Thomas Gleixner | c942fdd | 2019-05-27 08:55:06 +0200 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 2 | /* |
Grant Likely | ca632f5 | 2011-06-06 01:16:30 -0600 | [diff] [blame] | 3 | * Driver for LM70EVAL-LLP board for the LM70 sensor |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 4 | * |
| 5 | * Copyright (C) 2006 Kaiwan N Billimoria <kaiwan@designergraphix.com> |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 6 | */ |
| 7 | |
Sudip Mukherjee | 22de54a | 2015-12-07 16:17:35 +0530 | [diff] [blame] | 8 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 9 | |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 10 | #include <linux/init.h> |
| 11 | #include <linux/module.h> |
| 12 | #include <linux/kernel.h> |
| 13 | #include <linux/delay.h> |
| 14 | #include <linux/device.h> |
| 15 | #include <linux/parport.h> |
| 16 | #include <linux/sysfs.h> |
| 17 | #include <linux/workqueue.h> |
| 18 | |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 19 | #include <linux/spi/spi.h> |
| 20 | #include <linux/spi/spi_bitbang.h> |
| 21 | |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 22 | /* |
| 23 | * The LM70 communicates with a host processor using a 3-wire variant of |
| 24 | * the SPI/Microwire bus interface. This driver specifically supports an |
| 25 | * NS LM70 LLP Evaluation Board, interfacing to a PC using its parallel |
| 26 | * port to bitbang an SPI-parport bridge. Accordingly, this is an SPI |
| 27 | * master controller driver. The hwmon/lm70 driver is a "SPI protocol |
| 28 | * driver", layered on top of this one and usable without the lm70llp. |
| 29 | * |
Kaiwan N Billimoria | 2b73005 | 2009-01-07 16:37:34 +0100 | [diff] [blame] | 30 | * Datasheet and Schematic: |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 31 | * The LM70 is a temperature sensor chip from National Semiconductor; its |
| 32 | * datasheet is available at http://www.national.com/pf/LM/LM70.html |
Kaiwan N Billimoria | 2b73005 | 2009-01-07 16:37:34 +0100 | [diff] [blame] | 33 | * The schematic for this particular board (the LM70EVAL-LLP) is |
| 34 | * available (on page 4) here: |
| 35 | * http://www.national.com/appinfo/tempsensors/files/LM70LLPEVALmanual.pdf |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 36 | * |
Mauro Carvalho Chehab | 9cdd273 | 2019-07-31 17:08:50 -0300 | [diff] [blame] | 37 | * Also see Documentation/spi/spi-lm70llp.rst. The SPI<->parport code here is |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 38 | * (heavily) based on spi-butterfly by David Brownell. |
| 39 | * |
| 40 | * The LM70 LLP connects to the PC parallel port in the following manner: |
| 41 | * |
| 42 | * Parallel LM70 LLP |
| 43 | * Port Direction JP2 Header |
| 44 | * ----------- --------- ------------ |
| 45 | * D0 2 - - |
| 46 | * D1 3 --> V+ 5 |
| 47 | * D2 4 --> V+ 5 |
| 48 | * D3 5 --> V+ 5 |
| 49 | * D4 6 --> V+ 5 |
| 50 | * D5 7 --> nCS 8 |
| 51 | * D6 8 --> SCLK 3 |
| 52 | * D7 9 --> SI/O 5 |
| 53 | * GND 25 - GND 7 |
| 54 | * Select 13 <-- SI/O 1 |
| 55 | * |
| 56 | * Note that parport pin 13 actually gets inverted by the transistor |
| 57 | * arrangement which lets either the parport or the LM70 drive the |
Kaiwan N Billimoria | 2b73005 | 2009-01-07 16:37:34 +0100 | [diff] [blame] | 58 | * SI/SO signal (see the schematic for details). |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 59 | */ |
| 60 | |
| 61 | #define DRVNAME "spi-lm70llp" |
| 62 | |
| 63 | #define lm70_INIT 0xBE |
| 64 | #define SIO 0x10 |
| 65 | #define nCS 0x20 |
| 66 | #define SCLK 0x40 |
| 67 | |
| 68 | /*-------------------------------------------------------------------------*/ |
| 69 | |
| 70 | struct spi_lm70llp { |
| 71 | struct spi_bitbang bitbang; |
| 72 | struct parport *port; |
| 73 | struct pardevice *pd; |
| 74 | struct spi_device *spidev_lm70; |
| 75 | struct spi_board_info info; |
