1/*
  2 * Microchip KSZ series register access through SPI
  3 *
  4 * Copyright (C) 2017
  5 *
  6 * Permission to use, copy, modify, and/or distribute this software for any
  7 * purpose with or without fee is hereby granted, provided that the above
  8 * copyright notice and this permission notice appear in all copies.
  9 *
 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 17 */
 18
 19#include <asm/unaligned.h>
 20
 21#include <linux/delay.h>
 22#include <linux/kernel.h>
 23#include <linux/module.h>
 24#include <linux/spi/spi.h>
 25
 26#include "ksz_priv.h"
 27
 28/* SPI frame opcodes */
 29#define KS_SPIOP_RD			3
 30#define KS_SPIOP_WR			2
 31
 32#define SPI_ADDR_SHIFT			24
 33#define SPI_ADDR_MASK			(BIT(SPI_ADDR_SHIFT) - 1)
 34#define SPI_TURNAROUND_SHIFT		5
 35
 36static int ksz_spi_read_reg(struct spi_device *spi, u32 reg, u8 *val,
 37			    unsigned int len)
 38{
 39	u32 txbuf;
 40	int ret;
 41
 42	txbuf = reg & SPI_ADDR_MASK;
 43	txbuf |= KS_SPIOP_RD << SPI_ADDR_SHIFT;
 44	txbuf <<= SPI_TURNAROUND_SHIFT;
 45	txbuf = cpu_to_be32(txbuf);
 46
 47	ret = spi_write_then_read(spi, &txbuf, 4, val, len);
 48	return ret;
 49}
 50
 51static int ksz_spi_read(struct ksz_device *dev, u32 reg, u8 *data,
 52			unsigned int len)
 53{
 54	struct spi_device *spi = dev->priv;
 55
 56	return ksz_spi_read_reg(spi, reg, data, len);
 57}
 58
 59static int ksz_spi_read8(struct ksz_device *dev, u32 reg, u8 *val)
 60{
 61	return ksz_spi_read(dev, reg, val, 1);
 62}
 63
 64static int ksz_spi_read16(struct ksz_device *dev, u32 reg, u16 *val)
 65{
 66	int ret = ksz_spi_read(dev, reg, (u8 *)val, 2);
 67
 68	if (!ret)
 69		*val = be16_to_cpu(*val);
 70
 71	return ret;
 72}
 73
 74static int ksz_spi_read24(struct ksz_device *dev, u32 reg, u32 *val)
 75{
 76	int ret;
 77
 78	*val = 0;
 79	ret = ksz_spi_read(dev, reg, (u8 *)val, 3);
 80	if (!ret) {
 81		*val = be32_to_cpu(*val);
 82		/* convert to 24bit */
 83		*val >>= 8;
 84	}
 85
 86	return ret;
 87}
 88
 89static int ksz_spi_read32(struct ksz_device *dev, u32 reg, u32 *val)
 90{
 91	int ret = ksz_spi_read(dev, reg, (u8 *)val, 4);
 92
 93	if (!ret)
 94		*val = be32_to_cpu(*val);
 95
 96	return ret;
 97}
 98
 99static int ksz_spi_write_reg(struct spi_device *spi, u32 reg, u8 *val,
100			     unsigned int len)
101{
102	u32 txbuf;
103	u8 data[12];
104	int i;
105
106	txbuf = reg & SPI_ADDR_MASK;
107	txbuf |= (KS_SPIOP_WR << SPI_ADDR_SHIFT);
108	txbuf <<= SPI_TURNAROUND_SHIFT;
109	txbuf = cpu_to_be32(txbuf);
110
111	data[0] = txbuf & 0xFF;
112	data[1] = (txbuf & 0xFF00) >> 8;
113	data[2] = (txbuf & 0xFF0000) >> 16;
114	data[3] = (txbuf & 0xFF000000) >> 24;
115	for (i = 0; i < len; i++)
116		data[i + 4] = val[i];
117
118	return spi_write(spi, &data, 4 + len);
119}
120
121static int ksz_spi_write8(struct ksz_device *dev, u32 reg, u8 value)
122{
123	struct spi_device *spi = dev->priv;
124
125	return ksz_spi_write_reg(spi, reg, &value, 1);
126}
127
128static int ksz_spi_write16(struct ksz_device *dev, u32 reg, u16 value)
129{
130	struct spi_device *spi = dev->priv;
131
132	value = cpu_to_be16(value);
133	return ksz_spi_write_reg(spi, reg, (u8 *)&value, 2);
134}
135
136static int ksz_spi_write24(struct ksz_device *dev, u32 reg, u32 value)
137{
138	struct spi_device *spi = dev->priv;
139
140	/* make it to big endian 24bit from MSB */
141	value <<= 8;
142	value = cpu_to_be32(value);
143	return ksz_spi_write_reg(spi, reg, (u8 *)&value, 3);
144}
145
146static int ksz_spi_write32(struct ksz_device *dev, u32 reg, u32 value)
147{
148	struct spi_device *spi = dev->priv;
149
150	value = cpu_to_be32(value);
151	return ksz_spi_write_reg(spi, reg, (u8 *)&value, 4);
152}
153
154static const struct ksz_io_ops ksz_spi_ops = {
155	.read8 = ksz_spi_read8,
156	.read16 = ksz_spi_read16,
157	.read24 = ksz_spi_read24,
158	.read32 = ksz_spi_read32,
159	.write8 = ksz_spi_write8,
160	.write16 = ksz_spi_write16,
161	.write24 = ksz_spi_write24,
162	.write32 = ksz_spi_write32,
163};
164
165static int ksz_spi_probe(struct spi_device *spi)
166{
167	struct ksz_device *dev;
168	int ret;
169
170	dev = ksz_switch_alloc(&spi->dev, &ksz_spi_ops, spi);
171	if (!dev)
172		return -ENOMEM;
173
174	if (spi->dev.platform_data)
175		dev->pdata = spi->dev.platform_data;
176
177	ret = ksz_switch_register(dev);
178	if (ret)
179		return ret;
180
181	spi_set_drvdata(spi, dev);
182
183	return 0;
184}
185
186static int ksz_spi_remove(struct spi_device *spi)
187{
188	struct ksz_device *dev = spi_get_drvdata(spi);
189
190	if (dev)
191		ksz_switch_remove(dev);
192
193	return 0;
194}
195
196static const struct of_device_id ksz_dt_ids[] = {
197	{ .compatible = "microchip,ksz9477" },
198	{},
199};
200MODULE_DEVICE_TABLE(of, ksz_dt_ids);
201
202static struct spi_driver ksz_spi_driver = {
203	.driver = {
204		.name	= "ksz9477-switch",
205		.owner	= THIS_MODULE,
206		.of_match_table = of_match_ptr(ksz_dt_ids),
207	},
208	.probe	= ksz_spi_probe,
209	.remove	= ksz_spi_remove,
210};
211
212module_spi_driver(ksz_spi_driver);
213
214MODULE_AUTHOR("Woojung Huh <Woojung.Huh@microchip.com>");
215MODULE_DESCRIPTION("Microchip KSZ Series Switch SPI access Driver");
216MODULE_LICENSE("GPL");