diff options
Diffstat (limited to 'drivers/spi/spi-lantiq-ssc.c')
| -rw-r--r-- | drivers/spi/spi-lantiq-ssc.c | 983 |
1 files changed, 983 insertions, 0 deletions
diff --git a/drivers/spi/spi-lantiq-ssc.c b/drivers/spi/spi-lantiq-ssc.c new file mode 100644 index 000000000000..8a626f7fccea --- /dev/null +++ b/drivers/spi/spi-lantiq-ssc.c @@ -0,0 +1,983 @@ +/* + * Copyright (C) 2011-2015 Daniel Schwierzeck <daniel.schwierzeck@gmail.com> + * Copyright (C) 2016 Hauke Mehrtens <hauke@hauke-m.de> + * + * This program is free software; you can distribute it and/or modify it + * under the terms of the GNU General Public License (Version 2) as + * published by the Free Software Foundation. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of_device.h> +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/delay.h> +#include <linux/interrupt.h> +#include <linux/sched.h> +#include <linux/completion.h> +#include <linux/spinlock.h> +#include <linux/err.h> +#include <linux/gpio.h> +#include <linux/pm_runtime.h> +#include <linux/spi/spi.h> + +#ifdef CONFIG_LANTIQ +#include <lantiq_soc.h> +#endif + +#define SPI_RX_IRQ_NAME "spi_rx" +#define SPI_TX_IRQ_NAME "spi_tx" +#define SPI_ERR_IRQ_NAME "spi_err" +#define SPI_FRM_IRQ_NAME "spi_frm" + +#define SPI_CLC 0x00 +#define SPI_PISEL 0x04 +#define SPI_ID 0x08 +#define SPI_CON 0x10 +#define SPI_STAT 0x14 +#define SPI_WHBSTATE 0x18 +#define SPI_TB 0x20 +#define SPI_RB 0x24 +#define SPI_RXFCON 0x30 +#define SPI_TXFCON 0x34 +#define SPI_FSTAT 0x38 +#define SPI_BRT 0x40 +#define SPI_BRSTAT 0x44 +#define SPI_SFCON 0x60 +#define SPI_SFSTAT 0x64 +#define SPI_GPOCON 0x70 +#define SPI_GPOSTAT 0x74 +#define SPI_FPGO 0x78 +#define SPI_RXREQ 0x80 +#define SPI_RXCNT 0x84 +#define SPI_DMACON 0xec +#define SPI_IRNEN 0xf4 +#define SPI_IRNICR 0xf8 +#define SPI_IRNCR 0xfc + +#define SPI_CLC_SMC_S 16 /* Clock divider for sleep mode */ +#define SPI_CLC_SMC_M (0xFF << SPI_CLC_SMC_S) +#define SPI_CLC_RMC_S 8 /* Clock divider for normal run mode */ +#define SPI_CLC_RMC_M (0xFF << SPI_CLC_RMC_S) +#define SPI_CLC_DISS BIT(1) /* Disable status bit */ +#define SPI_CLC_DISR BIT(0) /* Disable request bit */ + +#define SPI_ID_TXFS_S 24 /* Implemented TX FIFO size */ +#define SPI_ID_TXFS_M (0x3F << SPI_ID_TXFS_S) +#define SPI_ID_RXFS_S 16 /* Implemented RX FIFO size */ +#define SPI_ID_RXFS_M (0x3F << SPI_ID_RXFS_S) +#define SPI_ID_MOD_S 8 /* Module ID */ +#define SPI_ID_MOD_M (0xff << SPI_ID_MOD_S) +#define SPI_ID_CFG_S 5 /* DMA interface support */ +#define SPI_ID_CFG_M (1 << SPI_ID_CFG_S) +#define SPI_ID_REV_M 0x1F /* Hardware revision number */ + +#define SPI_CON_BM_S 16 /* Data width selection */ +#define SPI_CON_BM_M (0x1F << SPI_CON_BM_S) +#define SPI_CON_EM BIT(24) /* Echo mode */ +#define SPI_CON_IDLE BIT(23) /* Idle bit value */ +#define SPI_CON_ENBV BIT(22) /* Enable byte valid control */ +#define SPI_CON_RUEN BIT(12) /* Receive underflow error enable */ +#define SPI_CON_TUEN BIT(11) /* Transmit underflow error enable */ +#define SPI_CON_AEN BIT(10) /* Abort error enable */ +#define SPI_CON_REN BIT(9) /* Receive overflow error enable */ +#define SPI_CON_TEN BIT(8) /* Transmit overflow error enable */ +#define SPI_CON_LB BIT(7) /* Loopback control */ +#define SPI_CON_PO BIT(6) /* Clock polarity control */ +#define SPI_CON_PH BIT(5) /* Clock