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path: root/drivers/spi/spi-imx.c
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2016-03-17spi: imx: Fix possible NULL pointer derefSascha Hauer
transfer could be NULL in spi_imx_can_dma() when it's called from spi_imx_setupxfer() with a NULL transfer. Test for a NULL pointer before dereferencing it. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Cc: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Mark Brown <broonie@kernel.org>
2016-03-17spi: imx: only do necessary changes to ECSPIx_CONFIGREGKnut Wohlrab
If the SPI chip select (CS) for a dedicated channel is done manually by the used higher device driver, the CS may be active while writing to ECSPIx_CONFIGREG. To prevent unwanted clock edges when selecting the clock mode, only do the necessary changes to the i.MX SPI configuration register and leave not selected channels untouched. To prevent unwanted clock edges on first use, an empty dummy transmission shall be done by the initialization procedure of the device driver of this channel. This will set the clock mode to the correct state. Signed-off-by: Knut Wohlrab <knut.wohlrab@de.bosch.com> Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com> Acked-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Mark Brown <broonie@kernel.org>
2016-02-26spi: imx: drop bogus tests for rx/tx bufs in DMA transferSascha Hauer
The driver tries to be clever by only setting up DMA channels when the corresponding sg tables are non NULL. The sg tables are embedded structs in struct spi_transfer, so they are guaranteed to be non NULL which makes the if(tx)/if(rx) tests completely bogus. The driver even sets the SPI_MASTER_MUST_RX / SPI_MASTER_MUST_TX flags which makes sure the sg tables are not only present but also non empty. Drop the tests and make the DMA path easier to follow. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Mark Brown <broonie@kernel.org>
2016-02-26spi: imx: set MX51_ECSPI_CTRL_SMC bit in setup functionSascha Hauer
Now that the config function knows whether we are doing DMA or not we can do the necessary register setup in the config function and no longer have to do this in the trigger function. With this the trigger function becomes a no-op for DMA, so instead of testing if we are doing DMA or not in the trigger function we simply no longer call it in the DMA case. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Mark Brown <broonie@kernel.org>
2016-02-26spi: imx: make some register defines simplerSascha Hauer
The watermark levels in the DMA register are write only, the driver should never have to read them back from the hardware. Replace the current _MASK and _OFFSET defines with defines taking the watermark level directly. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Mark Brown <broonie@kernel.org>
2016-02-26spi: imx: remove unnecessary bit clearing in mx51_ecspi_configSascha Hauer
This reverts patch 1476253cef (spi: imx: fix ecspi mode setup) The patch tried to fix something by clearing bits in the cfg variable, but cfg is initialized to zero on function entry. There are no bits to clear. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Mark Brown <broonie@kernel.org>
2016-02-26spi: imx: add support for all SPI word width for DMAAnton Bondarenko
DMA transfer for SPI was limited to up to 8 bits word size until now. Sync in SPI burst size and DMA bus width is necessary to correctly support 16 and 32 BPW. Signed-off-by: Anton Bondarenko <anton.bondarenko.sama@gmail.com> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Mark Brown <broonie@kernel.org>
2016-02-26spi: imx: drop unncessary dma_is_inited variableSascha Hauer
There's no need for an extra dma_is_inited variable when we can equally well check for the existence of a DMA channel. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Mark Brown <broonie@kernel.org>
