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Date: Sun, 9 Jul 2017 11:30:08 +0200
From: Jan Kiszka <jan.kiszka@....de>
To: Andy Shevchenko <andy.shevchenko@...il.com>
Cc: Daniel Mack <daniel@...que.org>,
Haojian Zhuang <haojian.zhuang@...il.com>,
Robert Jarzmik <robert.jarzmik@...e.fr>,
Mark Brown <broonie@...nel.org>,
linux-spi <linux-spi@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH] spi: pxa2xx: Only claim CS GPIOs when the slave device is
created
On 2017-07-08 23:48, Andy Shevchenko wrote:
> On Sat, Jul 8, 2017 at 11:41 AM, Jan Kiszka <jan.kiszka@....de> wrote:
>> From: Jan Kiszka <jan.kiszka@...mens.com>
>>
>> Avoid hogging chip select GPIOs just because they are listed for the
>> master. They might be mulitplexed and, if no slave device is attached,
>> used for different purposes. Moreover, this strategy avoids having to
>> allocate a cs_gpiods structure.
>>
>> Tested on the IOT2000 where the second SPI bus is connected to an
>> Arduino-compatible connector and multiplexed between SPI, GPIO and PWM
>> usage.
>
> Can we first switch the driver to use GPIO descriptors instead of
> plain integers?
-ENOPARSE
>
>>
>> Signed-off-by: Jan Kiszka <jan.kiszka@...mens.com>
>> ---
>> drivers/spi/spi-pxa2xx.c | 59 +++++++++++++++++-------------------------------
>> 1 file changed, 21 insertions(+), 38 deletions(-)
>>
>> diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c
>> index 38d053682892..be991266a6ce 100644
>> --- a/drivers/spi/spi-pxa2xx.c
>> +++ b/drivers/spi/spi-pxa2xx.c
>> @@ -1213,21 +1213,33 @@ static int setup_cs(struct spi_device *spi, struct chip_data *chip,
>> struct pxa2xx_spi_chip *chip_info)
>> {
>> struct driver_data *drv_data = spi_master_get_devdata(spi->master);
>> + struct device *pdev = &drv_data->pdev->dev;
>> + struct gpio_desc *gpiod;
>> int err = 0;
>> + int count;
>>
>> if (chip == NULL)
>> return 0;
>>
>> - if (drv_data->cs_gpiods) {
>> - struct gpio_desc *gpiod;
>> + count = gpiod_count(pdev, "cs");
>> + if (count > 0) {
>> + if (spi->chip_select >= count)
>> + return -EINVAL;
>> +
>> + gpiod = gpiod_get_index(pdev, "cs", spi->chip_select,
>> + GPIOD_OUT_HIGH);
>> + if (IS_ERR(gpiod)) {
>> + /* Means use native chip select */
>> + if (PTR_ERR(gpiod) == -ENOENT)
>> + return 0;
>>
>> - gpiod = drv_data->cs_gpiods[spi->chip_select];
>> - if (gpiod) {
>> - chip->gpio_cs = desc_to_gpio(gpiod);
>> - chip->gpio_cs_inverted = spi->mode & SPI_CS_HIGH;
>> - gpiod_set_value(gpiod, chip->gpio_cs_inverted);
>> + return PTR_ERR(gpiod);
>> }
>>
>> + chip->gpio_cs = desc_to_gpio(gpiod);
>> + chip->gpio_cs_inverted = spi->mode & SPI_CS_HIGH;
>> + gpiod_set_value(gpiod, chip->gpio_cs_inverted);
>> +
>> return 0;
>> }
>>
>> @@ -1415,8 +1427,7 @@ static void cleanup(struct spi_device *spi)
>> if (!chip)
>> return;
>>
>> - if (drv_data->ssp_type != CE4100_SSP && !drv_data->cs_gpiods &&
>> - gpio_is_valid(chip->gpio_cs))
>> + if (drv_data->ssp_type != CE4100_SSP && gpio_is_valid(chip->gpio_cs))
>> gpio_free(chip->gpio_cs);
>>
>> kfree(chip);
>> @@ -1752,38 +1763,10 @@ static int pxa2xx_spi_probe(struct platform_device *pdev)
>> master->num_chipselect = platform_info->num_chipselect;
>>
>> count = gpiod_count(&pdev->dev, "cs");
>> - if (count > 0) {
>> - int i;
>> -
>> + if (count > 0)
>> master->num_chipselect = max_t(int, count,
>> master->num_chipselect);
>>
>> - drv_data->cs_gpiods = devm_kcalloc(&pdev->dev,
>> - master->num_chipselect, sizeof(struct gpio_desc *),
>> - GFP_KERNEL);
>> - if (!drv_data->cs_gpiods) {
>> - status = -ENOMEM;
>> - goto out_error_clock_enabled;
>> - }
>> -
>> - for (i = 0; i < master->num_chipselect; i++) {
>> - struct gpio_desc *gpiod;
>> -
>> - gpiod = devm_gpiod_get_index(dev, "cs", i,
>> - GPIOD_OUT_HIGH);
>> - if (IS_ERR(gpiod)) {
>> - /* Means use native chip select */
>> - if (PTR_ERR(gpiod) == -ENOENT)
>> - continue;
>> -
>> - status = (int)PTR_ERR(gpiod);
>> - goto out_error_clock_enabled;
>> - } else {
>> - drv_data->cs_gpiods[i] = gpiod;
>> - }
>> - }
>> - }
>> -
>> tasklet_init(&drv_data->pump_transfers, pump_transfers,
>> (unsigned long)drv_data);
>>
>> --
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>
>
>
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