phase control */ +#define SPI_CON_HB BIT(4) /* Heading control */ +#define SPI_CON_RXOFF BIT(1) /* Switch receiver off */ +#define SPI_CON_TXOFF BIT(0) /* Switch transmitter off */ + +#define SPI_STAT_RXBV_S 28 +#define SPI_STAT_RXBV_M (0x7 << SPI_STAT_RXBV_S) +#define SPI_STAT_BSY BIT(13) /* Busy flag */ +#define SPI_STAT_RUE BIT(12) /* Receive underflow error flag */ +#define SPI_STAT_TUE BIT(11) /* Transmit underflow error flag */ +#define SPI_STAT_AE BIT(10) /* Abort error flag */ +#define SPI_STAT_RE BIT(9) /* Receive error flag */ +#define SPI_STAT_TE BIT(8) /* Transmit error flag */ +#define SPI_STAT_ME BIT(7) /* Mode error flag */ +#define SPI_STAT_MS BIT(1) /* Master/slave select bit */ +#define SPI_STAT_EN BIT(0) /* Enable bit */ +#define SPI_STAT_ERRORS (SPI_STAT_ME | SPI_STAT_TE | SPI_STAT_RE | \ + SPI_STAT_AE | SPI_STAT_TUE | SPI_STAT_RUE) + +#define SPI_WHBSTATE_SETTUE BIT(15) /* Set transmit underflow error flag */ +#define SPI_WHBSTATE_SETAE BIT(14) /* Set abort error flag */ +#define SPI_WHBSTATE_SETRE BIT(13) /* Set receive error flag */ +#define SPI_WHBSTATE_SETTE BIT(12) /* Set transmit error flag */ +#define SPI_WHBSTATE_CLRTUE BIT(11) /* Clear transmit underflow error flag */ +#define SPI_WHBSTATE_CLRAE BIT(10) /* Clear abort error flag */ +#define SPI_WHBSTATE_CLRRE BIT(9) /* Clear receive error flag */ +#define SPI_WHBSTATE_CLRTE BIT(8) /* Clear transmit error flag */ +#define SPI_WHBSTATE_SETME BIT(7) /* Set mode error flag */ +#define SPI_WHBSTATE_CLRME BIT(6) /* Clear mode error flag */ +#define SPI_WHBSTATE_SETRUE BIT(5) /* Set receive underflow error flag */ +#define SPI_WHBSTATE_CLRRUE BIT(4) /* Clear receive underflow error flag */ +#define SPI_WHBSTATE_SETMS BIT(3) /* Set master select bit */ +#define SPI_WHBSTATE_CLRMS BIT(2) /* Clear master select bit */ +#define SPI_WHBSTATE_SETEN BIT(1) /* Set enable bit (operational mode) */ +#define SPI_WHBSTATE_CLREN BIT(0) /* Clear enable bit (config mode */ +#define SPI_WHBSTATE_CLR_ERRORS (SPI_WHBSTATE_CLRRUE | SPI_WHBSTATE_CLRME | \ + SPI_WHBSTATE_CLRTE | SPI_WHBSTATE_CLRRE | \ + SPI_WHBSTATE_CLRAE | SPI_WHBSTATE_CLRTUE) + +#define SPI_RXFCON_RXFITL_S 8 /* FIFO interrupt trigger level */ +#define SPI_RXFCON_RXFITL_M (0x3F << SPI_RXFCON_RXFITL_S) +#define SPI_RXFCON_RXFLU BIT(1) /* FIFO flush */ +#define SPI_RXFCON_RXFEN BIT(0) /* FIFO enable */ + +#define SPI_TXFCON_TXFITL_S 8 /* FIFO interrupt trigger level */ +#define SPI_TXFCON_TXFITL_M (0x3F << SPI_TXFCON_TXFITL_S) +#define SPI_TXFCON_TXFLU BIT(1) /* FIFO flush */ +#define SPI_TXFCON_TXFEN BIT(0) /* FIFO enable */ + +#define SPI_FSTAT_RXFFL_S 0 +#define SPI_FSTAT_RXFFL_M (0x3f << SPI_FSTAT_RXFFL_S) +#define SPI_FSTAT_TXFFL_S 8 +#define SPI_FSTAT_TXFFL_M (0x3f << SPI_FSTAT_TXFFL_S) + +#define SPI_GPOCON_ISCSBN_S 8 +#define SPI_GPOCON_INVOUTN_S 0 + +#define SPI_FGPO_SETOUTN_S 8 +#define SPI_FGPO_CLROUTN_S 0 + +#define SPI_RXREQ_RXCNT_M 0xFFFF /* Receive count value */ +#define SPI_RXCNT_TODO_M 0xFFFF /* Recevie to-do value */ + +#define SPI_IRNEN_TFI BIT(4) /* TX finished interrupt */ +#define SPI_IRNEN_F BIT(3) /* Frame end interrupt request */ +#define SPI_IRNEN_E BIT(2) /* Error end interrupt request */ +#define SPI_IRNEN_T_XWAY BIT(1) /* Transmit end interrupt request */ +#define SPI_IRNEN_R_XWAY