Hi Sasha,
On Sun, Jan 12, 2025 at 07:41:33PM +0100, Sasha Finkelstein via B4 Relay wrote:
> From: Sasha Finkelstein <fnkl.kernel@xxxxxxxxx>
>
> Adds a driver for Apple touchscreens using the Z2 protocol.
>
> Signed-off-by: Janne Grunau <j@xxxxxxxxxx>
> Reviewed-by: Neal Gompa <neal@xxxxxxxxx>
> Signed-off-by: Sasha Finkelstein <fnkl.kernel@xxxxxxxxx>
> ---
> drivers/input/touchscreen/Kconfig | 13 +
> drivers/input/touchscreen/Makefile | 1 +
> drivers/input/touchscreen/apple_z2.c | 463 +++++++++++++++++++++++++++++++++++
> 3 files changed, 477 insertions(+)
>
> diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
> index 1a03de7fcfa66c0f60768be17d776a79e36e570e..6c885cc58f323b3628538d41460248f8ab1dbf7d 100644
> --- a/drivers/input/touchscreen/Kconfig
> +++ b/drivers/input/touchscreen/Kconfig
> @@ -103,6 +103,19 @@ config TOUCHSCREEN_ADC
> To compile this driver as a module, choose M here: the
> module will be called resistive-adc-touch.ko.
>
> +config TOUCHSCREEN_APPLE_Z2
> + tristate "Apple Z2 touchscreens"
> + default ARCH_APPLE
> + depends on SPI
> + help
> + Say Y here if you have an Apple device with
> + a touchscreen or a touchbar.
> +
> + If unsure, say N.
> +
> + To compile this driver as a module, choose M here: the
> + module will be called apple_z2.
> +
> config TOUCHSCREEN_AR1021_I2C
> tristate "Microchip AR1020/1021 i2c touchscreen"
> depends on I2C && OF
> diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
> index 82bc837ca01e2ee18c5e9c578765d55ef9fab6d4..97a025c6a3770fb80255246eb63c11688ebd79eb 100644
> --- a/drivers/input/touchscreen/Makefile
> +++ b/drivers/input/touchscreen/Makefile
> @@ -15,6 +15,7 @@ obj-$(CONFIG_TOUCHSCREEN_AD7879_I2C) += ad7879-i2c.o
> obj-$(CONFIG_TOUCHSCREEN_AD7879_SPI) += ad7879-spi.o
> obj-$(CONFIG_TOUCHSCREEN_ADC) += resistive-adc-touch.o
> obj-$(CONFIG_TOUCHSCREEN_ADS7846) += ads7846.o
> +obj-$(CONFIG_TOUCHSCREEN_APPLE_Z2) += apple_z2.o
> obj-$(CONFIG_TOUCHSCREEN_AR1021_I2C) += ar1021_i2c.o
> obj-$(CONFIG_TOUCHSCREEN_ATMEL_MXT) += atmel_mxt_ts.o
> obj-$(CONFIG_TOUCHSCREEN_AUO_PIXCIR) += auo-pixcir-ts.o
> diff --git a/drivers/input/touchscreen/apple_z2.c b/drivers/input/touchscreen/apple_z2.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..cf2cb19f857785748a96d8787b3af10e48033659
> --- /dev/null
> +++ b/drivers/input/touchscreen/apple_z2.c
> @@ -0,0 +1,463 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Apple Z2 touchscreen driver
> + *
> + * Copyright (C) The Asahi Linux Contributors
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/firmware.h>
> +#include <linux/input.h>
> +#include <linux/input/mt.h>
> +#include <linux/input/touchscreen.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/spi/spi.h>
> +#include <linux/unaligned.h>
> +
> +#define APPLE_Z2_NUM_FINGERS_OFFSET 16
> +#define APPLE_Z2_FINGERS_OFFSET 24
> +#define APPLE_Z2_TOUCH_STARTED 3
> +#define APPLE_Z2_TOUCH_MOVED 4
> +#define APPLE_Z2_CMD_READ_INTERRUPT_DATA 0xEB
> +#define APPLE_Z2_HBPP_CMD_BLOB 0x3001
> +#define APPLE_Z2_FW_MAGIC 0x5746325A
> +#define LOAD_COMMAND_INIT_PAYLOAD 0
> +#define LOAD_COMMAND_SEND_BLOB 1
> +#define LOAD_COMMAND_SEND_CALIBRATION 2
> +#define CAL_PROP_NAME "apple,z2-cal-blob"
> +
> +struct apple_z2 {
> + struct spi_device *spidev;
> + struct gpio_desc *reset_gpio;
> + struct input_dev *input_dev;
> + struct completion boot_irq;
> + bool booted;
> + int index_parity;
> + struct touchscreen_properties props;
> + const char *fw_name;
> + struct apple_z2_read_interrupt_cmd *len_cmd;
Can we make it u8 *tx_buf ?
