mirror of
https://github.com/Ysurac/openmptcprouter.git
synced 2025-03-09 15:40:20 +00:00
150 lines
4.8 KiB
Diff
150 lines
4.8 KiB
Diff
From fc7ca7f1cd650398f2ca42b5fb693bc977fb5ec2 Mon Sep 17 00:00:00 2001
|
|
From: Nick Hollinghurst <nick.hollinghurst@raspberrypi.com>
|
|
Date: Wed, 1 Mar 2023 17:57:11 +0000
|
|
Subject: [PATCH] drivers: spi: Fix spi-gpio to correctly implement
|
|
sck-idle-input
|
|
|
|
Formerly, if configured using DT, CS GPIOs were driven from spi.c
|
|
and it was possible for CS to be asserted (low) *before* starting
|
|
to drive SCK. CS GPIOs have been brought under control of this
|
|
driver in both ACPI and DT cases, with a fixup for GPIO polarity.
|
|
|
|
Signed-off-by: Nick Hollinghurst <nick.hollinghurst@raspberrypi.com>
|
|
---
|
|
drivers/spi/spi-gpio.c | 74 +++++++++++++++++++++++++++++-------------
|
|
1 file changed, 51 insertions(+), 23 deletions(-)
|
|
|
|
--- a/drivers/spi/spi-gpio.c
|
|
+++ b/drivers/spi/spi-gpio.c
|
|
@@ -37,6 +37,7 @@ struct spi_gpio {
|
|
struct gpio_desc *mosi;
|
|
bool sck_idle_input;
|
|
struct gpio_desc **cs_gpios;
|
|
+ bool cs_dont_invert;
|
|
};
|
|
|
|
/*----------------------------------------------------------------------*/
|
|
@@ -233,12 +234,18 @@ static void spi_gpio_chipselect(struct s
|
|
gpiod_set_value_cansleep(spi_gpio->sck, spi->mode & SPI_CPOL);
|
|
}
|
|
|
|
- /* Drive chip select line, if we have one */
|
|
+ /*
|
|
+ * Drive chip select line, if we have one.
|
|
+ * SPI chip selects are normally active-low, but when
|
|
+ * cs_dont_invert is set, we assume their polarity is
|
|
+ * controlled by the GPIO, and write '1' to assert.
|
|
+ */
|
|
if (spi_gpio->cs_gpios) {
|
|
struct gpio_desc *cs = spi_gpio->cs_gpios[spi->chip_select];
|
|
+ int val = ((spi->mode & SPI_CS_HIGH) || spi_gpio->cs_dont_invert) ?
|
|
+ is_active : !is_active;
|
|
|
|
- /* SPI chip selects are normally active-low */
|
|
- gpiod_set_value_cansleep(cs, (spi->mode & SPI_CS_HIGH) ? is_active : !is_active);
|
|
+ gpiod_set_value_cansleep(cs, val);
|
|
}
|
|
|
|
if (spi_gpio->sck_idle_input && !is_active)
|
|
@@ -254,12 +261,14 @@ static int spi_gpio_setup(struct spi_dev
|
|
/*
|
|
* The CS GPIOs have already been
|
|
* initialized from the descriptor lookup.
|
|
+ * Here we set them to the non-asserted state.
|
|
*/
|
|
if (spi_gpio->cs_gpios) {
|
|
cs = spi_gpio->cs_gpios[spi->chip_select];
|
|
if (!spi->controller_state && cs)
|
|
status = gpiod_direction_output(cs,
|
|
- !(spi->mode & SPI_CS_HIGH));
|
|
+ !((spi->mode & SPI_CS_HIGH) ||
|
|
+ spi_gpio->cs_dont_invert));
|
|
}
|
|
|
|
if (!status)
|
|
@@ -336,6 +345,38 @@ static int spi_gpio_request(struct devic
|
|
return PTR_ERR_OR_ZERO(spi_gpio->sck);
|
|
}
|
|
|
|
+/*
|
|
+ * In order to implement "sck-idle-input" (which requires SCK
|
|
+ * direction and CS level to be switched in a particular order),
|
|
+ * we need to control GPIO chip selects from within this driver.
