From bea738f7baffe7fede835cff88d0247072d2f9d7 Mon Sep 17 00:00:00 2001 From: Hubert Feurstein Date: Tue, 13 Sep 2011 21:59:50 +0200 Subject: [PATCH] spi: add atmel-spi driver Signed-off-by: Hubert Feurstein Signed-off-by: Sascha Hauer --- arch/arm/mach-at91/include/mach/board.h | 7 + drivers/spi/Kconfig | 5 + drivers/spi/Makefile | 1 + drivers/spi/atmel_spi.c | 321 ++++++++++++++++++++++++ drivers/spi/atmel_spi.h | 167 ++++++++++++ 5 files changed, 501 insertions(+) create mode 100644 drivers/spi/atmel_spi.c create mode 100644 drivers/spi/atmel_spi.h diff --git a/arch/arm/mach-at91/include/mach/board.h b/arch/arm/mach-at91/include/mach/board.h index 89caebb9c..e88834bad 100644 --- a/arch/arm/mach-at91/include/mach/board.h +++ b/arch/arm/mach-at91/include/mach/board.h @@ -22,6 +22,7 @@ #define __ASM_ARCH_BOARD_H #include +#include #include void atmel_nand_load_image(void *dest, int size, int pagesize, int blocksize); @@ -75,4 +76,10 @@ struct atmel_mci_platform_data { }; void at91_add_device_mci(short mmc_id, struct atmel_mci_platform_data *data); + +/* SPI Master platform data */ +struct at91_spi_platform_data { + int *chipselect; /* array of gpio_pins */ + int num_chipselect; /* chipselect array entry count */ +}; #endif diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig index c72493c01..9864d84ba 100644 --- a/drivers/spi/Kconfig +++ b/drivers/spi/Kconfig @@ -24,4 +24,9 @@ config DRIVER_SPI_ALTERA depends on NIOS2 depends on SPI +config DRIVER_SPI_ATMEL + bool "Atmel (AT91) SPI Master driver" + depends on ARCH_AT91 + depends on SPI + endmenu diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile index 90e141dae..101652ff8 100644 --- a/drivers/spi/Makefile +++ b/drivers/spi/Makefile @@ -1,3 +1,4 @@ obj-$(CONFIG_SPI) += spi.o obj-$(CONFIG_DRIVER_SPI_IMX) += imx_spi.o obj-$(CONFIG_DRIVER_SPI_ALTERA) += altera_spi.o +obj-$(CONFIG_DRIVER_SPI_ATMEL) += atmel_spi.o diff --git a/drivers/spi/atmel_spi.c b/drivers/spi/atmel_spi.c new file mode 100644 index 000000000..5f5ccb655 --- /dev/null +++ b/drivers/spi/atmel_spi.c @@ -0,0 +1,321 @@ +/* + * Driver for Atmel AT32 and AT91 SPI Controllers + * + * Copyright (C) 2011 Hubert Feurstein + * + * based on imx_spi.c by: + * Copyright (C) 2008 Sascha Hauer, Pengutronix + * + * based on atmel_spi.c from the linux kernel by: + * Copyright (C) 2006 Atmel Corporation + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + * + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "atmel_spi.h" + +struct atmel_spi { + struct spi_master master; + void __iomem *regs; + struct clk *clk; + int *cs_pins; +}; + +#define to_atmel_spi(p) container_of(p, struct atmel_spi, master) +#define SPI_XCHG_TIMEOUT (100 * MSECOND) + +/* + * Version 2 of the SPI controller has + * - CR.LASTXFER + * - SPI_MR.DIV32 may become FDIV or must-be-zero (here: always zero) + * - SPI_SR.TXEMPTY, SPI_SR.NSSR (and corresponding irqs) + * - SPI_CSRx.CSAAT + * - SPI_CSRx.SBCR allows faster clocking + * + * We can determine the controller version by reading the VERSION + * register, but I haven't checked that it exists on all chips, and + * this is cheaper anyway. + */ +static inline bool atmel_spi_is_v2(void) +{ + return !cpu_is_at91rm9200(); +} + +static int atmel_spi_setup(struct spi_device *spi) +{ + struct spi_master *master = spi->master; + struct atmel_spi *as = to_atmel_spi(master); + + u32 