) {
> +               for (i = 0; i < 8; i++) {
> +                       vmem_work[(j * 24) + i + 1] =
> +                               gamma[(mem[(j * 8) + i] >> 11) & 0x1F];
> +                       vmem_work[(j * 24) + (i + 8) + 1] =
> +                               gamma[(mem[(j * 8) + i] >> 6) & 0x1F];
> +                       vmem_work[(j * 24) + (i + 16) + 1] =
> +                               gamma[(mem[(j * 8) + i]) & 0x1F];
> +               }
> +       }
> +       rpisense_block_write(rpisense, vmem_work, 193);
> +}
> +
> +static struct fb_deferred_io rpisense_fb_defio = {
> +       .delay          = HZ/100,
> +       .deferred_io    = rpisense_fb_deferred_io,
> +};
> +
> +static int rpisense_fb_ioctl(struct fb_info *info, unsigned int cmd,
> +                            unsigned long arg)
> +{
> +       switch (cmd) {
> +       case SENSEFB_FBIOGET_GAMMA:
> +               if (copy_to_user((void __user *) arg, rpisense_fb_param.gamma,
> +                                sizeof(u8[32])))
> +                       return -EFAULT;
> +               return 0;
> +       case SENSEFB_FBIOSET_GAMMA:
> +               if (copy_from_user(gamma_user, (void __user *)arg,
> +                                  sizeof(u8[32])))
> +                       return -EFAULT;
> +               rpisense_fb_param.gamma = gamma_user;
> +               schedule_delayed_work(&info->deferred_work,
> +                                     rpisense_fb_defio.delay);
> +               return 0;
> +       case SENSEFB_FBIORESET_GAMMA:
> +               switch (arg) {
> +               case 0:
> +                       rpisense_fb_param.gamma = gamma_default;
> +                       break;
> +               case 1:
> +                       rpisense_fb_param.gamma = gamma_low;
> +                       break;
> +               case 2:
> +                       rpisense_fb_param.gamma = gamma_user;
> +                       break;
> +               default:
> +                       return -EINVAL;
> +               }
> +               schedule_delayed_work(&info->deferred_work,
> +                                     rpisense_fb_defio.delay);
> +               break;
> +       default:
> +               return -EINVAL;
> +       }
> +       return 0;
> +}
> +
> +static struct fb_ops rpisense_fb_ops = {
> +       .owner          = THIS_MODULE,
> +       .fb_read        = fb_sys_read,
> +       .fb_write       = rpisense_fb_write,
> +       .fb_fillrect    = rpisense_fb_fillrect,
> +       .fb_copyarea    = rpisense_fb_copyarea,
> +       .fb_imageblit   = rpisense_fb_imageblit,
> +       .fb_ioctl       = rpisense_fb_ioctl,
> +};
> +
> +static int rpisense_fb_probe(struct platform_device *pdev)
> +{
> +       struct fb_info *info;
> +       int ret = -ENOMEM;
> +       struct rpisense_fb *rpisense_fb;
> +
> +       rpisense = rpisense_get_dev();
> +       rpisense_fb = &rpisense->framebuffer;
> +
> +       rpisense_fb_param.vmem = vzalloc(rpisense_fb_param.vmemsize);
> +       if (!rpisense_fb_param.vmem)
> +               return ret;
> +
> +       rpisense_fb_param.vmem_work = devm_kmalloc(&pdev->dev, 193, GFP_KERNEL);
> +       if (!rpisense_fb_param.vmem_work)
> +               goto err_malloc;
> +
> +       info = framebuffer_alloc(0, &pdev->dev);
> +       if (!info) {
> +               dev_err(&pdev->dev, "Could not allocate framebuffer.\n");
> +               goto err_malloc;
> +       }
> +       rpisense_fb->info = info;
> +
> +       rpisense_fb_fix.smem_start = (unsigned long)rpisense_fb_param.vmem;
> +       rpisense_fb_fix.smem_len = rpisense_fb_param.vmemsize;
> +
> +       info->fbops = &rpisense_fb_ops;
> +       info->fix = rpisense_fb_fix;
> +       info->var = rpisense_fb_var;
> +       info->fbdefio = &rpisense_fb_defio;
> +       info->flags = FBINFO_FLAG_DEFAULT | FBINFO_VIRTFB;
> +       info->screen_base = rpisense_fb_param.vmem;
> +       info->screen_size = rpisense_fb_param.vmemsize;