|
|
+ */
|
|
+
|
|
+static int spi_gpio_probe_get_cs_gpios(struct device *dev,
|
|
+ struct spi_master *master,
|
|
+ bool gpio_defines_polarity)
|
|
+{
|
|
+ int i;
|
|
+ struct spi_gpio *spi_gpio = spi_master_get_devdata(master);
|
|
+
|
|
+ spi_gpio->cs_dont_invert = gpio_defines_polarity;
|
|
+ spi_gpio->cs_gpios = devm_kcalloc(dev, master->num_chipselect,
|
|
+ sizeof(*spi_gpio->cs_gpios),
|
|
+ GFP_KERNEL);
|
|
+ if (!spi_gpio->cs_gpios)
|
|
+ return -ENOMEM;
|
|
+
|
|
+ for (i = 0; i < master->num_chipselect; i++) {
|
|
+ spi_gpio->cs_gpios[i] =
|
|
+ devm_gpiod_get_index(dev, "cs", i,
|
|
+ gpio_defines_polarity ?
|
|
+ GPIOD_OUT_LOW : GPIOD_OUT_HIGH);
|
|
+ if (IS_ERR(spi_gpio->cs_gpios[i]))
|
|
+ return PTR_ERR(spi_gpio->cs_gpios[i]);
|
|
+ }
|
|
+
|
|
+ return 0;
|
|
+}
|
|
+
|
|
#ifdef CONFIG_OF
|
|
static const struct of_device_id spi_gpio_dt_ids[] = {
|
|
{ .compatible = "spi-gpio" },
|
|
@@ -346,10 +387,12 @@ MODULE_DEVICE_TABLE(of, spi_gpio_dt_ids)
|
|
static int spi_gpio_probe_dt(struct platform_device *pdev,
|
|
struct spi_master *master)
|
|
{
|
|
- master->dev.of_node = pdev->dev.of_node;
|
|
- master->use_gpio_descriptors = true;
|
|
+ struct device *dev = &pdev->dev;
|
|
|
|
- return 0;
|
|
+ master->dev.of_node = dev->of_node;
|
|
+ master->num_chipselect = gpiod_count(dev, "cs");
|
|
+
|
|
+ return spi_gpio_probe_get_cs_gpios(dev, master, true);
|
|
}
|
|
#else
|
|
static inline int spi_gpio_probe_dt(struct platform_device *pdev,
|
|
@@ -364,8 +407,6 @@ static int spi_gpio_probe_pdata(struct p
|
|
{
|
|
struct device *dev = &pdev->dev;
|
|
struct spi_gpio_platform_data *pdata = dev_get_platdata(dev);
|
|
- struct spi_gpio *spi_gpio = spi_master_get_devdata(master);
|
|
- int i;
|
|
|
|
#ifdef GENERIC_BITBANG
|
|
if (!pdata || !pdata->num_chipselect)
|
|
@@ -377,20 +418,7 @@ static int spi_gpio_probe_pdata(struct p
|
|
*/
|
|
master->num_chipselect = pdata->num_chipselect ?: 1;
|
|
|
|
- spi_gpio->cs_gpios = devm_kcalloc(dev, master->num_chipselect,
|
|
- sizeof(*spi_gpio->cs_gpios),
|
|
- GFP_KERNEL);
|
|
- if (!spi_gpio->cs_gpios)
|
|
- return -ENOMEM;
|
|
-
|
|
- for (i = 0; i < master->num_chipselect; i++) {
|
|
- spi_gpio->cs_gpios[i] = devm_gpiod_get_index(dev, "cs", i,
|
|
- GPIOD_OUT_HIGH);
|
|
- if (IS_ERR(spi_gpio->cs_gpios[i]))
|
|
- return PTR_ERR(spi_gpio->cs_gpios[i]);
|
|
- }
|
|
-
|
|
- return 0;
|
|
+ return spi_gpio_probe_get_cs_gpios(dev, master, false);
|
|
}
|
|
|
|
static int spi_gpio_probe(struct platform_device *pdev)
|