2016-02-26spi: imx: drop unnecessary read/modify/writeSascha Hauer
When the MX51_ECSPI_DMA is configured we control every single bit of the register, so there's no need to read/modify/write it. Instead just write the value we want to have in the register. Also, drop unnecessary check if we are actually doing DMA. The values written to the register have no effect in PIO mode and value written there during the last DMA transfer is still in the register, so we can equally well always write a value. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Mark Brown <broonie@kernel.org>
2016-02-26spi: imx: initialize usedma earlierSascha Hauer
The SoC specific config function does not know if DMA will be used or not. This information will be useful to configure the SPI controller correctly for DMA in following patches, so initialize the usedma variable before calling into the SoC specific config function. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Mark Brown <broonie@kernel.org>
2016-02-24spi: imx: drop fallback to PIOSascha Hauer
At the moment the driver decides to fallback to PIO mode the buffers are already mapped for DMA. It's a bug to access them with the CPU afterwards, so we cannot just fallback to PIO mode. It should not be necessary anyway, since we only use DMA when we verified that it's possible in the fist place, so when prep_slave_sg fails it's a bug, either in the SDMA driver or in the can_dma implementation. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Mark Brown <broonie@kernel.org>
2016-02-20spi: imx: replace fixed timeout with calculatedAnton Bondarenko
Fixed timeout value can fire while transaction is ongoing. This may happen because there are no strict requirements on SPI transaction duration. Dynamic timeout value is generated based on SCLK and transaction size. There is also 4 * SCLK delay between TX bursts related to HW internal CS change. Signed-off-by: Anton Bondarenko <anton.bondarenko.sama@gmail.com> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Mark Brown <broonie@kernel.org>
2016-02-20Merge remote-tracking branch 'spi/fix/imx' into spi-imxMark Brown
2016-02-18Merge tag 'spi-fix-v4.5-rc4' into spi-imxMark Brown
spi: Fixes for v4.5 A small clutch of driver specific fixes. The OMAP one is a bit worrying since it seems to be triggered by some changes in the runtime PM core code and I suspect there's other drivers across that are going to be using the same pattern outside of OMAP but nothing seems to be coming up in the testing people are doing.
2016-02-17spi: imx: use proper dev_* functions for driver messagesSascha Hauer
Add a struct device * member to the private driver data and use it to print messages using dev_* functions rather than pr_*. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Mark Brown <broonie@kernel.org>
2016-02-17spi: imx: allow only WML aligned transfers to use DMAAnton Bondarenko
RX DMA tail data handling doesn't work correctly in many cases with current implementation. It happens because SPI core was setup to generates both RX and RX TAIL events. And RX TAIL event does not work correctly. This can be easily verified by sending SPI transaction with size modulus WML(32 in our case) not equal 0. Also removing change introduced in f6ee9b582d2db652497b73c1f117591dfb6d3a90 since this change only fix usecases with transfer size from 33 to 128 bytes and doesn't fix 129 bytes and bigger. This is output from transaction with len 138 bytes in loopback mode at 10Mhz: TX0000: a3 97 a2 55 53 be f1 fc f9 79 6b 52 14 13 e9 e2 TX0010: 2d 51 8e 1f 56 08 57 27 a7 05 d4 d0 52 82 77 75 TX0020: 1b 99 4a ed 58 3d 6a 52 36 d5 24 4a 68 8e ad 95 TX0030: 5f 3c 35 b5 c4 8c dd 6c 11 32 3d e2 b4 b4 59 cf TX0040: ce 23 3d 27 df a7 f9 96 fc 1e e0 66 2c 0e 7b 8c TX0050: ca 30 42 8f