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spi: Reintroduce spi_set_cs_timing()
commit4ccf359849
("spi: remove spi_set_cs_timing()"), removed the method as noboby used it. Nobody used it probably because some SPI controllers use some default large cs-setup time that covers the usual cs-setup time required by the spi devices. There are though SPI controllers that have a smaller granularity for the cs-setup time and their default value can't fulfill the spi device requirements. That's the case for the at91 QSPI IPs where the default cs-setup time is half of the QSPI clock period. This was observed when using an sst26vf064b SPI NOR flash which needs a spi-cs-setup-ns = <7>; in order to be operated close to its maximum 104 MHz frequency. Call spi_set_cs_timing() in spi_setup() just before calling spi_set_cs(), as the latter needs the CS timings already set. If spi->controller->set_cs_timing is not set, the method will return 0. There's no functional impact expected for the existing drivers. Even if the spi-mt65xx.c and spi-tegra114.c drivers set the set_cs_timing method, there's no user for them as of now. The only tested user of this support will be a SPI NOR flash that comunicates with the Atmel QSPI controller for which the support follows in the next patches. One will notice that this support is a bit different from the one that was removed in commit4ccf359849
("spi: remove spi_set_cs_timing()"), because this patch adapts to the changes done after the removal: the move of the cs delays to the spi device, the retirement of the lelgacy GPIO handling. The mutex handling was removed from spi_set_cs_timing() because we now always call spi_set_cs_timing() in spi_setup(), which already handles the spi->controller->io_mutex, so use the mutex handling from spi_setup(). Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com> Link: https://lore.kernel.org/r/20221117105249.115649-4-tudor.ambarus@microchip.com Signed-off-by: Mark Brown <broonie@kernel.org>
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@ -3621,6 +3621,37 @@ static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
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return 0;
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}
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/**
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* spi_set_cs_timing - configure CS setup, hold, and inactive delays
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* @spi: the device that requires specific CS timing configuration
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*
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* Return: zero on success, else a negative error code.
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*/
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static int spi_set_cs_timing(struct spi_device *spi)
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{
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struct device *parent = spi->controller->dev.parent;
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int status = 0;
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if (spi->controller->set_cs_timing && !spi->cs_gpiod) {
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if (spi->controller->auto_runtime_pm) {
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status = pm_runtime_get_sync(parent);
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if (status < 0) {
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pm_runtime_put_noidle(parent);
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dev_err(&spi->controller->dev, "Failed to power device: %d\n",
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status);
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return status;
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}
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status = spi->controller->set_cs_timing(spi);
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pm_runtime_mark_last_busy(parent);
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pm_runtime_put_autosuspend(parent);
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} else {
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status = spi->controller->set_cs_timing(spi);
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}
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}
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return status;
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}
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/**
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* spi_setup - setup SPI mode and clock rate
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* @spi: the device whose settings are being modified
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@ -3717,6 +3748,12 @@ int spi_setup(struct spi_device *spi)
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}
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}
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status = spi_set_cs_timing(spi);
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if (status) {
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mutex_unlock(&spi->controller->io_mutex);
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return status;
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}
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if (spi->controller->auto_runtime_pm && spi->controller->set_cs) {
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status = pm_runtime_resume_and_get(spi->controller->dev.parent);
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if (status < 0) {
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