> + char *rx_buf;
Can we make it u8 *?
> +};
> +
> +struct apple_z2_finger {
> + u8 finger;
> + u8 state;
> + __le16 unknown2;
> + __le16 abs_x;
> + __le16 abs_y;
> + __le16 rel_x;
> + __le16 rel_y;
> + __le16 tool_major;
> + __le16 tool_minor;
> + __le16 orientation;
> + __le16 touch_major;
> + __le16 touch_minor;
> + __le16 unused[2];
> + __le16 pressure;
> + __le16 multi;
> +};
> +
> +struct apple_z2_hbpp_blob_hdr {
> + __le16 cmd;
> + __le16 len;
> + __le32 addr;
> + __le16 checksum;
> +};
> +
> +struct apple_z2_fw_hdr {
> + __le32 magic;
> + __le32 version;
> +};
> +
> +struct apple_z2_read_interrupt_cmd {
> + u8 cmd;
> + u8 counter;
> + u8 unused[12];
> + __le16 checksum;
> +};
> +
> +static void apple_z2_parse_touches(struct apple_z2 *z2, char *msg, size_t msg_len)
> +{
> + int i;
> + int nfingers;
> + int slot;
> + int slot_valid;
> + struct apple_z2_finger *fingers;
> +
> + if (msg_len <= APPLE_Z2_NUM_FINGERS_OFFSET)
> + return;
> + nfingers = msg[APPLE_Z2_NUM_FINGERS_OFFSET];
> + fingers = (struct apple_z2_finger *)(msg + APPLE_Z2_FINGERS_OFFSET);
Is this properly aligned? rx_buf is DMA aligned, but msg is +5 so we
start at an odd offset. APPLE_Z2_FINGERS_OFFSET is 24, so overall offset
is still odd. Do we have to mark apple_z2_finger as packed after all?
> + for (i = 0; i < nfingers; i++) {
> + slot = input_mt_get_slot_by_key(z2->input_dev, fingers[i].finger);
> + if (slot < 0) {
> + dev_warn(&z2->spidev->dev, "unable to get slot for finger\n");
> + continue;
> + }
> + slot_valid = fingers[i].state == APPLE_Z2_TOUCH_STARTED ||
> + fingers[i].state == APPLE_Z2_TOUCH_MOVED;
> + input_mt_slot(z2->input_dev, slot);
> + if (!input_mt_report_slot_state(z2->input_dev, MT_TOOL_FINGER, slot_valid))
> + continue;
> + touchscreen_report_pos(z2->input_dev, &z2->props, le16_to_cpu(fingers[i].abs_x),
> + le16_to_cpu(fingers[i].abs_y), true);
> + input_report_abs(z2->input_dev, ABS_MT_WIDTH_MAJOR,
> + le16_to_cpu(fingers[i].tool_major));
> + input_report_abs(z2->input_dev, ABS_MT_WIDTH_MINOR,
> + le16_to_cpu(fingers[i].tool_minor));
> + input_report_abs(z2->input_dev, ABS_MT_ORIENTATION,
> + le16_to_cpu(fingers[i].orientation));
> + input_report_abs(z2->input_dev, ABS_MT_TOUCH_MAJOR,
> + le16_to_cpu(fingers[i].touch_major));
> + input_report_abs(z2->input_dev, ABS_MT_TOUCH_MINOR,
> + le16_to_cpu(fingers[i].touch_minor));
> + }
> + input_mt_sync_frame(z2->input_dev);
> + input_sync(z2->input_dev);
> +}
> +
> +static int apple_z2_read_packet(struct apple_z2 *z2)
> +{
> + struct spi_message msg;
> + struct spi_transfer xfer;
> + int error;
> + size_t pkt_len;
> +
> + spi_message_init(&msg);
