apple_z2.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Apple Z2 touchscreen driver
  4 *
  5 * Copyright (C) The Asahi Linux Contributors
  6 */
  7
  8#include <linux/delay.h>
  9#include <linux/firmware.h>
 10#include <linux/input.h>
 11#include <linux/input/mt.h>
 12#include <linux/input/touchscreen.h>
 13#include <linux/interrupt.h>
 14#include <linux/module.h>
 15#include <linux/of.h>
 16#include <linux/spi/spi.h>
 17#include <linux/unaligned.h>
 18
 19#define APPLE_Z2_NUM_FINGERS_OFFSET      16
 20#define APPLE_Z2_FINGERS_OFFSET          24
 21#define APPLE_Z2_TOUCH_STARTED           3
 22#define APPLE_Z2_TOUCH_MOVED             4
 23#define APPLE_Z2_CMD_READ_INTERRUPT_DATA 0xEB
 24#define APPLE_Z2_REPLY_INTERRUPT_DATA    0xE1
 25#define APPLE_Z2_HBPP_CMD_BLOB           0x3001
 26#define APPLE_Z2_FW_MAGIC                0x5746325A
 27#define LOAD_COMMAND_INIT_PAYLOAD        0
 28#define LOAD_COMMAND_SEND_BLOB           1
 29#define LOAD_COMMAND_SEND_CALIBRATION    2
 30#define CAL_PROP_NAME                    "apple,z2-cal-blob"
 31
 32struct apple_z2 {
 33	struct spi_device *spidev;
 34	struct gpio_desc *reset_gpio;
 35	struct input_dev *input_dev;
 36	struct completion boot_irq;
 37	bool booted;
 38	int index_parity;
 39	struct touchscreen_properties props;
 40	const char *fw_name;
 41	u8 *tx_buf;
 42	u8 *rx_buf;
 43};
 44
 45struct apple_z2_finger {
 46	u8 finger;
 47	u8 state;
 48	__le16 unknown2;
 49	__le16 abs_x;
 50	__le16 abs_y;
 51	__le16 rel_x;
 52	__le16 rel_y;
 53	__le16 tool_major;
 54	__le16 tool_minor;
 55	__le16 orientation;
 56	__le16 touch_major;
 57	__le16 touch_minor;
 58	__le16 unused[2];
 59	__le16 pressure;
 60	__le16 multi;
 61} __packed;
 62
 63struct apple_z2_hbpp_blob_hdr {
 64	__le16 cmd;
 65	__le16 len;
 66	__le32 addr;
 67	__le16 checksum;
 68};
 69
 70struct apple_z2_fw_hdr {
 71	__le32 magic;
 72	__le32 version;
 73};
 74
 75struct apple_z2_read_interrupt_cmd {
 76	u8 cmd;
 77	u8 counter;
 78	u8 unused[12];
 79	__le16 checksum;
 80};
 81
 82static void apple_z2_parse_touches(struct apple_z2 *z2,
 83				   const u8 *msg, size_t msg_len)
 84{
 85	int i;
 86	int nfingers;
 87	int slot;
 88	int slot_valid;
 89	struct apple_z2_finger *fingers;
 90
 91	if (msg_len <= APPLE_Z2_NUM_FINGERS_OFFSET)
 92		return;
 93	nfingers = msg[APPLE_Z2_NUM_FINGERS_OFFSET];
 94	fingers = (struct apple_z2_finger *)(msg + APPLE_Z2_FINGERS_OFFSET);
 95	for (i = 0; i < nfingers; i++) {
 96		slot = input_mt_get_slot_by_key(z2->input_dev, fingers[i].finger);
 97		if (slot < 0) {
 98			dev_warn(&z2->spidev->dev, "unable to get slot for finger\n");
 99			continue;
100		}
101		slot_valid = fingers[i].state == APPLE_Z2_TOUCH_STARTED ||
102			     fingers[i].state == APPLE_Z2_TOUCH_MOVED;