BIT(0) /* Receive end interrupt request */ +#define SPI_IRNEN_R_XRX BIT(1) /* Transmit end interrupt request */ +#define SPI_IRNEN_T_XRX BIT(0) /* Receive end interrupt request */ +#define SPI_IRNEN_ALL 0x1F + +struct lantiq_ssc_hwcfg { + unsigned int irnen_r; + unsigned int irnen_t; +}; + +struct lantiq_ssc_spi { + struct spi_master *master; + struct device *dev; + void __iomem *regbase; + struct clk *spi_clk; + struct clk *fpi_clk; + const struct lantiq_ssc_hwcfg *hwcfg; + + spinlock_t lock; + struct workqueue_struct *wq; + struct work_struct work; + + const u8 *tx; + u8 *rx; + unsigned int tx_todo; + unsigned int rx_todo; + unsigned int bits_per_word; + unsigned int speed_hz; + unsigned int tx_fifo_size; + unsigned int rx_fifo_size; + unsigned int base_cs; +}; + +static u32 lantiq_ssc_readl(const struct lantiq_ssc_spi *spi, u32 reg) +{ + return __raw_readl(spi->regbase + reg); +} + +static void lantiq_ssc_writel(const struct lantiq_ssc_spi *spi, u32 val, + u32 reg) +{ + __raw_writel(val, spi->regbase + reg); +} + +static void lantiq_ssc_maskl(const struct lantiq_ssc_spi *spi, u32 clr, + u32 set, u32 reg) +{ + u32 val = __raw_readl(spi->regbase + reg); + + val &= ~clr; + val |= set; + __raw_writel(val, spi->regbase + reg); +} + +static unsigned int tx_fifo_level(const struct lantiq_ssc_spi *spi) +{ + u32 fstat = lantiq_ssc_readl(spi, SPI_FSTAT); + + return (fstat & SPI_FSTAT_TXFFL_M) >> SPI_FSTAT_TXFFL_S; +} + +static unsigned int rx_fifo_level(const struct lantiq_ssc_spi *spi) +{ + u32 fstat = lantiq_ssc_readl(spi, SPI_FSTAT); + + return fstat & SPI_FSTAT_RXFFL_M; +} + +static unsigned int tx_fifo_free(const struct lantiq_ssc_spi *spi) +{ + return spi->tx_fifo_size - tx_fifo_level(spi); +} + +static void rx_fifo_reset(const struct lantiq_ssc_spi *spi) +{ + u32 val = spi->rx_fifo_size << SPI_RXFCON_RXFITL_S; + + val |= SPI_RXFCON_RXFEN | SPI_RXFCON_RXFLU; + lantiq_ssc_writel(spi, val, SPI_RXFCON); +} + +static void tx_fifo_reset(const struct lantiq_ssc_spi *spi) +{ + u32 val = 1 << SPI_TXFCON_TXFITL_S; + + val |= SPI_TXFCON_TXFEN | SPI_TXFCON_TXFLU; + lantiq_ssc_writel(spi, val, SPI_TXFCON); +} + +static void rx_fifo_flush(const struct lantiq_ssc_spi *spi) +{ + lantiq_ssc_maskl(spi, 0, SPI_RXFCON_RXFLU, SPI_RXFCON); +} + +static void tx_fifo_flush(const struct lantiq_ssc_spi *spi) +{ + lantiq_ssc_maskl(spi, 0, SPI_TXFCON_TXFLU, SPI_TXFCON); +} + +static void hw_enter_config_mode(const struct lantiq_ssc_spi *spi) +{ + lantiq_ssc_writel(spi, SPI_WHBSTATE_CLREN, SPI_WHBSTATE); +} + +static void hw_enter_active_mode(const struct lantiq_ssc_spi *spi) +{ + lantiq_ssc_writel(spi, SPI_WHBSTATE_SETEN, SPI_WHBSTATE); +} + +static void hw_setup_speed_hz(const struct lantiq_ssc_spi *spi, + unsigned int max_speed_hz) +{ + u32 spi_clk, brt; + + /* + * SPI module clock is derived from FPI bus clock dependent on + * divider value in CLC.RMS which is always set to 1. + * + * f_SPI + * baudrate = -------------- + * 2 * (BR + 1) + */ + spi_clk = clk_get_rate(spi->fpi_clk) / 2; + + if (max_speed_hz > spi_clk) + brt = 0; + else + brt = spi_clk / max_speed_hz - 1; + + if (brt > 0xFFFF) + brt = 0xFFFF; + + dev_dbg(spi->dev, "spi_clk %u, max_speed_hz %u, brt %u\n", + spi_clk, max_speed_hz, brt); + + lantiq_ssc_writel(spi, brt, SPI_BRT); +} + +static void hw_setup_bits_per_word(const