kernel/git/stable/linux.git/drivers/spi/spi-dw.c, branch master

spi: dw: Add core suffix to the DW APB SSI core source file

2020-05-29T14:55:49+00:00

Generic DMA support is going to be part of the DW APB SSI core object. In order to preserve the kernel loadable module name as spi-dw.ko, let's add the "-core" suffix to the object with generic DW APB SSI code and build it into the target spi-dw.ko driver. Suggested-by: Andy Shevchenko Signed-off-by: Serge Semin Reviewed-by: Andy Shevchenko Cc: Georgy Vlasov Cc: Ramil Zaripov Cc: Alexey Malahov Cc: Thomas Bogendoerfer Cc: Feng Tang Cc: Rob Herring Cc: Arnd Bergmann Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200529131205.31838-10-Sergey.Semin@baikalelectronics.ru Signed-off-by: Mark Brown

spi: dw: Fix Rx-only DMA transfers

2020-05-29T14:55:48+00:00

Tx-only DMA transfers are working perfectly fine since in this case the code just ignores the Rx FIFO overflow interrupts. But it turns out the SPI Rx-only transfers are broken since nothing pushing any data to the shift registers, so the Rx FIFO is left empty and the SPI core subsystems just returns a timeout error. Since DW DMAC driver doesn't support something like cyclic write operations of a single byte to a device register, the only way to support the Rx-only SPI transfers is to fake it by using a dummy Tx-buffer. This is what we intend to fix in this commit by setting the SPI_CONTROLLER_MUST_TX flag for DMA-capable platform. Signed-off-by: Serge Semin Reviewed-by: Andy Shevchenko Cc: Georgy Vlasov Cc: Ramil Zaripov Cc: Alexey Malahov Cc: Thomas Bogendoerfer Cc: Arnd Bergmann Cc: Feng Tang Cc: Rob Herring Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200529131205.31838-9-Sergey.Semin@baikalelectronics.ru Signed-off-by: Mark Brown

spi: dw: Return any value retrieved from the dma_transfer callback

2020-05-29T14:55:42+00:00

DW APB SSI DMA-part of the driver may need to perform the requested SPI-transfer synchronously. In that case the dma_transfer() callback will return 0 as a marker of the SPI transfer being finished so the SPI core doesn't need to wait and may proceed with the SPI message trasnfers pumping procedure. This will be needed to fix the problem when DMA transactions are finished, but there is still data left in the SPI Tx/Rx FIFOs being sent/received. But for now make dma_transfer to return 1 as the normal dw_spi_transfer_one() method. Signed-off-by: Serge Semin Cc: Georgy Vlasov Cc: Ramil Zaripov Cc: Alexey Malahov Cc: Thomas Bogendoerfer Cc: Arnd Bergmann Cc: Andy Shevchenko Cc: Feng Tang Cc: Rob Herring Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200529131205.31838-3-Sergey.Semin@baikalelectronics.ru Signed-off-by: Mark Brown

spi: dw: Set xfer effective_speed_hz

2020-05-29T14:55:42+00:00

Seeing DW APB SSI controller doesn't support setting the exactly requested SPI bus frequency, but only a rounded frequency determined by means of the odd-numbered half-worded reference clock divider, it would be good to tune the SPI core up and initialize the current transfer effective_speed_hz. By doing so the core will be able to execute the xfer-related delays with better accuracy. Signed-off-by: Serge Semin Cc: Georgy Vlasov Cc: Ramil Zaripov Cc: Alexey Malahov Cc: Thomas Bogendoerfer Cc: Arnd Bergmann Cc: Feng Tang Cc: Andy Shevchenko Cc: Rob Herring Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200529131205.31838-2-Sergey.Semin@baikalelectronics.ru Signed-off-by: Mark Brown

spi: dw: Discard dma_width member of the dw_spi structure

2020-05-22T12:45:55+00:00

This member has exactly the same value as n_bytes of the DW SPI private data object, it's calculated at the same point of the transfer method, n_bytes isn't changed during the whole transfer, and they even serve for the same purpose - keep number of bytes per transfer word, though the dma_width is used only to calculate the DMA source/destination addresses width, which n_bytes could be also utilized for. Taking all of these into account let's replace the dma_width member usage with n_bytes one and remove the former. Signed-off-by: Serge Semin Reviewed-by: Andy Shevchenko Cc: Georgy Vlasov Cc: Ramil Zaripov Cc: Alexey Malahov Cc: Thomas Bogendoerfer Cc: Paul Burton Cc: Ralf Baechle Cc: Andy Shevchenko Cc: Arnd Bergmann Cc: Rob Herring Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200522000806.7381-6-Sergey.Semin@baikalelectronics.ru Signed-off-by: Mark Brown