103		input_mt_slot(z2->input_dev, slot);
104		if (!input_mt_report_slot_state(z2->input_dev, MT_TOOL_FINGER, slot_valid))
105			continue;
106		touchscreen_report_pos(z2->input_dev, &z2->props,
107				       le16_to_cpu(fingers[i].abs_x),
108				       le16_to_cpu(fingers[i].abs_y),
109				       true);
110		input_report_abs(z2->input_dev, ABS_MT_WIDTH_MAJOR,
111				 le16_to_cpu(fingers[i].tool_major));
112		input_report_abs(z2->input_dev, ABS_MT_WIDTH_MINOR,
113				 le16_to_cpu(fingers[i].tool_minor));
114		input_report_abs(z2->input_dev, ABS_MT_ORIENTATION,
115				 le16_to_cpu(fingers[i].orientation));
116		input_report_abs(z2->input_dev, ABS_MT_TOUCH_MAJOR,
117				 le16_to_cpu(fingers[i].touch_major));
118		input_report_abs(z2->input_dev, ABS_MT_TOUCH_MINOR,
119				 le16_to_cpu(fingers[i].touch_minor));
120	}
121	input_mt_sync_frame(z2->input_dev);
122	input_sync(z2->input_dev);
123}
124
125static int apple_z2_read_packet(struct apple_z2 *z2)
126{
127	struct apple_z2_read_interrupt_cmd *len_cmd = (void *)z2->tx_buf;
128	struct spi_transfer xfer;
129	int error;
130	size_t pkt_len;
131
132	memset(&xfer, 0, sizeof(xfer));
133	len_cmd->cmd = APPLE_Z2_CMD_READ_INTERRUPT_DATA;
134	len_cmd->counter = z2->index_parity + 1;
135	len_cmd->checksum =
136		cpu_to_le16(APPLE_Z2_CMD_READ_INTERRUPT_DATA + len_cmd->counter);
137	z2->index_parity = !z2->index_parity;
138	xfer.tx_buf = z2->tx_buf;
139	xfer.rx_buf = z2->rx_buf;
140	xfer.len = sizeof(*len_cmd);
141
142	error = spi_sync_transfer(z2->spidev, &xfer, 1);
143	if (error)
144		return error;
145
146	if (z2->rx_buf[0] != APPLE_Z2_REPLY_INTERRUPT_DATA)
147		return 0;
148
149	pkt_len = (get_unaligned_le16(z2->rx_buf + 1) + 8) & 0xfffffffc;
150
151	error = spi_read(z2->spidev, z2->rx_buf, pkt_len);
152	if (error)
153		return error;
154
155	apple_z2_parse_touches(z2, z2->rx_buf + 5, pkt_len - 5);
156
157	return 0;
158}
159
160static irqreturn_t apple_z2_irq(int irq, void *data)
161{
162	struct apple_z2 *z2 = data;
163
164	if (unlikely(!z2->booted))
165		complete(&z2->boot_irq);
166	else
167		apple_z2_read_packet(z2);
168
169	return IRQ_HANDLED;
170}
171
172/* Build calibration blob, caller is responsible for freeing the blob data. */
173static const u8 *apple_z2_build_cal_blob(struct apple_z2 *z2,
174					 u32 address, size_t *size)
175{
176	u8 *cal_data;
177	int cal_size;
178	size_t blob_size;
179	u32 checksum;
180	u16 checksum_hdr;
181	int i;
182	struct apple_z2_hbpp_blob_hdr *hdr;
183	int error;
184
185	if (!device_property_present(&z2->spidev->dev, CAL_PROP_NAME))
186		return NULL;
187
188	cal_size = device_property_count_u8(&z2->spidev->dev, CAL_PROP_NAME);
189	if (cal_size < 0)
190		return ERR_PTR(cal_size);
191
192	blob_size = sizeof(struct apple_z2_hbpp_blob_hdr) + cal_size + sizeof(__le32);