struct lantiq_ssc_spi *spi, + unsigned int bits_per_word) +{ + u32 bm; + + /* CON.BM value = bits_per_word - 1 */ + bm = (bits_per_word - 1) << SPI_CON_BM_S; + + lantiq_ssc_maskl(spi, SPI_CON_BM_M, bm, SPI_CON); +} + +static void hw_setup_clock_mode(const struct lantiq_ssc_spi *spi, + unsigned int mode) +{ + u32 con_set = 0, con_clr = 0; + + /* + * SPI mode mapping in CON register: + * Mode CPOL CPHA CON.PO CON.PH + * 0 0 0 0 1 + * 1 0 1 0 0 + * 2 1 0 1 1 + * 3 1 1 1 0 + */ + if (mode & SPI_CPHA) + con_clr |= SPI_CON_PH; + else + con_set |= SPI_CON_PH; + + if (mode & SPI_CPOL) + con_set |= SPI_CON_PO | SPI_CON_IDLE; + else + con_clr |= SPI_CON_PO | SPI_CON_IDLE; + + /* Set heading control */ + if (mode & SPI_LSB_FIRST) + con_clr |= SPI_CON_HB; + else + con_set |= SPI_CON_HB; + + /* Set loopback mode */ + if (mode & SPI_LOOP) + con_set |= SPI_CON_LB; + else + con_clr |= SPI_CON_LB; + + lantiq_ssc_maskl(spi, con_clr, con_set, SPI_CON); +} + +static void lantiq_ssc_hw_init(const struct lantiq_ssc_spi *spi) +{ + const struct lantiq_ssc_hwcfg *hwcfg = spi->hwcfg; + + /* + * Set clock divider for run mode to 1 to + * run at same frequency as FPI bus + */ + lantiq_ssc_writel(spi, 1 << SPI_CLC_RMC_S, SPI_CLC); + + /* Put controller into config mode */ + hw_enter_config_mode(spi); + + /* Clear error flags */ + lantiq_ssc_maskl(spi, 0, SPI_WHBSTATE_CLR_ERRORS, SPI_WHBSTATE); + + /* Enable error checking, disable TX/RX */ + lantiq_ssc_writel(spi, SPI_CON_RUEN | SPI_CON_AEN | SPI_CON_TEN | + SPI_CON_REN | SPI_CON_TXOFF | SPI_CON_RXOFF, SPI_CON); + + /* Setup default SPI mode */ + hw_setup_bits_per_word(spi, spi->bits_per_word); + hw_setup_clock_mode(spi, SPI_MODE_0); + + /* Enable master mode and clear error flags */ + lantiq_ssc_writel(spi, SPI_WHBSTATE_SETMS | SPI_WHBSTATE_CLR_ERRORS, + SPI_WHBSTATE); + + /* Reset GPIO/CS registers */ + lantiq_ssc_writel(spi, 0, SPI_GPOCON); + lantiq_ssc_writel(spi, 0xFF00, SPI_FPGO); + + /* Enable and flush FIFOs */ + rx_fifo_reset(spi); + tx_fifo_reset(spi); + + /* Enable interrupts */ + lantiq_ssc_writel(spi, hwcfg->irnen_t | hwcfg->irnen_r | SPI_IRNEN_E, + SPI_IRNEN); +} + +static int lantiq_ssc_setup(struct spi_device *spidev) +{ + struct spi_master *master = spidev->master; + struct lantiq_ssc_spi *spi = spi_master_get_devdata(master); + unsigned int cs = spidev->chip_select; + u32 gpocon; + + /* GPIOs are used for CS */ + if (gpio_is_valid(spidev->cs_gpio)) + return 0; + + dev_dbg(spi->dev, "using internal chipselect %u\n", cs); + + if (cs < spi->base_cs) { + dev_err(spi->dev, + "chipselect %i too small (min %i)\n", cs, spi->base_cs); + return -EINVAL; + } + + /* set GPO pin to CS mode */ + gpocon = 1 << ((cs - spi->base_cs) + SPI_GPOCON_ISCSBN_S); + + /* invert GPO pin */ + if (spidev->mode & SPI_CS_HIGH) + gpocon |= 1 << (cs - spi->base_cs); + + lantiq_ssc_maskl(spi, 0, gpocon, SPI_GPOCON); + + return 0; +} + +static int lantiq_ssc_prepare_message(struct spi_master *master, + struct spi_message *message) +{ + struct lantiq_ssc_spi *spi = spi_master_get_devdata(master); + + hw_enter_config_mode(spi); + hw_setup_clock_mode(spi, message->spi->mode); + hw_enter_active_mode(spi); + + return 0; +} + +static void hw_setup_transfer(struct lantiq_ssc_spi *spi, + struct spi_device *spidev, struct spi_transfer *t) +{ + unsigned int speed_hz = t->speed_hz; + unsigned int bits_per_word = t->bits_per_word; + u32 con; + + if (bits_per_word != spi->bits_per_word || + speed_hz != spi->speed_hz) { + hw_enter_config_mode(spi); + hw_setup_speed_hz(spi, speed_hz); + hw_setup_bits_per_word(spi, bits_per_word); + hw_enter_active_mode(spi); + + spi->speed_hz = speed_hz; + spi->bits_per_word = bits_per_word; + } + + /* Configure transmitter and receiver */ + con = lantiq_ssc_readl(spi, SPI_CON); + if (t->tx_buf) + con &= ~SPI_CON_TXOFF; + else + con |= SPI_CON_TXOFF; + + if (t->rx_buf) + con &= ~SPI_CON_RXOFF; + else + con |= SPI_CON_RXOFF; + + lantiq_ssc_writel(spi, con, SPI_CON); +} + +static int lantiq_ssc_unprepare_message(struct spi_master *master, + struct spi_message *message) +{ + struct lantiq_ssc_spi *spi = spi_master_get_devdata(master); + + flush_workqueue(spi->wq); + + /* Disable transmitter and receiver while idle */ + lantiq_ssc_maskl(spi, 0, SPI_CON_TXOFF | SPI_CON_RXOFF, SPI_CON); + + return 0; +} + +static void tx_fifo_write(struct lantiq_ssc_spi *spi) +{ + const u8 *tx8; + const u16 *tx16; + const u32 *tx32; + u32 data; + unsigned int tx_free = tx_fifo_free(spi); + + while (spi->tx_todo && tx_free) { + switch (spi->bits_per_word) { + case 2 ... 8: + tx8 = spi->tx; + data = *tx8; + spi->tx_todo--; + spi->tx++; + break; + case 16: + tx16 = (u16 *) spi->tx; + data = *tx16; + spi->tx_todo -= 2; + spi->tx += 2; + break; + case 32: + tx32 = (u32 *) spi->tx; + data = *tx32; + spi->tx_todo -= 4; + spi->tx += 4; + break; + default: + WARN_ON(1); + data = 0; + break; + } + + lantiq_ssc_writel(spi, data, SPI_TB); + tx_free--; + } +} + +static void rx_fifo_read_full_duplex(struct lantiq_ssc_spi *spi) +{ + u8 *rx8; + u16 *rx16; + u32 *rx32; + u32 data; + unsigned int rx_fill = rx_fifo_level(spi); + + while (rx_fill) { + data = lantiq_ssc_readl(spi, SPI_RB); + + switch (spi->bits_per_word) { + case 2 ... 8: + rx8 = spi->rx; + *rx8 = data; + spi->rx_todo--; + spi->rx++; + break; + case 16: + rx16 = (u16 *) spi->rx; + *rx16 = data; + spi->rx_todo -= 2; + spi->rx += 2; + break; + case 32: + rx32 = (u32 *) spi->rx; + *rx32 = data; + spi->rx_todo -= 4; + spi->rx += 4; + break; + default: + WARN_ON(1); + break; + } + + rx_fill--; + } +} + +static void rx_fifo_read_half_duplex(struct lantiq_ssc_spi *spi) +{ + u32 data, *rx32; + u8 *rx8; + unsigned int rxbv, shift; + unsigned int rx_fill = rx_fifo_level(spi); + + /* + * In RX-only mode the bits per word value is ignored by HW. A value + * of 32 is used instead. Thus all 4 bytes per FIFO must be read. + * If remaining RX bytes are less than 4, the FIFO must be read + * differently. The amount of received and valid bytes is indicated + * by STAT.RXBV register value. + */ + while (rx_fill) { + if (spi->rx_todo < 4) { + rxbv = (lantiq_ssc_readl(spi, SPI_STAT) & + SPI_STAT_RXBV_M) >> SPI_STAT_RXBV_S; + data = lantiq_ssc_readl(spi, SPI_RB); + + shift = (rxbv - 1) * 8; + rx8 = spi->rx; + + while (rxbv) { + *rx8++ = (data >> shift) & 0xFF; + rxbv--; + shift -= 8; + spi->rx_todo--; + spi->rx++; + } + } else { + data = lantiq_ssc_readl(spi, SPI_RB); + rx32 = (u32 *) spi->rx; + + *rx32++ = data; + spi->rx_todo -= 4; + spi->rx += 4; + } + rx_fill--; + } +} + +static void rx_request(struct lantiq_ssc_spi *spi) +{ + unsigned