bc 9f 7b ce d1 b8 b1 87 ec 8a d6 bb TX0060: 2e 15 63 0e 3c dc a4 3a 7a 06 20 a7 93 1b 34 dd TX0070: 4c f5 ec 88 96 68 d6 68 a0 09 6f 8e 93 47 c9 41 TX0080: db ac cf 97 89 f3 51 05 79 71 RX0000: a3 97 a2 55 53 be f1 fc f9 79 6b 52 14 13 e9 e2 RX0010: 2d 51 8e 1f 56 08 57 27 a7 05 d4 d0 52 82 77 75 RX0020: 1b 99 4a ed 58 3d 6a 52 36 d5 24 4a 68 8e ad 95 RX0030: 5f 3c 35 00 00 b5 00 00 00 c4 00 00 8c 00 00 dd RX0040: 6c 11 32 3d e2 b4 b4 59 cf ce 23 3d 27 df a7 f9 RX0050: 96 fc 1e e0 66 2c 0e 7b 8c ca 30 42 8f 1f 1f bc RX0060: 9f 7b ce d1 b8 b1 87 ec 8a d6 bb 2e 15 63 0e ed RX0070: ed 3c 58 58 58 dc 3d 3d a4 6a 6a 3a 52 52 7a 36 RX0080: 06 20 a7 93 1b 34 dd 4c f5 ec Zeros at offset 33 and 34 caused by reading empty RX FIFO which not possible if DMA RX read was triggered by RX event. This mean DMA was triggered by RX TAIL event. Signed-off-by: Anton Bondarenko <anton.bondarenko.sama@gmail.com> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Mark Brown <broonie@kernel.org>
2016-01-22spi: imx: fix spi resource leak with dma transferGao Pan
In spi_imx_dma_transfer(), when desc_rx = dmaengine_prep_slave_sg() fails, the context goes to label no_dma and then return. However, the memory allocated for desc_tx has not been freed yet, which leads to resource leak. Signed-off-by: Gao Pan <pandy.gao@nxp.com> Reviewed-by: Fugang Duan <B38611@freescale.com> Signed-off-by: Mark Brown <broonie@kernel.org>
2015-12-15spi: imx: defer spi initialization, if DMA engine isAnton Bondarenko
If SPI device supports DMA mode, but DMA controller is not yet available due to e.g. a delay in the corresponding kernel module initialization, retry to initialize SPI driver later on instead of falling back into PIO only mode. Signed-off-by: Anton Bondarenko <anton.bondarenko.sama@gmail.com> Signed-off-by: Mark Brown <broonie@kernel.org>
2015-12-15spi: imx: return error from dma channel requestAnton Bondarenko
On SDMA initialization return exactly the same error, which is reported by dma_request_slave_channel_reason(), it is a preceding change to defer SPI DMA initialization, if SDMA module is not yet available. Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com> Signed-off-by: Anton Bondarenko <anton.bondarenko.sama@gmail.com> Signed-off-by: Mark Brown <broonie@kernel.org>
2015-12-15spi: imx: enable loopback only for ECSPI controller familyAnton Bondarenko
Limit SPI_LOOP mode to ECSPI controller (iMX.51, iMX53 and i.MX6) only since there is no support in other families specific code for now. Signed-off-by: Anton Bondarenko <anton.bondarenko.sama@gmail.com> Signed-off-by: Mark Brown <broonie@kernel.org>
2015-12-15spi: imx: fix loopback mode setup after controller resetAnton Bondarenko
If controller hold in reset it's not possible to write any register except CTRL. So all other registers must be updated only after controller bring out from reset. Signed-off-by: Anton Bondarenko <anton.bondarenko.sama@gmail.com> Signed-off-by: Mark Brown <broonie@kernel.org>
2015-12-07spi: imx: add function to check for IMX51 family controllerAnton Bondarenko
Similar to other controller type checks add check function for IMX51. It includes IMX53 and IMX6. Signed-off-by: Anton Bondarenko <anton.bondarenko.sama@gmail.com> Signed-off-by: Mark Brown <broonie@kernel.org>
2015-12-07spi: imx: replace multiple watermarks with single for RX, TX and RXTAnton Bondarenko
There is no need to have different watermarks levels since they are the same. Merge them into one WML parameter. Signed-off-by: Anton Bondarenko <anton.bondarenko.sama@gmail.com> Signed-off-by: Mark Brown <broonie@kernel.org>
2015-12-07spi: imx: reorder HW operations enable order to avoid possible RX data lossAnton Bondarenko
