+// 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>
* 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;
};
/*----------------------------------------------------------------------*/
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 */
static inline void setsck(const struct spi_device *spi, int is_on)
{
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 */
* 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);
* 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
};
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);
-
- if (!of_id)
- return 0;
+ master->dev.of_node = pdev->dev.of_node;
+ master->use_gpio_descriptors = true;
- pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
- if (!pdata)
- return -ENOMEM;
+ return 0;
+}
+#else
+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;
- 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;
- }
+#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;
- pdata->num_chipselect = tmp;
- pdev->dev.platform_data = pdata;
+ spi_gpio->cs_gpios = devm_kcalloc(dev, master->num_chipselect,
+ sizeof(*spi_gpio->cs_gpios),
+ GFP_KERNEL);
+ if (!spi_gpio->cs_gpios)
+ return -ENOMEM;
- return 1;
+ 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]);
+ }
-error_free:
- devm_kfree(&pdev->dev, pdata);
- return ret;
+ return 0;
}
-#else
-static inline int spi_gpio_probe_dt(struct platform_device *pdev)
+
+static void spi_gpio_put(void *data)
{
- return 0;
+ spi_master_put(data);
}
-#endif
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;
+ const struct of_device_id *of_id;
- 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
+ of_id = of_match_device(spi_gpio_dt_ids, &pdev->dev);
- master = spi_alloc_master(&pdev->dev, sizeof(*spi_gpio));
+ master = spi_alloc_master(dev, sizeof(*spi_gpio));
if (!master)
return -ENOMEM;
- 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;
+ status = devm_add_action_or_reset(&pdev->dev, spi_gpio_put, master);
+ if (status)
+ return status;
- platform_set_drvdata(pdev, spi_gpio);
+ if (of_id)
+ status = spi_gpio_probe_dt(pdev, master);
+ else
+ status = spi_gpio_probe_pdata(pdev, master);
- /* Determine if we have chip selects connected */
- spi_gpio->has_cs = !!pdata->num_chipselect;
+ if (status)
+ return status;
- spi_gpio->pdev = pdev;
- if (pdata)
- spi_gpio->pdata = *pdata;
+ spi_gpio = spi_master_get_devdata(master);
- 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_3WIRE_HIZ | SPI_CPHA | SPI_CPOL |
SPI_CS_HIGH;
- master->flags = master_flags;
+ 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;
-
- 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;
+ 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) {
+ 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;
- status = spi_bitbang_start(&spi_gpio->bitbang);
+ status = spi_bitbang_init(&spi_gpio->bitbang);
if (status)
- spi_master_put(master);
-
- return status;
-}
-
-static int spi_gpio_remove(struct platform_device *pdev)
-{
- struct spi_gpio *spi_gpio;
-
- spi_gpio = platform_get_drvdata(pdev);
-
- /* stop() unregisters child devices too */
- spi_bitbang_stop(&spi_gpio->bitbang);
-
- spi_master_put(spi_gpio->bitbang.master);
+ return status;
- return 0;
+ return devm_spi_register_master(&pdev->dev, spi_master_get(master));
}
MODULE_ALIAS("platform:" DRIVER_NAME);
.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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