From 1543e317f1da31b75942316931e8f491a8920811 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Thu, 04 Jan 2024 10:08:02 +0000
Subject: [PATCH] disable FB
---
kernel/drivers/spi/spi-gpio.c | 282 +++++++++++++++++++++++++------------------------------
1 files changed, 129 insertions(+), 153 deletions(-)
diff --git a/kernel/drivers/spi/spi-gpio.c b/kernel/drivers/spi/spi-gpio.c
index 341d295..3ffdab6 100644
--- a/kernel/drivers/spi/spi-gpio.c
+++ b/kernel/drivers/spi/spi-gpio.c
@@ -1,18 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
/*
* SPI master driver using generic bitbanged GPIO
*
* Copyright (C) 2006,2008 David Brownell
* Copyright (C) 2017 Linus Walleij
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
*/
#include <linux/kernel.h>
#include <linux/module.h>
@@ -35,20 +26,16 @@
* platform_device->driver_data ... points to spi_gpio
*
* spi->controller_state ... reserved for bitbang framework code
- * spi->controller_data ... holds chipselect GPIO
*
* spi->master->dev.driver_data ... points to spi_gpio->bitbang
*/
struct spi_gpio {
struct spi_bitbang bitbang;
- struct spi_gpio_platform_data pdata;
- struct platform_device *pdev;
struct gpio_desc *sck;
struct gpio_desc *miso;
struct gpio_desc *mosi;
struct gpio_desc **cs_gpios;
- bool has_cs;
};
/*----------------------------------------------------------------------*/
@@ -94,12 +81,6 @@
bang = spi_master_get_devdata(spi->master);
spi_gpio = container_of(bang, struct spi_gpio, bitbang);
return spi_gpio;
-}
-
-static inline struct spi_gpio_platform_data *__pure
-spi_to_pdata(const struct spi_device *spi)
-{
- return &spi_to_spi_gpio(spi)->pdata;
}
/* These helpers are in turn called by the bitbang inlines */
@@ -224,7 +205,7 @@
gpiod_set_value_cansleep(spi_gpio->sck, spi->mode & SPI_CPOL);
/* Drive chip select line, if we have one */
- if (spi_gpio->has_cs) {
+ if (spi_gpio->cs_gpios) {
struct gpio_desc *cs = spi_gpio->cs_gpios[spi->chip_select];
/* SPI chip selects are normally active-low */
@@ -242,10 +223,12 @@
* The CS GPIOs have already been
* initialized from the descriptor lookup.
*/
- cs = spi_gpio->cs_gpios[spi->chip_select];
- if (!spi->controller_state && cs)
- status = gpiod_direction_output(cs,
- !(spi->mode & SPI_CS_HIGH));
+ 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));
+ }
if (!status)
status = spi_bitbang_setup(spi);
@@ -256,11 +239,39 @@
static int spi_gpio_set_direction(struct spi_device *spi, bool output)
{
struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi);
+ int ret;
if (output)
return gpiod_direction_output(spi_gpio->mosi, 1);
- else
- return gpiod_direction_input(spi_gpio->mosi);
+
+ /*
+ * Only change MOSI to an input if using 3WIRE mode.
+ * Otherwise, MOSI could be left floating if there is
+ * no pull resistor connected to the I/O pin, or could
+ * be left logic high if there is a pull-up. Transmitting
+ * logic high when only clocking MISO data in can put some
+ * SPI devices in to a bad state.
+ */
+ if (spi->mode & SPI_3WIRE) {
+ ret = gpiod_direction_input(spi_gpio->mosi);
+ if (ret)
+ return ret;
+ }
+ /*
+ * Send a turnaround high impedance cycle when switching
+ * from output to input. Theoretically there should be
+ * a clock delay here, but as has been noted above, the
+ * nsec delay function for bit-banged GPIO is simply
+ * {} because bit-banging just doesn't get fast enough
+ * anyway.
+ */
+ if (spi->mode & SPI_3WIRE_HIZ) {
+ gpiod_set_value_cansleep(spi_gpio->sck,
+ !(spi->mode & SPI_CPOL));
+ gpiod_set_value_cansleep(spi_gpio->sck,
+ !!(spi->mode & SPI_CPOL));
+ }
+ return 0;
}
static void spi_gpio_cleanup(struct spi_device *spi)
@@ -278,41 +289,18 @@
* floating signals. (A weak pulldown would save power too, but many
* drivers expect to see all-ones data as the no slave "response".)