The overflow may happen due to rescheduling for another task and/or interrupt if we enable SPI HW before starting RX DMA. So RX DMA enabled first to make sure data would be read out from FIFO ASAP. TX DMA enabled next to start filling TX FIFO with new data. And finaly SPI HW enabled to start actual data transfer. The risk rise in case of heavy system load and high SPI clock. Signed-off-by: Anton Bondarenko <anton.bondarenko.sama@gmail.com> Signed-off-by: Mark Brown <broonie@kernel.org>
2015-12-07spi: imx: terminate RX DMA transaction in case of TX DMA timeoutAnton Bondarenko
Not only TX DMA should be terminated, but RX DMA also. It's required to avoid accidential DMA memory writes from RX DMA channel and properly terminate transaction. Signed-off-by: Anton Bondarenko <anton.bondarenko.sama@gmail.com> Signed-off-by: Mark Brown <broonie@kernel.org>
2015-12-04spi: imx: Add loopback mode supportFabio Estevam
Loopback mode can be activated by setting bit LBC (LoopBack Control) of register ECSPI_TESTREG. Add support for it. Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com> Signed-off-by: Mark Brown <broonie@kernel.org>
2015-10-23spi: imx: fix ecspi mode setupAndrew Y. Kuksov
Fixed problem with setting spi mode 0 or 1 after setting mode 2 or 3 SPI_MODE_0 and SPI_MODE_1 requires clock low when inactive. SPI_MODE_2 and SPI_MODE_3 requires clk high when inactive. Currently driver can just set bits in fields SCLK_PHA (SPI Clock/Data Phase Control), SCLK_POL (SPI Clock Polarity Control), SCLK_CTL (controls the inactive state of SCLK) ans SS_POL (SPI SS Polarity Select) of ECSPIx_CONFIGREG register. This patch allows driver to clear corresponding bits in these fields. Signed-off-by: Andrew Y. Kuksov <qxovxp@gmail.com> Signed-off-by: Mark Brown <broonie@kernel.org>
2015-07-24spi: imx: Fix small DMA transfersSascha Hauer
DMA transfers must be greater than the watermark level size. spi_imx->rx_wml and spi_imx->tx_wml contain the watermark level in 32bit words whereas struct spi_transfer contains the transfer len in bytes. Fix the check if DMA is possible for a transfer accordingly. This fixes transfers with sizes between 33 and 128 bytes for which previously was claimed that DMA is possible. Fixes: f62caccd12c17e4 (spi: spi-imx: add DMA support) Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Cc: stable@vger.kernel.org Signed-off-by: Mark Brown <broonie@kernel.org>
2015-05-01spi: imx: Constify platform_device_idKrzysztof Kozlowski
The platform_device_id is not modified by the driver and core uses it as const. Signed-off-by: Krzysztof Kozlowski <k.kozlowski.k@gmail.com> Signed-off-by: Mark Brown <broonie@kernel.org>
2015-04-11Merge remote-tracking branches 'spi/topic/fsl-cspi', 'spi/topic/fsl-dspi', ↵Mark Brown
'spi/topic/imx' and 'spi/topic/of-id' into spi-next
2015-04-01spi: imx: read back the RX/TX watermark levels earlierLucas Stach
They are used to decide if the controller can do DMA on a buffer of a specific length and thus are needed before any transfer is attempted. This fixes a memory leak where the SPI core uses the drivers can_dma() callback to determine if a buffer needs to be mapped. As the watermark levels aren't correct at that point the driver falsely claims to be able to DMA the buffer when it fact it isn't. After the transfer has been done the core uses the same callback to determine if it needs to unmap the buffers. As the driver now correctly claims to not being able to DMA the buffer the core doesn't attempt to unmap the buffer which leaves the SGT leaking. Fixes: f62caccd12c17e4 (spi: spi-imx: add DMA support) Signed-off-by: Lucas Stach <l.stach@pengutronix.de> Signed-off-by: Mark Brown <broonie@kernel.org> Cc: stable@vger.kernel.org
2015-03-03spi: spi-imx: use correct enumeration typeStefan Agner
The fourth argument of dmaengine_prep_slave_sg needs to be of the enumeration type dma_transfer_direction instead of dma_data_direction. Since the used enumeration values actually stay the same, this is not an actual issue at runtime. Signed-off-by: Stefan Agner <stefan@agner.ch> Signed-off-by: Mark Brown <broonie@kernel.org>