193	u8 *blob_data __free(kfree) = kzalloc(blob_size, GFP_KERNEL);
194	if (!blob_data)
195		return ERR_PTR(-ENOMEM);
196
197	hdr = (struct apple_z2_hbpp_blob_hdr *)blob_data;
198	hdr->cmd = cpu_to_le16(APPLE_Z2_HBPP_CMD_BLOB);
199	hdr->len = cpu_to_le16(round_up(cal_size, 4) / 4);
200	hdr->addr = cpu_to_le32(address);
201
202	checksum_hdr = 0;
203	for (i = 2; i < 8; i++)
204		checksum_hdr += blob_data[i];
205	hdr->checksum = cpu_to_le16(checksum_hdr);
206
207	cal_data = blob_data + sizeof(struct apple_z2_hbpp_blob_hdr);
208	error = device_property_read_u8_array(&z2->spidev->dev, CAL_PROP_NAME,
209					      cal_data, cal_size);
210	if (error)
211		return ERR_PTR(error);
212
213	checksum = 0;
214	for (i = 0; i < cal_size; i++)
215		checksum += cal_data[i];
216	put_unaligned_le32(checksum, cal_data + cal_size);
217
218	*size = blob_size;
219	return no_free_ptr(blob_data);
220}
221
222static int apple_z2_send_firmware_blob(struct apple_z2 *z2, const u8 *data,
223				       u32 size, bool init)
224{
225	struct spi_message msg;
226	struct spi_transfer blob_xfer, ack_xfer;
227	int error;
228
229	z2->tx_buf[0] = 0x1a;
230	z2->tx_buf[1] = 0xa1;
231
232	spi_message_init(&msg);
233	memset(&blob_xfer, 0, sizeof(blob_xfer));
234	memset(&ack_xfer, 0, sizeof(ack_xfer));
235
236	blob_xfer.tx_buf = data;
237	blob_xfer.len = size;
238	blob_xfer.bits_per_word = init ? 8 : 16;
239	spi_message_add_tail(&blob_xfer, &msg);
240
241	ack_xfer.tx_buf = z2->tx_buf;
242	ack_xfer.len = 2;
243	spi_message_add_tail(&ack_xfer, &msg);
244
245	reinit_completion(&z2->boot_irq);
246	error = spi_sync(z2->spidev, &msg);
247	if (error)
248		return error;
249
250	/* Irq only happens sometimes, but the thing boots reliably nonetheless */
251	wait_for_completion_timeout(&z2->boot_irq, msecs_to_jiffies(20));
252
253	return 0;
254}
255
256static int apple_z2_upload_firmware(struct apple_z2 *z2)
257{
258	const struct apple_z2_fw_hdr *fw_hdr;
259	size_t fw_idx = sizeof(struct apple_z2_fw_hdr);
260	int error;
261	u32 load_cmd;
262	u32 address;
263	bool init;
264	size_t size;
265
266	const struct firmware *fw __free(firmware) = NULL;
267	error = request_firmware(&fw, z2->fw_name, &z2->spidev->dev);
268	if (error) {
269		dev_err(&z2->spidev->dev, "unable to load firmware\n");
270		return error;
271	}
272
273	fw_hdr = (const struct apple_z2_fw_hdr *)fw->data;
274	if (le32_to_cpu(fw_hdr->magic) != APPLE_Z2_FW_MAGIC || le32_to_cpu(fw_hdr->version) != 1) {
275		dev_err(&z2->spidev->dev, "invalid firmware header\n");
276		return -EINVAL;
277	}
278
279	/*
280	 * This will interrupt the upload half-way if the file is malformed
281	 * As the device has no non-volatile storage to corrupt, and gets reset
282	 * on boot anyway, this is fine.