*/
-static int spi_gpio_request(struct device *dev,
- struct spi_gpio *spi_gpio,
- unsigned int num_chipselects,
- u16 *mflags)
+static int spi_gpio_request(struct device *dev, struct spi_gpio *spi_gpio)
{
- int i;
-
spi_gpio->mosi = devm_gpiod_get_optional(dev, "mosi", GPIOD_OUT_LOW);
if (IS_ERR(spi_gpio->mosi))
return PTR_ERR(spi_gpio->mosi);
- if (!spi_gpio->mosi)
- /* HW configuration without MOSI pin */
- *mflags |= SPI_MASTER_NO_TX;
spi_gpio->miso = devm_gpiod_get_optional(dev, "miso", GPIOD_IN);
if (IS_ERR(spi_gpio->miso))
return PTR_ERR(spi_gpio->miso);
- /*
- * No setting SPI_MASTER_NO_RX here - if there is only a MOSI
- * pin connected the host can still do RX by changing the
- * direction of the line.
- */
spi_gpio->sck = devm_gpiod_get(dev, "sck", GPIOD_OUT_LOW);
- if (IS_ERR(spi_gpio->sck))
- return PTR_ERR(spi_gpio->sck);
-
- for (i = 0; i < num_chipselects; 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 PTR_ERR_OR_ZERO(spi_gpio->sck);
}
#ifdef CONFIG_OF
@@ -322,139 +310,128 @@
};
MODULE_DEVICE_TABLE(of, spi_gpio_dt_ids);
-static int spi_gpio_probe_dt(struct platform_device *pdev)
+static int spi_gpio_probe_dt(struct platform_device *pdev,
+ struct spi_master *master)
{
- int ret;
- u32 tmp;
- struct spi_gpio_platform_data *pdata;
- struct device_node *np = pdev->dev.of_node;
- const struct of_device_id *of_id =
- of_match_device(spi_gpio_dt_ids, &pdev->dev);
+ master->dev.of_node = pdev->dev.of_node;
+ master->use_gpio_descriptors = true;
- if (!of_id)
- return 0;
-
- pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
- if (!pdata)
- return -ENOMEM;
-
-
- ret = of_property_read_u32(np, "num-chipselects", &tmp);
- if (ret < 0) {
- dev_err(&pdev->dev, "num-chipselects property not found\n");
- goto error_free;
- }
-
- pdata->num_chipselect = tmp;
- pdev->dev.platform_data = pdata;
-
- return 1;
-
-error_free:
- devm_kfree(&pdev->dev, pdata);
- return ret;
+ return 0;
}
#else
-static inline int spi_gpio_probe_dt(struct platform_device *pdev)
+static inline int spi_gpio_probe_dt(struct platform_device *pdev,
+ struct spi_master *master)
{
return 0;
}
#endif
+
+static int spi_gpio_probe_pdata(struct platform_device *pdev,
+ struct spi_master *master)
+{
+ 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)
+ return -ENODEV;
+#endif
+ /*
+ * The master needs to think there is a chipselect even if not
+ * connected
+ */
+ 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;
+}
static int spi_gpio_probe(struct platform_device *pdev)
{
int status;
struct spi_master *master;
struct spi_gpio *spi_gpio;
- struct spi_gpio_platform_data *pdata;
- u16 master_flags = 0;
- bool use_of = 0;
+ struct device *dev = &pdev->dev;
+ struct spi_bitbang *bb;
- status = spi_gpio_probe_dt(pdev);
- if (status < 0)
- return status;
- if (status > 0)
- use_of = 1;
-
- pdata = dev_get_platdata(&pdev->dev);
-#ifdef GENERIC_BITBANG
- if (!pdata || (!use_of && !pdata->num_chipselect))
- return -ENODEV;
-#endif
-
- master = devm_spi_alloc_master(&pdev->dev, sizeof(*spi_gpio));
+ master = devm_spi_alloc_master(dev, sizeof(*spi_gpio));
if (!master)
return -ENOMEM;
+ if (pdev->dev.of_node)
+ status = spi_gpio_probe_dt(pdev, master);
+ else
+ status = spi_gpio_probe_pdata(pdev, master);
+
+ if (status)
+ return status;
+
spi_gpio = spi_master_get_devdata(master);
- spi_gpio->cs_gpios = devm_kcalloc(&pdev->dev,
- pdata->num_chipselect,
- sizeof(*spi_gpio->cs_gpios),
- GFP_KERNEL);
- if (!spi_gpio->cs_gpios)
- return -ENOMEM;
-
- platform_set_drvdata(pdev, spi_gpio);
-
- /* Determine if we have chip selects connected */
- spi_gpio->has_cs = !!pdata->num_chipselect;
-
- spi_gpio->pdev = pdev;
- if (pdata)
- spi_gpio->pdata = *pdata;
-
- status = spi_gpio_request(&pdev->dev, spi_gpio,
- pdata->num_chipselect, &master_flags);
+ status = spi_gpio_request(dev, spi_gpio);
if (status)
return status;
master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);
- master->mode_bits = SPI_3WIRE | SPI_CPHA | SPI_CPOL | SPI_CS_HIGH;
- master->flags = master_flags;
+ master->mode_bits = SPI_3WIRE | SPI_3WIRE_HIZ | SPI_CPHA | SPI_CPOL |
+ SPI_CS_HIGH;
+ if (!spi_gpio->mosi) {
+ /* HW configuration without MOSI pin
+ *
+ * No setting SPI_MASTER_NO_RX here - if there is only
+ * a MOSI pin connected the host can still do RX by
+ * changing the direction of the line.
