diff options
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/spi_lm70llp.c | 33 |
1 files changed, 12 insertions, 21 deletions
diff --git a/drivers/spi/spi_lm70llp.c b/drivers/spi/spi_lm70llp.c index af6526767e2a..568c781ad91c 100644 --- 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@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_to_pp(struct spi_device *spi) 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_device *spi, int value) */ 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 parport *p) 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 parport *p) /* power down */ parport_write_data(pp->port, 0); - msleep(10); parport_release(pp->pd); parport_unregister_device(pp->pd); |