Orange Pi5 kernel

 // SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Driver for LM70EVAL-LLP board for the LM70 sensor
 *
 * Copyright (C) 2006 Kaiwan N Billimoria <kaiwan@designergraphix.com>
 */
 
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/parport.h>
#include <linux/sysfs.h>
#include <linux/workqueue.h>
 
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
 
/*
 * The LM70 communicates with a host processor using a 3-wire variant of
 * the SPI/Microwire bus interface. This driver specifically supports an
 * NS LM70 LLP Evaluation Board, interfacing to a PC using its parallel
 * port to bitbang an SPI-parport bridge.  Accordingly, this is an SPI
 * 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.rst.  The SPI<->parport code here is
 * (heavily) based on spi-butterfly by David Brownell.
 *
 * The LM70 LLP connects to the PC parallel port in the following manner:
 *
 *   Parallel                 LM70 LLP
 *     Port      Direction   JP2 Header
 *  -----------  ---------  ------------
 *      D0    2      -         -
 *      D1    3     -->      V+   5
 *      D2    4     -->      V+   5
 *      D3    5     -->      V+   5
 *      D4    6     -->      V+   5
 *      D5    7     -->      nCS  8
 *      D6    8     -->      SCLK 3
 *      D7    9     -->      SI/O 5
 *     GND   25      -       GND  7
 *    Select 13     <--      SI/O 1
 *
 * 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 (see the schematic for details).
 */
 
#define DRVNAME		"spi-lm70llp"
 
#define lm70_INIT	0xBE
#define SIO		0x10
#define nCS		0x20
#define SCLK		0x40
 
/*-------------------------------------------------------------------------*/
 
struct spi_lm70llp {
<------>struct spi_bitbang	bitbang;
<------>struct parport		*port;
<------>struct pardevice	*pd;
<------>struct spi_device	*spidev_lm70;
<------>struct spi_board_info	info;
<------>//struct device		*dev;
};
 
/* REVISIT : ugly global ; provides "exclusive open" facility */
static struct spi_lm70llp *lm70llp;
 
/*-------------------------------------------------------------------*/
 
static inline struct spi_lm70llp *spidev_to_pp(struct spi_device *spi)
{
<------>return spi->controller_data;
}
 
/*---------------------- LM70 LLP eval board-specific inlines follow */
 
/* NOTE:  we don't actually need to reread the output values, since they'll
 * still be what we wrote before.  Plus, going through parport builds in
 * a ~1ms/operation delay; these SPI transfers could easily be faster.
 */
 
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);
}
 
static inline void clkHigh(struct spi_lm70llp *pp)
{
<------>u8 data = parport_read_data(pp->port);
 
<------>parport_write_data(pp->port, data | SCLK);
}
 
static inline void clkLow(struct spi_lm70llp *pp)
{
<------>u8 data = parport_read_data(pp->port);
 
<------>parport_write_data(pp->port, data & ~SCLK);
}
 
/*------------------------- SPI-LM70-specific inlines ----------------------*/
 
static inline void spidelay(unsigned d)
{
<------>udelay(d);
}
 
static inline void setsck(struct spi_device *s, int is_on)
{
<------>struct spi_lm70llp *pp = spidev_to_pp(s);
 
<------>if (is_on)
<------><------>clkHigh(pp);
<------>else
<------><------>clkLow(pp);
}
 
static inline void setmosi(struct spi_device *s, int is_on)
{
<------>/* FIXME update D7 ... this way we can put the chip
<------> * into shutdown mode and read the manufacturer ID,
<------> * but we can't put it back into operational mode.
<------> */
}
 
/*
 * getmiso:
 * Why do we return 0 when the SIO line is high and vice-versa?
 * The fact is, the lm70 eval board from NS (which this driver drives),
 * is wired in just such a way : when the lm70's SIO goes high, a transistor
 * switches it to low reflecting this on the parport (pin 13), and vice-versa.
 */
static inline int getmiso(struct spi_device *s)
{
<------>struct spi_lm70llp *pp = spidev_to_pp(s);
 
