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-bitbang.c | 131 ++++++++++++++++++++++++-------------------
1 files changed, 74 insertions(+), 57 deletions(-)
diff --git a/kernel/drivers/spi/spi-bitbang.c b/kernel/drivers/spi/spi-bitbang.c
index 06cf938..3d8948a 100644
--- a/kernel/drivers/spi/spi-bitbang.c
+++ b/kernel/drivers/spi/spi-bitbang.c
@@ -1,15 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
/*
* polling/bitbanging SPI master controller driver utilities
- *
- * 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/spinlock.h>
@@ -183,13 +174,15 @@
}
EXPORT_SYMBOL_GPL(spi_bitbang_setup_transfer);
-/**
+/*
* spi_bitbang_setup - default setup for per-word I/O loops
*/
int spi_bitbang_setup(struct spi_device *spi)
{
struct spi_bitbang_cs *cs = spi->controller_state;
struct spi_bitbang *bitbang;
+ bool initial_setup = false;
+ int retval;
bitbang = spi_master_get_devdata(spi->master);
@@ -198,39 +191,34 @@
if (!cs)
return -ENOMEM;
spi->controller_state = cs;
+ initial_setup = true;
}
/* per-word shift register access, in hardware or bitbanging */
cs->txrx_word = bitbang->txrx_word[spi->mode & (SPI_CPOL|SPI_CPHA)];
- if (!cs->txrx_word)
- return -EINVAL;
+ if (!cs->txrx_word) {
+ retval = -EINVAL;
+ goto err_free;
+ }
if (bitbang->setup_transfer) {
- int retval = bitbang->setup_transfer(spi, NULL);
+ retval = bitbang->setup_transfer(spi, NULL);
if (retval < 0)
- return retval;
+ goto err_free;
}
dev_dbg(&spi->dev, "%s, %u nsec/bit\n", __func__, 2 * cs->nsecs);
- /* NOTE we _need_ to call chipselect() early, ideally with adapter
- * setup, unless the hardware defaults cooperate to avoid confusion
- * between normal (active low) and inverted chipselects.
- */
-
- /* deselect chip (low or high) */
- mutex_lock(&bitbang->lock);
- if (!bitbang->busy) {
- bitbang->chipselect(spi, BITBANG_CS_INACTIVE);
- ndelay(cs->nsecs);
- }
- mutex_unlock(&bitbang->lock);
-
return 0;
+
+err_free:
+ if (initial_setup)
+ kfree(cs);
+ return retval;
}
EXPORT_SYMBOL_GPL(spi_bitbang_setup);
-/**
+/*
* spi_bitbang_cleanup - default cleanup for per-word I/O loops
*/
void spi_bitbang_cleanup(struct spi_device *spi)
@@ -348,6 +336,59 @@
/*----------------------------------------------------------------------*/
+int spi_bitbang_init(struct spi_bitbang *bitbang)
+{
+ struct spi_master *master = bitbang->master;
+ bool custom_cs;
+
+ if (!master)
+ return -EINVAL;
+ /*
+ * We only need the chipselect callback if we are actually using it.
+ * If we just use GPIO descriptors, it is surplus. If the
+ * SPI_MASTER_GPIO_SS flag is set, we always need to call the
+ * driver-specific chipselect routine.
+ */
+ custom_cs = (!master->use_gpio_descriptors ||
+ (master->flags & SPI_MASTER_GPIO_SS));
+
+ if (custom_cs && !bitbang->chipselect)
+ return -EINVAL;
+
+ mutex_init(&bitbang->lock);
+
+ if (!master->mode_bits)
+ master->mode_bits = SPI_CPOL | SPI_CPHA | bitbang->flags;
+
+ if (master->transfer || master->transfer_one_message)
+ return -EINVAL;
+
+ master->prepare_transfer_hardware = spi_bitbang_prepare_hardware;
+ master->unprepare_transfer_hardware = spi_bitbang_unprepare_hardware;
+ master->transfer_one = spi_bitbang_transfer_one;
+ /*
+ * When using GPIO descriptors, the ->set_cs() callback doesn't even
+ * get called unless SPI_MASTER_GPIO_SS is set.
+ */
+ if (custom_cs)
+ master->set_cs = spi_bitbang_set_cs;
+
+ if (!bitbang->txrx_bufs) {
+ bitbang->use_dma = 0;
+ bitbang->txrx_bufs = spi_bitbang_bufs;
+ if (!master->setup) {
+ if (!bitbang->setup_transfer)
+ bitbang->setup_transfer =
+ spi_bitbang_setup_transfer;
+ master->setup = spi_bitbang_setup;
+ master->cleanup = spi_bitbang_cleanup;
+ }
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(spi_bitbang_init);
+
/**
* spi_bitbang_start - start up a polled/bitbanging SPI master driver
* @bitbang: driver handle
@@ -381,33 +422,9 @@
struct spi_master *master = bitbang->master;
int ret;
- if (!master || !bitbang->chipselect)
- return -EINVAL;
-
- mutex_init(&bitbang->lock);
-
- if (!master->mode_bits)
- master->mode_bits = SPI_CPOL | SPI_CPHA | bitbang->flags;
-
- if (master->transfer || master->transfer_one_message)
- return -EINVAL;
-
- master->prepare_transfer_hardware = spi_bitbang_prepare_hardware;
- master->unprepare_transfer_hardware = spi_bitbang_unprepare_hardware;
- master->transfer_one = spi_bitbang_transfer_one;
- master->set_cs = spi_bitbang_set_cs;
-
- if (!bitbang->txrx_bufs) {
- bitbang->use_dma = 0;
- bitbang->txrx_bufs = spi_bitbang_bufs;
- if (!master->setup) {
- if (!bitbang->setup_transfer)
- bitbang->setup_transfer =
- spi_bitbang_setup_transfer;
- master->setup = spi_bitbang_setup;
- master->cleanup = spi_bitbang_cleanup;
- }
- }
+ ret = spi_bitbang_init(bitbang);
+ if (ret)
+ return ret;
/* driver may get busy before register() returns, especially
* if someone registered boardinfo for devices
@@ -420,7 +437,7 @@
}
EXPORT_SYMBOL_GPL(spi_bitbang_start);
-/**
+/*
* spi_bitbang_stop - stops the task providing spi communication
*/
void spi_bitbang_stop(struct spi_bitbang *bitbang)
--
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