int rxreq, rxreq_max; + + /* + * To avoid receive overflows at high clocks it is better to request + * only the amount of bytes that fits into all FIFOs. This value + * depends on the FIFO size implemented in hardware. + */ + rxreq = spi->rx_todo; + rxreq_max = spi->rx_fifo_size * 4; + if (rxreq > rxreq_max) + rxreq = rxreq_max; + + lantiq_ssc_writel(spi, rxreq, SPI_RXREQ); +} + +static irqreturn_t lantiq_ssc_xmit_interrupt(int irq, void *data) +{ + struct lantiq_ssc_spi *spi = data; + + if (spi->tx) { + if (spi->rx && spi->rx_todo) + rx_fifo_read_full_duplex(spi); + + if (spi->tx_todo) + tx_fifo_write(spi); + else if (!tx_fifo_level(spi)) + goto completed; + } else if (spi->rx) { + if (spi->rx_todo) { + rx_fifo_read_half_duplex(spi); + + if (spi->rx_todo) + rx_request(spi); + else + goto completed; + } else { + goto completed; + } + } + + return IRQ_HANDLED; + +completed: + queue_work(spi->wq, &spi->work); + + return IRQ_HANDLED; +} + +static irqreturn_t lantiq_ssc_err_interrupt(int irq, void *data) +{ + struct lantiq_ssc_spi *spi = data; + u32 stat = lantiq_ssc_readl(spi, SPI_STAT); + + if (!(stat & SPI_STAT_ERRORS)) + return IRQ_NONE; + + if (stat & SPI_STAT_RUE) + dev_err(spi->dev, "receive underflow error\n"); + if (stat & SPI_STAT_TUE) + dev_err(spi->dev, "transmit underflow error\n"); + if (stat & SPI_STAT_AE) + dev_err(spi->dev, "abort error\n"); + if (stat & SPI_STAT_RE) + dev_err(spi->dev, "receive overflow error\n"); + if (stat & SPI_STAT_TE) + dev_err(spi->dev, "transmit overflow error\n"); + if (stat & SPI_STAT_ME) + dev_err(spi->dev, "mode error\n"); + + /* Clear error flags */ + lantiq_ssc_maskl(spi, 0, SPI_WHBSTATE_CLR_ERRORS, SPI_WHBSTATE); + + /* set bad status so it can be retried */ + if (spi->master->cur_msg) + spi->master->cur_msg->status = -EIO; + queue_work(spi->wq, &spi->work); + + return IRQ_HANDLED; +} + +static int transfer_start(struct lantiq_ssc_spi *spi, struct spi_device *spidev, + struct spi_transfer *t) +{ + unsigned long flags; + + spin_lock_irqsave(&spi->lock, flags); + + spi->tx = t->tx_buf; + spi->rx = t->rx_buf; + + if (t->tx_buf) { + spi->tx_todo = t->len; + + /* initially fill TX FIFO */ + tx_fifo_write(spi); + } + + if (spi->rx) { + spi->rx_todo = t->len; + + /* start shift clock in RX-only mode */ + if (!spi->tx) + rx_request(spi); + } + + spin_unlock_irqrestore(&spi->lock, flags); + + return t->len; +} + +/* + * The driver only gets an interrupt when the FIFO is empty, but there + * is an additional shift register from which the data is written to + * the wire. We get the last interrupt when the controller starts to + * write the last word to the wire, not when it is finished. Do busy + * waiting till it finishes. + */ +static void lantiq_ssc_bussy_work(struct work_struct *work) +{ + struct lantiq_ssc_spi *spi; + unsigned long long timeout = 8LL * 1000LL; + unsigned long end; + + spi = container_of(work, typeof(*spi), work); + + do_div(timeout, spi->speed_hz); + timeout += timeout + 100; /* some tolerance */ + + end = jiffies + msecs_to_jiffies(timeout); + do { + u32 stat = lantiq_ssc_readl(spi, SPI_STAT); + + if (!