1c5d0fc48b
This patch reworks the SPI access and fixes several probems: - tcan4x5x_regmap_gather_write(), tcan4x5x_regmap_read(): Do not place variable "addr" on stack and use it as buffer for SPI transfer. Buffers for SPI transfers must be allocated from DMA save memory. - tcan4x5x_regmap_gather_write(), tcan4x5x_regmap_read(): Halfe number of SPI transfers by using a single buffer + memcpy(). This improves the performance, especially on SPI controllers, which use interrupt based transfers. - Use "8" bits per word, not "32". This makes it possible to use this driver on SoCs like the Raspberry Pi, which SPI host controller drivers only support 8 bits per word. Note: this breaks half duplex only controllers. Support for them will be re-added in the next patch. Reviewed-by: Dan Murphy <dmurphy@ti.com> Tested-by: Sean Nyekjaer <sean@geanix.com> Link: https://lore.kernel.org/r/20201215231746.1132907-16-mkl@pengutronix.de Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.