diff options
Diffstat (limited to 'drivers/spi/spi-bcm2835.c')
| -rw-r--r-- | drivers/spi/spi-bcm2835.c | 69 |
1 files changed, 36 insertions, 33 deletions
diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c index e7bb27146..e709887eb 100644 --- a/drivers/spi/spi-bcm2835.c +++ b/drivers/spi/spi-bcm2835.c @@ -11,6 +11,7 @@ * spi-atmel.c, Copyright (C) 2006 Atmel Corporation */ +#include <linux/cleanup.h> #include <linux/clk.h> #include <linux/completion.h> #include <linux/debugfs.h> @@ -26,9 +27,10 @@ #include <linux/of_address.h> #include <linux/platform_device.h> #include <linux/gpio/consumer.h> -#include <linux/gpio/machine.h> /* FIXME: using chip internals */ -#include <linux/gpio/driver.h> /* FIXME: using chip internals */ +#include <linux/gpio/machine.h> /* FIXME: using GPIO lookup tables */ #include <linux/of_irq.h> +#include <linux/overflow.h> +#include <linux/slab.h> #include <linux/spi/spi.h> /* SPI register offsets */ @@ -83,6 +85,7 @@ MODULE_PARM_DESC(polling_limit_us, * struct bcm2835_spi - BCM2835 SPI controller * @regs: base address of register map * @clk: core clock, divided to calculate serial clock + * @cs_gpio: chip-select GPIO descriptor * @clk_hz: core clock cached speed * @irq: interrupt, signals TX FIFO empty or RX FIFO ¾ full * @tfr: SPI transfer currently processed @@ -117,6 +120,7 @@ MODULE_PARM_DESC(polling_limit_us, struct bcm2835_spi { void __iomem *regs; struct clk *clk; + struct gpio_desc *cs_gpio; unsigned long clk_hz; int irq; struct spi_transfer *tfr; @@ -1156,15 +1160,11 @@ static void bcm2835_spi_handle_err(struct spi_controller *ctlr, bcm2835_spi_reset_hw(bs); } -static int chip_match_name(struct gpio_chip *chip, void *data) -{ - return !strcmp(chip->label, data); -} - static void bcm2835_spi_cleanup(struct spi_device *spi) { struct bcm2835_spidev *target = spi_get_ctldata(spi); struct spi_controller *ctlr = spi->controller; + struct bcm2835_spi *bs = spi_controller_get_devdata(ctlr); if (target->clear_rx_desc) dmaengine_desc_free(target->clear_rx_desc); @@ -1175,6 +1175,9 @@ static void bcm2835_spi_cleanup(struct spi_device *spi) sizeof(u32), DMA_TO_DEVICE); + gpiod_put(bs->cs_gpio); + spi_set_csgpiod(spi, 0, NULL); + kfree(target); } @@ -1221,7 +1224,7 @@ static int bcm2835_spi_setup(struct spi_device *spi) struct spi_controller *ctlr = spi->controller; struct bcm2835_spi *bs = spi_controller_get_devdata(ctlr); struct bcm2835_spidev *target = spi_get_ctldata(spi); - struct gpio_chip *chip; + struct gpiod_lookup_table *lookup __free(kfree) = NULL; int ret; u32 cs; @@ -1288,29 +1291,36 @@ static int bcm2835_spi_setup(struct spi_device *spi) } /* - * Translate native CS to GPIO + * TODO: The code below is a slightly better alternative to the utter + * abuse of the GPIO API that I found here before. It creates a + * temporary lookup table, assigns it to the SPI device, gets the GPIO + * descriptor and then releases the lookup table. * - * FIXME: poking around in the gpiolib internals like this is - * not very good practice. Find a way to locate the real problem - * and fix it. Why is the GPIO descriptor in spi->cs_gpiod - * sometimes not assigned correctly? Erroneous device trees? + * More on the problem that it addresses: + * https://www.spinics.net/lists/linux-gpio/msg36218.html */ + lookup = kzalloc(struct_size(lookup, table, 2), GFP_KERNEL); + if (!lookup) { + ret = -ENOMEM; + goto err_cleanup; + } - /* get the gpio chip for the base */ - chip = gpiochip_find("pinctrl-bcm2835", chip_match_name); - if (!chip) - return 0; + lookup->dev_id = dev_name(&spi->dev); + lookup->table[0] = GPIO_LOOKUP("pinctrl-bcm2835", + 8 - (spi_get_chipselect(spi, 0)), + "cs", GPIO_LOOKUP_FLAGS_DEFAULT); + + gpiod_add_lookup_table(lookup); - spi_set_csgpiod(spi, 0, gpiochip_request_own_desc(chip, - 8 - (spi_get_chipselect(spi, 0)), - DRV_NAME, - GPIO_LOOKUP_FLAGS_DEFAULT, - GPIOD_OUT_LOW)); - if (IS_ERR(spi_get_csgpiod(spi, 0))) { - ret = PTR_ERR(spi_get_csgpiod(spi, 0)); + bs->cs_gpio = gpiod_get(&spi->dev, "cs", GPIOD_OUT_LOW); + gpiod_remove_lookup_table(lookup); + if (IS_ERR(bs->cs_gpio)) { + ret = PTR_ERR(bs->cs_gpio); goto err_cleanup; } + spi_set_csgpiod(spi, 0, bs->cs_gpio); + /* and set up the "mode" and level */ dev_info(&spi->dev, "setting up native-CS%i to use GPIO\n", spi_get_chipselect(spi, 0)); @@ -1352,7 +1362,7 @@ static int bcm2835_spi_probe(struct platform_device *pdev) if (IS_ERR(bs->regs)) return PTR_ERR(bs->regs); - bs->clk = devm_clk_get(&pdev->dev, NULL); + bs->clk = devm_clk_get_enabled(&pdev->dev, NULL); if (IS_ERR(bs->clk)) return dev_err_probe(&pdev->dev, PTR_ERR(bs->clk), "could not get clk\n"); @@ -1363,14 +1373,11 @@ static int bcm2835_spi_probe(struct platform_device *pdev) if (bs->irq < 0) return bs->irq; - err = clk_prepare_enable(bs->clk); - if (err) - return err; bs->clk_hz = clk_get_rate(bs->clk); err = bcm2835_dma_init(ctlr, &pdev->dev, bs); if (err) - goto out_clk_disable; + return err; /* initialise the hardware with the default polarities */ bcm2835_wr(bs, BCM2835_SPI_CS, @@ -1396,8 +1403,6 @@ static int bcm2835_spi_probe(struct platform_device *pdev) out_dma_release: bcm2835_dma_release(ctlr, bs); -out_clk_disable: - clk_disable_unprepare(bs->clk); return err; } @@ -1415,8 +1420,6 @@ static void bcm2835_spi_remove(struct platform_device *pdev) /* Clear FIFOs, and disable the HW block */ bcm2835_wr(bs, BCM2835_SPI_CS, BCM2835_SPI_CS_CLEAR_RX | BCM2835_SPI_CS_CLEAR_TX); - - clk_disable_unprepare(bs->clk); } static const struct of_device_id bcm2835_spi_match[] = { |