diff options
Diffstat (limited to 'drivers/staging/kpc2000/kpc_spi/spi_driver.c')
| -rw-r--r-- | drivers/staging/kpc2000/kpc_spi/spi_driver.c | 507 |
1 files changed, 507 insertions, 0 deletions
diff --git a/drivers/staging/kpc2000/kpc_spi/spi_driver.c b/drivers/staging/kpc2000/kpc_spi/spi_driver.c new file mode 100644 index 000000000000..86df16547a92 --- /dev/null +++ b/drivers/staging/kpc2000/kpc_spi/spi_driver.c @@ -0,0 +1,507 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * KP2000 SPI controller driver + * + * Copyright (C) 2014-2018 Daktronics + * Author: Matt Sickler <matt.sickler@daktronics.com> + * Very loosely based on spi-omap2-mcspi.c + */ + +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/io-64-nonatomic-lo-hi.h> +#include <linux/module.h> +#include <linux/device.h> +#include <linux/delay.h> +#include <linux/platform_device.h> +#include <linux/err.h> +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/slab.h> +#include <linux/pm_runtime.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/gcd.h> +#include <linux/spi/spi.h> +#include <linux/spi/flash.h> +#include <linux/mtd/partitions.h> + +#include "../kpc.h" +#include "spi_parts.h" + + +/*************** + * SPI Defines * + ***************/ +#define KP_SPI_REG_CONFIG 0x0 /* 0x00 */ +#define KP_SPI_REG_STATUS 0x1 /* 0x08 */ +#define KP_SPI_REG_FFCTRL 0x2 /* 0x10 */ +#define KP_SPI_REG_TXDATA 0x3 /* 0x18 */ +#define KP_SPI_REG_RXDATA 0x4 /* 0x20 */ + +#define KP_SPI_CLK 48000000 +#define KP_SPI_MAX_FIFODEPTH 64 +#define KP_SPI_MAX_FIFOWCNT 0xFFFF + +#define KP_SPI_REG_CONFIG_TRM_TXRX 0 +#define KP_SPI_REG_CONFIG_TRM_RX 1 +#define KP_SPI_REG_CONFIG_TRM_TX 2 + +#define KP_SPI_REG_STATUS_RXS 0x01 +#define KP_SPI_REG_STATUS_TXS 0x02 +#define KP_SPI_REG_STATUS_EOT 0x04 +#define KP_SPI_REG_STATUS_TXFFE 0x10 +#define KP_SPI_REG_STATUS_TXFFF 0x20 +#define KP_SPI_REG_STATUS_RXFFE 0x40 +#define KP_SPI_REG_STATUS_RXFFF 0x80 + + + +/****************** + * SPI Structures * + ******************/ +struct kp_spi { + struct spi_master *master; + u64 __iomem *base; + unsigned long phys; + struct device *dev; + int fifo_depth; + unsigned int pin_dir:1; +}; + + +struct kp_spi_controller_state { + void __iomem *base; + unsigned long phys; + unsigned char chip_select; + int word_len; + s64 conf_cache; +}; + + +union kp_spi_config { + /* use this to access individual elements */ + struct __attribute__((packed)) spi_config_bitfield { + unsigned int pha : 1; /* spim_clk Phase */ + unsigned int pol : 1; /* spim_clk Polarity */ + unsigned int epol : 1; /* spim_csx Polarity */ + unsigned int dpe : 1; /* Transmission Enable */ + unsigned int wl : 5; /* Word Length */ + unsigned int : 3; + unsigned int trm : 2; /* TxRx Mode */ + unsigned int cs : 4; /* Chip Select */ + unsigned int wcnt : 7; /* Word Count */ + unsigned int ffen : 1; /* FIFO Enable */ + unsigned int spi_en : 1; /* SPI Enable */ + unsigned int : 5; + } bitfield; + /* use this to grab the whole register */ + u32 reg; +}; + + + +union kp_spi_status { + struct __attribute__((packed)) spi_status_bitfield { + unsigned int rx : 1; /* Rx Status */ + unsigned int tx : 1; /* Tx Status */ + unsigned int eo : 1; /* End of Transfer */ + unsigned int : 1; + unsigned int txffe : 1; /* Tx FIFO Empty */ + unsigned int txfff : 1; /* Tx FIFO Full */ + unsigned int rxffe : 1; /* Rx FIFO Empty */ + unsigned int rxfff : 1; /* Rx FIFO Full */ + unsigned int : 24; + } bitfield; + u32 reg; +}; + + + +union kp_spi_ffctrl { + struct __attribute__((packed)) spi_ffctrl_bitfield { + unsigned int ffstart : 1; /* FIFO Start */ + unsigned int : 31; + } bitfield; + u32 reg; +}; + + + +/*************** + * SPI Helpers * + ***************/ +static inline int +kp_spi_bytes_per_word(int word_len) +{ + if (word_len <= 8){ + return 1; + } + else if (word_len <= 16) { + return 2; + } + else { /* word_len <= 32 */ + return 4; + } +} + +static inline u64 +kp_spi_read_reg(struct kp_spi_controller_state *cs, int idx) +{ + u64 __iomem *addr = cs->base; + u64 val; + + addr += idx; + if ((idx == KP_SPI_REG_CONFIG) && (cs->conf_cache >= 0)){ + return cs->conf_cache; + } + val = readq((void*)addr); + return val; +} + +static inline void +kp_spi_write_reg(struct kp_spi_controller_state *cs, int idx, u64 val) +{ + u64 __iomem *addr = cs->base; + addr += idx; + writeq(val, (void*)addr); + if (idx == KP_SPI_REG_CONFIG) + cs->conf_cache = val; +} + +static int +kp_spi_wait_for_reg_bit(struct kp_spi_controller_state *cs, int idx, unsigned long bit) +{ + unsigned long timeout; + timeout = jiffies + msecs_to_jiffies(1000); + while (!(kp_spi_read_reg(cs, idx) & bit)) { + if (time_after(jiffies, timeout)) { + if (!(kp_spi_read_reg(cs, idx) & bit)) { + return -ETIMEDOUT; + } else { + return 0; + } + } + cpu_relax(); + } + return 0; +} + +static unsigned +kp_spi_txrx_pio(struct spi_device *spidev, struct spi_transfer *transfer) +{ + struct kp_spi_controller_state *cs = spidev->controller_state; + unsigned int count = transfer->len; + unsigned int c = count; + + int i; + u8 *rx = transfer->rx_buf; + const u8 *tx = transfer->tx_buf; + int processed = 0; + + if (tx) { + for (i = 0 ; i < c ; i++) { + char val = *tx++; + + if (kp_spi_wait_for_reg_bit(cs, KP_SPI_REG_STATUS, KP_SPI_REG_STATUS_TXS) < 0) { + goto out; + } + + kp_spi_write_reg(cs, KP_SPI_REG_TXDATA, val); + processed++; + } + } + else if(rx) { + for (i = 0 ; i < c ; i++) { + char test=0; + + kp_spi_write_reg(cs, KP_SPI_REG_TXDATA, 0x00); + + if (kp_spi_wait_for_reg_bit(cs, KP_SPI_REG_STATUS, KP_SPI_REG_STATUS_RXS) < 0) { + goto out; + } + + test = kp_spi_read_reg(cs, KP_SPI_REG_RXDATA); + *rx++ = test; + processed++; + } + } + + if (kp_spi_wait_for_reg_bit(cs, KP_SPI_REG_STATUS, KP_SPI_REG_STATUS_EOT) < 0) { + //TODO: Figure out how to abort transaction?? This has never happened in practice though... + } + + out: + return processed; +} + +/***************** + * SPI Functions * + *****************/ +static int +kp_spi_setup(struct spi_device *spidev) +{ + union kp_spi_config sc; + struct kp_spi *kpspi = spi_master_get_devdata(spidev->master); + struct kp_spi_controller_state *cs; + + /* setup controller state */ + cs = spidev->controller_state; + if (!cs) { + cs = kzalloc(sizeof(*cs), GFP_KERNEL); + if(!cs) { + return -ENOMEM; + } + cs->base = kpspi->base; + cs->phys = kpspi->phys; + cs->chip_select = spidev->chip_select; + cs->word_len = spidev->bits_per_word; + cs->conf_cache = -1; + spidev->controller_state = cs; + } + + /* set config register */ + sc.bitfield.wl = spidev->bits_per_word - 1; + sc.bitfield.cs = spidev->chip_select; + sc.bitfield.spi_en = 0; + sc.bitfield.trm = 0; + sc.bitfield.ffen = 0; + kp_spi_write_reg(spidev->controller_state, KP_SPI_REG_CONFIG, sc.reg); + return 0; +} + +static int +kp_spi_transfer_one_message(struct spi_master *master, struct spi_message *m) +{ + struct kp_spi_controller_state *cs; + struct spi_device *spidev; + struct kp_spi *kpspi; + struct spi_transfer *transfer; + union kp_spi_config sc; + int status = 0; + + spidev = m->spi; + kpspi = spi_master_get_devdata(master); + m->actual_length = 0; + m->status = 0; + + cs = spidev->controller_state; + + /* reject invalid messages and transfers */ + if (list_empty(&m->transfers)) { + return -EINVAL; + } + + /* validate input */ + list_for_each_entry(transfer, &m->transfers, transfer_list) { + const void *tx_buf = transfer->tx_buf; + void *rx_buf = transfer->rx_buf; + unsigned len = transfer->len; + + if (transfer->speed_hz > KP_SPI_CLK || (len && !(rx_buf || tx_buf))) { + dev_dbg(kpspi->dev, " transfer: %d Hz, %d %s%s, %d bpw\n", + transfer->speed_hz, + len, + tx_buf ? "tx" : "", + rx_buf ? "rx" : "", + transfer->bits_per_word); + dev_dbg(kpspi->dev, " transfer -EINVAL\n"); + return -EINVAL; + } + if (transfer->speed_hz && (transfer->speed_hz < (KP_SPI_CLK >> 15))) { + dev_dbg(kpspi->dev, "speed_hz %d below minimum %d Hz\n", + transfer->speed_hz, + KP_SPI_CLK >> 15); + dev_dbg(kpspi->dev, " speed_hz -EINVAL\n"); + return -EINVAL; + } + } + + /* assert chip select to start the sequence*/ + sc.reg = kp_spi_read_reg(cs, KP_SPI_REG_CONFIG); + sc.bitfield.spi_en = 1; + kp_spi_write_reg(cs, KP_SPI_REG_CONFIG, sc.reg); + + /* work */ + if (kp_spi_wait_for_reg_bit(cs, KP_SPI_REG_STATUS, KP_SPI_REG_STATUS_EOT) < 0) { + dev_info(kpspi->dev, "EOT timed out\n"); + goto out; + } + + /* do the transfers for this message */ + list_for_each_entry(transfer, &m->transfers, transfer_list) { + if (transfer->tx_buf == NULL && transfer->rx_buf == NULL && transfer->len) { + status = -EINVAL; + break; + } + + /* transfer */ + if (transfer->len) { + unsigned int word_len = spidev->bits_per_word; + unsigned count; + + /* set up the transfer... */ + sc.reg = kp_spi_read_reg(cs, KP_SPI_REG_CONFIG); + + /* ...direction */ + if (transfer->tx_buf) { + sc.bitfield.trm = KP_SPI_REG_CONFIG_TRM_TX; + } + else if (transfer->rx_buf) { + sc.bitfield.trm = KP_SPI_REG_CONFIG_TRM_RX; + } + + /* ...word length */ + if (transfer->bits_per_word) { + word_len = transfer->bits_per_word; + } + cs->word_len = word_len; + sc.bitfield.wl = word_len-1; + + /* ...chip select */ + sc.bitfield.cs = spidev->chip_select; + + /* ...and write the new settings */ + kp_spi_write_reg(cs, KP_SPI_REG_CONFIG, sc.reg); + + /* do the transfer */ + count = kp_spi_txrx_pio(spidev, transfer); + m->actual_length += count; + + if (count != transfer->len) { + status = -EIO; + break; + } + } + + if (transfer->delay_usecs) { + udelay(transfer->delay_usecs); + } + } + + /* de-assert chip select to end the sequence */ + sc.reg = kp_spi_read_reg(cs, KP_SPI_REG_CONFIG); + sc.bitfield.spi_en = 0; + kp_spi_write_reg(cs, KP_SPI_REG_CONFIG, sc.reg); + + out: + /* done work */ + spi_finalize_current_message(master); + return 0; +} + +static void +kp_spi_cleanup(struct spi_device *spidev) +{ + struct kp_spi_controller_state *cs = spidev->controller_state; + if (cs) { + kfree(cs); + } +} + + + +/****************** + * Probe / Remove * + ******************/ +static int +kp_spi_probe(struct platform_device *pldev) +{ + struct kpc_core_device_platdata *drvdata; + struct spi_master *master; + struct kp_spi *kpspi; + struct resource *r; + int status = 0; + int i; + + drvdata = pldev->dev.platform_data; + if (!drvdata){ + dev_err(&pldev->dev, "kp_spi_probe: platform_data is NULL!\n"); + return -ENODEV; + } + + master = spi_alloc_master(&pldev->dev, sizeof(struct kp_spi)); + if (master == NULL) { + dev_err(&pldev->dev, "kp_spi_probe: master allocation failed\n"); + return -ENOMEM; + } + + /* set up the spi functions */ + master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH; + master->bits_per_word_mask = (unsigned int)SPI_BPW_RANGE_MASK(4, 32); + master->setup = kp_spi_setup; + master->transfer_one_message = kp_spi_transfer_one_message; + master->cleanup = kp_spi_cleanup; + + platform_set_drvdata(pldev, master); + + kpspi = spi_master_get_devdata(master); + kpspi->master = master; + kpspi->dev = &pldev->dev; + + master->num_chipselect = 4; + if (pldev->id != -1) { + master->bus_num = pldev->id; + } + kpspi->pin_dir = 0; + + r = platform_get_resource(pldev, IORESOURCE_MEM, 0); + if (r == NULL) { + dev_err(&pldev->dev, "kp_spi_probe: Unable to get platform resources\n"); + status = -ENODEV; + goto free_master; + } + + kpspi->phys = (unsigned long)ioremap_nocache(r->start, resource_size(r)); + kpspi->base = (u64 __iomem *)kpspi->phys; + + status = spi_register_master(master); + if (status < 0) { + dev_err(&pldev->dev, "Unable to register SPI device\n"); + goto free_master; + } + + /* register the slave boards */ + #define NEW_SPI_DEVICE_FROM_BOARD_INFO_TABLE(table) \ + for (i = 0 ; i < ARRAY_SIZE(table) ; i++) { \ + spi_new_device(master, &(table[i])); \ + } + + switch ((drvdata->card_id & 0xFFFF0000) >> 16){ + case PCI_DEVICE_ID_DAKTRONICS_KADOKA_P2KR0: + NEW_SPI_DEVICE_FROM_BOARD_INFO_TABLE(p2kr0_board_info); + break; + default: + dev_err(&pldev->dev, "Unknown hardware, cant know what partition table to use!\n"); + goto free_master; + break; + } + + return status; + + free_master: + spi_master_put(master); + return status; +} + +static int +kp_spi_remove(struct platform_device *pldev) +{ + struct spi_master * master = platform_get_drvdata(pldev); + spi_unregister_master(master); + return 0; +} + + +static struct platform_driver kp_spi_driver = { + .driver = { + .name = KP_DRIVER_NAME_SPI, + }, + .probe = kp_spi_probe, + .remove = kp_spi_remove, +}; + +module_platform_driver(kp_spi_driver); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:kp_spi"); |