2 * Copyright (c) 2014 Google, Inc
5 * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com.
7 * Influenced by code from:
8 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
10 * SPDX-License-Identifier: GPL-2.0+
21 DECLARE_GLOBAL_DATA_PTR;
23 struct soft_spi_platdata {
25 struct gpio_desc sclk;
26 struct gpio_desc mosi;
27 struct gpio_desc miso;
31 struct soft_spi_priv {
35 static int soft_spi_scl(struct udevice *dev, int bit)
37 struct udevice *bus = dev_get_parent(dev);
38 struct soft_spi_platdata *plat = dev_get_platdata(bus);
40 dm_gpio_set_value(&plat->sclk, bit);
45 static int soft_spi_sda(struct udevice *dev, int bit)
47 struct udevice *bus = dev_get_parent(dev);
48 struct soft_spi_platdata *plat = dev_get_platdata(bus);
50 dm_gpio_set_value(&plat->mosi, bit);
55 static int soft_spi_cs_activate(struct udevice *dev)
57 struct udevice *bus = dev_get_parent(dev);
58 struct soft_spi_platdata *plat = dev_get_platdata(bus);
60 dm_gpio_set_value(&plat->cs, 0);
61 dm_gpio_set_value(&plat->sclk, 0);
62 dm_gpio_set_value(&plat->cs, 1);
67 static int soft_spi_cs_deactivate(struct udevice *dev)
69 struct udevice *bus = dev_get_parent(dev);
70 struct soft_spi_platdata *plat = dev_get_platdata(bus);
72 dm_gpio_set_value(&plat->cs, 0);
77 static int soft_spi_claim_bus(struct udevice *dev)
80 * Make sure the SPI clock is in idle state as defined for
83 return soft_spi_scl(dev, 0);
86 static int soft_spi_release_bus(struct udevice *dev)
92 /*-----------------------------------------------------------------------
95 * This writes "bitlen" bits out the SPI MOSI port and simultaneously clocks
96 * "bitlen" bits in the SPI MISO port. That's just the way SPI works.
98 * The source of the outgoing bits is the "dout" parameter and the
99 * destination of the input bits is the "din" parameter. Note that "dout"
100 * and "din" can point to the same memory location, in which case the
101 * input data overwrites the output data (since both are buffered by
102 * temporary variables, this is OK).
104 static int soft_spi_xfer(struct udevice *dev, unsigned int bitlen,
105 const void *dout, void *din, unsigned long flags)
107 struct udevice *bus = dev_get_parent(dev);
108 struct soft_spi_priv *priv = dev_get_priv(bus);
109 struct soft_spi_platdata *plat = dev_get_platdata(bus);
112 const u8 *txd = dout;
114 int cpha = priv->mode & SPI_CPHA;
117 debug("spi_xfer: slave %s:%s dout %08X din %08X bitlen %u\n",
118 dev->parent->name, dev->name, *(uint *)txd, *(uint *)rxd,
121 if (flags & SPI_XFER_BEGIN)
122 soft_spi_cs_activate(dev);
124 for (j = 0; j < bitlen; j++) {
126 * Check if it is time to work on a new byte.
141 soft_spi_scl(dev, 0);
142 soft_spi_sda(dev, !!(tmpdout & 0x80));
143 udelay(plat->spi_delay_us);
145 soft_spi_scl(dev, 0);
147 soft_spi_scl(dev, 1);
149 tmpdin |= dm_gpio_get_value(&plat->miso);
151 udelay(plat->spi_delay_us);
153 soft_spi_scl(dev, 1);
156 * If the number of bits isn't a multiple of 8, shift the last
157 * bits over to left-justify them. Then store the last byte
161 if ((bitlen % 8) != 0)
162 tmpdin <<= 8 - (bitlen % 8);
166 if (flags & SPI_XFER_END)
167 soft_spi_cs_deactivate(dev);
172 static int soft_spi_set_speed(struct udevice *dev, unsigned int speed)
174 /* Accept any speed */
178 static int soft_spi_set_mode(struct udevice *dev, unsigned int mode)
180 struct soft_spi_priv *priv = dev_get_priv(dev);
187 static const struct dm_spi_ops soft_spi_ops = {
188 .claim_bus = soft_spi_claim_bus,
189 .release_bus = soft_spi_release_bus,
190 .xfer = soft_spi_xfer,
191 .set_speed = soft_spi_set_speed,
192 .set_mode = soft_spi_set_mode,
195 static int soft_spi_ofdata_to_platdata(struct udevice *dev)
197 struct soft_spi_platdata *plat = dev->platdata;
198 const void *blob = gd->fdt_blob;
199 int node = dev->of_offset;
201 plat->spi_delay_us = fdtdec_get_int(blob, node, "spi-delay-us", 0);
206 static int soft_spi_probe(struct udevice *dev)
208 struct spi_slave *slave = dev_get_parent_priv(dev);
209 struct soft_spi_platdata *plat = dev->platdata;
210 int cs_flags, clk_flags;
212 cs_flags = (slave->mode & SPI_CS_HIGH) ? 0 : GPIOD_ACTIVE_LOW;
213 clk_flags = (slave->mode & SPI_CPOL) ? GPIOD_ACTIVE_LOW : 0;
214 if (gpio_request_by_name(dev, "cs-gpio", 0, &plat->cs,
215 GPIOD_IS_OUT | cs_flags) ||
216 gpio_request_by_name(dev, "sclk-gpio", 0, &plat->sclk,
217 GPIOD_IS_OUT | clk_flags) ||
218 gpio_request_by_name(dev, "mosi-gpio", 0, &plat->mosi,
219 GPIOD_IS_OUT | GPIOD_IS_OUT_ACTIVE) ||
220 gpio_request_by_name(dev, "miso-gpio", 0, &plat->miso,
227 static const struct udevice_id soft_spi_ids[] = {
228 { .compatible = "u-boot,soft-spi" },
232 U_BOOT_DRIVER(soft_spi) = {
235 .of_match = soft_spi_ids,
236 .ops = &soft_spi_ops,
237 .ofdata_to_platdata = soft_spi_ofdata_to_platdata,
238 .platdata_auto_alloc_size = sizeof(struct soft_spi_platdata),
239 .priv_auto_alloc_size = sizeof(struct soft_spi_priv),
240 .probe = soft_spi_probe,