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Subject[PATCH 06/12] spi: gpio: Don't request CS GPIO in DT use-case
Date
DT use-case already relies on SPI core to control CS (requested by
of_spi_register_master() and controlled spi_set_cs()), so there's no
need to try to request those GPIO in spi-gpio code. Change the code
such that spi-gpio's CS related code is only used if device is probed
via pdata.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Chris Healy <cphealy@gmail.com>
Cc: linux-spi@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
---
drivers/spi/spi-gpio.c | 134 ++++++++++++++++++-----------------------
1 file changed, 59 insertions(+), 75 deletions(-)

diff --git a/drivers/spi/spi-gpio.c b/drivers/spi/spi-gpio.c
index 1cff30adc836..8feb036aaf36 100644
--- a/drivers/spi/spi-gpio.c
+++ b/drivers/spi/spi-gpio.c
@@ -47,7 +47,6 @@ struct spi_gpio {
struct gpio_desc *miso;
struct gpio_desc *mosi;
struct gpio_desc **cs_gpios;
- bool has_cs;
};

/*----------------------------------------------------------------------*/
@@ -217,7 +216,7 @@ static void spi_gpio_chipselect(struct spi_device *spi, int is_active)
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 */
@@ -235,10 +234,12 @@ static int spi_gpio_setup(struct spi_device *spi)
* 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);
@@ -291,11 +292,8 @@ static void spi_gpio_cleanup(struct spi_device *spi)
*/
static int spi_gpio_request(struct device *dev,
struct spi_gpio *spi_gpio,
- unsigned int num_chipselects,
u16 *mflags)
{
- 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);
@@ -316,13 +314,6 @@ static int spi_gpio_request(struct device *dev,
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;
}

@@ -333,90 +324,87 @@ static const struct of_device_id spi_gpio_dt_ids[] = {
};
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;
-}
-#else
-static inline int spi_gpio_probe_dt(struct platform_device *pdev)
-{
return 0;
}
-#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;
struct device *dev = &pdev->dev;
struct spi_bitbang *bb;
+ const struct of_device_id *of_id;
u16 master_flags = 0;
- bool use_of = 0;
-
- status = spi_gpio_probe_dt(pdev);
- if (status < 0)
- return status;
- if (status > 0)
- use_of = 1;

- pdata = dev_get_platdata(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(dev, sizeof(*spi_gpio));
if (!master)
return -ENOMEM;

- spi_gpio = spi_master_get_devdata(master);
+ if (of_id)
+ status = spi_gpio_probe_dt(pdev, master);
+ else
+ status = spi_gpio_probe_pdata(pdev, master);

- spi_gpio->cs_gpios = devm_kcalloc(dev,
- pdata->num_chipselect,
- sizeof(*spi_gpio->cs_gpios),
- GFP_KERNEL);
- if (!spi_gpio->cs_gpios)
- return -ENOMEM;
+ if (status)
+ return status;

- platform_set_drvdata(pdev, spi_gpio);
+ spi_gpio = spi_master_get_devdata(master);

- /* Determine if we have chip selects connected */
- spi_gpio->has_cs = !!pdata->num_chipselect;
+ platform_set_drvdata(pdev, spi_gpio);

spi_gpio->pdev = pdev;

- status = spi_gpio_request(dev, spi_gpio,
- pdata->num_chipselect, &master_flags);
+ status = spi_gpio_request(dev, spi_gpio, &master_flags);
if (status)
return status;

@@ -425,13 +413,9 @@ static int spi_gpio_probe(struct platform_device *pdev)
SPI_CS_HIGH;
master->flags = master_flags;
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 = dev->of_node;
-#endif
+
bb = &spi_gpio->bitbang;
bb->master = master;
bb->chipselect = spi_gpio_chipselect;
--
2.20.1
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