> +       info->pseudo_palette = pseudo_palette;
> +
> +       if (lowlight)
> +               rpisense_fb_param.gamma = gamma_low;
> +
> +       fb_deferred_io_init(info);
> +
> +       ret = register_framebuffer(info);
> +       if (ret < 0) {
> +               dev_err(&pdev->dev, "Could not register framebuffer.\n");
> +               goto err_fballoc;
> +       }
> +
> +       fb_info(info, "%s frame buffer device\n", info->fix.id);
> +       schedule_delayed_work(&info->deferred_work, rpisense_fb_defio.delay);
> +       return 0;
> +err_fballoc:
> +       framebuffer_release(info);
> +err_malloc:
> +       vfree(rpisense_fb_param.vmem);
> +       return ret;
> +}
> +
> +static int rpisense_fb_remove(struct platform_device *pdev)
> +{
> +       struct rpisense_fb *rpisense_fb = &rpisense->framebuffer;
> +       struct fb_info *info = rpisense_fb->info;
> +
> +       if (info) {
> +               unregister_framebuffer(info);
> +               fb_deferred_io_cleanup(info);
> +               framebuffer_release(info);
> +               vfree(rpisense_fb_param.vmem);
> +       }
> +
> +       return 0;
> +}
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id rpisense_fb_id[] = {
> +       { .compatible = "raspberrypi,rpi-sense-fb" },
> +       { },
> +};
> +MODULE_DEVICE_TABLE(of, rpisense_fb_id);
> +#endif
> +
> +static struct platform_device_id rpisense_fb_device_id[] = {
> +       { .name = "rpi-sense-fb" },
> +       { },
> +};
> +MODULE_DEVICE_TABLE(platform, rpisense_fb_device_id);
> +
> +static struct platform_driver rpisense_fb_driver = {
> +       .probe = rpisense_fb_probe,
> +       .remove = rpisense_fb_remove,
> +       .driver = {
> +               .name = "rpi-sense-fb",
> +               .owner = THIS_MODULE,
> +       },
> +};
> +
> +module_platform_driver(rpisense_fb_driver);
> +
> +MODULE_DESCRIPTION("Raspberry Pi Sense HAT framebuffer driver");
> +MODULE_AUTHOR("Serge Schneider <serge at raspberrypi.org>");
> +MODULE_LICENSE("GPL");
> +
> diff --git a/include/linux/mfd/rpisense.h b/include/linux/mfd/rpisense.h
> new file mode 100644
> index 000000000000..0718b6f0eddb
> --- /dev/null
> +++ b/include/linux/mfd/rpisense.h
> @@ -0,0 +1,66 @@
> +/* 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
> + */
> +
> +#ifndef __LINUX_MFD_RPISENSE_CORE_H_
> +#define __LINUX_MFD_RPISENSE_CORE_H_
> +
> +#include <linux/input.h>
> +#include <linux/interrupt.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/platform_device.h>
> +
> +/*
> + * Register values.
> + */
> +#define RPISENSE_FB                    0x00
> +#define RPISENSE_WAI                   0xF0
> +#define RPISENSE_VER                   0xF1
> +#define RPISENSE_KEYS                  0xF2
> +#define RPISENSE_EE_WP                 0xF3
> +
> +#define RPISENSE_ID                    's'
> +
> +#define SENSEFB_FBIO_IOC_MAGIC 0xF1
> +
> +#define SENSEFB_FBIOGET_GAMMA _IO(SENSEFB_FBIO_IOC_MAGIC, 0)
> +#define SENSEFB_FBIOSET_GAMMA _IO(SENSEFB_FBIO_IOC_MAGIC, 1)
> +#define SENSEFB_FBIORESET_GAMMA _IO(SENSEFB_FBIO_IOC_MAGIC, 2)
> +
> +struct rpisense_fb {
> +       struct platform_device *pdev;
> +       struct fb_info *info;
> +};
> +
> +
> +struct rpisense_js {
> +       struct platform_device *pdev;
> +       struct input_dev *keys_dev;
> +       struct gpio_desc *keys_desc;
> +       struct work_struct keys_work_s;
> +       int keys_irq;
> +};
> +
> +
> +struct rpisense {
> +       struct device *dev;
> +       struct i2c_client *i2c_client;
> +
> +       /* Client devices */
> +       struct rpisense_js joystick;
> +       struct rpisense_fb framebuffer;
> +};
> +
> +struct rpisense *rpisense_get_dev(void);
> +s32 rpisense_reg_read(struct rpisense *rpisense, int reg);
> +int rpisense_reg_write(struct rpisense *rpisense, int reg, u16 val);
> +int rpisense_block_write(struct rpisense *rpisense, const char *buf, int count);
> +
> +#endif
> --
> 2.27.0
>
>
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