diff options
Diffstat (limited to 'drivers/spi/spi-axi-spi-engine.c')
| -rw-r--r-- | drivers/spi/spi-axi-spi-engine.c | 68 |
1 files changed, 53 insertions, 15 deletions
diff --git a/drivers/spi/spi-axi-spi-engine.c b/drivers/spi/spi-axi-spi-engine.c index e358ac5b4509..447e5a962dee 100644 --- a/drivers/spi/spi-axi-spi-engine.c +++ b/drivers/spi/spi-axi-spi-engine.c @@ -46,6 +46,7 @@ #define SPI_ENGINE_INST_ASSERT 0x1 #define SPI_ENGINE_INST_WRITE 0x2 #define SPI_ENGINE_INST_MISC 0x3 +#define SPI_ENGINE_INST_CS_INV 0x4 #define SPI_ENGINE_CMD_REG_CLK_DIV 0x0 #define SPI_ENGINE_CMD_REG_CONFIG 0x1 @@ -73,6 +74,8 @@ SPI_ENGINE_CMD(SPI_ENGINE_INST_MISC, SPI_ENGINE_MISC_SLEEP, (delay)) #define SPI_ENGINE_CMD_SYNC(id) \ SPI_ENGINE_CMD(SPI_ENGINE_INST_MISC, SPI_ENGINE_MISC_SYNC, (id)) +#define SPI_ENGINE_CMD_CS_INV(flags) \ + SPI_ENGINE_CMD(SPI_ENGINE_INST_CS_INV, 0, (flags)) struct spi_engine_program { unsigned int length; @@ -111,6 +114,8 @@ struct spi_engine { struct spi_engine_message_state msg_state; struct completion msg_complete; unsigned int int_enable; + /* shadows hardware CS inversion flag state */ + u8 cs_inv; }; static void spi_engine_program_add_cmd(struct spi_engine_program *p, @@ -164,16 +169,20 @@ static void spi_engine_gen_xfer(struct spi_engine_program *p, bool dry, } static void spi_engine_gen_sleep(struct spi_engine_program *p, bool dry, - int delay_ns, u32 sclk_hz) + int delay_ns, int inst_ns, u32 sclk_hz) { unsigned int t; - /* negative delay indicates error, e.g. from spi_delay_to_ns() */ - if (delay_ns <= 0) + /* + * Negative delay indicates error, e.g. from spi_delay_to_ns(). And if + * delay is less that the instruction execution time, there is no need + * for an extra sleep instruction since the instruction execution time + * will already cover the required delay. + */ + if (delay_ns < 0 || delay_ns <= inst_ns) return; - /* rounding down since executing the instruction adds a couple of ticks delay */ - t = DIV_ROUND_DOWN_ULL((u64)delay_ns * sclk_hz, NSEC_PER_SEC); + t = DIV_ROUND_UP_ULL((u64)(delay_ns - inst_ns) * sclk_hz, NSEC_PER_SEC); while (t) { unsigned int n = min(t, 256U); @@ -220,10 +229,16 @@ static void spi_engine_compile_message(struct spi_message *msg, bool dry, struct spi_device *spi = msg->spi; struct spi_controller *host = spi->controller; struct spi_transfer *xfer; - int clk_div, new_clk_div; + int clk_div, new_clk_div, inst_ns; bool keep_cs = false; u8 bits_per_word = 0; + /* + * Take into account instruction execution time for more accurate sleep + * times, especially when the delay is small. + */ + inst_ns = DIV_ROUND_UP(NSEC_PER_SEC, host->max_speed_hz); + clk_div = 1; spi_engine_program_add_cmd(p, dry, @@ -252,7 +267,7 @@ static void spi_engine_compile_message(struct spi_message *msg, bool dry, spi_engine_gen_xfer(p, dry, xfer); spi_engine_gen_sleep(p, dry, spi_delay_to_ns(&xfer->delay, xfer), - xfer->effective_speed_hz); + inst_ns, xfer->effective_speed_hz); if (xfer->cs_change) { if (list_is_last(&xfer->transfer_list, &msg->transfers)) { @@ -262,7 +277,7 @@ static void spi_engine_compile_message(struct spi_message *msg, bool dry, spi_engine_gen_cs(p, dry, spi, false); spi_engine_gen_sleep(p, dry, spi_delay_to_ns( - &xfer->cs_change_delay, xfer), + &xfer->cs_change_delay, xfer), inst_ns, xfer->effective_speed_hz); if (!list_next_entry(xfer, transfer_list)->cs_off) @@ -530,6 +545,29 @@ static int spi_engine_unoptimize_message(struct spi_message *msg) return 0; } +static int spi_engine_setup(struct spi_device *device) +{ + struct spi_controller *host = device->controller; + struct spi_engine *spi_engine = spi_controller_get_devdata(host); + + if (device->mode & SPI_CS_HIGH) + spi_engine->cs_inv |= BIT(spi_get_chipselect(device, 0)); + else + spi_engine->cs_inv &= ~BIT(spi_get_chipselect(device, 0)); + + writel_relaxed(SPI_ENGINE_CMD_CS_INV(spi_engine->cs_inv), + spi_engine->base + SPI_ENGINE_REG_CMD_FIFO); + + /* + * In addition to setting the flags, we have to do a CS assert command + * to make the new setting actually take effect. + */ + writel_relaxed(SPI_ENGINE_CMD_ASSERT(0, 0xff), + spi_engine->base + SPI_ENGINE_REG_CMD_FIFO); + + return 0; +} + static int spi_engine_transfer_one_message(struct spi_controller *host, struct spi_message *msg) { @@ -653,16 +691,16 @@ static int spi_engine_probe(struct platform_device *pdev) host->unoptimize_message = spi_engine_unoptimize_message; host->num_chipselect = 8; + /* Some features depend of the IP core version. */ + if (ADI_AXI_PCORE_VER_MINOR(version) >= 2) { + host->mode_bits |= SPI_CS_HIGH; + host->setup = spi_engine_setup; + } + if (host->max_speed_hz == 0) return dev_err_probe(&pdev->dev, -EINVAL, "spi_clk rate is 0"); - ret = devm_spi_register_controller(&pdev->dev, host); - if (ret) - return ret; - - platform_set_drvdata(pdev, host); - - return 0; + return devm_spi_register_controller(&pdev->dev, host); } static const struct of_device_id spi_engine_match_table[] = { |