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path: root/drivers/spi/spi-gpio.c
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Diffstat (limited to 'drivers/spi/spi-gpio.c')
-rw-r--r--drivers/spi/spi-gpio.c123
1 files changed, 43 insertions, 80 deletions
diff --git a/drivers/spi/spi-gpio.c b/drivers/spi/spi-gpio.c
index 909cce109bba..ea5f1b10b79e 100644
--- a/drivers/spi/spi-gpio.c
+++ b/drivers/spi/spi-gpio.c
@@ -5,17 +5,17 @@
* Copyright (C) 2006,2008 David Brownell
* Copyright (C) 2017 Linus Walleij
*/
+#include <linux/gpio/consumer.h>
#include <linux/kernel.h>
+#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
-#include <linux/gpio/consumer.h>
-#include <linux/of.h>
+#include <linux/property.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#include <linux/spi/spi_gpio.h>
-
/*
* This bitbanging SPI host driver should help make systems usable
* when a native hardware SPI engine is not available, perhaps because
@@ -39,42 +39,14 @@ struct spi_gpio {
/*----------------------------------------------------------------------*/
-/*
- * Because the overhead of going through four GPIO procedure calls
- * per transferred bit can make performance a problem, this code
- * is set up so that you can use it in either of two ways:
- *
- * - The slow generic way: set up platform_data to hold the GPIO
- * numbers used for MISO/MOSI/SCK, and issue procedure calls for
- * each of them. This driver can handle several such busses.
- *
- * - The quicker inlined way: only helps with platform GPIO code
- * that inlines operations for constant GPIOs. This can give
- * you tight (fast!) inner loops, but each such bus needs a
- * new driver. You'll define a new C file, with Makefile and
- * Kconfig support; the C code can be a total of six lines:
- *
- * #define DRIVER_NAME "myboard_spi2"
- * #define SPI_MISO_GPIO 119
- * #define SPI_MOSI_GPIO 120
- * #define SPI_SCK_GPIO 121
- * #define SPI_N_CHIPSEL 4
- * #include "spi-gpio.c"
- */
-
-#ifndef DRIVER_NAME
#define DRIVER_NAME "spi_gpio"
-#define GENERIC_BITBANG /* vs tight inlines */
-
-#endif
-
/*----------------------------------------------------------------------*/
static inline struct spi_gpio *__pure
spi_to_spi_gpio(const struct spi_device *spi)
{
- const struct spi_bitbang *bang;
+ struct spi_bitbang *bang;
struct spi_gpio *spi_gpio;
bang = spi_controller_get_devdata(spi->controller);
@@ -236,11 +208,19 @@ static void spi_gpio_chipselect(struct spi_device *spi, int is_active)
}
}
+static void spi_gpio_set_mosi_idle(struct spi_device *spi)
+{
+ struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi);
+
+ gpiod_set_value_cansleep(spi_gpio->mosi,
+ !!(spi->mode & SPI_MOSI_IDLE_HIGH));
+}
+
static int spi_gpio_setup(struct spi_device *spi)
{
struct gpio_desc *cs;
- int status = 0;
struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi);
+ int ret;
/*
* The CS GPIOs have already been
@@ -248,15 +228,14 @@ static int spi_gpio_setup(struct spi_device *spi)
*/
if (spi_gpio->cs_gpios) {
cs = spi_gpio->cs_gpios[spi_get_chipselect(spi, 0)];
- if (!spi->controller_state && cs)
- status = gpiod_direction_output(cs,
- !(spi->mode & SPI_CS_HIGH));
+ if (!spi->controller_state && cs) {
+ ret = gpiod_direction_output(cs, !(spi->mode & SPI_CS_HIGH));
+ if (ret)
+ return ret;
+ }
}
- if (!status)
- status = spi_bitbang_setup(spi);
-
- return status;
+ return spi_bitbang_setup(spi);
}
static int spi_gpio_set_direction(struct spi_device *spi, bool output)
@@ -326,29 +305,6 @@ static int spi_gpio_request(struct device *dev, struct spi_gpio *spi_gpio)