> + memset(&xfer, 0, sizeof(xfer));
> +
> + z2->len_cmd->cmd = APPLE_Z2_CMD_READ_INTERRUPT_DATA;
> + z2->len_cmd->counter = z2->index_parity + 1;
> + z2->len_cmd->checksum =
> + cpu_to_le16(APPLE_Z2_CMD_READ_INTERRUPT_DATA + 1 + z2->index_parity);
> + z2->index_parity = !z2->index_parity;
> + xfer.tx_buf = z2->len_cmd;
> + xfer.rx_buf = z2->rx_buf;
> + xfer.len = sizeof(*z2->len_cmd);
> +
> + spi_message_add_tail(&xfer, &msg);
> + error = spi_sync(z2->spidev, &msg);
Why not spi_sync_transfer() ?
> + if (error)
> + return error;
> +
> + pkt_len = (get_unaligned_le16(z2->rx_buf + 1) + 8) & (-4);
> +
> + spi_message_init(&msg);
> + memset(&xfer, 0, sizeof(xfer));
> + xfer.rx_buf = z2->rx_buf;
> + xfer.len = pkt_len;
> +
> + spi_message_add_tail(&xfer, &msg);
> + error = spi_sync(z2->spidev, &msg);
Maybe simple spi_read()?
> +
> + if (error)
> + return error;
> +
> + apple_z2_parse_touches(z2, z2->rx_buf + 5, pkt_len - 5);
> +
> + return 0;
> +}
> +
> +static irqreturn_t apple_z2_irq(int irq, void *data)
> +{
> + struct spi_device *spi = data;
> + struct apple_z2 *z2 = spi_get_drvdata(spi);
> +
> + if (unlikely(!z2->booted))
> + complete(&z2->boot_irq);
> + else
> + apple_z2_read_packet(z2);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int apple_z2_build_cal_blob(struct apple_z2 *z2, u32 address, size_t cal_size, char *data)
> +{
> + u16 len_words = (cal_size + 3) / 4;
> + size_t hdr_size = sizeof(struct apple_z2_hbpp_blob_hdr);
> + u32 checksum = 0;
> + u16 checksum_hdr = 0;
> + int i;
> + struct apple_z2_hbpp_blob_hdr *hdr;
> + int error;
> +
> + hdr = (struct apple_z2_hbpp_blob_hdr *)data;
> + hdr->cmd = cpu_to_le16(APPLE_Z2_HBPP_CMD_BLOB);
> + hdr->len = cpu_to_le16(len_words);
> + hdr->addr = cpu_to_le32(address);
> +
> + for (i = 2; i < 8; i++)
> + checksum_hdr += data[i];
> +
> + hdr->checksum = cpu_to_le16(checksum_hdr);
> + error = device_property_read_u8_array(&z2->spidev->dev, CAL_PROP_NAME,
> + data + hdr_size, cal_size);
> + if (error)
> + return error;
> +
> + for (i = 0; i < cal_size; i++)
> + checksum += data[i + hdr_size];
> +
> + put_unaligned_le32(checksum, data + cal_size + hdr_size);
> + return 0;
> +}
> +
> +static int apple_z2_send_firmware_blob(struct apple_z2 *z2, const char *data, u32 size, u8 bpw)
> +{
> + struct spi_message msg;
> + struct spi_transfer blob_xfer, ack_xfer;
> + int error;
> + char *int_ack __free(kfree) = NULL;
> +
> + int_ack = kzalloc(2, GFP_KERNEL);
When using __free() the preferred form is
char *int_ack __free(kfree) = kzalloc(2, GFP_KERNEL);
instead of pre-declaring the variable with the rest at the beginning of
the function.
