From aae7147dfc522062b3448f67f5517d32fbdab1fb Mon Sep 17 00:00:00 2001 From: Murali Karicheri Date: Tue, 11 Dec 2012 16:20:39 -0500 Subject: spi/davinci: add OF support for the spi controller This adds OF support to DaVinci SPI controller to configure platform data through device bindings. Also replaces clk_enable() with of clk_prepare_enable() as well as clk_disable() with clk_disable_unprepare(). Signed-off-by: Murali Karicheri Signed-off-by: Grant Likely --- drivers/spi/spi-davinci.c | 102 +++++++++++++++++++++++++++++++++++++++------- 1 file changed, 88 insertions(+), 14 deletions(-) (limited to 'drivers/spi/spi-davinci.c') diff --git a/drivers/spi/spi-davinci.c b/drivers/spi/spi-davinci.c index 13661e129d96..50bd2cdc52de 100644 --- a/drivers/spi/spi-davinci.c +++ b/drivers/spi/spi-davinci.c @@ -28,6 +28,8 @@ #include #include #include +#include +#include #include #include #include @@ -135,7 +137,7 @@ struct davinci_spi { int dma_rx_chnum; int dma_tx_chnum; - struct davinci_spi_platform_data *pdata; + struct davinci_spi_platform_data pdata; void (*get_rx)(u32 rx_data, struct davinci_spi *); u32 (*get_tx)(struct davinci_spi *); @@ -213,7 +215,7 @@ static void davinci_spi_chipselect(struct spi_device *spi, int value) bool gpio_chipsel = false; dspi = spi_master_get_devdata(spi->master); - pdata = dspi->pdata; + pdata = &dspi->pdata; if (pdata->chip_sel && chip_sel < pdata->num_chipselect && pdata->chip_sel[chip_sel] != SPI_INTERN_CS) @@ -392,7 +394,7 @@ static int davinci_spi_setup(struct spi_device *spi) struct davinci_spi_platform_data *pdata; dspi = spi_master_get_devdata(spi->master); - pdata = dspi->pdata; + pdata = &dspi->pdata; /* if bits per word length is zero then set it default 8 */ if (!spi->bits_per_word) @@ -534,7 +536,7 @@ static int davinci_spi_bufs(struct spi_device *spi, struct spi_transfer *t) struct scatterlist sg_rx, sg_tx; dspi = spi_master_get_devdata(spi->master); - pdata = dspi->pdata; + pdata = &dspi->pdata; spicfg = (struct davinci_spi_config *)spi->controller_data; if (!spicfg) spicfg = &davinci_spi_default_cfg; @@ -758,6 +760,70 @@ rx_dma_failed: return r; } +#if defined(CONFIG_OF) +static const struct of_device_id davinci_spi_of_match[] = { + { + .compatible = "ti,dm644x-spi", + }, + { + .compatible = "ti,da8xx-spi", + .data = (void *)SPI_VERSION_2, + }, + { }, +}; +MODULE_DEVICE_TABLE(of, davini_spi_of_match); + +/** + * spi_davinci_get_pdata - Get platform data from DTS binding + * @pdev: ptr to platform data + * @dspi: ptr to driver data + * + * Parses and populates pdata in dspi from device tree bindings. + * + * NOTE: Not all platform data params are supported currently. + */ +static int spi_davinci_get_pdata(struct platform_device *pdev, + struct davinci_spi *dspi) +{ + struct device_node *node = pdev->dev.of_node; + struct davinci_spi_platform_data *pdata; + unsigned int num_cs, intr_line = 0; + const struct of_device_id *match; + + pdata = &dspi->pdata; + + pdata->version = SPI_VERSION_1; + match = of_match_device(of_match_ptr(davinci_spi_of_match), + &pdev->dev); + if (!match) + return -ENODEV; + + /* match data has the SPI version number for SPI_VERSION_2 */ + if (match->data == (void *)SPI_VERSION_2) + pdata->version = SPI_VERSION_2; + + /* + * default num_cs is 1 and all chipsel are internal to the chip + * indicated by chip_sel being NULL. GPIO based CS is not + * supported yet in DT bindings. + */ + num_cs = 1; + of_property_read_u32(node, "num-cs", &num_cs); + pdata->num_chipselect = num_cs; + of_property_read_u32(node, "ti,davinci-spi-intr-line", &intr_line); + pdata->intr_line = intr_line; + return 0; +} +#else +#define davinci_spi_of_match NULL +static struct davinci_spi_platform_data + *spi_davinci_get_pdata(struct platform_device *pdev, + struct davinci_spi *dspi) +{ + return -ENODEV; +} +#endif + /** * davinci_spi_probe - probe function for SPI Master Controller * @pdev: platform_device structure which contains plateform specific data @@ -780,12 +846,6 @@ static int davinci_spi_probe(struct platform_device *pdev) int i = 0, ret = 0; u32 spipc0; - pdata = pdev->dev.platform_data; - if (pdata == NULL) { - ret = -ENODEV; - goto err; - } - master = spi_alloc_master(&pdev->dev, sizeof(struct davinci_spi)); if (master == NULL) { ret = -ENOMEM; @@ -800,6 +860,19 @@ static int davinci_spi_probe(struct platform_device *pdev) goto free_master; } + if (pdev->dev.platform_data) { + pdata = pdev->dev.platform_data; + dspi->pdata = *pdata; + } else { + /* update dspi pdata with that from the DT */ + ret = spi_davinci_get_pdata(pdev, dspi); + if (ret < 0) + goto free_master; + } + + /* pdata in dspi is now updated and point pdata to that */ + pdata = &dspi->pdata; + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (r == NULL) { ret = -ENOENT; @@ -807,7 +880,6 @@ static int davinci_spi_probe(struct platform_device *pdev) } dspi->pbase = r->start; - dspi->pdata = pdata; mem = request_mem_region(r->start, resource_size(r), pdev->name); if (mem == NULL) { @@ -843,8 +915,9 @@ static int davinci_spi_probe(struct platform_device *pdev) ret = -ENODEV; goto put_master; } - clk_enable(dspi->clk); + clk_prepare_enable(dspi->clk); + master->dev.of_node = pdev->dev.of_node; master->bus_num = pdev->id; master->num_chipselect = pdata->num_chipselect; master->setup = davinci_spi_setup; @@ -927,7 +1000,7 @@ free_dma: dma_release_channel(dspi->dma_rx); dma_release_channel(dspi->dma_tx); free_clk: - clk_disable(dspi->clk); + clk_disable_unprepare(dspi->clk); clk_put(dspi->clk); put_master: spi_master_put(master); @@ -963,7 +1036,7 @@ static int davinci_spi_remove(struct platform_device *pdev) spi_bitbang_stop(&dspi->bitbang); - clk_disable(dspi->clk); + clk_disable_unprepare(dspi->clk); clk_put(dspi->clk); spi_master_put(master); free_irq(dspi->irq, dspi); @@ -978,6 +1051,7 @@ static struct platform_driver davinci_spi_driver = { .driver = { .name = "spi_davinci", .owner = THIS_MODULE, + .of_match_table = davinci_spi_of_match, }, .probe = davinci_spi_probe, .remove = davinci_spi_remove, -- cgit v1.2.3 From 32310aaf5c410dd3dc701556cc9bbeff0847c7c9 Mon Sep 17 00:00:00 2001 From: Murali Karicheri Date: Fri, 21 Dec 2012 15:13:26 -0500 Subject: spi/davinci: use request_threaded_irq() to fix deadlock With RT pre-empt patch applied to Linux kernel, the irq handler will be force converted to an irq thread. spi driver can get back to back messages from the slave device. In such cases, IRQ thread doesn't get a chance to run to read the slave data. Hence the irq handler must be run in hard irq context to read/write data from slave device. Otherwise, the kernel goes into a deadlock. This patch fixes this issue when PREEMPT_RT_FULL is enabled in the kernel. A dummy thread function is provided to satisfy the request_threaded_irq() API. Passing a NULL for function also causes the irq handler to be executed in the thread context. Signed-off-by: Murali Karicheri Signed-off-by: Grant Likely --- drivers/spi/spi-davinci.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) (limited to 'drivers/spi/spi-davinci.c') diff --git a/drivers/spi/spi-davinci.c b/drivers/spi/spi-davinci.c index 50bd2cdc52de..8234d2259722 100644 --- a/drivers/spi/spi-davinci.c +++ b/drivers/spi/spi-davinci.c @@ -701,6 +701,19 @@ err_alloc_dummy_buf: return ret; } +/** + * dummy_thread_fn - dummy thread function + * @irq: IRQ number for this SPI Master + * @context_data: structure for SPI Master controller davinci_spi + * + * This is to satisfy the request_threaded_irq() API so that the irq + * handler is called in interrupt context. + */ +static irqreturn_t dummy_thread_fn(s32 irq, void *data) +{ + return IRQ_HANDLED; +} + /** * davinci_spi_irq - Interrupt handler for SPI Master Controller * @irq: IRQ number for this SPI Master @@ -899,8 +912,8 @@ static int davinci_spi_probe(struct platform_device *pdev) goto unmap_io; } - ret = request_irq(dspi->irq, davinci_spi_irq, 0, dev_name(&pdev->dev), - dspi); + ret = request_threaded_irq(dspi->irq, davinci_spi_irq, dummy_thread_fn, + 0, dev_name(&pdev->dev), dspi); if (ret) goto unmap_io; -- cgit v1.2.3