scbr, csr; + unsigned int bits = spi->bits_per_word; + unsigned long bus_hz; + + if (spi->controller_data) { + csr = (u32)spi->controller_data; + spi_writel(as, CSR0, csr); + return 0; + } + + dev_dbg(master->dev, "%s mode 0x%08x bits_per_word: %d speed: %d\n", + __func__, spi->mode, spi->bits_per_word, + spi->max_speed_hz); + + bus_hz = clk_get_rate(as->clk); + if (!atmel_spi_is_v2()) + bus_hz /= 2; + + if (spi->max_speed_hz) { + /* + * Calculate the lowest divider that satisfies the + * constraint, assuming div32/fdiv/mbz == 0. + */ + scbr = DIV_ROUND_UP(bus_hz, spi->max_speed_hz); + + /* + * If the resulting divider doesn't fit into the + * register bitfield, we can't satisfy the constraint. + */ + if (scbr >= (1 << SPI_SCBR_SIZE)) { + dev_dbg(master->dev, + "setup: %d Hz too slow, scbr %u; min %ld Hz\n", + spi->max_speed_hz, scbr, bus_hz/255); + return -EINVAL; + } + } else { + /* speed zero means "as slow as possible" */ + scbr = 0xff; + } + + csr = SPI_BF(SCBR, scbr) | SPI_BF(BITS, bits - 8); + if (spi->mode & SPI_CPOL) + csr |= SPI_BIT(CPOL); + if (!(spi->mode & SPI_CPHA)) + csr |= SPI_BIT(NCPHA); + + /* DLYBS is mostly irrelevant since we manage chipselect using GPIOs. + * + * DLYBCT would add delays between words, slowing down transfers. + * It could potentially be useful to cope with DMA bottlenecks, but + * in those cases it's probably best to just use a lower bitrate. + */ + csr |= SPI_BF(DLYBS, 0); + csr |= SPI_BF(DLYBCT, 0); + + /* gpio_direction_output(npcs_pin, !(spi->mode & SPI_CS_HIGH)); */ + dev_dbg(master->dev, + "setup: %lu Hz bpw %u mode 0x%x -> csr%d %08x\n", + bus_hz / scbr, bits, spi->mode, spi->chip_select, csr); + + spi_writel(as, CSR0, csr); + + /* + * store the csr-setting when bits are defined. This happens usually + * after the specific spi_device driver has been probed. + */ + if (bits > 0) + spi->controller_data = (void *)csr; + + return 0; +} + +static void atmel_spi_chipselect(struct spi_device *spi, struct atmel_spi *as, int on) +{ + struct spi_master *master = &as->master; + int cs_pin; + int val = ((spi->mode & SPI_CS_HIGH) != 0) == on; + + BUG_ON(spi->chip_select >= master->num_chipselect); + cs_pin = as->cs_pins[spi->chip_select]; + + gpio_direction_output(cs_pin, val); +} + +static int atmel_spi_xchg(struct atmel_spi *as, u32 tx_val) +{ + uint64_t start; + + start = get_time_ns(); + while (!(spi_readl(as, SR) & SPI_BIT(TDRE))) { + if (is_timeout(start, SPI_XCHG_TIMEOUT)) { + dev_err(as->master.dev, "tx timeout\n"); + return -ETIMEDOUT; + } + } + spi_writel(as, TDR, tx_val); + + start = get_time_ns(); + while (!(spi_readl(as, SR) & SPI_BIT(RDRF))) { + if (is_timeout(start, SPI_XCHG_TIMEOUT)) { + dev_err(as->master.dev, "rx timeout\n"); + return -ETIMEDOUT; + } + } + return spi_readl(as, RDR) & 0xffff; +} + +static int atmel_spi_transfer(struct spi_device *spi, struct spi_message *mesg) +{ + int ret; + struct spi_master *master = spi->master; + struct atmel_spi *as = to_atmel_spi(master); + struct spi_transfer *t = NULL; + unsigned int bits = spi->bits_per_word; + + ret = master->setup(spi); + if (ret < 0) { + dev_dbg(master->dev, "transfer: master setup failed\n"); + return ret; + } + + dev_dbg(master->dev, " csr0: %08x\n", spi_readl(as, CSR0)); + +#ifdef VERBOSE + list_for_each_entry(t, &mesg->transfers, transfer_list) { + dev_dbg(master->dev, + " xfer %p: len %u tx %p