> + if (!int_ack)
> + return -ENOMEM;
> + int_ack[0] = 0x1a;
> + int_ack[1] = 0xa1;
Can this reuse tx_buf in the device?
> +
> + spi_message_init(&msg);
> + memset(&blob_xfer, 0, sizeof(blob_xfer));
> + memset(&ack_xfer, 0, sizeof(ack_xfer));
> +
> + blob_xfer.tx_buf = data;
> + blob_xfer.len = size;
> + blob_xfer.bits_per_word = bpw;
> + spi_message_add_tail(&blob_xfer, &msg);
> +
> + ack_xfer.tx_buf = int_ack;
> + ack_xfer.len = 2;
> + spi_message_add_tail(&ack_xfer, &msg);
> +
> + reinit_completion(&z2->boot_irq);
> + error = spi_sync(z2->spidev, &msg);
> + if (error)
> + return error;
> + wait_for_completion_timeout(&z2->boot_irq, msecs_to_jiffies(20));
Why not handling timeouts?
> + return 0;
> +}
> +
> +static int apple_z2_upload_firmware(struct apple_z2 *z2)
> +{
> + const struct apple_z2_fw_hdr *fw_hdr;
> + size_t fw_idx = sizeof(struct apple_z2_fw_hdr);
> + int error;
> + u32 load_cmd;
> + u32 size;
> + u32 address;
> + char *data;
> + u8 bits_per_word;
> + size_t cal_size;
> + const struct firmware *fw __free(firmware) = NULL;
> +
> + error = request_firmware(&fw, z2->fw_name, &z2->spidev->dev);
Please keep the last 2 lines together and separate from declaration
block.
> + if (error) {
> + dev_err(&z2->spidev->dev, "unable to load firmware");
> + return error;
> + }
> +
> + fw_hdr = (const struct apple_z2_fw_hdr *)fw->data;
> + if (le32_to_cpu(fw_hdr->magic) != APPLE_Z2_FW_MAGIC || le32_to_cpu(fw_hdr->version) != 1) {
> + dev_err(&z2->spidev->dev, "invalid firmware header");
> + return -EINVAL;
> + }
> +
> + /*
> + * This will interrupt the upload half-way if the file is malformed
> + * As the device has no non-volatile storage to corrupt, and gets reset
> + * on boot anyway, this is fine.
> + */
> + while (fw_idx < fw->size) {
> + if (fw->size - fw_idx < 8) {
> + dev_err(&z2->spidev->dev, "firmware malformed");
> + return -EINVAL;
> + }
> +
> + load_cmd = le32_to_cpu(*(__le32 *)(fw->data + fw_idx));
> + fw_idx += sizeof(u32);
> + if (load_cmd == LOAD_COMMAND_INIT_PAYLOAD || load_cmd == LOAD_COMMAND_SEND_BLOB) {
> + size = le32_to_cpu(*(__le32 *)(fw->data + fw_idx));
> + fw_idx += sizeof(u32);
> + if (fw->size - fw_idx < size) {
> + dev_err(&z2->spidev->dev, "firmware malformed");
> + return -EINVAL;
> + }
> + bits_per_word = load_cmd == LOAD_COMMAND_SEND_BLOB ? 16 : 8;
> + error = apple_z2_send_firmware_blob(z2, fw->data + fw_idx,
> + size, bits_per_word);
> + if (error)
> + return error;
> + fw_idx += size;
> + } else if (load_cmd == 2) {
We have LOAD_COMMAND_INIT_PAYLOAD and LOAD_COMMAND_SEND_BLOB, can we
have name for "2" as well please?