<------>return ((SIO == (parport_read_status(pp->port) & SIO)) ? 0 : 1);
}
 
/*--------------------------------------------------------------------*/
 
#include "spi-bitbang-txrx.h"
 
static void lm70_chipselect(struct spi_device *spi, int value)
{
<------>struct spi_lm70llp *pp = spidev_to_pp(spi);
 
<------>if (value)
<------><------>assertCS(pp);
<------>else
<------><------>deassertCS(pp);
}
 
/*
 * Our actual bitbanger routine.
 */
static u32 lm70_txrx(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits,
<------><------>     unsigned flags)
{
<------>return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits);
}
 
static void spi_lm70llp_attach(struct parport *p)
{
<------>struct pardevice	*pd;
<------>struct spi_lm70llp	*pp;
<------>struct spi_master	*master;
<------>int			status;
<------>struct pardev_cb	lm70llp_cb;
 
<------>if (lm70llp) {
<------><------>pr_warn("spi_lm70llp instance already loaded. Aborting.\n");
<------><------>return;
<------>}
 
<------>/* TODO:  this just _assumes_ a lm70 is there ... no probe;
<------> * the lm70 driver could verify it, reading the manf ID.
<------> */
 
<------>master = spi_alloc_master(p->physport->dev, sizeof *pp);
<------>if (!master) {
<------><------>status = -ENOMEM;
<------><------>goto out_fail;
<------>}
<------>pp = spi_master_get_devdata(master);
 
<------>/*
<------> * SPI and bitbang hookup.
<------> */
<------>pp->bitbang.master = master;
<------>pp->bitbang.chipselect = lm70_chipselect;
<------>pp->bitbang.txrx_word[SPI_MODE_0] = lm70_txrx;
<------>pp->bitbang.flags = SPI_3WIRE;
 
<------>/*
<------> * Parport hookup
<------> */
<------>pp->port = p;
<------>memset(&lm70llp_cb, 0, sizeof(lm70llp_cb));
<------>lm70llp_cb.private = pp;
<------>lm70llp_cb.flags = PARPORT_FLAG_EXCL;
<------>pd = parport_register_dev_model(p, DRVNAME, &lm70llp_cb, 0);
 
<------>if (!pd) {
<------><------>status = -ENOMEM;
<------><------>goto out_free_master;
<------>}
<------>pp->pd = pd;
 
<------>status = parport_claim(pd);
<------>if (status < 0)
<------><------>goto out_parport_unreg;
 
<------>/*
<------> * Start SPI ...
<------> */
<------>status = spi_bitbang_start(&pp->bitbang);
<------>if (status < 0) {
<------><------>dev_warn(&pd->dev, "spi_bitbang_start failed with status %d\n",
<------><------><------> status);
<------><------>goto out_off_and_release;
<------>}
 
<------>/*
<------> * The modalias name MUST match the device_driver name
<------> * for the bus glue code to match and subsequently bind them.
<------> * We are binding to the generic drivers/hwmon/lm70.c device
<------> * driver.
<------> */
<------>strcpy(pp->info.modalias, "lm70");
<------>pp->info.max_speed_hz = 6 * 1000 * 1000;
<------>pp->info.chip_select = 0;
<------>pp->info.mode = SPI_3WIRE | SPI_MODE_0;
 
<------>/* power up the chip, and let the LM70 control SI/SO */
<------>parport_write_data(pp->port, lm70_INIT);
 
<------>/* Enable access to our primary data structure via
<------> * the board info's (void *)controller_data.
<------> */
<------>pp->info.controller_data = pp;
<------>pp->spidev_lm70 = spi_new_device(pp->bitbang.master, &pp->info);
<------>if (pp->spidev_lm70)
<------><------>dev_dbg(&pp->spidev_lm70->dev, "spidev_lm70 at %s\n",
<------><------><------>dev_name(&pp->spidev_lm70->dev));
<------>else {
<------><------>dev_warn(&pd->dev, "spi_new_device failed\n");
<------><------>status = -ENODEV;
<------><------>goto out_bitbang_stop;
<------>}
<------>pp->spidev_lm70->bits_per_word = 8;
 
