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https://gitlab.rtems.org/rtems/rtos/rtems.git
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bc959e983f
Add "(void) param;" annotation to address unused parameter warnings. Found with GCC's warning -Wunused-parameter.
134 lines
3.9 KiB
C
134 lines
3.9 KiB
C
/* Trivial i2c driver for the maxim DS1621 temperature sensor;
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* just implements reading constant conversions with 8-bit
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* resolution.
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* Demonstrates the implementation of a i2c high-level driver.
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*/
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/*
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* Authorship
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* ----------
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* This software was created by
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* Till Straumann <strauman@slac.stanford.edu>, 2005,
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* Stanford Linear Accelerator Center, Stanford University.
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*
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* Acknowledgement of sponsorship
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* ------------------------------
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* This software was produced by
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* the Stanford Linear Accelerator Center, Stanford University,
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* under Contract DE-AC03-76SFO0515 with the Department of Energy.
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*
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* Government disclaimer of liability
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* ----------------------------------
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* Neither the United States nor the United States Department of Energy,
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* nor any of their employees, makes any warranty, express or implied, or
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* assumes any legal liability or responsibility for the accuracy,
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* completeness, or usefulness of any data, apparatus, product, or process
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* disclosed, or represents that its use would not infringe privately owned
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* rights.
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*
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* Stanford disclaimer of liability
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* --------------------------------
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* Stanford University makes no representations or warranties, express or
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* implied, nor assumes any liability for the use of this software.
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*
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* Stanford disclaimer of copyright
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* --------------------------------
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* Stanford University, owner of the copyright, hereby disclaims its
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* copyright and all other rights in this software. Hence, anyone may
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* freely use it for any purpose without restriction.
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*
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* Maintenance of notices
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* ----------------------
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* In the interest of clarity regarding the origin and status of this
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* SLAC software, this and all the preceding Stanford University notices
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* are to remain affixed to any copy or derivative of this software made
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* or distributed by the recipient and are to be affixed to any copy of
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* software made or distributed by the recipient that contains a copy or
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* derivative of this software.
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*
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* ------------------ SLAC Software Notices, Set 4 OTT.002a, 2004 FEB 03
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*/
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#include <rtems.h>
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#include <rtems/libi2c.h>
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#include <libchip/i2c-ds1621.h>
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#include <rtems/libio.h>
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static rtems_status_code
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ds1621_init (rtems_device_major_number major, rtems_device_minor_number minor,
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void *arg)
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{
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(void) major;
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(void) arg;
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int sc;
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unsigned char csr[2] = { DS1621_CMD_CSR_ACCESS, 0 }, cmd;
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/* First start command acquires a lock for the bus */
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/* Initialize; switch continuous conversion on */
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sc = rtems_libi2c_start_write_bytes (minor, csr, 1);
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if (sc < 0)
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return -sc;
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sc = rtems_libi2c_start_read_bytes (minor, csr + 1, 1);
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if (sc < 0)
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return -sc;
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csr[1] &= ~DS1621_CSR_1SHOT;
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sc = rtems_libi2c_start_write_bytes (minor, csr, 2);
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if (sc < 0)
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return -sc;
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/* Start conversion */
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cmd = DS1621_CMD_START_CONV;
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sc = rtems_libi2c_start_write_bytes (minor, &cmd, 1);
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if (sc < 0)
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return -sc;
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/* sending 'stop' relinquishes the bus mutex -- don't hold it
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* across system calls!
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*/
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return rtems_libi2c_send_stop (minor);
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}
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static rtems_status_code
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ds1621_read (rtems_device_major_number major, rtems_device_minor_number minor,
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void *arg)
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{
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(void) major;
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int sc;
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rtems_libio_rw_args_t *rwargs = arg;
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unsigned char cmd = DS1621_CMD_READ_TEMP;
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sc = rtems_libi2c_start_write_bytes (minor, &cmd, 1);
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if (sc < 0)
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return -sc;
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if (sc < 1)
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return RTEMS_IO_ERROR;
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sc = rtems_libi2c_start_read_bytes(minor, (unsigned char *)rwargs->buffer, 1);
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if (sc < 0) {
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rwargs->bytes_moved = 0;
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return -sc;
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}
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rwargs->bytes_moved = 1;
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return rtems_libi2c_send_stop (minor);
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}
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static rtems_driver_address_table myops = {
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.initialization_entry = ds1621_init,
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.read_entry = ds1621_read,
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};
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static rtems_libi2c_drv_t my_drv_tbl = {
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.ops = &myops,
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.size = sizeof (my_drv_tbl),
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};
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rtems_libi2c_drv_t *i2c_ds1621_driver_descriptor = &my_drv_tbl;
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