> + address = le32_to_cpu(*(u32 *)(fw->data + fw_idx));
> + fw_idx += sizeof(u32);
> + cal_size = device_property_count_u8(&z2->spidev->dev, CAL_PROP_NAME);
> + if (cal_size != 0) {
> + size = cal_size + sizeof(struct apple_z2_hbpp_blob_hdr) + 4;
> + data = kzalloc(size, GFP_KERNEL);
> + error = apple_z2_build_cal_blob(z2, address, cal_size, data);
> + if (!error)
> + error = apple_z2_send_firmware_blob(z2, data, size, 16);
> + kfree(data);
> + if (error)
> + return error;
> + }
> + } else {
> + dev_err(&z2->spidev->dev, "firmware malformed");
> + return -EINVAL;
> + }
> + if (fw_idx % 4 != 0)
> + fw_idx += 4 - (fw_idx % 4);
> + }
> +
> +
> + z2->booted = true;
> + apple_z2_read_packet(z2);
> + return 0;
> +}
> +
> +static int apple_z2_boot(struct apple_z2 *z2)
> +{
> + int timeout;
> + int error;
> +
> + enable_irq(z2->spidev->irq);
> + gpiod_direction_output(z2->reset_gpio, 0);
I think you need reinit_completion() here.
> + timeout = wait_for_completion_timeout(&z2->boot_irq, msecs_to_jiffies(20));
> + if (timeout == 0)
> + return -ETIMEDOUT;
> +
> + error = apple_z2_upload_firmware(z2);
> + if (error) {
> + gpiod_direction_output(z2->reset_gpio, 1);
> + disable_irq(z2->spidev->irq);
> + }
> + return error;
> +}
> +
> +static int apple_z2_probe(struct spi_device *spi)
> +{
> + struct device *dev = &spi->dev;
> + struct apple_z2 *z2;
> + int error;
> +
> + z2 = devm_kzalloc(dev, sizeof(*z2), GFP_KERNEL);
> + if (!z2)
> + return -ENOMEM;
> +
> + z2->len_cmd = devm_kzalloc(dev, sizeof(*z2->len_cmd), GFP_KERNEL);
> + z2->rx_buf = devm_kzalloc(dev, 4096, GFP_KERNEL);
> + if (!z2->len_cmd || !z2->rx_buf)
> + return -ENOMEM;
> +
> + z2->spidev = spi;
> + init_completion(&z2->boot_irq);
> + spi_set_drvdata(spi, z2);
> +
> + z2->reset_gpio = devm_gpiod_get_index(dev, "reset", 0, 0);
Why devm_gpiod_get_index() and not devm_gpiod_get()? Also, why don't
you start with GPIOD_OUT_HIGH and use gpiod_set_value() instead of
gpiod_direction_outout()?