<------>lm70llp = pp;
<------>return;
 
out_bitbang_stop:
<------>spi_bitbang_stop(&pp->bitbang);
out_off_and_release:
<------>/* power down */
<------>parport_write_data(pp->port, 0);
<------>mdelay(10);
<------>parport_release(pp->pd);
out_parport_unreg:
<------>parport_unregister_device(pd);
out_free_master:
<------>spi_master_put(master);
out_fail:
<------>pr_info("spi_lm70llp probe fail, status %d\n", status);
}
 
static void spi_lm70llp_detach(struct parport *p)
{
<------>struct spi_lm70llp		*pp;
 
<------>if (!lm70llp || lm70llp->port != p)
<------><------>return;
 
<------>pp = lm70llp;
<------>spi_bitbang_stop(&pp->bitbang);
 
<------>/* power down */
<------>parport_write_data(pp->port, 0);
 
<------>parport_release(pp->pd);
<------>parport_unregister_device(pp->pd);
 
<------>spi_master_put(pp->bitbang.master);
 
<------>lm70llp = NULL;
}
 
static struct parport_driver spi_lm70llp_drv = {
<------>.name =		DRVNAME,
<------>.match_port =	spi_lm70llp_attach,
<------>.detach =	spi_lm70llp_detach,
<------>.devmodel =	true,
};
 
static int __init init_spi_lm70llp(void)
{
<------>return parport_register_driver(&spi_lm70llp_drv);
}
module_init(init_spi_lm70llp);
 
static void __exit cleanup_spi_lm70llp(void)
{
<------>parport_unregister_driver(&spi_lm70llp_drv);
}
module_exit(cleanup_spi_lm70llp);
 
MODULE_AUTHOR("Kaiwan N Billimoria <kaiwan@designergraphix.com>");
MODULE_DESCRIPTION(
<------>"Parport adapter for the National Semiconductor LM70 LLP eval board");
MODULE_LICENSE("GPL");

	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* Driver for LM70EVAL-LLP board for the LM70 sensor
	*
	* Copyright (C) 2006 Kaiwan N Billimoria <kaiwan@designergraphix.com>
	*/

	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/delay.h>
	#include <linux/device.h>
	#include <linux/parport.h>
	#include <linux/sysfs.h>
	#include <linux/workqueue.h>

	#include <linux/spi/spi.h>
	#include <linux/spi/spi_bitbang.h>

	/*
	* The LM70 communicates with a host processor using a 3-wire variant of
	* the SPI/Microwire bus interface. This driver specifically supports an
	* NS LM70 LLP Evaluation Board, interfacing to a PC using its parallel
	* port to bitbang an SPI-parport bridge. Accordingly, this is an SPI
	* 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.rst. The SPI<->parport code here is
	* (heavily) based on spi-butterfly by David Brownell.
	*
	* The LM70 LLP connects to the PC parallel port in the following manner:
	*
	* Parallel LM70 LLP
	* Port Direction JP2 Header
	* ----------- --------- ------------
	* D0 2 - -
	* D1 3 --> V+ 5
	* D2 4 --> V+ 5
	* D3 5 --> V+ 5
	* D4 6 --> V+ 5
	* D5 7 --> nCS 8
	* D6 8 --> SCLK 3
	* D7 9 --> SI/O 5
	* GND 25 - GND 7
	* Select 13 <-- SI/O 1
	*
	* 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 (see the schematic for details).
	*/

	#define DRVNAME "spi-lm70llp"

	#define lm70_INIT 0xBE
	#define SIO 0x10
	#define nCS 0x20
	#define SCLK 0x40

	/-------------------------------------------------------------------------/

	struct spi_lm70llp {
	<------>struct spi_bitbang bitbang;
	<------>struct parport *port;
	<------>struct pardevice *pd;
	<------>struct spi_device *spidev_lm70;
	<------>struct spi_board_info info;
	<------>//struct device *dev;
	};

	/* REVISIT : ugly global ; provides "exclusive open" facility */
	static struct spi_lm70llp *lm70llp;

