On Wednesday 12 November 2008, Jean Delvare wrote: > David, can we get this patch reviewed and pushed upstream quickly? So > that I can finally take Manuel's patch adding support for the TMP121. Yeah, appended. I made some minor updates, notably: - using URLs from National's website - listing the real name of the eval board (!) - there is no "D9" bit in any byte; explain that change better - restore a comment of mine :) And different patch comments -- sorry, I lost the first set. Jean, I think it's best if you merge this through your tree along with Manuel's patch. - Dave ============ CUT HERE From: Kaiwan N Billimoria <kaiwan at designergraphix.com> This fixes a byteswap bug in the LM70 temperature sensor driver, which was previously covered up by a converse bug in the driver for the LM70EVAL-LLP board (which is also fixed). Other fixes: doc updates, remove an annoying msleep(), and improve three-wire protocol handling. Signed-off-by: Kaiwan N Billimoria <kaiwan at designergraphix.com> [ dbrownell at users.sourceforge.net: doc and whitespace tweaks ] Signed-off-by: David Brownell <dbrownell at users.sourceforge.net> --- Documentation/hwmon/lm70 | 4 ++++ Documentation/spi/spi-lm70llp | 10 ++++++++++ drivers/hwmon/lm70.c | 9 +++++---- drivers/spi/spi_lm70llp.c | 33 ++++++++++++--------------------- 4 files changed, 31 insertions(+), 25 deletions(-) --- a/Documentation/hwmon/lm70 +++ b/Documentation/hwmon/lm70 @@ -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 "SPI protocol driver" interfacing +with a "SPI master controller driver", see drivers/spi/spi_lm70llp.c +and its associated documentation. + Thanks to --------- Jean Delvare <khali at linux-fr.org> for mentoring the hwmon-side driver --- a/Documentation/spi/spi-lm70llp +++ b/Documentation/spi/spi-lm70llp @@ -13,10 +13,20 @@ 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 a SPI master controller driver. It can be used in conjunction with +(layered under) the LM70 logical driver (a "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 LM70EVAL-LLP) is +available (on page 4) here: + + http://www.national.com/appinfo/tempsensors/files/LM70LLPEVALmanual.pdf + The hardware interfacing on the LM70 LLP eval board is as follows: Parallel LM70 LLP --- a/drivers/hwmon/lm70.c +++ b/drivers/hwmon/lm70.c @@ -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%02x rxbuf[1] : 0x%02x raw=0x%04x\n", + rxbuf[0], rxbuf[1], raw); /* * The "raw" temperature read into rxbuf[] is a 16-bit signed 2's @@ -109,6 +108,8 @@ static int __devinit lm70_probe(struct s if ((spi->mode & (SPI_CPOL|SPI_CPHA)) || !(spi->mode & SPI_3WIRE)) return -EINVAL; + /* NOTE: we assume 8-bit words, and convert to 16 bits manually */ + p_lm70 = kzalloc(sizeof *p_lm70, GFP_KERNEL); if (!p_lm70) return -ENOMEM; --- a/drivers/spi/spi_lm70llp.c +++ b/drivers/spi/spi_lm70llp.c @@ -1,5 +1,5 @@ /* - * spi_lm70llp.c - driver for lm70llp eval board for the LM70 sensor + * spi_lm70llp.c - driver for LM70EVAL-LLP board for the LM70 sensor * * Copyright (C) 2006 Kaiwan N Billimoria <kaiwan at designergraphix.com> * @@ -40,8 +40,12 @@ * 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 + * The schematic for this particular board (the LM70EVAL-LLP) is + * available (on page 4) here: + * http://www.national.com/appinfo/tempsensors/files/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 +110,16 @@ static inline struct spi_lm70llp *spidev static inline void deassertCS(struct spi_lm70llp *pp) { u8 data = parport_read_data(pp->port); + + data &= ~0x80; /* pull D7/SI-out 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; /* pull D7/SI-out high so lm70 drives SO-in */ parport_write_data(pp->port, data & ~nCS); } @@ -184,22 +192,7 @@ 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 +286,9 @@ 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 +318,6 @@ 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);