2015-02-08Merge remote-tracking branches 'spi/topic/img-spfi', 'spi/topic/imx', ↵Mark Brown
'spi/topic/inline', 'spi/topic/meson' and 'spi/topic/mxs' into spi-next
2015-02-04spi: spi-imx: cleanup wait_for_completion handlingNicholas Mc Guire
return type of wait_for_completion_timeout is unsigned long not int and always returns >=0 , this patch adds a suitable return variable and simplifies the return value checking as there is no < 0 case. Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
2015-02-03spi: imx: use pio mode for i.mx6dlRobin Gong
For TKT238285 hardware issue which may cause txfifo store data twice can only be caught on i.mx6dl, we use pio mode instead of DMA mode on i.mx6dl. Fixes: f62caccd12c17e4 (spi: spi-imx: add DMA support) Signed-off-by: Robin Gong <b38343@freescale.com> Signed-off-by: Mark Brown <broonie@kernel.org> Cc: stable@vger.kernel.org
2014-12-30spi: spi-imx: Do not store the irq number in the private structureFabio Estevam
The irq number is only used inside the probe function, so there is really no need to store it in the private structure. Use a local 'irq' variable to hold the the irq number instead. Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com> Signed-off-by: Mark Brown <broonie@kernel.org>
2014-10-20spi: drop owner assignment from platform_driversWolfram Sang
A platform_driver does not need to set an owner, it will be populated by the driver core. Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2014-09-17spi: spi-imx: add DMA supportRobin Gong
Enable DMA support on i.mx6. The read speed can increase from 600KB/s to 1.2MB/s on i.mx6q. You can disable or enable dma function in dts. If not set "dma-names" in dts, spi will use PIO mode. This patch only validate on i.mx6, not i.mx5, but encourage ones to apply this patch on i.mx5 since they share the same IP. Note: Sometime, there is a weid data in rxfifo after one full tx/rx transfer finish by DMA on i.mx6dl, so we disable dma functhion on i.mx6dl. Signed-off-by: Frank Li <Frank.Li@freescale.com> Signed-off-by: Robin Gong <b38343@freescale.com> Acked-by: Marek Vasut <marex@denx.de> Signed-off-by: Mark Brown <broonie@kernel.org>
2014-03-30Merge remote-tracking branches 'spi/topic/imx', 'spi/topic/init', ↵Mark Brown
'spi/topic/mpc512x-psc', 'spi/topic/mpc52xx', 'spi/topic/mxs', 'spi/topic/nuc900', 'spi/topic/oc-tiny' and 'spi/topic/octeon' into spi-next
2014-03-30Merge remote-tracking branches 'spi/topic/bus-num', 'spi/topic/cleanup', ↵Mark Brown
'spi/topic/clps711x', 'spi/topic/coldfire', 'spi/topic/completion' and 'spi/topic/davinci' into spi-next
2014-02-28spi: spi-imx: spi_imx_remove: do not disable disabled clocksPhilippe De Muyter
Currently, at module removal, one gets the following warnings: ------------[ cut here ]------------ WARNING: at drivers/clk/clk.c:780 clk_disable+0x18/0x24() Modules linked in: spi_imx(-) [last unloaded: ev76c560] CPU: 1 PID: 16337 Comm: rmmod Tainted: G W 3.10.17-80548-g90191eb-dirty #33 [<80013b4c>] (unwind_backtrace+0x0/0xf8) from [<800115dc>] (show_stack+0x10/0x14) [<800115dc>] (show_stack+0x10/0x14) from [<800257b8>] (warn_slowpath_common+0x4c/0x68) [<800257b8>] (warn_slowpath_common+0x4c/0x68) from [<800257f0>] (warn_slowpath_null+0x1c/0x24) [<800257f0>] (warn_slowpath_null+0x1c/0x24) from [<803f60ec>] (clk_disable+0x18/0x24) [<803f60ec>] (clk_disable+0x18/0x24) from [<7f02c9cc>] (spi_imx_remove+0x54/0x9c [spi_imx]) [<7f02c9cc>] (spi_imx_remove+0x54/0x9c [spi_imx]) from [<8025868c>] (platform_drv_remove+0x18/0x1c) [<8025868c>] (platform_drv_remove+0x18/0x1c) from [<80256f60>] (__device_release_driver+0x70/0xcc) [<80256f60>] (__device_release_driver+0x70/0xcc) from [<80257770>] (driver_detach+0xcc/0xd0) [<80257770>] (driver_detach+0xcc/0xd0) from [<80256d90>] (bus_remove_driver+0x7c/0xc0) [<80256d90>] (bus_remove_driver+0x7c/0xc0) from [<80068668>] (SyS_delete_module+0x144/0x1f8) [<80068668>] (SyS_delete_module+0x144/0x1f8) from [<8000e080>] (ret_fast_syscall+0x0/0x30) ---[ end trace 1f5df9ad54996300 ]--- ------------[ cut here ]------------ WARNING: at drivers/clk/clk.c:780 clk_disable+0x18/0x24() Modules linked in: spi_imx(-) [last unloaded: ev76c560] CPU: 1 PID: 16337 Comm: rmmod Tainted: G W 3.10.17-80548-g90191eb-dirty #33 [<80013b4c>] (unwind_backtrace+0x0/0xf8) from [<800115dc>] (show_stack+0x10/0x14) [<800115dc>] (show_stack+0x10/0x14) from [<800257b8>] (warn_slowpath_common+0x4c/0x68) [<800257b8>] (warn_slowpath_common+0x4c/0x68) from [<800257f0>] (warn_slowpath_null+0x1c/0x24) [<800257f0>] (warn_slowpath_null+0x1c/0x24) from [<803f60ec>] (clk_disable+0x18/0x24) [<803f60ec>] (clk_disable+0x18/0x24) from [<7f02c9e8>] (spi_imx_remove+0x70/0x9c [spi_imx]) [<7f02c9e8>] (spi_imx_remove+0x70/0x9c [spi_imx]) from [<8025868c>] (platform_drv_remove+0x18/0x1c) [<8025868c>] (platform_drv_remove+0x18/0x1c) from [<80256f60>] (__device_release_driver+0x70/0xcc) [<80256f60>] (__device_release_driver+0x70/0xcc) from [<80257770>] (driver_detach+0xcc/0xd0) [<80257770>] (driver_detach+0xcc/0xd0) from [<80256d90>] (bus_remove_driver+0x7c/0xc0) [<80256d90>] (bus_remove_driver+0x7c/0xc0) from [<80068668>] (SyS_delete_module+0x144/0x1f8) [<80068668>] (SyS_delete_module+0x144/0x1f8) from [<8000e080>] (ret_fast_syscall+0x0/0x30) ---[ end trace 1f5df9ad54996301 ]--- Since commit 9e556dcc55774c9a1032f32baa0e5cfafede8b70, "spi: spi-imx: only enable the clocks when we start to transfer a message", clocks are always disabled except when transmitting messages. There is thus no need to disable them at module removal. Fixes: 9e556dcc55774 (spi: spi-imx: only enable the clocks when we start to transfer a message) Signed-off-by: Philippe De Muyter <phdm@macqel.be> Acked-by: Huang Shijie <b32955@freescale.com> Signed-off-by: Mark Brown <broonie@linaro.org> Cc: stable@vger.kernel.org
2014-02-23spi/imx: Use dev_name() for request_irq() to distinguish SPIsAlexander Shiyan
Signed-off-by: Alexander Shiyan <shc_work@mail.ru> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-02-14spi: spi-imx: Propagate the real error code on platform_get_irq() failureFabio Estevam
No need to return a 'fake' return value on platform_get_irq() failure. Just return the error code itself instead. Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-02-10spi: Use reinit_completion at appropriate placesAxel Lin
Calling init_completion() once is enough. For the rest of the iterations, call reinit_completion() instead. Signed-off-by: Axel Lin <axel.lin@ingics.com> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-02-03spi: delete non-required instances of include <linux/init.h>Paul Gortmaker
None of these files are actually using any __init type directives and hence don't need to include <linux/init.h>. Most are just a left over from __devinit and __cpuinit removal, or simply due to code getting copied from one driver to the next. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Mark Brown <broonie@linaro.org>
2013-12-20spi: spi-imx: Fix out-of-order CS/SCLK operation at low speedsMarek Vasut