	/-------------------------------------------------------------------/

	static inline struct spi_lm70llp spidev_to_pp(struct spi_device spi)
	{
	<------>return spi->controller_data;
	}

	/---------------------- LM70 LLP eval board-specific inlines follow /

	/* NOTE: we don't actually need to reread the output values, since they'll
	* still be what we wrote before. Plus, going through parport builds in
	* a ~1ms/operation delay; these SPI transfers could easily be faster.
	*/

	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);
	}

	static inline void clkHigh(struct spi_lm70llp *pp)
	{
	<------>u8 data = parport_read_data(pp->port);

	<------>parport_write_data(pp->port, data \| SCLK);
	}

	static inline void clkLow(struct spi_lm70llp *pp)
	{
	<------>u8 data = parport_read_data(pp->port);

	<------>parport_write_data(pp->port, data & ~SCLK);
	}

	/------------------------- SPI-LM70-specific inlines ----------------------/

	static inline void spidelay(unsigned d)
	{
	<------>udelay(d);
	}

	static inline void setsck(struct spi_device *s, int is_on)
	{
	<------>struct spi_lm70llp *pp = spidev_to_pp(s);

	<------>if (is_on)
	<------><------>clkHigh(pp);
	<------>else
	<------><------>clkLow(pp);
	}

	static inline void setmosi(struct spi_device *s, int is_on)
	{
	<------>/* FIXME update D7 ... this way we can put the chip
	<------> * into shutdown mode and read the manufacturer ID,
	<------> * but we can't put it back into operational mode.
	<------> */
	}

	/*
	* getmiso:
	* Why do we return 0 when the SIO line is high and vice-versa?
	* The fact is, the lm70 eval board from NS (which this driver drives),
	* is wired in just such a way : when the lm70's SIO goes high, a transistor
	* switches it to low reflecting this on the parport (pin 13), and vice-versa.
	*/
	static inline int getmiso(struct spi_device *s)
	{
	<------>struct spi_lm70llp *pp = spidev_to_pp(s);

	<------>return ((SIO == (parport_read_status(pp->port) & SIO)) ? 0 : 1);
	}

	/--------------------------------------------------------------------/

	#include "spi-bitbang-txrx.h"

	static void lm70_chipselect(struct spi_device *spi, int value)
	{
	<------>struct spi_lm70llp *pp = spidev_to_pp(spi);

	<------>if (value)
	<------><------>assertCS(pp);
	<------>else
	<------><------>deassertCS(pp);
	}

	/*
	* Our actual bitbanger routine.
	*/
	static u32 lm70_txrx(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits,
	<------><------> unsigned flags)
	{
	<------>return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits);
	}

	static void spi_lm70llp_attach(struct parport *p)
	{
	<------>struct pardevice *pd;
	<------>struct spi_lm70llp *pp;
	<------>struct spi_master *master;
	<------>int status;
	<------>struct pardev_cb lm70llp_cb;

	<------>if (lm70llp) {
	<------><------>pr_warn("spi_lm70llp instance already loaded. Aborting.\n");
	<------><------>return;
	<------>}

	<------>/* TODO: this just _assumes_ a lm70 is there ... no probe;
	<------> * the lm70 driver could verify it, reading the manf ID.
	<------> */

	<------>master = spi_alloc_master(p->physport->dev, sizeof *pp);
	<------>if (!master) {
	<------><------>status = -ENOMEM;
	<------><------>goto out_fail;
	<------>}
	<------>pp = spi_master_get_devdata(master);

	<------>/*
	<------> * SPI and bitbang hookup.
	<------> */
	<------>pp->bitbang.master = master;
	<------>pp->bitbang.chipselect = lm70_chipselect;
	<------>pp->bitbang.txrx_word[SPI_MODE_0] = lm70_txrx;
	<------>pp->bitbang.flags = SPI_3WIRE;

	<------>/*
	<------> * Parport hookup
	<------> */
	<------>pp->port = p;
	<------>memset(&lm70llp_cb, 0, sizeof(lm70llp_cb));
	<------>lm70llp_cb.private = pp;
	<------>lm70llp_cb.flags = PARPORT_FLAG_EXCL;
	<------>pd = parport_register_dev_model(p, DRVNAME, &lm70llp_cb, 0);