spi: dw: Fix native CS being unset

2020-05-15T17:29:15+00:00

Commit 6e0a32d6f376 ("spi: dw: Fix default polarity of native chipselect") attempted to fix the problem when GPIO active-high chip-select is utilized to communicate with some SPI slave. It fixed the problem, but broke the normal native CS support. At the same time the reversion commit ada9e3fcc175 ("spi: dw: Correct handling of native chipselect") didn't solve the problem either, since it just inverted the set_cs() polarity perception without taking into account that CS-high might be applicable. Here is what is done to finally fix the problem. DW SPI controller demands any native CS being set in order to proceed with data transfer. So in order to activate the SPI communications we must set any bit in the Slave Select DW SPI controller register no matter whether the platform requests the GPIO- or native CS. Preferably it should be the bit corresponding to the SPI slave CS number. But currently the dw_spi_set_cs() method activates the chip-select only if the second argument is false. Since the second argument of the set_cs callback is expected to be a boolean with "is-high" semantics (actual chip-select pin state value), the bit in the DW SPI Slave Select register will be set only if SPI core requests the driver to set the CS in the low state. So this will work for active-low GPIO-based CS case, and won't work for active-high CS setting the bit when SPI core actually needs to deactivate the CS. This commit fixes the problem for all described cases. So no matter whether an SPI slave needs GPIO- or native-based CS with active-high or low signal the corresponding bit will be set in SER. Signed-off-by: Serge Semin Fixes: ada9e3fcc175 ("spi: dw: Correct handling of native chipselect") Fixes: 6e0a32d6f376 ("spi: dw: Fix default polarity of native chipselect") Reviewed-by: Charles Keepax Reviewed-by: Andy Shevchenko Acked-by: Linus Walleij Link: https://lore.kernel.org/r/20200515104758.6934-5-Sergey.Semin@baikalelectronics.ru Signed-off-by: Mark Brown

spi: dw: Get rid of dma_inited flag

2020-05-07T12:43:00+00:00

This flag is superfluous in all cases where it's being used, i.e. * ->can_dma() won't be called without dma_inited == 1 * DMA ->exit() callback can rely on txchan and rxchan variables So, get rid of dma_inited flag. Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20200507115449.8093-2-andriy.shevchenko@linux.intel.com Signed-off-by: Mark Brown

spi: dw: Propagate struct device pointer to ->dma_init() callback

2020-05-06T17:11:35+00:00

In some cases, one of which is coming soon, we would like to have a struct device pointer to request DMA channel. For this purpose propagate it to ->dma_init() callback in DMA ops. Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20200506153025.21441-7-andriy.shevchenko@linux.intel.com Signed-off-by: Mark Brown

spi: dw: Remove unused variable in CR0 configuring hooks

2020-05-06T17:11:31+00:00

After enabling new IP support in the driver couple of variables were left unused compiler is not happy about: .../spi-dw.c: In function ‘dw_spi_update_cr0’: .../spi-dw.c:264:17: warning: unused variable ‘dws’ [-Wunused-variable] 264 | struct dw_spi *dws = spi_controller_get_devdata(master); | ^~~ .../spi-dw.c: In function ‘dw_spi_update_cr0_v1_01a’: .../spi-dw.c:285:17: warning: unused variable ‘dws’ [-Wunused-variable] 285 | struct dw_spi *dws = spi_controller_get_devdata(master); | ^~~ Drop them for good. Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20200506153025.21441-2-andriy.shevchenko@linux.intel.com Signed-off-by: Mark Brown

spi: dw: Add support for DesignWare DWC_ssi

2020-05-05T14:07:59+00:00

This patch adds initial support for DesignWare DWC_ssi soft IP. DWC_ssi is the enhanced version of DW_apb_ssi, which is currently supported by this driver. Their registers are same, but the bit fields of register CTRLR0 are different. DWC_ssi has additional features compared to DW_apb_ssi. Major enhancements in DWC_ssi are hyper bus protocol, boot mode support and advanced XIP support. DWC_ssi is an AHB slave device, whilst DW_apb_ssi is an APB slave device. Register offset DW_ssi DW_apb_ssi CTRLR0 0x00 0x00 CTRLR1 0x04 0x04 SSIENR 0x08 0x08 MWCR 0x0c 0x0c SER 0x10 0x10 BAUDR 0x14 0x14 TXFTLR 0x18 0x18 RXFTLR 0x1c 0x1c TXFLR 0x20 0x20 RXFLR 0x24 0x24 SR 0x28 0x28 IMR 0x2c 0x2c ISR 0x30 0x30 RISR 0x34 0x34 TXOICR 0x38 0x38 RXOICR 0x3c 0x3c RXUICR 0x40 0x40 MSTICR 0x44 0x44 ICR 0x48 0x48 DMACR 0x4c 0x4c DMATDLR 0x50 0x50 DMARDLR 0x54 0x54 IDR 0x58 0x58 SSI_VERSION_ID 0x5c 0x5c DRx (0 to 35) 0x60+i*0x4 0x60+i*0x4 RX_SAMPLE_DLY 0xf0 0xf0 SPI_CTRLR0 0xf4 0xf4 TXD_DRIVE_EDGE 0xf8 0xf8 XIP_MODE_BITS 0xfc RSVD Register configuration - CTRLR0 DW_ssi DW_apb_ssi SPI_HYPERBUS_EN bit[24] NONE SPI_FRF bit[23:22] bit[22:21] DFS_32 NONE bit[20:16] CFS bit[19:16] bit[15:12] SSTE bit[14] bit[24] SRL bit[13] bit[11] SLV_OE bit[12] bit[10] TMOD bit[11:10] bit[9:8] SCPOL | SPHA bit[9:8] bit[7:6] FRF bit[7:6] bit[5:4] DFS bit[4:0] bit[3:0] The documents used are [1] DW_apb_ssi_databook.pdf version 4.01a (2016.10a). [2] DWC_ssi_databook.pdf version 1.01a. Signed-off-by: Wan Ahmad Zainie Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20200505130618.554-4-wan.ahmad.zainie.wan.mohamad@intel.com Signed-off-by: Mark Brown