return PTR_ERR_OR_ZERO(spi_gpio->sck);
}
-#ifdef CONFIG_OF
-static const struct of_device_id spi_gpio_dt_ids[] = {
- { .compatible = "spi-gpio" },
- {}
-};
-MODULE_DEVICE_TABLE(of, spi_gpio_dt_ids);
-
-static int spi_gpio_probe_dt(struct platform_device *pdev,
- struct spi_controller *host)
-{
- host->dev.of_node = pdev->dev.of_node;
- host->use_gpio_descriptors = true;
-
- return 0;
-}
-#else
-static inline int spi_gpio_probe_dt(struct platform_device *pdev,
- struct spi_controller *host)
-{
- return 0;
-}
-#endif
-
static int spi_gpio_probe_pdata(struct platform_device *pdev,
struct spi_controller *host)
{
@@ -357,16 +313,14 @@ static int spi_gpio_probe_pdata(struct platform_device *pdev,
struct spi_gpio *spi_gpio = spi_controller_get_devdata(host);
int i;
-#ifdef GENERIC_BITBANG
- if (!pdata || !pdata->num_chipselect)
+ if (!pdata)
return -ENODEV;
-#endif
- /*
- * The host needs to think there is a chipselect even if not
- * connected
- */
- host->num_chipselect = pdata->num_chipselect ?: 1;
+ /* It's just one always-selected device, fine to continue */
+ if (!pdata->num_chipselect)
+ return 0;
+
+ host->num_chipselect = pdata->num_chipselect;
spi_gpio->cs_gpios = devm_kcalloc(dev, host->num_chipselect,
sizeof(*spi_gpio->cs_gpios),
GFP_KERNEL);
@@ -389,19 +343,21 @@ static int spi_gpio_probe(struct platform_device *pdev)
struct spi_controller *host;
struct spi_gpio *spi_gpio;
struct device *dev = &pdev->dev;
+ struct fwnode_handle *fwnode = dev_fwnode(dev);
struct spi_bitbang *bb;
host = devm_spi_alloc_host(dev, sizeof(*spi_gpio));
if (!host)
return -ENOMEM;
- if (pdev->dev.of_node)
- status = spi_gpio_probe_dt(pdev, host);
- else
+ if (fwnode) {
+ device_set_node(&host->dev, fwnode);
+ host->use_gpio_descriptors = true;
+ } else {
status = spi_gpio_probe_pdata(pdev, host);
-
- if (status)
- return status;
+ if (status)
+ return status;
+ }
spi_gpio = spi_controller_get_devdata(host);
@@ -411,7 +367,8 @@ static int spi_gpio_probe(struct platform_device *pdev)
host->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);
host->mode_bits = SPI_3WIRE | SPI_3WIRE_HIZ | SPI_CPHA | SPI_CPOL |
- SPI_CS_HIGH | SPI_LSB_FIRST;
+ SPI_CS_HIGH | SPI_LSB_FIRST | SPI_MOSI_IDLE_LOW |
+ SPI_MOSI_IDLE_HIGH;
if (!spi_gpio->mosi) {
/* HW configuration without MOSI pin
*
@@ -436,6 +393,7 @@ static int spi_gpio_probe(struct platform_device *pdev)
host->flags |= SPI_CONTROLLER_GPIO_SS;
bb->chipselect = spi_gpio_chipselect;
bb->set_line_direction = spi_gpio_set_direction;
+ bb->set_mosi_idle = spi_gpio_set_mosi_idle;
if (host->flags & SPI_CONTROLLER_NO_TX) {
bb->txrx_word[SPI_MODE_0] = spi_gpio_spec_txrx_word_mode0;
@@ -457,12 +415,16 @@ static int spi_gpio_probe(struct platform_device *pdev)
return devm_spi_register_controller(&pdev->dev, host);
}
-MODULE_ALIAS("platform:" DRIVER_NAME);
+static const struct of_device_id spi_gpio_dt_ids[] = {
+ { .compatible = "spi-gpio" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, spi_gpio_dt_ids);
static struct platform_driver spi_gpio_driver = {
.driver = {
.name = DRIVER_NAME,
- .of_match_table = of_match_ptr(spi_gpio_dt_ids),
+ .of_match_table = spi_gpio_dt_ids,
},
.probe = spi_gpio_probe,
};
@@ -471,3 +433,4 @@ module_platform_driver(spi_gpio_driver);
MODULE_DESCRIPTION("SPI host driver using generic bitbanged GPIO ");
MODULE_AUTHOR("David Brownell");
MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRIVER_NAME);
generated by cgit (git 2.34.1) at 2025-07-13 16:12:24 +0000