	<------>if (!pd) {
	<------><------>status = -ENOMEM;
	<------><------>goto out_free_master;
	<------>}
	<------>pp->pd = pd;

	<------>status = parport_claim(pd);
	<------>if (status < 0)
	<------><------>goto out_parport_unreg;

	<------>/*
	<------> * Start SPI ...
	<------> */
	<------>status = spi_bitbang_start(&pp->bitbang);
	<------>if (status < 0) {
	<------><------>dev_warn(&pd->dev, "spi_bitbang_start failed with status %d\n",
	<------><------><------> status);
	<------><------>goto out_off_and_release;
	<------>}

	<------>/*
	<------> * The modalias name MUST match the device_driver name
	<------> * for the bus glue code to match and subsequently bind them.
	<------> * We are binding to the generic drivers/hwmon/lm70.c device
	<------> * driver.
	<------> */
	<------>strcpy(pp->info.modalias, "lm70");
	<------>pp->info.max_speed_hz = 6 * 1000 * 1000;
	<------>pp->info.chip_select = 0;
	<------>pp->info.mode = SPI_3WIRE \| SPI_MODE_0;

	<------>/* power up the chip, and let the LM70 control SI/SO */
	<------>parport_write_data(pp->port, lm70_INIT);

	<------>/* Enable access to our primary data structure via
	<------> * the board info's (void *)controller_data.
	<------> */
	<------>pp->info.controller_data = pp;
	<------>pp->spidev_lm70 = spi_new_device(pp->bitbang.master, &pp->info);
	<------>if (pp->spidev_lm70)
	<------><------>dev_dbg(&pp->spidev_lm70->dev, "spidev_lm70 at %s\n",
	<------><------><------>dev_name(&pp->spidev_lm70->dev));
	<------>else {
	<------><------>dev_warn(&pd->dev, "spi_new_device failed\n");
	<------><------>status = -ENODEV;
	<------><------>goto out_bitbang_stop;
	<------>}
	<------>pp->spidev_lm70->bits_per_word = 8;

	<------>lm70llp = pp;
	<------>return;

	out_bitbang_stop:
	<------>spi_bitbang_stop(&pp->bitbang);
	out_off_and_release:
	<------>/* power down */
	<------>parport_write_data(pp->port, 0);
	<------>mdelay(10);
	<------>parport_release(pp->pd);
	out_parport_unreg:
	<------>parport_unregister_device(pd);
	out_free_master:
	<------>spi_master_put(master);
	out_fail:
	<------>pr_info("spi_lm70llp probe fail, status %d\n", status);
	}

	static void spi_lm70llp_detach(struct parport *p)
	{
	<------>struct spi_lm70llp *pp;

	<------>if (!lm70llp \|\| lm70llp->port != p)
	<------><------>return;

	<------>pp = lm70llp;
	<------>spi_bitbang_stop(&pp->bitbang);

	<------>/* power down */
	<------>parport_write_data(pp->port, 0);

	<------>parport_release(pp->pd);
	<------>parport_unregister_device(pp->pd);

	<------>spi_master_put(pp->bitbang.master);

	<------>lm70llp = NULL;
	}

	static struct parport_driver spi_lm70llp_drv = {
	<------>.name = DRVNAME,
	<------>.match_port = spi_lm70llp_attach,
	<------>.detach = spi_lm70llp_detach,
	<------>.devmodel = true,
	};

	static int __init init_spi_lm70llp(void)
	{
	<------>return parport_register_driver(&spi_lm70llp_drv);
	}
	module_init(init_spi_lm70llp);

	static void __exit cleanup_spi_lm70llp(void)
	{
	<------>parport_unregister_driver(&spi_lm70llp_drv);
	}
	module_exit(cleanup_spi_lm70llp);

	MODULE_AUTHOR("Kaiwan N Billimoria <kaiwan@designergraphix.com>");
	MODULE_DESCRIPTION(
	<------>"Parport adapter for the National Semiconductor LM70 LLP eval board");
	MODULE_LICENSE("GPL");