1 // SPDX-License-Identifier: (GPL-2.0 OR MIT)
3  * SPI core driver for the Ocelot chip family.
6  * SPI to the VSC7511, VSC7512, VSC7513 and VSC7514 chips. The main functions
7  * are to prepare the chip's SPI interface for a specific bus speed, and a host
11  * Copyright 2021-2022 Innovative Advantage Inc.
13  * Author: Colin Foster <colin.foster@in-advantage.com>
24 #include <linux/spi/spi.h>
63 	 * The SPI address must be big-endian, but we want the payload to match  in ocelot_spi_initialize()
68 	 * 0b00: little-endian, MSB first  in ocelot_spi_initialize()
72 	 * 0b01: big-endian, MSB first  in ocelot_spi_initialize()
76 	 * 0b10: little-endian, LSB first  in ocelot_spi_initialize()
80 	 * 0b11: big-endian, LSB first  in ocelot_spi_initialize()
84 	err = regmap_write(ddata->cpuorg_regmap, REG_DEV_CPUORG_IF_CTRL, val);  in ocelot_spi_initialize()
91 	 * first payload bit is shifted out too quickly, the read will fail.  in ocelot_spi_initialize()
93 	val = ddata->spi_padding_bytes;  in ocelot_spi_initialize()
94 	err = regmap_write(ddata->cpuorg_regmap, REG_DEV_CPUORG_IF_CFGSTAT, val);  in ocelot_spi_initialize()
100 	 * will verify several different things. The first is that the number of  in ocelot_spi_initialize()
107 	 * the SPI bus frequency.  in ocelot_spi_initialize()
115 	err = regmap_read(ddata->cpuorg_regmap, REG_DEV_CPUORG_IF_CFGSTAT, &val);  in ocelot_spi_initialize()
120 		return -ENODEV;  in ocelot_spi_initialize()
147 	struct spi_device *spi;  in ocelot_spi_regmap_bus_read()  local
151 	spi = to_spi_device(dev);  in ocelot_spi_regmap_bus_read()
157 	if (ddata->spi_padding_bytes) {  in ocelot_spi_regmap_bus_read()
158 		xfers[index].len = ddata->spi_padding_bytes;  in ocelot_spi_regmap_bus_read()
159 		xfers[index].tx_buf = ddata->dummy_buf;  in ocelot_spi_regmap_bus_read()
168 	return spi_sync_transfer(spi, xfers, index);  in ocelot_spi_regmap_bus_read()
174 	struct spi_device *spi = to_spi_device(dev);  in ocelot_spi_regmap_bus_write()  local
176 	return spi_write(spi, data, count);  in ocelot_spi_regmap_bus_write()
190 	regmap_config.name = res->name;  in ocelot_spi_init_regmap()
191 	regmap_config.max_register = resource_size(res) - 1;  in ocelot_spi_init_regmap()
192 	regmap_config.reg_base = res->start;  in ocelot_spi_init_regmap()
198 static int ocelot_spi_probe(struct spi_device *spi)  in ocelot_spi_probe()  argument
200 	struct device *dev = &spi->dev;  in ocelot_spi_probe()
207 		return -ENOMEM;  in ocelot_spi_probe()
209 	spi_set_drvdata(spi, ddata);  in ocelot_spi_probe()
211 	if (spi->max_speed_hz <= 500000) {  in ocelot_spi_probe()
212 		ddata->spi_padding_bytes = 0;  in ocelot_spi_probe()
220 		ddata->spi_padding_bytes = 1 + (spi->max_speed_hz / HZ_PER_MHZ + 2) / 8;  in ocelot_spi_probe()
222 		ddata->dummy_buf = devm_kzalloc(dev, ddata->spi_padding_bytes, GFP_KERNEL);  in ocelot_spi_probe()
223 		if (!ddata->dummy_buf)  in ocelot_spi_probe()
224 			return -ENOMEM;  in ocelot_spi_probe()
227 	spi->bits_per_word = 8;  in ocelot_spi_probe()
229 	err = spi_setup(spi);  in ocelot_spi_probe()
231 		return dev_err_probe(&spi->dev, err, "Error performing SPI setup\n");  in ocelot_spi_probe()
237 	ddata->cpuorg_regmap = r;  in ocelot_spi_probe()
243 	ddata->gcb_regmap = r;  in ocelot_spi_probe()
246 	 * The chip must be set up for SPI before it gets initialized and reset.  in ocelot_spi_probe()
252 		return dev_err_probe(dev, err, "Error initializing SPI bus\n");  in ocelot_spi_probe()
259 	 * A chip reset will clear the SPI configuration, so it needs to be done  in ocelot_spi_probe()
264 		return dev_err_probe(dev, err, "Error initializing SPI bus after reset\n");  in ocelot_spi_probe()
277 MODULE_DEVICE_TABLE(spi, ocelot_spi_ids);
287 		.name = "ocelot-soc",
295 MODULE_DESCRIPTION("SPI Controlled Ocelot Chip Driver");
296 MODULE_AUTHOR("Colin Foster <colin.foster@in-advantage.com>");