/*      $NetBSD: adc.c,v 1.16 2023/12/20 15:34:45 thorpej Exp $ */

/*
* Copyright (c) 2003 Valeriy E. Ushakov
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
*    derived from this software without specific prior written permission
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: adc.c,v 1.16 2023/12/20 15:34:45 thorpej Exp $");

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/device.h>
#include <sys/systm.h>

#include <sh3/adcreg.h>
#include <sh3/dev/adcvar.h>

#define ADC_(x)    (*((volatile uint8_t *)SH7709_AD ## x))


static int      adc_match(device_t, cfdata_t, void *);
static void     adc_attach(device_t, device_t, void *);

CFATTACH_DECL_NEW(adc, 0,
   adc_match, adc_attach, NULL, NULL);

static int      adc_search(device_t, cfdata_t, const int *, void *);
static int      adc_print(void *, const char *);


static int
adc_match(device_t parent, cfdata_t cf, void *aux)
{

       /* REMINDER: also in 7727 and 7729 */
       if ((cpu_product != CPU_PRODUCT_7709)
           && (cpu_product != CPU_PRODUCT_7709A)
           && (cpu_product != CPU_PRODUCT_7706))
               return (0);

       if (strcmp(cf->cf_name, "adc") != 0)
               return (0);

       return (1);
}


static void
adc_attach(device_t parent, device_t self, void *aux)
{

       ADC_(CSR) = 0;
       ADC_(CR) = 0;

       aprint_naive("\n");
       aprint_normal("\n");

       config_search(self, NULL,
           CFARGS(.search = adc_search));

       /*
        * XXX: TODO: provide hooks to manage power.  For now register
        * null hooks which is no worse than before.
        *
        * NB: ADC registers are reset by standby!
        */
       if (!pmf_device_register(self, NULL, NULL))
               aprint_error_dev(self, "unable to establish power handler\n");
}


static int
adc_search(device_t parent, cfdata_t cf, const int *ldesc, void *aux)
{

       if (config_probe(parent, cf, NULL))
               config_attach(parent, cf, NULL, adc_print, CFARGS_NONE);

       return (0);
}


static int
adc_print(void *aux, const char *pnp)
{

       return (pnp ? QUIET : UNCONF);
}


/*
* Sample specified ADC channel.
* Must be called at spltty().
*/
int
adc_sample_channel(int chan)
{
       volatile uint8_t *hireg;
       volatile uint8_t *loreg;
       int regoff;
       uint8_t csr;
       int timo;
#ifdef DIAGNOSTIC
       uint8_t cr;
       char bits[128];
#endif
       if ((chan < 0) || (chan >= 8))
               return (-1);

       regoff = (chan & 0x03) << 2;
       hireg = (volatile uint8_t *)(SH7709_ADDRAH + regoff);
       loreg = (volatile uint8_t *)(SH7709_ADDRAL + regoff);

       /* the loop below typically takes 27 iterations on j680 */
       timo = 300;

#ifdef DIAGNOSTIC
       csr = ADC_(CSR);
       if ((csr & SH7709_ADCSR_ADST) != 0) {
               /* another conversion is in progress?! */
               snprintb(bits, sizeof(bits), SH7709_ADCSR_BITS, csr);
               printf("adc_sample_channel(%d): CSR=%s", chan, bits);
               cr = ADC_(CR);
               cr &= ~0x07;    /* three lower bits always read as 1s */
               snprintb(bits, sizeof(bits), SH7709_ADCR_BITS, cr);
               printf(", CR=%s\n", bits);
               return (-1);
       }
#endif

       /* start scanning */
       ADC_(CSR) = chan | SH7709_ADCSR_ADST | SH7709_ADCSR_CKS;

       do {
               csr = ADC_(CSR);
               if (timo-- == 0)
                       break;
       } while ((csr & SH7709_ADCSR_ADF) == 0);

       /* stop scanning */
       csr &= ~(SH7709_ADCSR_ADF | SH7709_ADCSR_ADST);
       ADC_(CSR) = csr;

       if (timo <= 0) {
               printf("adc_sample_channel(%d): timed out\n", chan);
               return (-1);
       }

       /*
        * 10 bit of data: bits [9..2] in the high register, bits
        * [1..0] in the bits [7..6] of the low register.
        */
       return (((*hireg << 8) | *loreg) >> 6);
}