[people/ms/u-boot.git] / drivers / twserial / soft_tws.c

/*
 * (C) Copyright 2009
 * Detlev Zundel, DENX Software Engineering, dzu@denx.de.
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

#define TWS_IMPLEMENTATION
#include <common.h>

/*=====================================================================*/
/*                         Public Functions                            */
/*=====================================================================*/

/*-----------------------------------------------------------------------
 * Read bits
 */
int tws_read(uchar *buffer, int len)
{
	int rem = len;
	uchar accu, shift;

	debug("tws_read: buffer %p len %d\n", buffer, len);

	/* Configure the data pin for input */
	tws_data_config_output(0);

	/* Disable WR, i.e. setup a read */
	tws_wr(0);
	udelay(1);

	/* Rise CE */
	tws_ce(1);
	udelay(1);

	for (; rem > 0; ) {
		for (shift = 0, accu = 0;
		     (rem > 0) && (shift < 8);
		     rem--, shift++) {
			tws_clk(1);
			udelay(10);
			accu |= (tws_data_read() << shift); /* LSB first */
			tws_clk(0);
			udelay(10);
		}
		*buffer++ = accu;
	}

	/* Lower CE */
	tws_ce(0);

	return len - rem;
}


/*-----------------------------------------------------------------------
 * Write bits
 */
int tws_write(uchar *buffer, int len)
{
	int rem = len;
	uchar accu, shift;

	debug("tws_write: buffer %p len %d\n", buffer, len);

	/* Configure the data pin for output */
	tws_data_config_output(1);

	/* Enable WR, i.e. setup a write */
	tws_wr(1);
	udelay(1);

	/* Rise CE */
	tws_ce(1);
	udelay(1);

	for (; rem > 0; ) {
		for (shift = 0, accu = *buffer++;
		     (rem > 0) && (shift < 8);
		     rem--, shift++) {
			tws_data(accu & 0x01); /* LSB first */
			tws_clk(1);
			udelay(10);
			tws_clk(0);
			udelay(10);
			accu >>= 1;
		}
	}

	/* Lower CE */
	tws_ce(0);

	return len - rem;
}
Commit	Line	Data
572e6179 DZ	1	/*
	2	* (C) Copyright 2009
	3	* Detlev Zundel, DENX Software Engineering, dzu@denx.de.
	4	*
1a459660	5	* SPDX-License-Identifier: GPL-2.0+
572e6179 DZ	6	*/
	7
	8	#define TWS_IMPLEMENTATION
	9	#include <common.h>
	10
	11	/=====================================================================/
	12	/* Public Functions */
	13	/=====================================================================/
	14
	15	/*-----------------------------------------------------------------------
	16	* Read bits
	17	*/
	18	int tws_read(uchar *buffer, int len)
	19	{
	20	int rem = len;
	21	uchar accu, shift;
	22
	23	debug("tws_read: buffer %p len %d\n", buffer, len);
	24
	25	/* Configure the data pin for input */
	26	tws_data_config_output(0);
	27
	28	/* Disable WR, i.e. setup a read */
	29	tws_wr(0);
	30	udelay(1);
	31
	32	/* Rise CE */
	33	tws_ce(1);
	34	udelay(1);
	35
	36	for (; rem > 0; ) {
	37	for (shift = 0, accu = 0;
	38	(rem > 0) && (shift < 8);
	39	rem--, shift++) {
	40	tws_clk(1);
	41	udelay(10);
	42	accu \|= (tws_data_read() << shift); /* LSB first */
	43	tws_clk(0);
	44	udelay(10);
	45	}
	46	*buffer++ = accu;
	47	}
	48
	49	/* Lower CE */
	50	tws_ce(0);
	51
	52	return len - rem;
	53	}
	54
	55
	56	/*-----------------------------------------------------------------------
	57	* Write bits
	58	*/
	59	int tws_write(uchar *buffer, int len)
	60	{
	61	int rem = len;
	62	uchar accu, shift;
	63
	64	debug("tws_write: buffer %p len %d\n", buffer, len);
	65
	66	/* Configure the data pin for output */
	67	tws_data_config_output(1);
	68
	69	/* Enable WR, i.e. setup a write */
70	tws_wr(1);
71	udelay(1);
72
73	/* Rise CE */
74	tws_ce(1);
75	udelay(1);
76
77	for (; rem > 0; ) {
78	for (shift = 0, accu = *buffer++;
79	(rem > 0) && (shift < 8);
80	rem--, shift++) {
81	tws_data(accu & 0x01); /* LSB first */
82	tws_clk(1);
83	udelay(10);
84	tws_clk(0);
85	udelay(10);
86	accu >>= 1;
87	}
88	}
89
90	/* Lower CE */
91	tws_ce(0);
92
93	return len - rem;
94	}