283	 */
284	while (fw_idx < fw->size) {
285		if (fw->size - fw_idx < 8) {
286			dev_err(&z2->spidev->dev, "firmware malformed\n");
287			return -EINVAL;
288		}
289
290		load_cmd = le32_to_cpup((__force __le32 *)(fw->data + fw_idx));
291		fw_idx += sizeof(u32);
292		if (load_cmd == LOAD_COMMAND_INIT_PAYLOAD || load_cmd == LOAD_COMMAND_SEND_BLOB) {
293			size = le32_to_cpup((__force __le32 *)(fw->data + fw_idx));
294			fw_idx += sizeof(u32);
295			if (fw->size - fw_idx < size) {
296				dev_err(&z2->spidev->dev, "firmware malformed\n");
297				return -EINVAL;
298			}
299			init = load_cmd == LOAD_COMMAND_INIT_PAYLOAD;
300			error = apple_z2_send_firmware_blob(z2, fw->data + fw_idx,
301							    size, init);
302			if (error)
303				return error;
304			fw_idx += size;
305		} else if (load_cmd == LOAD_COMMAND_SEND_CALIBRATION) {
306			address = le32_to_cpup((__force __le32 *)(fw->data + fw_idx));
307			fw_idx += sizeof(u32);
308
309			const u8 *data __free(kfree) =
310				apple_z2_build_cal_blob(z2, address, &size);
311			if (IS_ERR(data))
312				return PTR_ERR(data);
313
314			if (data) {
315				error = apple_z2_send_firmware_blob(z2, data, size, false);
316				if (error)
317					return error;
318			}
319		} else {
320			dev_err(&z2->spidev->dev, "firmware malformed\n");
321			return -EINVAL;
322		}
323		fw_idx = round_up(fw_idx, 4);
324	}
325
326
327	z2->booted = true;
328	apple_z2_read_packet(z2);
329	return 0;
330}
331
332static int apple_z2_boot(struct apple_z2 *z2)
333{
334	int error;
335
336	reinit_completion(&z2->boot_irq);
337	enable_irq(z2->spidev->irq);
338	gpiod_set_value(z2->reset_gpio, 0);
339	if (!wait_for_completion_timeout(&z2->boot_irq, msecs_to_jiffies(20)))
340		return -ETIMEDOUT;
341
342	error = apple_z2_upload_firmware(z2);
343	if (error) {
344		gpiod_set_value(z2->reset_gpio, 1);
345		disable_irq(z2->spidev->irq);
346		return error;
347	}
348
349	return 0;
350}
351
352static int apple_z2_probe(struct spi_device *spi)
353{
354	struct device *dev = &spi->dev;
355	struct apple_z2 *z2;
356	int error;
357
358	z2 = devm_kzalloc(dev, sizeof(*z2), GFP_KERNEL);
359	if (!z2)
360		return -ENOMEM;
361
362	z2->tx_buf = devm_kzalloc(dev, sizeof(struct apple_z2_read_interrupt_cmd), GFP_KERNEL);
363	if (!z2->tx_buf)
364		return -ENOMEM;
365	/* 4096 will end up being rounded up to 8192 due to devres header */
366	z2->rx_buf = devm_kzalloc(dev, 4000, GFP_KERNEL);
367	if (!z2->rx_buf)
368		return -ENOMEM;
369
370	z2->spidev = spi;
371	init_completion(&z2->boot_irq);
372	spi_set_drvdata(spi, z2);
373
374	/* Reset the device on boot */
375	z2->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
376	if (IS_ERR(z2->reset_gpio))
377		return dev_err_probe(dev, PTR_ERR(z2->reset_gpio), "unable to get reset\n");
378
379	error = devm_request_threaded_irq(dev, z2->spidev->irq, NULL, apple_z2_irq,
380					  IRQF_ONESHOT | IRQF_NO_AUTOEN,
381					  "apple-z2-irq", z2);
382	if (error)
383		return dev_err_probe(dev, error, "unable to request irq\n");
384
385	error = device_property_read_string(dev, "firmware-name", &z2->fw_name);
386	if (error)
387		return dev_err_probe(dev, error, "unable to get firmware name\n");