Tony Jones | 49dce68 | 2007-10-16 01:27:48 -0700 | [diff] [blame] | 76 | //struct device *dev; |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 77 | }; |
| 78 | |
| 79 | /* REVISIT : ugly global ; provides "exclusive open" facility */ |
| 80 | static struct spi_lm70llp *lm70llp; |
| 81 | |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 82 | /*-------------------------------------------------------------------*/ |
| 83 | |
| 84 | static inline struct spi_lm70llp *spidev_to_pp(struct spi_device *spi) |
| 85 | { |
| 86 | return spi->controller_data; |
| 87 | } |
| 88 | |
| 89 | /*---------------------- LM70 LLP eval board-specific inlines follow */ |
| 90 | |
| 91 | /* NOTE: we don't actually need to reread the output values, since they'll |
| 92 | * still be what we wrote before. Plus, going through parport builds in |
| 93 | * a ~1ms/operation delay; these SPI transfers could easily be faster. |
| 94 | */ |
| 95 | |
| 96 | static inline void deassertCS(struct spi_lm70llp *pp) |
| 97 | { |
| 98 | u8 data = parport_read_data(pp->port); |
Kaiwan N Billimoria | 2b73005 | 2009-01-07 16:37:34 +0100 | [diff] [blame] | 99 | |
| 100 | data &= ~0x80; /* pull D7/SI-out low while de-asserted */ |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 101 | parport_write_data(pp->port, data | nCS); |
| 102 | } |
| 103 | |
| 104 | static inline void assertCS(struct spi_lm70llp *pp) |
| 105 | { |
| 106 | u8 data = parport_read_data(pp->port); |
Kaiwan N Billimoria | 2b73005 | 2009-01-07 16:37:34 +0100 | [diff] [blame] | 107 | |
| 108 | data |= 0x80; /* pull D7/SI-out high so lm70 drives SO-in */ |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 109 | parport_write_data(pp->port, data & ~nCS); |
| 110 | } |
| 111 | |
| 112 | static inline void clkHigh(struct spi_lm70llp *pp) |
| 113 | { |
| 114 | u8 data = parport_read_data(pp->port); |
Sudip Mukherjee | 832329d | 2015-12-03 18:29:54 +0530 | [diff] [blame] | 115 | |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 116 | parport_write_data(pp->port, data | SCLK); |
| 117 | } |
| 118 | |
| 119 | static inline void clkLow(struct spi_lm70llp *pp) |
| 120 | { |
| 121 | u8 data = parport_read_data(pp->port); |
Sudip Mukherjee | 832329d | 2015-12-03 18:29:54 +0530 | [diff] [blame] | 122 | |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 123 | parport_write_data(pp->port, data & ~SCLK); |
| 124 | } |
| 125 | |
| 126 | /*------------------------- SPI-LM70-specific inlines ----------------------*/ |
| 127 | |
| 128 | static inline void spidelay(unsigned d) |
| 129 | { |
| 130 | udelay(d); |
| 131 | } |
| 132 | |
| 133 | static inline void setsck(struct spi_device *s, int is_on) |
| 134 | { |
| 135 | struct spi_lm70llp *pp = spidev_to_pp(s); |
| 136 | |
| 137 | if (is_on) |
| 138 | clkHigh(pp); |
| 139 | else |
| 140 | clkLow(pp); |
| 141 | } |
| 142 | |
| 143 | static inline void setmosi(struct spi_device *s, int is_on) |
| 144 | { |
| 145 | /* FIXME update D7 ... this way we can put the chip |
| 146 | * into shutdown mode and read the manufacturer ID, |
| 147 | * but we can't put it back into operational mode. |
| 148 | */ |
| 149 | } |
| 150 | |
| 151 | /* |
| 152 | * getmiso: |
| 153 | * Why do we return 0 when the SIO line is high and vice-versa? |
| 154 | * The fact is, the lm70 eval board from NS (which this driver drives), |
| 155 | * is wired in just such a way : when the lm70's SIO goes high, a transistor |
| 156 | * switches it to low reflecting this on the parport (pin 13), and vice-versa. |
| 157 | */ |
| 158 | static inline int getmiso(struct spi_device *s) |
| 159 | { |
| 160 | struct spi_lm70llp *pp = spidev_to_pp(s); |
Sudip Mukherjee | 832329d | 2015-12-03 18:29:54 +0530 | [diff] [blame] | 161 | |
Sudip Mukherjee | 74bdced | 2015-12-03 18:29:57 +0530 | [diff] [blame] | 162 | return ((SIO == (parport_read_status(pp->port) & SIO)) ? 0 : 1); |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 163 | } |