Problem: -------- The problem this patch addresses has the following assumptions about the SPI bus setup: - The hardware used to find this is Freescale i.MX537 @ 1200MHz - The SPI SCLK operate at very low speed, less than 200 kHz - There are two SPI devices attached to the bus - Each device uses different GPIO for chipselect - Each device requires different SCLK signal polarity The observation of the SCLK and GPIO chipselect lines with a logic analyzer shows, that the SCLK polarity change does sometimes happen after the GPIO chipselect is asserted. The SPI slave device reacts on that by counting the SCLK polarity change as a clock pulse, which disrupts the communication with the SPI slave device. Explanation: ------------ We found an interesting correlation, that the maximum delay between the write into the ECSPIx_CONFIGREG register and the change of SCLK polarity at each SCLK frequency of 10 kHz, 20 kHz, 50 kHz and 100 kHz is 100 uS, 50 uS, 20 uS and 10 uS respectively. This lead us to a theory, that at SCLK frequency of 1 Hz, the delay would be 1 S. Therefore, the time it takes for the write to ECSPIx_CONFIGREG to take effect in the hardware is up to the duration of 1 tick of the SCLK clock. During this delay period, if the SCLK frequency is too low, the execution of the spi-imx.c driver can advance so much, that the GPIO chipselect will be asserted. The GPIO chipselect is asserted almost immediatelly. Solution: --------- The solution this patch presents is simple. We calculate the resulting SCLK clock first by dividing the ECSPI block clock by both dividers that are to be programmed into the configuration register. Based on the resulting SCLK clock, we derive the delay it will take for the changes to get really applied. We are extra careful here so we delay twice as long as we should. Note that the patch does not create additional overhead at high speeds as the delay will likely be close to zero there. Signed-off-by: Marek Vasut <marex@denx.de> To: linux-spi@vger.kernel.org Cc: Fabio Estevam <fabio.estevam@freescale.com> Cc: Huang Shijie <b32955@freescale.com> Cc: Mark Brown <broonie@kernel.org> Cc: Sascha Hauer <s.hauer@pengutronix.de> Cc: Shawn Guo <shawn.guo@linaro.org> Signed-off-by: Mark Brown <broonie@linaro.org>
2013-10-25Merge remote-tracking branch 'spi/topic/imx' into spi-nextMark Brown
2013-10-23spi: spi-imx: only enable the clocks when we start to transfer a messageHuang Shijie
Current code keeps the clocks enabled all the time, it wastes the power when there is no operaiton on the spi controller. In order to save the power, this patch adds the two hooks: spi_imx_prepare_message: enable the clocks for this message spi_imx_unprepare_message: disable the clocks. This patch also disables the clocks in the end of the probe. Signed-off-by: Huang Shijie <b32955@freescale.com> Signed-off-by: Mark Brown <broonie@linaro.org>
2013-09-17spi: bitbang: Let spi_bitbang_start() take a reference to masterAxel Lin
Many drivers that use bitbang library have a leak on probe error paths. This is because once a spi_master_get() call succeeds, we need an additional spi_master_put() call to free the memory. Fix this issue by moving the code taking a reference to master to spi_bitbang_start(), so spi_bitbang_start() will take a reference to master on success. With this change, the caller is responsible for calling spi_bitbang_stop() to decrement the reference and spi_master_put() as counterpart of spi_alloc_master() to prevent a memory leak. So now we have below patten for drivers using bitbang library: probe: spi_alloc_master -> Init reference count to 1 spi_bitbang_start -> Increment reference count remove: spi_bitbang_stop -> Decrement reference count spi_master_put -> Decrement reference count (reference count reaches 0) Fixup all users accordingly. Signed-off-by: Axel Lin <axel.lin@ingics.com> Suggested-by: Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de> Acked-by: Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de> Signed-off-by: Mark Brown <broonie@linaro.org>
2013-07-29spi/imx: expose module alias for loading from device-treeNiels de Vos
Enable auto loading by udev when spi-imx is compiled as a module. Signed-off-by: Niels de Vos <ndevos@redhat.com> Signed-off-by: Mark Brown <broonie@linaro.org>
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