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spi: spi-ep93xx: simplify GPIO chip selects

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This driver requires a GPIO line to be used for the chip select of
each SPI device.

Remove the ep93xx_spi_chip_ops definition from the platform data
and use the spi core GPIO handling for the chip selects.

Fix all the ep93xx platforms that use this driver and remove the
old Documentation.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
H Hartley Sweeten
2017-02-16 13:07:37 -07:00
committed by Mark Brown
parent fafd679407
commit 55f0cd3fb9
6 changed files with 74 additions and 369 deletions
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105
Documentation/spi/ep93xx_spi
View File

@@ -1,105 +0,0 @@
Cirrus EP93xx SPI controller driver HOWTO
=========================================
ep93xx_spi driver brings SPI master support for EP93xx SPI controller. Chip
selects are implemented with GPIO lines.
NOTE: If possible, don't use SFRMOUT (SFRM1) signal as a chip select. It will
not work correctly (it cannot be controlled by software). Use GPIO lines
instead.
Sample configuration
====================
Typically driver configuration is done in platform board files (the files under
arch/arm/mach-ep93xx/*.c). In this example we configure MMC over SPI through
this driver on TS-7260 board. You can adapt the code to suit your needs.
This example uses EGPIO9 as SD/MMC card chip select (this is wired in DIO1
header on the board).
You need to select CONFIG_MMC_SPI to use mmc_spi driver.
arch/arm/mach-ep93xx/ts72xx.c:
...
#include <linux/gpio.h>
#include <linux/spi/spi.h>
#include <linux/platform_data/spi-ep93xx.h>
/* this is our GPIO line used for chip select */
#define MMC_CHIP_SELECT_GPIO EP93XX_GPIO_LINE_EGPIO9
static int ts72xx_mmc_spi_setup(struct spi_device *spi)
{
int err;
err = gpio_request(MMC_CHIP_SELECT_GPIO, spi->modalias);
if (err)
return err;
gpio_direction_output(MMC_CHIP_SELECT_GPIO, 1);
return 0;
}
static void ts72xx_mmc_spi_cleanup(struct spi_device *spi)
{
gpio_set_value(MMC_CHIP_SELECT_GPIO, 1);
gpio_direction_input(MMC_CHIP_SELECT_GPIO);
gpio_free(MMC_CHIP_SELECT_GPIO);
}
static void ts72xx_mmc_spi_cs_control(struct spi_device *spi, int value)
{
gpio_set_value(MMC_CHIP_SELECT_GPIO, value);
}
static struct ep93xx_spi_chip_ops ts72xx_mmc_spi_ops = {
.setup = ts72xx_mmc_spi_setup,
.cleanup = ts72xx_mmc_spi_cleanup,
.cs_control = ts72xx_mmc_spi_cs_control,
};
static struct spi_board_info ts72xx_spi_devices[] __initdata = {
{
.modalias = "mmc_spi",
.controller_data = &ts72xx_mmc_spi_ops,
/*
* We use 10 MHz even though the maximum is 7.4 MHz. The driver
* will limit it automatically to max. frequency.
*/
.max_speed_hz = 10 * 1000 * 1000,
.bus_num = 0,
.chip_select = 0,
.mode = SPI_MODE_0,
},
};
static struct ep93xx_spi_info ts72xx_spi_info = {
.num_chipselect = ARRAY_SIZE(ts72xx_spi_devices),
};
static void __init ts72xx_init_machine(void)
{
...
ep93xx_register_spi(&ts72xx_spi_info, ts72xx_spi_devices,
ARRAY_SIZE(ts72xx_spi_devices));
}
The driver can use DMA for the transfers also. In this case ts72xx_spi_info
becomes:
static struct ep93xx_spi_info ts72xx_spi_info = {
.num_chipselect = ARRAY_SIZE(ts72xx_spi_devices),
.use_dma = true;
};
Note that CONFIG_EP93XX_DMA should be enabled as well.
Thanks to
=========
Martin Guy, H. Hartley Sweeten and others who helped me during development of
the driver. Simplemachines.it donated me a Sim.One board which I used testing
the driver on EP9307.