fix: drivers patch make raspberry pi 5 work properly

1 files changed, 70 insertions, 27 deletions

diff --git a/drivers/spi/spi-gpio.c b/drivers/spi/spi-gpio.c
index 4f192e013cd6..139641fd2329 100644
--- a/drivers/spi/spi-gpio.c
+++ b/drivers/spi/spi-gpio.c
@@ -11,6 +11,7 @@
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/property.h>
+#include <linux/delay.h>
 
 #include <linux/spi/spi.h>
 #include <linux/spi/spi_bitbang.h>
@@ -35,6 +36,8 @@ struct spi_gpio {
 	struct gpio_desc		*miso;
 	struct gpio_desc		*mosi;
 	struct gpio_desc		**cs_gpios;
+	bool				sck_idle_input;
+	bool                            cs_dont_invert;
 };
 
 /*----------------------------------------------------------------------*/
@@ -108,12 +111,18 @@ static inline int getmiso(const struct spi_device *spi)
 }
 
 /*
- * NOTE:  this clocks "as fast as we can".  It "should" be a function of the
- * requested device clock.  Software overhead means we usually have trouble
- * reaching even one Mbit/sec (except when we can inline bitops), so for now
- * we'll just assume we never need additional per-bit slowdowns.
+ * Generic bit-banged GPIO SPI might free-run at something in the range
+ * 1Mbps ~ 10Mbps (depending on the platform), and some SPI devices may
+ * need to be clocked at a lower rate. ndelay() is often implemented by
+ * udelay() with rounding up, so do the delay only for nsecs >= 500
+ * (<= 1Mbps). The conditional test adds a small overhead.
  */
-#define spidelay(nsecs)	do {} while (0)
+
+static inline void spidelay(unsigned long nsecs)
+{
+	if (nsecs >= 500)
+		ndelay(nsecs);
+}
 
 #include "spi-bitbang-txrx.h"
 
@@ -224,16 +233,29 @@ static void spi_gpio_chipselect(struct spi_device *spi, int is_active)
 	struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi);
 
 	/* set initial clock line level */
-	if (is_active)
-		gpiod_set_value_cansleep(spi_gpio->sck, spi->mode & SPI_CPOL);
+	if (is_active) {
+		if (spi_gpio->sck_idle_input)
+			gpiod_direction_output(spi_gpio->sck, spi->mode & SPI_CPOL);
+		else
+			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_get_chipselect(spi, 0)];
+		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)
+		gpiod_direction_input(spi_gpio->sck);
 }
 
 static void spi_gpio_set_mosi_idle(struct spi_device *spi)
@@ -253,11 +275,14 @@ static int spi_gpio_setup(struct spi_device *spi)
 	/*
 	 * 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_get_chipselect(spi, 0)];
 		if (!spi->controller_state && cs) {
-			ret = gpiod_direction_output(cs, !(spi->mode & SPI_CS_HIGH));
+			ret = gpiod_direction_output(cs,
+							!((spi->mode & SPI_CS_HIGH) ||
+							   spi_gpio->cs_dont_invert));
 			if (ret)
 				return ret;
 		}
@@ -329,17 +354,48 @@ static int spi_gpio_request(struct device *dev, struct spi_gpio *spi_gpio)
 	if (IS_ERR(spi_gpio->miso))
 		return PTR_ERR(spi_gpio->miso);
 
+	spi_gpio->sck_idle_input = device_property_read_bool(dev, "sck-idle-input");
 	spi_gpio->sck = devm_gpiod_get(dev, "sck", GPIOD_OUT_LOW);
 	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_controller *master,
+				       bool gpio_defines_polarity)
+{
+	int i;
+	struct spi_gpio *spi_gpio = spi_controller_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;
+}
+
 static int spi_gpio_probe_pdata(struct platform_device *pdev,
 				struct spi_controller *host)
 {
 	struct device *dev = &pdev->dev;
 	struct spi_gpio_platform_data *pdata = dev_get_platdata(dev);
-	struct spi_gpio *spi_gpio = spi_controller_get_devdata(host);
-	int i;
 
 #ifdef GENERIC_BITBANG
 	if (!pdata || !pdata->num_chipselect)
@@ -351,20 +407,7 @@ static int spi_gpio_probe_pdata(struct platform_device *pdev,
 	 */
 	host->num_chipselect = pdata->num_chipselect ?: 1;
 
-	spi_gpio->cs_gpios = devm_kcalloc(dev, host->num_chipselect,
-					  sizeof(*spi_gpio->cs_gpios),
-					  GFP_KERNEL);
-	if (!spi_gpio->cs_gpios)
-		return -ENOMEM;
-
-	for (i = 0; i < host->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, host, false);
 }
 
 static int spi_gpio_probe(struct platform_device *pdev)