1 // SPDX-License-Identifier: GPL-2.0+
3 * Copyright (c) 2006 Ben Warren, Qstreams Networks Inc.
4 * With help from the common/soft_spi and arch/powerpc/cpu/mpc8260 drivers
11 #include <asm/mpc8xxx_spi.h>
14 SPI_EV_NE = BIT(31 - 22), /* Receiver Not Empty */
15 SPI_EV_NF = BIT(31 - 23), /* Transmitter Not Full */
19 SPI_MODE_LOOP = BIT(31 - 1), /* Loopback mode */
20 SPI_MODE_CI = BIT(31 - 2), /* Clock invert */
21 SPI_MODE_CP = BIT(31 - 3), /* Clock phase */
22 SPI_MODE_DIV16 = BIT(31 - 4), /* Divide clock source by 16 */
23 SPI_MODE_REV = BIT(31 - 5), /* Reverse mode - MSB first */
24 SPI_MODE_MS = BIT(31 - 6), /* Always master */
25 SPI_MODE_EN = BIT(31 - 7), /* Enable interface */
27 SPI_MODE_LEN_MASK = 0xf00000,
28 SPI_MODE_PM_MASK = 0xf0000,
30 SPI_COM_LST = BIT(31 - 9),
33 static inline u32 to_prescale_mod(u32 val)
35 return (min(val, (u32)15) << 16);
38 static void set_char_len(spi8xxx_t *spi, u32 val)
40 clrsetbits_be32(&spi->mode, SPI_MODE_LEN_MASK, (val << 20));
43 #define SPI_TIMEOUT 1000
45 struct spi_slave *spi_setup_slave(uint bus, uint cs, uint max_hz, uint mode)
47 struct spi_slave *slave;
49 if (!spi_cs_is_valid(bus, cs))
52 slave = spi_alloc_slave_base(bus, cs);
57 * TODO: Some of the code in spi_init() should probably move
58 * here, or into spi_claim_bus() below.
64 void spi_free_slave(struct spi_slave *slave)
71 spi8xxx_t *spi = &((immap_t *)(CONFIG_SYS_IMMR))->spi;
74 * SPI pins on the MPC83xx are not muxed, so all we do is initialize
77 out_be32(&spi->mode, SPI_MODE_REV | SPI_MODE_MS | SPI_MODE_EN);
78 /* Use SYSCLK / 8 (16.67MHz typ.) */
79 clrsetbits_be32(&spi->mode, SPI_MODE_PM_MASK, to_prescale_mod(1));
80 /* Clear all SPI events */
81 setbits_be32(&spi->event, 0xffffffff);
82 /* Mask all SPI interrupts */
83 clrbits_be32(&spi->mask, 0xffffffff);
84 /* LST bit doesn't do anything, so disregard */
85 out_be32(&spi->com, 0);
88 int spi_claim_bus(struct spi_slave *slave)
93 void spi_release_bus(struct spi_slave *slave)
97 int spi_xfer(struct spi_slave *slave, uint bitlen, const void *dout, void *din,
100 spi8xxx_t *spi = &((immap_t *)(CONFIG_SYS_IMMR))->spi;
102 int num_blks = DIV_ROUND_UP(bitlen, 32);
104 debug("%s: slave %u:%u dout %08X din %08X bitlen %u\n", __func__,
105 slave->bus, slave->cs, *(uint *)dout, *(uint *)din, bitlen);
107 if (flags & SPI_XFER_BEGIN)
108 spi_cs_activate(slave);
110 /* Clear all SPI events */
111 setbits_be32(&spi->event, 0xffffffff);
113 /* Handle data in 32-bit chunks */
117 uchar xfer_bitlen = (bitlen >= 32 ? 32 : bitlen);
119 clrbits_be32(&spi->mode, SPI_MODE_EN);
121 /* Set up length for this transfer */
123 if (bitlen <= 4) /* 4 bits or less */
124 set_char_len(spi, 3);
125 else if (bitlen <= 16) /* at most 16 bits */
126 set_char_len(spi, bitlen - 1);
127 else /* more than 16 bits -> full 32 bit transfer */
128 set_char_len(spi, 0);
130 setbits_be32(&spi->mode, SPI_MODE_EN);
132 /* Shift data so it's msb-justified */
133 tmpdout = *(u32 *)dout >> (32 - xfer_bitlen);
136 /* Set up the next iteration if sending > 32 bits */
141 /* Write the data out */
142 out_be32(&spi->tx, tmpdout);
144 debug("*** %s: ... %08x written\n", __func__, tmpdout);
147 * Wait for SPI transmit to get out
148 * or time out (1 second = 1000 ms)
149 * The NE event must be read and cleared first
151 for (tm = 0; tm < SPI_TIMEOUT; ++tm) {
152 u32 event = in_be32(&spi->event);
153 bool have_ne = event & SPI_EV_NE;
154 bool have_nf = event & SPI_EV_NF;
159 tmpdin = in_be32(&spi->rx);
160 setbits_be32(&spi->event, SPI_EV_NE);
162 *(u32 *)din = (tmpdin << (32 - xfer_bitlen));
163 if (xfer_bitlen == 32) {
164 /* Advance output buffer by 32 bits */
169 * Only bail when we've had both NE and NF events.
170 * This will cause timeouts on RO devices, so maybe
171 * in the future put an arbitrary delay after writing
172 * the device. Arbitrary delays suck, though...
178 if (tm >= SPI_TIMEOUT)
179 debug("*** %s: Time out during SPI transfer\n",
182 debug("*** %s: transfer ended. Value=%08x\n", __func__, tmpdin);
185 if (flags & SPI_XFER_END)
186 spi_cs_deactivate(slave);