spi_lm70llp driver: -changed the bits_per_word setting. -removed the convoluted if (first_time) ... else ... logic from the bit-banging routine; it now invokes a single bitbang_txrx_* call as required. -better control over the parport D9 line in (de)assert inline routines (see schematic for details). lm70 driver: -parse and save raw temperature in 'correct' byte-order. Documentation/ updates as appropriate. Signed-off-by: Kaiwan N Billimoria <kaiwan at designergraphix.com> --- diff -uprN -X a/Documentation/dontdiff a/Documentation/hwmon/lm70 b/Documentation/hwmon/lm70 --- a/Documentation/hwmon/lm70 2008-10-10 03:43:53.000000000 +0530 +++ b/Documentation/hwmon/lm70 2008-11-12 12:17:21.000000000 +0530 @@ -25,6 +25,10 @@ complement digital temperature (sent via driver for interpretation. This driver makes use of the kernel's in-core SPI support. +As a real (in-tree) example of this "logical SPI protocol driver" interfacing +with a "physical SPI master controller" driver, see drivers/spi/spi_lm70llp +and it's associated documentation. + Thanks to --------- Jean Delvare <khali at linux-fr.org> for mentoring the hwmon-side driver diff -uprN -X a/Documentation/dontdiff a/Documentation/spi/spi-lm70llp b/Documentation/spi/spi-lm70llp --- a/Documentation/spi/spi-lm70llp 2008-10-10 03:43:53.000000000 +0530 +++ b/Documentation/spi/spi-lm70llp 2008-11-12 12:13:50.000000000 +0530 @@ -13,10 +13,19 @@ Description This driver provides glue code connecting a National Semiconductor LM70 LLP temperature sensor evaluation board to the kernel's SPI core subsystem. +This is an SPI master controller driver. It can be used in conjunction with +(layered under) the LM70 logical driver (an "SPI protocol driver"). In effect, this driver turns the parallel port interface on the eval board into a SPI bus with a single device, which will be driven by the generic LM70 driver (drivers/hwmon/lm70.c). + +Hardware Interfacing +-------------------- +The schematic for this particular board (the LM70LLP eval board) is +available (on page 4) here: +http://www.designergraphix.com/pull/spi_lm70/LM70LLPEVALmanual.pdf + The hardware interfacing on the LM70 LLP eval board is as follows: Parallel LM70 LLP @@ -67,3 +76,4 @@ Thanks to o David Brownell for mentoring the SPI-side driver development. o Dr.Craig Hollabaugh for the (early) "manual" bitbanging driver version. o Nadir Billimoria for help interpreting the circuit schematic. + diff -uprN -X a/Documentation/dontdiff a/drivers/hwmon/lm70.c b/drivers/hwmon/lm70.c --- a/drivers/hwmon/lm70.c 2008-10-10 03:43:53.000000000 +0530 +++ b/drivers/hwmon/lm70.c 2008-11-12 12:18:34.000000000 +0530 @@ -65,10 +65,9 @@ static ssize_t lm70_sense_temp(struct de "spi_write_then_read failed with status %d\n", status); goto out; } - dev_dbg(dev, "rxbuf[1] : 0x%x rxbuf[0] : 0x%x\n", rxbuf[1], rxbuf[0]); - - raw = (rxbuf[1] << 8) + rxbuf[0]; - dev_dbg(dev, "raw=0x%x\n", raw); + raw = (rxbuf[0] << 8) + rxbuf[1]; + dev_dbg(dev, "rxbuf[0] : 0x%x rxbuf[1] : 0x%x raw=0x%08x\n", + rxbuf[0], rxbuf[1], raw); /* * The "raw" temperature read into rxbuf[] is a 16-bit signed 2's diff -uprN -X a/Documentation/dontdiff a/drivers/spi/spi_lm70llp.c b/drivers/spi/spi_lm70llp.c --- a/drivers/spi/spi_lm70llp.c 2008-10-10 03:43:53.000000000 +0530 +++ b/drivers/spi/spi_lm70llp.c 2008-11-12 12:12:16.000000000 +0530 @@ -1,5 +1,5 @@ /* - * spi_lm70llp.c - driver for lm70llp eval board for the LM70 sensor + * spi_lm70llp.c - driver for LM70LLP eval board for the LM70 sensor * * Copyright (C) 2006 Kaiwan N Billimoria <kaiwan at designergraphix.com> * @@ -27,11 +27,9 @@ #include <linux/sysfs.h> #include <linux/workqueue.h> - #include <linux/spi/spi.h> #include <linux/spi/spi_bitbang.h> - /* * The LM70 communicates with a host processor using a 3-wire variant of * the SPI/Microwire bus interface. This driver specifically supports an @@ -40,8 +38,14 @@ * master controller driver. The hwmon/lm70 driver is a "SPI protocol * driver", layered on top of this one and usable without the lm70llp. * + * Datasheet and Schematic: * The LM70 is a temperature sensor chip from National Semiconductor; its * datasheet is available at http://www.national.com/pf/LM/LM70.html + * You can also find it here: + * http://www.designergraphix.com/pull/spi_lm70/LM70.pdf + * The schematic for this particular board (the LM70LLP eval board) is + * available (on page 4) here: + * http://www.designergraphix.com/pull/spi_lm70/LM70LLPEVALmanual.pdf * * Also see Documentation/spi/spi-lm70llp. The SPI<->parport code here is * (heavily) based on spi-butterfly by David Brownell. @@ -64,7 +68,7 @@ * * Note that parport pin 13 actually gets inverted by the transistor * arrangement which lets either the parport or the LM70 drive the - * SI/SO signal. + * SI/SO signal (see the schematic for details). */ #define DRVNAME "spi-lm70llp" @@ -106,12 +110,14 @@ static inline struct spi_lm70llp *spidev static inline void deassertCS(struct spi_lm70llp *pp) { u8 data = parport_read_data(pp->port); + data &= ~0x80; /* keep D9 low while de-asserted */ parport_write_data(pp->port, data | nCS); } static inline void assertCS(struct spi_lm70llp *pp) { u8 data = parport_read_data(pp->port); + data |= 0x80; /* keep D9 high while asserted */ parport_write_data(pp->port, data & ~nCS); } @@ -184,22 +190,7 @@ static void lm70_chipselect(struct spi_d */ static u32 lm70_txrx(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits) { - static u32 sio=0; - static int first_time=1; - - /* First time: perform SPI bitbang and return the LSB of - * the result of the SPI call. - */ - if (first_time) { - sio = bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits); - first_time=0; - return (sio & 0x00ff); - } - /* Return the MSB of the result of the SPI call */ - else { - first_time=1; - return (sio >> 8); - } + return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits); } static void spi_lm70llp_attach(struct parport *p) @@ -293,10 +284,9 @@ static void spi_lm70llp_attach(struct pa status = -ENODEV; goto out_bitbang_stop; } - pp->spidev_lm70->bits_per_word = 16; + pp->spidev_lm70->bits_per_word = 8; lm70llp = pp; - return; out_bitbang_stop: @@ -326,7 +316,6 @@ static void spi_lm70llp_detach(struct pa /* power down */ parport_write_data(pp->port, 0); - msleep(10); parport_release(pp->pd); parport_unregister_device(pp->pd);