(stat & SPI_STAT_BSY)) { + spi_finalize_current_transfer(spi->master); + return; + } + + cond_resched(); + } while (!time_after_eq(jiffies, end)); + + if (spi->master->cur_msg) + spi->master->cur_msg->status = -EIO; + spi_finalize_current_transfer(spi->master); +} + +static void lantiq_ssc_handle_err(struct spi_master *master, + struct spi_message *message) +{ + struct lantiq_ssc_spi *spi = spi_master_get_devdata(master); + + /* flush FIFOs on timeout */ + rx_fifo_flush(spi); + tx_fifo_flush(spi); +} + +static void lantiq_ssc_set_cs(struct spi_device *spidev, bool enable) +{ + struct lantiq_ssc_spi *spi = spi_master_get_devdata(spidev->master); + unsigned int cs = spidev->chip_select; + u32 fgpo; + + if (!!(spidev->mode & SPI_CS_HIGH) == enable) + fgpo = (1 << (cs - spi->base_cs)); + else + fgpo = (1 << (cs - spi->base_cs + SPI_FGPO_SETOUTN_S)); + + lantiq_ssc_writel(spi, fgpo, SPI_FPGO); +} + +static int lantiq_ssc_transfer_one(struct spi_master *master, + struct spi_device *spidev, + struct spi_transfer *t) +{ + struct lantiq_ssc_spi *spi = spi_master_get_devdata(master); + + hw_setup_transfer(spi, spidev, t); + + return transfer_start(spi, spidev, t); +} + +static const struct lantiq_ssc_hwcfg lantiq_ssc_xway = { + .irnen_r = SPI_IRNEN_R_XWAY, + .irnen_t = SPI_IRNEN_T_XWAY, +}; + +static const struct lantiq_ssc_hwcfg lantiq_ssc_xrx = { + .irnen_r = SPI_IRNEN_R_XRX, + .irnen_t = SPI_IRNEN_T_XRX, +}; + +static const struct of_device_id lantiq_ssc_match[] = { + { .compatible = "lantiq,ase-spi", .data = &lantiq_ssc_xway, }, + { .compatible = "lantiq,falcon-spi", .data = &lantiq_ssc_xrx, }, + { .compatible = "lantiq,xrx100-spi", .data = &lantiq_ssc_xrx, }, + {}, +}; +MODULE_DEVICE_TABLE(of, lantiq_ssc_match); + +static int lantiq_ssc_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct spi_master *master; + struct resource *res; + struct lantiq_ssc_spi *spi; + const struct lantiq_ssc_hwcfg *hwcfg; + const struct of_device_id *match; + int err, rx_irq, tx_irq, err_irq; + u32 id, supports_dma, revision; + unsigned int num_cs; + + match = of_match_device(lantiq_ssc_match, dev); + if (!match) { + dev_err(dev, "no device match\n"); + return -EINVAL; + } + hwcfg = match->data; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) { + dev_err(dev, "failed to get resources\n"); + return -ENXIO; + } + + rx_irq = platform_get_irq_byname(pdev, SPI_RX_IRQ_NAME); + if (rx_irq < 0) { + dev_err(dev, "failed to get %s\n", SPI_RX_IRQ_NAME); + return -ENXIO; + } + + tx_irq = platform_get_irq_byname(pdev, SPI_TX_IRQ_NAME); + if (tx_irq < 0) { + dev_err(dev, "failed to get %s\n", SPI_TX_IRQ_NAME); + return -ENXIO; + } + + err_irq = platform_get_irq_byname(pdev, SPI_ERR_IRQ_NAME); + if (err_irq < 0) { + dev_err(dev, "failed to get %s\n", SPI_ERR_IRQ_NAME); + return -ENXIO; + } + + master = spi_alloc_master(dev, sizeof(struct lantiq_ssc_spi)); + if (!master) + return -ENOMEM; + + spi = spi_master_get_devdata(master); + spi->master = master; + spi->dev = dev; + spi->hwcfg = hwcfg; + platform_set_drvdata(pdev, spi); + + spi->regbase = devm_ioremap_resource(dev, res); + if (IS_ERR(spi->regbase)) { + err = PTR_ERR(spi->regbase); + goto err_master_put; + } + + err = devm_request_irq(dev, rx_irq, lantiq_ssc_xmit_interrupt, + 0, SPI_RX_IRQ_NAME, spi); + if (err) + goto err_master_put; + + err = devm_request_irq(dev, tx_irq, lantiq_ssc_xmit_interrupt, + 0, SPI_TX_IRQ_NAME, spi); + if (err) + goto err_master_put; + + err = devm_request_irq(dev, err_irq, lantiq_ssc_err_interrupt, + 