diff options
Diffstat (limited to 'include/linux/platform_data/spi-imx.h')
| -rw-r--r-- | include/linux/platform_data/spi-imx.h | 29 |
1 files changed, 17 insertions, 12 deletions
diff --git a/include/linux/platform_data/spi-imx.h b/include/linux/platform_data/spi-imx.h index 6f012fefa1a2..328f670d10bd 100644 --- a/include/linux/platform_data/spi-imx.h +++ b/include/linux/platform_data/spi-imx.h @@ -5,24 +5,29 @@ /* * struct spi_imx_master - device.platform_data for SPI controller devices. - * @chipselect: Array of chipselects for this master. Numbers >= 0 mean gpio - * pins, numbers < 0 mean internal CSPI chipselects according - * to MXC_SPI_CS(). Normally you want to use gpio based chip - * selects as the CSPI module tries to be intelligent about - * when to assert the chipselect: The CSPI module deasserts the - * chipselect once it runs out of input data. The other problem - * is that it is not possible to mix between high active and low - * active chipselects on one single bus using the internal - * chipselects. Unfortunately Freescale decided to put some + * @chipselect: Array of chipselects for this master or NULL. Numbers >= 0 + * mean GPIO pins, -ENOENT means internal CSPI chipselect + * matching the position in the array. E.g., if chipselect[1] = + * -ENOENT then a SPI slave using chip select 1 will use the + * native SS1 line of the CSPI. Omitting the array will use + * all native chip selects. + + * Normally you want to use gpio based chip selects as the CSPI + * module tries to be intelligent about when to assert the + * chipselect: The CSPI module deasserts the chipselect once it + * runs out of input data. The other problem is that it is not + * possible to mix between high active and low active chipselects + * on one single bus using the internal chipselects. + * Unfortunately, on some SoCs, Freescale decided to put some * chipselects on dedicated pins which are not usable as gpios, * so we have to support the internal chipselects. - * @num_chipselect: ARRAY_SIZE(chipselect) + * + * @num_chipselect: If @chipselect is specified, ARRAY_SIZE(chipselect), + * otherwise the number of native chip selects. */ struct spi_imx_master { int *chipselect; int num_chipselect; }; -#define MXC_SPI_CS(no) ((no) - 32) - #endif /* __MACH_SPI_H_*/ |