+ */
+ master->flags = SPI_MASTER_NO_TX;
+ }
+
master->bus_num = pdev->id;
- /* The master needs to think there is a chipselect even if not connected */
- master->num_chipselect = spi_gpio->has_cs ? pdata->num_chipselect : 1;
master->setup = spi_gpio_setup;
master->cleanup = spi_gpio_cleanup;
-#ifdef CONFIG_OF
- master->dev.of_node = pdev->dev.of_node;
-#endif
- spi_gpio->bitbang.master = master;
- spi_gpio->bitbang.chipselect = spi_gpio_chipselect;
- spi_gpio->bitbang.set_line_direction = spi_gpio_set_direction;
+ bb = &spi_gpio->bitbang;
+ bb->master = master;
+ /*
+ * There is some additional business, apart from driving the CS GPIO
+ * line, that we need to do on selection. This makes the local
+ * callback for chipselect always get called.
+ */
+ master->flags |= SPI_MASTER_GPIO_SS;
+ bb->chipselect = spi_gpio_chipselect;
+ bb->set_line_direction = spi_gpio_set_direction;
- if ((master_flags & SPI_MASTER_NO_TX) == 0) {
- spi_gpio->bitbang.txrx_word[SPI_MODE_0] = spi_gpio_txrx_word_mode0;
- spi_gpio->bitbang.txrx_word[SPI_MODE_1] = spi_gpio_txrx_word_mode1;
- spi_gpio->bitbang.txrx_word[SPI_MODE_2] = spi_gpio_txrx_word_mode2;
- spi_gpio->bitbang.txrx_word[SPI_MODE_3] = spi_gpio_txrx_word_mode3;
+ if (master->flags & SPI_MASTER_NO_TX) {
+ bb->txrx_word[SPI_MODE_0] = spi_gpio_spec_txrx_word_mode0;
+ bb->txrx_word[SPI_MODE_1] = spi_gpio_spec_txrx_word_mode1;
+ bb->txrx_word[SPI_MODE_2] = spi_gpio_spec_txrx_word_mode2;
+ bb->txrx_word[SPI_MODE_3] = spi_gpio_spec_txrx_word_mode3;
} else {
- spi_gpio->bitbang.txrx_word[SPI_MODE_0] = spi_gpio_spec_txrx_word_mode0;
- spi_gpio->bitbang.txrx_word[SPI_MODE_1] = spi_gpio_spec_txrx_word_mode1;
- spi_gpio->bitbang.txrx_word[SPI_MODE_2] = spi_gpio_spec_txrx_word_mode2;
- spi_gpio->bitbang.txrx_word[SPI_MODE_3] = spi_gpio_spec_txrx_word_mode3;
+ bb->txrx_word[SPI_MODE_0] = spi_gpio_txrx_word_mode0;
+ bb->txrx_word[SPI_MODE_1] = spi_gpio_txrx_word_mode1;
+ bb->txrx_word[SPI_MODE_2] = spi_gpio_txrx_word_mode2;
+ bb->txrx_word[SPI_MODE_3] = spi_gpio_txrx_word_mode3;
}
- spi_gpio->bitbang.setup_transfer = spi_bitbang_setup_transfer;
+ bb->setup_transfer = spi_bitbang_setup_transfer;
- return spi_bitbang_start(&spi_gpio->bitbang);
-}
+ status = spi_bitbang_init(&spi_gpio->bitbang);
+ if (status)
+ return status;
-static int spi_gpio_remove(struct platform_device *pdev)
-{
- struct spi_gpio *spi_gpio;
- struct spi_gpio_platform_data *pdata;
-
- spi_gpio = platform_get_drvdata(pdev);
- pdata = dev_get_platdata(&pdev->dev);
-
- /* stop() unregisters child devices too */
- spi_bitbang_stop(&spi_gpio->bitbang);
-
- spi_master_put(spi_gpio->bitbang.master);
-
- return 0;
+ return devm_spi_register_master(&pdev->dev, master);
}
MODULE_ALIAS("platform:" DRIVER_NAME);
@@ -465,7 +442,6 @@
.of_match_table = of_match_ptr(spi_gpio_dt_ids),
},
.probe = spi_gpio_probe,
- .remove = spi_gpio_remove,
};
module_platform_driver(spi_gpio_driver);
--
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