Sudip Mukherjee | 832329d | 2015-12-03 18:29:54 +0530 | [diff] [blame] | 164 | |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 165 | /*--------------------------------------------------------------------*/ |
| 166 | |
Grant Likely | ca632f5 | 2011-06-06 01:16:30 -0600 | [diff] [blame] | 167 | #include "spi-bitbang-txrx.h" |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 168 | |
| 169 | static void lm70_chipselect(struct spi_device *spi, int value) |
| 170 | { |
| 171 | struct spi_lm70llp *pp = spidev_to_pp(spi); |
| 172 | |
| 173 | if (value) |
| 174 | assertCS(pp); |
| 175 | else |
| 176 | deassertCS(pp); |
| 177 | } |
| 178 | |
| 179 | /* |
| 180 | * Our actual bitbanger routine. |
| 181 | */ |
Lorenzo Bianconi | 304d343 | 2018-07-28 10:19:13 +0200 | [diff] [blame] | 182 | static u32 lm70_txrx(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits, |
| 183 | unsigned flags) |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 184 | { |
Lorenzo Bianconi | 304d343 | 2018-07-28 10:19:13 +0200 | [diff] [blame] | 185 | return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits); |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 186 | } |
| 187 | |
| 188 | static void spi_lm70llp_attach(struct parport *p) |
| 189 | { |
| 190 | struct pardevice *pd; |
| 191 | struct spi_lm70llp *pp; |
| 192 | struct spi_master *master; |
| 193 | int status; |
Sudip Mukherjee | 2baed30 | 2015-12-03 18:29:59 +0530 | [diff] [blame] | 194 | struct pardev_cb lm70llp_cb; |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 195 | |
| 196 | if (lm70llp) { |
Sudip Mukherjee | 22de54a | 2015-12-07 16:17:35 +0530 | [diff] [blame] | 197 | pr_warn("spi_lm70llp instance already loaded. Aborting.\n"); |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 198 | return; |
| 199 | } |
| 200 | |
| 201 | /* TODO: this just _assumes_ a lm70 is there ... no probe; |
| 202 | * the lm70 driver could verify it, reading the manf ID. |
| 203 | */ |
| 204 | |
| 205 | master = spi_alloc_master(p->physport->dev, sizeof *pp); |
| 206 | if (!master) { |
| 207 | status = -ENOMEM; |
| 208 | goto out_fail; |
| 209 | } |
| 210 | pp = spi_master_get_devdata(master); |
| 211 | |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 212 | /* |
| 213 | * SPI and bitbang hookup. |
| 214 | */ |
Axel Lin | 94c69f7 | 2013-09-10 15:43:41 +0800 | [diff] [blame] | 215 | pp->bitbang.master = master; |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 216 | pp->bitbang.chipselect = lm70_chipselect; |
| 217 | pp->bitbang.txrx_word[SPI_MODE_0] = lm70_txrx; |
| 218 | pp->bitbang.flags = SPI_3WIRE; |
| 219 | |
| 220 | /* |
| 221 | * Parport hookup |
| 222 | */ |
| 223 | pp->port = p; |
Sudip Mukherjee | 2baed30 | 2015-12-03 18:29:59 +0530 | [diff] [blame] | 224 | memset(&lm70llp_cb, 0, sizeof(lm70llp_cb)); |
| 225 | lm70llp_cb.private = pp; |
| 226 | lm70llp_cb.flags = PARPORT_FLAG_EXCL; |
| 227 | pd = parport_register_dev_model(p, DRVNAME, &lm70llp_cb, 0); |
| 228 | |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 229 | if (!pd) { |
| 230 | status = -ENOMEM; |
| 231 | goto out_free_master; |
| 232 | } |
| 233 | pp->pd = pd; |
| 234 | |
| 235 | status = parport_claim(pd); |
| 236 | if (status < 0) |
| 237 | goto out_parport_unreg; |
| 238 | |
| 239 | /* |
| 240 | * Start SPI ... |
| 241 | */ |
| 242 | status = spi_bitbang_start(&pp->bitbang); |
| 243 | if (status < 0) { |
Sudip Mukherjee | 46c52c2 | 2015-12-07 16:17:34 +0530 | [diff] [blame] | 244 | dev_warn(&pd->dev, "spi_bitbang_start failed with status %d\n", |
| 245 | status); |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 246 | goto out_off_and_release; |
| 247 | } |
| 248 | |
| 249 | /* |
| 250 | * The modalias name MUST match the device_driver name |
| 251 | * for the bus glue code to match and subsequently bind them. |
| 252 | * We are binding to the generic drivers/hwmon/lm70.c device |
| 253 | * driver. |
| 254 | */ |
