1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
6  * Copyright (c) 2017-2018 Panasas
49 #include <dev/smbus/smbconf.h>
58 /* SMBus methods */
71  * parent imcsmb_pci's registers that we will use. Create the smbus(4) device,
72  * which any SMBus slave device drivers will connect to.
87 	sc->dev = dev;  in imcsmb_attach()
88 	sc->imcsmb_pci = device_get_parent(dev);  in imcsmb_attach()
89 	sc->regs = device_get_ivars(dev);  in imcsmb_attach()
91 	/* Create the smbus child */  in imcsmb_attach()
92 	sc->smbus = device_add_child(dev, "smbus", DEVICE_UNIT_ANY);  in imcsmb_attach()
93 	if (sc->smbus == NULL) {  in imcsmb_attach()
95 		device_printf(dev, "Child smbus not added\n");  in imcsmb_attach()
100 	/* Attach the smbus child. */  in imcsmb_attach()
121 	device_set_desc(dev, "iMC SMBus controller");  in imcsmb_probe()
127  * function to quiesce / restart firmware tasks which might use the SMBus.
138  *      Tell's the rest of the SMBus subsystem to allow or disallow waiting;
157 		rc = imcsmb_pci_request_bus(sc->imcsmb_pci);  in imcsmb_callback()
161 		imcsmb_pci_release_bus(sc->imcsmb_pci);  in imcsmb_callback()
181  *      The SMBus address of the target device.
184  *      The SMBus command for the target device; this is the offset for SPDs,
205  *      The SMBus address of the target device.
208  *      The SMBus command for the target device; this is the offset for SPDs,
229  *      The SMBus address of the target device.
232  *      The SMBus command for the target device; this is the offset for SPDs,
253  *      The SMBus address of the target device.
256  *      The SMBus command for the target device; this is the offset for SPDs,
271  * SMBus controller.
278  *      The SMBus address of the target device.
281  *      The SMBus command for the target device; this is the offset for SPDs,
319 	orig_cntl_val = pci_read_config(sc->imcsmb_pci,  in imcsmb_transfer()
320 	    sc->regs->smb_cntl, 4);  in imcsmb_transfer()
363 	/* [26:24] The three non-DTI, non-R/W bits of the slave address. */  in imcsmb_transfer()
375 			 * endianness for word operations on I2C vs SMBus!  in imcsmb_transfer()
382 			 * the temperature sensors are I2C. Thus, byte-swap the  in imcsmb_transfer()
395 	/* Write the updated value to the control register first, to disable  in imcsmb_transfer()
398 	pci_write_config(sc->imcsmb_pci, sc->regs->smb_cntl, cntl_val, 4);  in imcsmb_transfer()
400 	/* Poll on the BUSY bit in the status register until clear, or timeout.  in imcsmb_transfer()
401 	 * We just cleared the auto-poll bit, so we need to make sure the device  in imcsmb_transfer()
402 	 * is idle before issuing a command. We can safely timeout after 35 ms,  in imcsmb_transfer()
403 	 * as this is the maximum time the SMBus spec allows for a transaction.  in imcsmb_transfer()
405 	for (i = 4; i != 0; i--) {  in imcsmb_transfer()
406 		stat_val = pci_read_config(sc->imcsmb_pci, sc->regs->smb_stat,  in imcsmb_transfer()
415 		device_printf(sc->dev,  in imcsmb_transfer()
416 		    "transfer: timeout waiting for device to settle\n");  in imcsmb_transfer()
420 	 * starts the SMBus command.  in imcsmb_transfer()
422 	pci_write_config(sc->imcsmb_pci, sc->regs->smb_cmd, cmd_val, 4);  in imcsmb_transfer()
424 	/* Wait for WRITE_DATA_DONE/READ_DATA_VALID to be set, or timeout and  in imcsmb_transfer()
427 	for (i = 35000; i != 0; i -= 10)  in imcsmb_transfer()
430 		stat_val = pci_read_config(sc->imcsmb_pci, sc->regs->smb_stat,  in imcsmb_transfer()
452 		device_printf(dev, "transfer timeout\n");  in imcsmb_transfer()
456 	/* It is generally the case that this bit indicates non-ACK, but it  in imcsmb_transfer()
461 		/* While it is not documented, empirically, SPD page-change  in imcsmb_transfer()
475 			 * above, byte-swap.  in imcsmb_transfer()
492 	pci_write_config(sc->imcsmb_pci, sc->regs->smb_cntl, orig_cntl_val, 4);  in imcsmb_transfer()
503 	/* smbus methods */
520 MODULE_DEPEND(imcsmb, smbus, SMBUS_MINVER, SMBUS_PREFVER, SMBUS_MAXVER);
523 DRIVER_MODULE(smbus, imcsmb, smbus_driver, 0, 0);