1 // SPDX-License-Identifier: GPL-2.0
5  * This device driver implements a TCG PTP FIFO interface over SPI for chips
15 #include <linux/spi/spi.h>
23  * - can go to sleep not earlier than after CR50_SLEEP_DELAY_MSEC.
24  * - needs up to CR50_WAKE_START_DELAY_USEC to wake after sleep.
25  * - requires waiting for "ready" IRQ, if supported; or waiting for at least
27  * - waits for up to CR50_FLOW_CONTROL for flow control 'ready' indication.
66 	cr50_phy->irq_confirmed = true;  in cr50_spi_irq_handler()
67 	complete(&cr50_phy->spi_phy.ready);  in cr50_spi_irq_handler()
78 	unsigned long allowed_access = phy->last_access + phy->access_delay;  in cr50_ensure_access_delay()
80 	struct device *dev = &phy->spi_phy.spi_device->dev;  in cr50_ensure_access_delay()
88 	if (time_in_range_open(time_now, phy->last_access, allowed_access)) {  in cr50_ensure_access_delay()
89 		unsigned long remaining, timeout = allowed_access - time_now;  in cr50_ensure_access_delay()
91 		remaining = wait_for_completion_timeout(&phy->spi_phy.ready,  in cr50_ensure_access_delay()
93 		if (!remaining && phy->irq_confirmed)  in cr50_ensure_access_delay()
97 	if (phy->irq_needs_confirmation) {  in cr50_ensure_access_delay()
98 		unsigned int attempt = ++phy->irq_confirmation_attempt;  in cr50_ensure_access_delay()
100 		if (phy->irq_confirmed) {  in cr50_ensure_access_delay()
101 			phy->irq_needs_confirmation = false;  in cr50_ensure_access_delay()
102 			phy->access_delay = CR50_READY_IRQ_TIMEOUT;  in cr50_ensure_access_delay()
106 			phy->irq_needs_confirmation = false;  in cr50_ensure_access_delay()
107 			dev_warn(dev, "IRQ not confirmed - will use delays\n");  in cr50_ensure_access_delay()
113  * Cr50 might go to sleep if there is no SPI activity for some time and
114  * miss the first few bits/bytes on the bus. In such case, wake it up
125 	return !time_in_range_open(jiffies, phy->last_access,  in cr50_needs_waking()
126 				   phy->spi_phy.wake_after);  in cr50_needs_waking()
131 	struct tpm_tis_spi_phy *phy = &cr50_phy->spi_phy;  in cr50_wake_if_needed()
142 		spi_sync_transfer(phy->spi_device, &spi_cs_wake, 1);  in cr50_wake_if_needed()
149 	phy->wake_after = jiffies + msecs_to_jiffies(CR50_SLEEP_DELAY_MSEC);  in cr50_wake_if_needed()
153  * Flow control: clock the bus and wait for cr50 to set LSB before
162 	struct device *dev = &phy->spi_device->dev;  in cr50_spi_flow_control()
167 	spi_xfer->len = 1;  in cr50_spi_flow_control()
172 		ret = spi_sync_locked(phy->spi_device, &m);  in cr50_spi_flow_control()
178 			return -EBUSY;  in cr50_spi_flow_control()
180 	} while (!(phy->iobuf[0] & 0x01));  in cr50_spi_flow_control()
192 	mutex_lock(&cr50_phy->time_track_mutex);  in tpm_tis_spi_cr50_transfer()
195 	 * only device on that spi bus.  in tpm_tis_spi_cr50_transfer()
202 	cr50_phy->last_access = jiffies;  in tpm_tis_spi_cr50_transfer()
203 	mutex_unlock(&cr50_phy->time_track_mutex);  in tpm_tis_spi_cr50_transfer()
239 	tpm_tis_write8(data, TPM_CR50_FW_VER(data->locality), 0);  in cr50_print_fw_version()
243 		tpm_tis_read_bytes(data, TPM_CR50_FW_VER(data->locality), 4,  in cr50_print_fw_version()
250 	dev_info(&phy->spi_device->dev, "Cr50 firmware version: %s\n", fw_ver);  in cr50_print_fw_version()
253 int cr50_spi_probe(struct spi_device *spi)  in cr50_spi_probe()  argument
260 	cr50_phy = devm_kzalloc(&spi->dev, sizeof(*cr50_phy), GFP_KERNEL);  in cr50_spi_probe()
262 		return -ENOMEM;  in cr50_spi_probe()
264 	phy = &cr50_phy->spi_phy;  in cr50_spi_probe()
265 	phy->flow_control = cr50_spi_flow_control;  in cr50_spi_probe()
266 	phy->wake_after = jiffies;  in cr50_spi_probe()
267 	init_completion(&phy->ready);  in cr50_spi_probe()
269 	cr50_phy->access_delay = CR50_NOIRQ_ACCESS_DELAY;  in cr50_spi_probe()
270 	cr50_phy->last_access = jiffies;  in cr50_spi_probe()
271 	mutex_init(&cr50_phy->time_track_mutex);  in cr50_spi_probe()
273 	if (spi->irq > 0) {  in cr50_spi_probe()
274 		ret = devm_request_irq(&spi->dev, spi->irq,  in cr50_spi_probe()
279 			if (ret == -EPROBE_DEFER)  in cr50_spi_probe()
281 			dev_warn(&spi->dev, "Requesting IRQ %d failed: %d\n",  in cr50_spi_probe()
282 				 spi->irq, ret);  in cr50_spi_probe()
294 			cr50_phy->irq_needs_confirmation = true;  in cr50_spi_probe()
297 		dev_warn(&spi->dev,  in cr50_spi_probe()
298 			 "No IRQ - will use delays between transactions.\n");  in cr50_spi_probe()
301 	ret = tpm_tis_spi_init(spi, phy, -1, &tpm_spi_cr50_phy_ops);  in cr50_spi_probe()
305 	cr50_print_fw_version(&phy->priv);  in cr50_spi_probe()
307 	chip = dev_get_drvdata(&spi->dev);  in cr50_spi_probe()
308 	chip->flags |= TPM_CHIP_FLAG_FIRMWARE_POWER_MANAGED;  in cr50_spi_probe()
317 	struct tpm_tis_data *data = dev_get_drvdata(&chip->dev);  in tpm_tis_spi_resume()
323 	phy->wake_after = jiffies;  in tpm_tis_spi_resume()