| 255 | strcpy(pp->info.modalias, "lm70"); |
| 256 | pp->info.max_speed_hz = 6 * 1000 * 1000; |
| 257 | pp->info.chip_select = 0; |
| 258 | pp->info.mode = SPI_3WIRE | SPI_MODE_0; |
| 259 | |
| 260 | /* power up the chip, and let the LM70 control SI/SO */ |
| 261 | parport_write_data(pp->port, lm70_INIT); |
| 262 | |
| 263 | /* Enable access to our primary data structure via |
| 264 | * the board info's (void *)controller_data. |
| 265 | */ |
| 266 | pp->info.controller_data = pp; |
| 267 | pp->spidev_lm70 = spi_new_device(pp->bitbang.master, &pp->info); |
| 268 | if (pp->spidev_lm70) |
| 269 | dev_dbg(&pp->spidev_lm70->dev, "spidev_lm70 at %s\n", |
Sudip Mukherjee | 44dc0fd | 2015-12-03 18:29:56 +0530 | [diff] [blame] | 270 | dev_name(&pp->spidev_lm70->dev)); |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 271 | else { |
Sudip Mukherjee | 46c52c2 | 2015-12-07 16:17:34 +0530 | [diff] [blame] | 272 | dev_warn(&pd->dev, "spi_new_device failed\n"); |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 273 | status = -ENODEV; |
| 274 | goto out_bitbang_stop; |
| 275 | } |
Kaiwan N Billimoria | 2b73005 | 2009-01-07 16:37:34 +0100 | [diff] [blame] | 276 | pp->spidev_lm70->bits_per_word = 8; |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 277 | |
| 278 | lm70llp = pp; |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 279 | return; |
| 280 | |
| 281 | out_bitbang_stop: |
| 282 | spi_bitbang_stop(&pp->bitbang); |
| 283 | out_off_and_release: |
| 284 | /* power down */ |
| 285 | parport_write_data(pp->port, 0); |
| 286 | mdelay(10); |
| 287 | parport_release(pp->pd); |
| 288 | out_parport_unreg: |
| 289 | parport_unregister_device(pd); |
| 290 | out_free_master: |
Sudip Mukherjee | 25fb1a4 | 2015-12-03 18:29:55 +0530 | [diff] [blame] | 291 | spi_master_put(master); |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 292 | out_fail: |
Sudip Mukherjee | 22de54a | 2015-12-07 16:17:35 +0530 | [diff] [blame] | 293 | pr_info("spi_lm70llp probe fail, status %d\n", status); |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 294 | } |
| 295 | |
| 296 | static void spi_lm70llp_detach(struct parport *p) |
| 297 | { |
| 298 | struct spi_lm70llp *pp; |
| 299 | |
| 300 | if (!lm70llp || lm70llp->port != p) |
| 301 | return; |
| 302 | |
| 303 | pp = lm70llp; |
| 304 | spi_bitbang_stop(&pp->bitbang); |
| 305 | |
| 306 | /* power down */ |
| 307 | parport_write_data(pp->port, 0); |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 308 | |
| 309 | parport_release(pp->pd); |
| 310 | parport_unregister_device(pp->pd); |
| 311 | |
Sudip Mukherjee | 25fb1a4 | 2015-12-03 18:29:55 +0530 | [diff] [blame] | 312 | spi_master_put(pp->bitbang.master); |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 313 | |
| 314 | lm70llp = NULL; |
| 315 | } |
| 316 | |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 317 | static struct parport_driver spi_lm70llp_drv = { |
| 318 | .name = DRVNAME, |
Sudip Mukherjee | 2baed30 | 2015-12-03 18:29:59 +0530 | [diff] [blame] | 319 | .match_port = spi_lm70llp_attach, |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 320 | .detach = spi_lm70llp_detach, |
Sudip Mukherjee | 2baed30 | 2015-12-03 18:29:59 +0530 | [diff] [blame] | 321 | .devmodel = true, |
Kaiwan N Billimoria | 78961a57 | 2007-07-17 04:04:05 -0700 | [diff] [blame] | 322 | }; |
| 323 | |
| 324 | static int __init init_spi_lm70llp(void) |
| 325 | { |
| 326 | return parport_register_driver(&spi_lm70llp_drv); |
| 327 | } |
| 328 | module_init(init_spi_lm70llp); |
| 329 | |
| 330 | static void __exit cleanup_spi_lm70llp(void) |
| 331 | { |
| 332 | parport_unregister_driver(&spi_lm70llp_drv); |
| 333 | } |
| 334 | module_exit(cleanup_spi_lm70llp); |
| 335 | |
| 336 | MODULE_AUTHOR("Kaiwan N Billimoria <kaiwan@designergraphix.com>"); |
| 337 | MODULE_DESCRIPTION( |
| 338 | "Parport adapter for the National Semiconductor LM70 LLP eval board"); |
| 339 | MODULE_LICENSE("GPL"); |