mirror of
https://github.com/brain-hackers/u-boot-brain
synced 2024-07-23 03:19:43 +09:00
83d290c56f
When U-Boot started using SPDX tags we were among the early adopters and there weren't a lot of other examples to borrow from. So we picked the area of the file that usually had a full license text and replaced it with an appropriate SPDX-License-Identifier: entry. Since then, the Linux Kernel has adopted SPDX tags and they place it as the very first line in a file (except where shebangs are used, then it's second line) and with slightly different comment styles than us. In part due to community overlap, in part due to better tag visibility and in part for other minor reasons, switch over to that style. This commit changes all instances where we have a single declared license in the tag as both the before and after are identical in tag contents. There's also a few places where I found we did not have a tag and have introduced one. Signed-off-by: Tom Rini <trini@konsulko.com>
144 lines
3.3 KiB
C
144 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* LPC32xx SSP interface (SPI mode)
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*
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* (C) Copyright 2014 DENX Software Engineering GmbH
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* Written-by: Albert ARIBAUD <albert.aribaud@3adev.fr>
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*/
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#include <common.h>
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#include <linux/compat.h>
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#include <asm/io.h>
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#include <malloc.h>
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#include <spi.h>
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#include <asm/arch/clk.h>
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/* SSP chip registers */
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struct ssp_regs {
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u32 cr0;
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u32 cr1;
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u32 data;
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u32 sr;
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u32 cpsr;
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u32 imsc;
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u32 ris;
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u32 mis;
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u32 icr;
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u32 dmacr;
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};
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/* CR1 register defines */
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#define SSP_CR1_SSP_ENABLE 0x0002
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/* SR register defines */
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#define SSP_SR_TNF 0x0002
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/* SSP status RX FIFO not empty bit */
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#define SSP_SR_RNE 0x0004
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/* lpc32xx spi slave */
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struct lpc32xx_spi_slave {
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struct spi_slave slave;
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struct ssp_regs *regs;
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};
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static inline struct lpc32xx_spi_slave *to_lpc32xx_spi_slave(
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struct spi_slave *slave)
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{
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return container_of(slave, struct lpc32xx_spi_slave, slave);
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}
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/* spi_init is called during boot when CONFIG_CMD_SPI is defined */
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void spi_init(void)
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{
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/*
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* nothing to do: clocking was enabled in lpc32xx_ssp_enable()
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* and configuration will be done in spi_setup_slave()
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*/
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}
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/* the following is called in sequence by do_spi_xfer() */
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struct spi_slave *spi_setup_slave(uint bus, uint cs, uint max_hz, uint mode)
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{
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struct lpc32xx_spi_slave *lslave;
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/* we only set up SSP0 for now, so ignore bus */
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if (mode & SPI_3WIRE) {
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pr_err("3-wire mode not supported");
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return NULL;
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}
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if (mode & SPI_SLAVE) {
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pr_err("slave mode not supported\n");
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return NULL;
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}
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if (mode & SPI_PREAMBLE) {
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pr_err("preamble byte skipping not supported\n");
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return NULL;
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}
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lslave = spi_alloc_slave(struct lpc32xx_spi_slave, bus, cs);
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if (!lslave) {
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printf("SPI_error: Fail to allocate lpc32xx_spi_slave\n");
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return NULL;
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}
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lslave->regs = (struct ssp_regs *)SSP0_BASE;
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/*
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* 8 bit frame, SPI fmt, 500kbps -> clock divider is 26.
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* Set SCR to 0 and CPSDVSR to 26.
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*/
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writel(0x7, &lslave->regs->cr0); /* 8-bit chunks, SPI, 1 clk/bit */
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writel(26, &lslave->regs->cpsr); /* SSP clock = HCLK/26 = 500kbps */
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writel(0, &lslave->regs->imsc); /* do not raise any interrupts */
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writel(0, &lslave->regs->icr); /* clear any pending interrupt */
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writel(0, &lslave->regs->dmacr); /* do not do DMAs */
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writel(SSP_CR1_SSP_ENABLE, &lslave->regs->cr1); /* enable SSP0 */
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return &lslave->slave;
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}
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void spi_free_slave(struct spi_slave *slave)
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{
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struct lpc32xx_spi_slave *lslave = to_lpc32xx_spi_slave(slave);
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debug("(lpc32xx) spi_free_slave: 0x%08x\n", (u32)lslave);
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free(lslave);
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}
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int spi_claim_bus(struct spi_slave *slave)
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{
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/* only one bus and slave so far, always available */
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return 0;
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}
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int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
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const void *dout, void *din, unsigned long flags)
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{
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struct lpc32xx_spi_slave *lslave = to_lpc32xx_spi_slave(slave);
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int bytelen = bitlen >> 3;
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int idx_out = 0;
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int idx_in = 0;
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int start_time;
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start_time = get_timer(0);
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while ((idx_out < bytelen) || (idx_in < bytelen)) {
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int status = readl(&lslave->regs->sr);
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if ((idx_out < bytelen) && (status & SSP_SR_TNF))
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writel(((u8 *)dout)[idx_out++], &lslave->regs->data);
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if ((idx_in < bytelen) && (status & status & SSP_SR_RNE))
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((u8 *)din)[idx_in++] = readl(&lslave->regs->data);
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if (get_timer(start_time) >= CONFIG_LPC32XX_SSP_TIMEOUT)
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return -1;
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}
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return 0;
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}
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void spi_release_bus(struct spi_slave *slave)
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{
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/* do nothing */
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}
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