drivers/mfd/stmpe-spi.c

Source file repositories/reference/linux-study-clean/drivers/mfd/stmpe-spi.c

File Facts

System
Linux kernel
Corpus path
drivers/mfd/stmpe-spi.c
Extension
.c
Size
3420 bytes
Lines
149
Domain
Driver Families
Bucket
drivers/mfd
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-only
/*
 * ST Microelectronics MFD: stmpe's spi client specific driver
 *
 * Copyright (C) ST Microelectronics SA 2011
 *
 * Author: Viresh Kumar <vireshk@kernel.org> for ST Microelectronics
 */

#include <linux/spi/spi.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/types.h>
#include "stmpe.h"

#define READ_CMD	(1 << 7)

static int spi_reg_read(struct stmpe *stmpe, u8 reg)
{
	struct spi_device *spi = stmpe->client;
	int status = spi_w8r16(spi, reg | READ_CMD);

	return (status < 0) ? status : status >> 8;
}

static int spi_reg_write(struct stmpe *stmpe, u8 reg, u8 val)
{
	struct spi_device *spi = stmpe->client;
	u16 cmd = (val << 8) | reg;

	return spi_write(spi, (const u8 *)&cmd, 2);
}

static int spi_block_read(struct stmpe *stmpe, u8 reg, u8 length, u8 *values)
{
	int ret, i;

	for (i = 0; i < length; i++) {
		ret = spi_reg_read(stmpe, reg + i);
		if (ret < 0)
			return ret;
		*(values + i) = ret;
	}

	return 0;
}

static int spi_block_write(struct stmpe *stmpe, u8 reg, u8 length,
		const u8 *values)
{
	int ret = 0, i;

	for (i = length; i > 0; i--, reg++) {
		ret = spi_reg_write(stmpe, reg, *(values + i - 1));
		if (ret < 0)
			return ret;
	}

	return ret;
}

static void spi_init(struct stmpe *stmpe)
{
	struct spi_device *spi = stmpe->client;

	spi->bits_per_word = 8;

	/* This register is only present for stmpe811 */
	if (stmpe->variant->id_val == 0x0811)
		spi_reg_write(stmpe, STMPE811_REG_SPI_CFG, spi->mode);

	if (spi_setup(spi) < 0)
		dev_dbg(&spi->dev, "spi_setup failed\n");
}

static struct stmpe_client_info spi_ci = {
	.read_byte = spi_reg_read,
	.write_byte = spi_reg_write,
	.read_block = spi_block_read,
	.write_block = spi_block_write,
	.init = spi_init,
};

static int
stmpe_spi_probe(struct spi_device *spi)
{
	const struct spi_device_id *id = spi_get_device_id(spi);

Annotation

Implementation Notes