388
389	z2->input_dev = devm_input_allocate_device(dev);
390	if (!z2->input_dev)
391		return -ENOMEM;
392
393	z2->input_dev->name = (char *)spi_get_device_id(spi)->driver_data;
394	z2->input_dev->phys = "apple_z2";
395	z2->input_dev->id.bustype = BUS_SPI;
396
397	/* Allocate the axes before setting from DT */
398	input_set_abs_params(z2->input_dev, ABS_MT_POSITION_X, 0, 0, 0, 0);
399	input_set_abs_params(z2->input_dev, ABS_MT_POSITION_Y, 0, 0, 0, 0);
400	touchscreen_parse_properties(z2->input_dev, true, &z2->props);
401	input_abs_set_res(z2->input_dev, ABS_MT_POSITION_X, 100);
402	input_abs_set_res(z2->input_dev, ABS_MT_POSITION_Y, 100);
403	input_set_abs_params(z2->input_dev, ABS_MT_WIDTH_MAJOR, 0, 65535, 0, 0);
404	input_set_abs_params(z2->input_dev, ABS_MT_WIDTH_MINOR, 0, 65535, 0, 0);
405	input_set_abs_params(z2->input_dev, ABS_MT_TOUCH_MAJOR, 0, 65535, 0, 0);
406	input_set_abs_params(z2->input_dev, ABS_MT_TOUCH_MINOR, 0, 65535, 0, 0);
407	input_set_abs_params(z2->input_dev, ABS_MT_ORIENTATION, -32768, 32767, 0, 0);
408
409	error = input_mt_init_slots(z2->input_dev, 256, INPUT_MT_DIRECT);
410	if (error)
411		return dev_err_probe(dev, error, "unable to initialize multitouch slots\n");
412
413	error = input_register_device(z2->input_dev);
414	if (error)
415		return dev_err_probe(dev, error, "unable to register input device\n");
416
417	/* Wait for device reset to finish */
418	usleep_range(5000, 10000);
419	error = apple_z2_boot(z2);
420	if (error)
421		return error;
422
423	return 0;
424}
425
426static void apple_z2_shutdown(struct spi_device *spi)
427{
428	struct apple_z2 *z2 = spi_get_drvdata(spi);
429
430	disable_irq(z2->spidev->irq);
431	gpiod_direction_output(z2->reset_gpio, 1);
432	z2->booted = false;
433}
434
435static int apple_z2_suspend(struct device *dev)
436{
437	apple_z2_shutdown(to_spi_device(dev));
438
439	return 0;
440}
441
442static int apple_z2_resume(struct device *dev)
443{
444	struct apple_z2 *z2 = spi_get_drvdata(to_spi_device(dev));
445
446	return apple_z2_boot(z2);
447}
448
449static DEFINE_SIMPLE_DEV_PM_OPS(apple_z2_pm, apple_z2_suspend, apple_z2_resume);
450
451static const struct of_device_id apple_z2_of_match[] = {
452	{ .compatible = "apple,j293-touchbar" },
453	{ .compatible = "apple,j493-touchbar" },
454	{}
455};
456MODULE_DEVICE_TABLE(of, apple_z2_of_match);
457
458static struct spi_device_id apple_z2_of_id[] = {
459	{ .name = "j293-touchbar", .driver_data = (kernel_ulong_t)"MacBookPro17,1 Touch Bar" },
460	{ .name = "j493-touchbar", .driver_data = (kernel_ulong_t)"Mac14,7 Touch Bar" },
461	{}
462};
463MODULE_DEVICE_TABLE(spi, apple_z2_of_id);
464
465static struct spi_driver apple_z2_driver = {
466	.driver = {
467		.name	= "apple-z2",
468		.pm	= pm_sleep_ptr(&apple_z2_pm),
469		.of_match_table = apple_z2_of_match,
470		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
471	},
472	.id_table = apple_z2_of_id,
473	.probe    = apple_z2_probe,
474	.remove   = apple_z2_shutdown,
475};
476
477module_spi_driver(apple_z2_driver);
478
479MODULE_LICENSE("GPL");
480MODULE_FIRMWARE("apple/dfrmtfw-*.bin");
481MODULE_DESCRIPTION("Apple Z2 touchscreens driver");