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spi: cadence: Convert to use CS GPIO descriptors 

This converts the Cadence SPI master driver to use GPIO
descriptors for chip select handling.

The Cadence driver was allocating a state container just
to hold the requested GPIO line and contained lots of
polarity inversion code. As this is all handled by gpiolib
and a simple devm_* request in the core, and as the driver
is fully device tree only, most of this code chunk goes
away in favour of central handling. The setup/cleanup
callbacks goes away.

This driver does NOT drive the CS line by setting the
value of the GPIO so it relies on the SPI core to do
this, which should work just fine with the descriptors.

Cc: Wei Yongjun <weiyongjun1@huawei.com>
Cc: Janek Kotas <jank@cadence.com>
Cc: Linuxarm <linuxarm@huawei.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Linus Walleij 2019-01-07 16:51:53 +01:00 committed by Mark Brown
parent efc92fbb87
commit cfeefa79dc
No known key found for this signature in database
GPG Key ID: 24D68B725D5487D0
1 changed files with 2 additions and 65 deletions
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67
drivers/spi/spi-cadence.c
View File

@ -13,7 +13,7 @@
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
@ -128,10 +128,6 @@ struct cdns_spi {
u32 is_decoded_cs;
};
struct cdns_spi_device_data {
bool gpio_requested;
};
/* Macros for the SPI controller read/write */
static inline u32 cdns_spi_read(struct cdns_spi *xspi, u32 offset)
{
@ -469,64 +465,6 @@ static int cdns_unprepare_transfer_hardware(struct spi_master *master)
return 0;
}
static int cdns_spi_setup(struct spi_device *spi)
{
int ret = -EINVAL;
struct cdns_spi_device_data *cdns_spi_data = spi_get_ctldata(spi);
/* this is a pin managed by the controller, leave it alone */
if (spi->cs_gpio == -ENOENT)
return 0;
/* this seems to be the first time we're here */
if (!cdns_spi_data) {
cdns_spi_data = kzalloc(sizeof(*cdns_spi_data), GFP_KERNEL);
if (!cdns_spi_data)
return -ENOMEM;
cdns_spi_data->gpio_requested = false;
spi_set_ctldata(spi, cdns_spi_data);
}
/* if we haven't done so, grab the gpio */
if (!cdns_spi_data->gpio_requested && gpio_is_valid(spi->cs_gpio)) {
ret = gpio_request_one(spi->cs_gpio,
(spi->mode & SPI_CS_HIGH) ?
GPIOF_OUT_INIT_LOW : GPIOF_OUT_INIT_HIGH,
dev_name(&spi->dev));
if (ret)
dev_err(&spi->dev, "can't request chipselect gpio %d\n",
spi->cs_gpio);
else
cdns_spi_data->gpio_requested = true;
} else {
if (gpio_is_valid(spi->cs_gpio)) {
int mode = ((spi->mode & SPI_CS_HIGH) ?
GPIOF_OUT_INIT_LOW : GPIOF_OUT_INIT_HIGH);
ret = gpio_direction_output(spi->cs_gpio, mode);
if (ret)
dev_err(&spi->dev, "chipselect gpio %d setup failed (%d)\n",
spi->cs_gpio, ret);
}
}
return ret;
}
static void cdns_spi_cleanup(struct spi_device *spi)
{
struct cdns_spi_device_data *cdns_spi_data = spi_get_ctldata(spi);
if (cdns_spi_data) {
if (cdns_spi_data->gpio_requested)
gpio_free(spi->cs_gpio);
kfree(cdns_spi_data);
spi_set_ctldata(spi, NULL);
}
}
/**
* cdns_spi_probe - Probe method for the SPI driver
* @pdev: Pointer to the platform_device structure
@ -621,13 +559,12 @@ static int cdns_spi_probe(struct platform_device *pdev)
goto clk_dis_all;
}
master->use_gpio_descriptors = true;
master->prepare_transfer_hardware = cdns_prepare_transfer_hardware;
master->prepare_message = cdns_prepare_message;
master->transfer_one = cdns_transfer_one;
master->unprepare_transfer_hardware = cdns_unprepare_transfer_hardware;
master->set_cs = cdns_spi_chipselect;
master->setup = cdns_spi_setup;
master->cleanup = cdns_spi_cleanup;
master->auto_runtime_pm = true;
master->mode_bits = SPI_CPOL | SPI_CPHA;