rx %p\n", + t, t->len, t->tx_buf, t->rx_buf); + } +#endif + atmel_spi_chipselect(spi, as, 1); + list_for_each_entry(t, &mesg->transfers, transfer_list) { + u32 tx_val; + int i = 0, rx_val; + + if (bits <= 8) { + const u8 *txbuf = t->tx_buf; + u8 *rxbuf = t->rx_buf; + + while (i < t->len) { + tx_val = txbuf ? txbuf[i] : 0; + + rx_val = atmel_spi_xchg(as, tx_val); + if (rx_val < 0) { + ret = rx_val; + goto out; + } + + if (rxbuf) + rxbuf[i] = rx_val; + i++; + } + } else if (bits <= 16) { + const u16 *txbuf = t->tx_buf; + u16 *rxbuf = t->rx_buf; + + while (i < t->len >> 1) { + tx_val = txbuf ? txbuf[i] : 0; + + rx_val = atmel_spi_xchg(as, tx_val); + if (rx_val < 0) { + ret = rx_val; + goto out; + } + + if (rxbuf) + rxbuf[i] = rx_val; + i++; + } + } + } +out: + atmel_spi_chipselect(spi, as, 0); + return ret; +} + +static int atmel_spi_probe(struct device_d *dev) +{ + int ret = 0; + struct spi_master *master; + struct atmel_spi *as; + struct at91_spi_platform_data *pdata = dev->platform_data; + + if (!pdata) { + dev_err(dev, "missing platform data\n"); + return -EINVAL; + } + + as = xzalloc(sizeof(*as)); + + master = &as->master; + master->dev = dev; + + as->clk = clk_get(dev, "spi_clk"); + if (IS_ERR(as->clk)) { + dev_err(dev, "no spi_clk\n"); + ret = PTR_ERR(as->clk); + goto out_free; + } + + master->setup = atmel_spi_setup; + master->transfer = atmel_spi_transfer; + master->num_chipselect = pdata->num_chipselect; + as->cs_pins = pdata->chipselect; + as->regs = dev_request_mem_region(dev, 0); + + /* Initialize the hardware */ + clk_enable(as->clk); + spi_writel(as, CR, SPI_BIT(SWRST)); + spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */ + spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS)); + spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS)); + spi_writel(as, CR, SPI_BIT(SPIEN)); + + dev_dbg(dev, "Atmel SPI Controller at initialized\n"); + + ret = spi_register_master(master); + if (ret) + goto out_reset_hw; + + return 0; + +out_reset_hw: + spi_writel(as, CR, SPI_BIT(SWRST)); + spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */ + clk_disable(as->clk); + clk_put(as->clk); +out_free: + free(as); + return ret; +} + +static struct driver_d atmel_spi_driver = { + .name = "atmel_spi", + .probe = atmel_spi_probe, +}; + +static int atmel_spi_init(void) +{ + register_driver(&atmel_spi_driver); + return 0; +} + +device_initcall(atmel_spi_init); diff --git a/drivers/spi/atmel_spi.h b/drivers/spi/atmel_spi.h new file mode 100644 index 000000000..38ce11998 --- /dev/null +++ b/drivers/spi/atmel_spi.h @@ -0,0 +1,167 @@ +/* + * Register definitions for Atmel Serial Peripheral Interface (SPI) + * + * Copyright (C) 2006 Atmel Corporation + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ +#ifndef __ATMEL_SPI_H__ +#define __ATMEL_SPI_H__ + +/* SPI register offsets */ +#define SPI_CR 0x0000 +#define SPI_MR 0x0004 +#define SPI_RDR 0x0008 +#define SPI_TDR 0x000c +#define SPI_SR 0x0010 +#define SPI_IER 0x0014 +#define SPI_IDR 0x0018 +#define SPI_IMR 0x001c +#define SPI_CSR0 0x0030 +#define SPI_CSR1 0x0034 +#define SPI_CSR2 0x0038 +#define SPI_CSR3 0x003c +#define SPI_RPR 0x0100 +#define SPI_RCR 0x0104 +#define SPI_TPR 0x0108 +#define SPI_TCR 0x010c +#define SPI_RNPR 0x0110 +#define SPI_RNCR 0x0114 +#define SPI_TNPR 0x0118 +#define SPI_TNCR 0x011c +#define SPI_PTCR 0x0120 +#define SPI_PTSR 0x0124 + +/* Bitfields in CR */ +#define SPI_SPIEN_OFFSET 0 +#define SPI_SPIEN_SIZE 1 +#define SPI_SPIDIS_OFFSET 1 +#define SPI_SPIDIS_SIZE 1 +#define SPI_SWRST_OFFSET 7 +#define SPI_SWRST_SIZE 1 +#define SPI_LASTXFER_OFFSET 24 +#define SPI_LASTXFER_SIZE 1 + +/* Bitfields in MR */ +#define SPI_MSTR_OFFSET 0 +#define SPI_MSTR_SIZE 1 +#define SPI_PS_OFFSET 1 +#define SPI_PS_SIZE 1 +#define SPI_PCSDEC_OFFSET 2 +#define SPI_PCSDEC_SIZE 1 +#define SPI_FDIV_OFFSET 3 +#define SPI_FDIV_SIZE 1 +#define SPI_MODFDIS_OFFSET 4 +#define SPI_MODFDIS_SIZE 1 +#define SPI_LLB_OFFSET 7 +#define SPI_LLB_SIZE 1 +#define SPI_PCS_OFFSET 16 +#define SPI_PCS_SIZE 4 +#define SPI_DLYBCS_OFFSET 24 +#define SPI_DLYBCS_SIZE 8 + +/* Bitfields in RDR */ +#define SPI_RD_OFFSET 0 +#define SPI_RD_SIZE 16 + +/* Bitfields in TDR */ +#define SPI_TD_OFFSET 0 +#define SPI_TD_SIZE 16 + +/* Bitfields in SR */ +#define SPI_RDRF_OFFSET 0 +#define SPI_RDRF_SIZE 1 +#define SPI_TDRE_OFFSET 1 +#define SPI_TDRE_SIZE 1 +#define SPI_MODF_OFFSET 2 +#define SPI_MODF_SIZE 1 +#define SPI_OVRES_OFFSET 3 +#define SPI_OVRES_SIZE 1 +#define SPI_ENDRX_OFFSET 4 +#define SPI_ENDRX_SIZE 1 +#define SPI_ENDTX_OFFSET 5 +#define SPI_ENDTX_SIZE 1 +#define SPI_RXBUFF_OFFSET 6 +#define SPI_RXBUFF_SIZE 1 +#define SPI_TXBUFE_OFFSET 7 +#define SPI_TXBUFE_SIZE 1 +#define SPI_NSSR_OFFSET 8 +#define SPI_NSSR_SIZE 1 +#define SPI_TXEMPTY_OFFSET 9 +#define SPI_TXEMPTY_SIZE 1 +#define SPI_SPIENS_OFFSET 16 +#define SPI_SPIENS_SIZE 1 + +/* Bitfields in CSR0 */ +#define SPI_CPOL_OFFSET 0 +#define SPI_CPOL_SIZE 1 +#define SPI_NCPHA_OFFSET 1 +#define SPI_NCPHA_SIZE 1 +#define SPI_CSAAT_OFFSET 3 +#define SPI_CSAAT_SIZE 1 +#define SPI_BITS_OFFSET 4 +#define SPI_BITS_SIZE 4 +#define SPI_SCBR_OFFSET 8 +#define SPI_SCBR_SIZE 8 +#define SPI_DLYBS_OFFSET 16 +#define SPI_DLYBS_SIZE 8 +#define SPI_DLYBCT_OFFSET 24 +#define SPI_DLYBCT_SIZE 8 + +/* Bitfields in RCR */ +#define SPI_RXCTR_OFFSET 0 +#define SPI_RXCTR_SIZE 16 + +/* Bitfields in TCR */ +#define SPI_TXCTR_OFFSET 0 +#define SPI_TXCTR_SIZE 16 + +/* Bitfields in RNCR */ +#define SPI_RXNCR_OFFSET 0 +#define SPI_RXNCR_SIZE 16 + +/* Bitfields in TNCR */ +#define SPI_TXNCR_OFFSET 0 +#define SPI_TXNCR_SIZE 16 + +/* Bitfields in PTCR */ +#define SPI_RXTEN_OFFSET 0 +#define SPI_RXTEN_SIZE 1 +#define SPI_RXTDIS_OFFSET 1 +#define SPI_RXTDIS_SIZE 1 +#define SPI_TXTEN_OFFSET 8 +#define SPI_TXTEN_SIZE 1 +#define SPI_TXTDIS_OFFSET 9 +#define SPI_TXTDIS_SIZE 1 + +/* Constants for BITS */ +#define SPI_BITS_8_BPT 0 +#define SPI_BITS_9_BPT 1 +#define SPI_BITS_10_BPT 2 +#define SPI_BITS_11_BPT 3 +#define SPI_BITS_12_BPT 4 +#define SPI_BITS_13_BPT 5 +#define SPI_BITS_14_BPT 6 +#define SPI_BITS_15_BPT 7 +#define SPI_BITS_16_BPT 8 + +/* Bit manipulation macros */ +#define SPI_BIT(name) \ + (1 << SPI_##name##_OFFSET) +#define SPI_BF(name, value) \ + (((value) & ((1 << SPI_##name##_SIZE) - 1)) << SPI_##name##_OFFSET) +#define SPI_BFEXT(name, value) \ + (((value) >> SPI_##name##_OFFSET) & ((1 << SPI_##name##_SIZE) - 1)) +#define SPI_BFINS(name, value, old) \ + (((old) & ~(((1 << SPI_##name##_SIZE) - 1) << SPI_##name##_OFFSET)) \ + | SPI_BF(name, value)) + +/* Register access macros */ +#define spi_readl(port, reg) \ + __raw_readl((port)->regs + SPI_##reg) +#define spi_writel(port, reg, value) \ + __raw_writel((value), (port)->regs + SPI_##reg) + +#endif /* __ATMEL_SPI_H__ */