> + if (IS_ERR(z2->reset_gpio))
> + return dev_err_probe(dev, PTR_ERR(z2->reset_gpio), "unable to get reset");
> +
> + error = devm_request_threaded_irq(dev, z2->spidev->irq, NULL,
> + apple_z2_irq, IRQF_ONESHOT | IRQF_NO_AUTOEN,
> + "apple-z2-irq", spi);
> + if (error)
> + return dev_err_probe(dev, z2->spidev->irq, "unable to request irq");
> +
> + error = device_property_read_string(dev, "firmware-name", &z2->fw_name);
> + if (error)
> + return dev_err_probe(dev, error, "unable to get firmware name");
> +
> + z2->input_dev = devm_input_allocate_device(dev);
> + if (!z2->input_dev)
> + return -ENOMEM;
> + z2->input_dev->name = (char *)spi_get_device_id(spi)->driver_data;
> + z2->input_dev->phys = "apple_z2";
> + z2->input_dev->id.bustype = BUS_SPI;
> +
> + /* Allocate the axes before setting from DT */
> + input_set_abs_params(z2->input_dev, ABS_MT_POSITION_X, 0, 0, 0, 0);
> + input_set_abs_params(z2->input_dev, ABS_MT_POSITION_Y, 0, 0, 0, 0);
> + touchscreen_parse_properties(z2->input_dev, true, &z2->props);
> + input_abs_set_res(z2->input_dev, ABS_MT_POSITION_X, 100);
> + input_abs_set_res(z2->input_dev, ABS_MT_POSITION_Y, 100);
> + input_set_abs_params(z2->input_dev, ABS_MT_WIDTH_MAJOR, 0, 65535, 0, 0);
> + input_set_abs_params(z2->input_dev, ABS_MT_WIDTH_MINOR, 0, 65535, 0, 0);
> + input_set_abs_params(z2->input_dev, ABS_MT_TOUCH_MAJOR, 0, 65535, 0, 0);
> + input_set_abs_params(z2->input_dev, ABS_MT_TOUCH_MINOR, 0, 65535, 0, 0);
> + input_set_abs_params(z2->input_dev, ABS_MT_ORIENTATION, -32768, 32767, 0, 0);
> +
> + input_set_drvdata(z2->input_dev, z2);
> +
> + error = input_mt_init_slots(z2->input_dev, 256, INPUT_MT_DIRECT);
> + if (error)
> + return dev_err_probe(dev, error, "unable to initialize multitouch slots");
> +
> + error = input_register_device(z2->input_dev);
> + if (error)
> + return dev_err_probe(dev, error, "unable to register input device");
> +
> + /* Reset the device on boot */
> + gpiod_direction_output(z2->reset_gpio, 1);
> + usleep_range(5000, 10000);
> + error = apple_z2_boot(z2);
> + if (error)
> + return error;
> + return 0;
> +}
> +
> +static void apple_z2_shutdown(struct spi_device *spi)
> +{
> + struct apple_z2 *z2 = spi_get_drvdata(spi);
> +
> + disable_irq(z2->spidev->irq);
> + gpiod_direction_output(z2->reset_gpio, 1);
> + z2->booted = false;
> +}
> +
> +static int apple_z2_suspend(struct device *dev)
> +{
> + apple_z2_shutdown(to_spi_device(dev));
> + return 0;
> +}
> +
> +static int apple_z2_resume(struct device *dev)
> +{
> + struct apple_z2 *z2 = spi_get_drvdata(to_spi_device(dev));
> +
> + return apple_z2_boot(z2);
> +}
> +
> +static DEFINE_SIMPLE_DEV_PM_OPS(apple_z2_pm, apple_z2_suspend, apple_z2_resume);
> +
> +static const struct of_device_id apple_z2_of_match[] = {
> + { .compatible = "apple,j293-touchbar" },
> + { .compatible = "apple,j493-touchbar" },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, apple_z2_of_match);
> +
> +static struct spi_device_id apple_z2_of_id[] = {
> + { .name = "j293-touchbar", .driver_data = (kernel_ulong_t)"MacBookPro17,1 Touch Bar" },
> + { .name = "j493-touchbar", .driver_data = (kernel_ulong_t)"Mac14,7 Touch Bar" },
> + {}
> +};
> +MODULE_DEVICE_TABLE(spi, apple_z2_of_id);
> +
> +static struct spi_driver apple_z2_driver = {
> + .driver = {
> + .name = "apple-z2",
> + .pm = pm_sleep_ptr(&apple_z2_pm),
> + .of_match_table = apple_z2_of_match,
You decided not to mark the driver for async probing... Why? Do you see
userspace unhappy if you do so?
> + },
> + .id_table = apple_z2_of_id,
> + .probe = apple_z2_probe,
> + .remove = apple_z2_shutdown,
> +};
> +
> +module_spi_driver(apple_z2_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_FIRMWARE("apple/dfrmtfw-*.bin");
> +MODULE_DESCRIPTION("Apple Z2 touchscreens driver");
>
> --
> 2.48.0
>
>
Thanks.
--
Dmitry