0, SPI_ERR_IRQ_NAME, spi); + if (err) + goto err_master_put; + + spi->spi_clk = devm_clk_get(dev, "gate"); + if (IS_ERR(spi->spi_clk)) { + err = PTR_ERR(spi->spi_clk); + goto err_master_put; + } + err = clk_prepare_enable(spi->spi_clk); + if (err) + goto err_master_put; + + /* + * Use the old clk_get_fpi() function on Lantiq platform, till it + * supports common clk. + */ +#if defined(CONFIG_LANTIQ) && !defined(CONFIG_COMMON_CLK) + spi->fpi_clk = clk_get_fpi(); +#else + spi->fpi_clk = clk_get(dev, "freq"); +#endif + if (IS_ERR(spi->fpi_clk)) { + err = PTR_ERR(spi->fpi_clk); + goto err_clk_disable; + } + + num_cs = 8; + of_property_read_u32(pdev->dev.of_node, "num-cs", &num_cs); + + spi->base_cs = 1; + of_property_read_u32(pdev->dev.of_node, "base-cs", &spi->base_cs); + + spin_lock_init(&spi->lock); + spi->bits_per_word = 8; + spi->speed_hz = 0; + + master->dev.of_node = pdev->dev.of_node; + master->num_chipselect = num_cs; + master->setup = lantiq_ssc_setup; + master->set_cs = lantiq_ssc_set_cs; + master->handle_err = lantiq_ssc_handle_err; + master->prepare_message = lantiq_ssc_prepare_message; + master->unprepare_message = lantiq_ssc_unprepare_message; + master->transfer_one = lantiq_ssc_transfer_one; + master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST | SPI_CS_HIGH | + SPI_LOOP; + master->bits_per_word_mask = SPI_BPW_RANGE_MASK(2, 8) | + SPI_BPW_MASK(16) | SPI_BPW_MASK(32); + + spi->wq = alloc_ordered_workqueue(dev_name(dev), 0); + if (!spi->wq) { + err = -ENOMEM; + goto err_clk_put; + } + INIT_WORK(&spi->work, lantiq_ssc_bussy_work); + + id = lantiq_ssc_readl(spi, SPI_ID); + spi->tx_fifo_size = (id & SPI_ID_TXFS_M) >> SPI_ID_TXFS_S; + spi->rx_fifo_size = (id & SPI_ID_RXFS_M) >> SPI_ID_RXFS_S; + supports_dma = (id & SPI_ID_CFG_M) >> SPI_ID_CFG_S; + revision = id & SPI_ID_REV_M; + + lantiq_ssc_hw_init(spi); + + dev_info(dev, + "Lantiq SSC SPI controller (Rev %i, TXFS %u, RXFS %u, DMA %u)\n", + revision, spi->tx_fifo_size, spi->rx_fifo_size, supports_dma); + + err = devm_spi_register_master(dev, master); + if (err) { + dev_err(dev, "failed to register spi_master\n"); + goto err_wq_destroy; + } + + return 0; + +err_wq_destroy: + destroy_workqueue(spi->wq); +err_clk_put: + clk_put(spi->fpi_clk); +err_clk_disable: + clk_disable_unprepare(spi->spi_clk); +err_master_put: + spi_master_put(master); + + return err; +} + +static int lantiq_ssc_remove(struct platform_device *pdev) +{ + struct lantiq_ssc_spi *spi = platform_get_drvdata(pdev); + + lantiq_ssc_writel(spi, 0, SPI_IRNEN); + lantiq_ssc_writel(spi, 0, SPI_CLC); + rx_fifo_flush(spi); + tx_fifo_flush(spi); + hw_enter_config_mode(spi); + + destroy_workqueue(spi->wq); + clk_disable_unprepare(spi->spi_clk); + clk_put(spi->fpi_clk); + + return 0; +} + +static struct platform_driver lantiq_ssc_driver = { + .probe = lantiq_ssc_probe, + .remove = lantiq_ssc_remove, + .driver = { + .name = "spi-lantiq-ssc", + .owner = THIS_MODULE, + .of_match_table = lantiq_ssc_match, + }, +}; +module_platform_driver(lantiq_ssc_driver); + +MODULE_DESCRIPTION("Lantiq SSC SPI controller driver"); +MODULE_AUTHOR("Daniel Schwierzeck <daniel.schwierzeck@gmail.com>"); +MODULE_AUTHOR("Hauke Mehrtens <hauke@hauke-m.de>"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:spi-lantiq-ssc"); |