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Date:	Sat, 15 Dec 2012 00:27:58 +0000
From:	Grant Likely <grant.likely@...retlab.ca>
To:	Murali Karicheri <m-karicheri2@...com>, rob.herring@...xeda.com,
	rob@...dley.net, devicetree-discuss@...ts.ozlabs.org,
	linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
	spi-devel-general@...ts.sourceforge.net,
	davinci-linux-open-source@...ux.davincidsp.com,
	linux-keystone@...t.ti.com
Cc:	Murali Karicheri <m-karicheri2@...com>
Subject: Re: [PATCH - v2] spi: davinci: add OF support for the spi controller

On Tue, 11 Dec 2012 16:20:39 -0500, Murali Karicheri <m-karicheri2@...com> wrote:
> 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 <m-karicheri2@...com>
> Reviewed-by : Grant Likely <grant.likely@...retlab.ca>

Applied, thanks.

I did remove the OF_ALIAS_N property though. I know the COMPATIBLE one
uses it, but it is actually kind of redundant since it can also be
determined by counting the number of OF_ALIAS_* entries, and having the
_N one in there means extra work needs to be done to filter it out.

Also, I had to add a #ifndef _LINUX_OF_PRIVATE_H wrapper around the
whole header file. This is needed for all header files to protect
against multiple includes.

g.

> ---
>  - Change log
>  - v2 - changed the compatibility strings to include soc name
>       -  changed ti,davinci-num-cs to num-cs
>    v1 - removed attribute for spi version. instead, compatibility string is
>          modified to include version info.
>       - pdata ptr in davinci_spi_platform_data is replaced with struct itself.
>       - spi_davinci_get_pdata() now populates the pdata in the above structure
>          with parsed values from DT bindings.
>       - rebased to v3.7 rc7 of linux-next
>       - replaces clk_* APIs with their prepare/unprepare version
>  .../devicetree/bindings/spi/spi-davinci.txt        |   51 ++++++++++
>  drivers/spi/spi-davinci.c                          |  102 +++++++++++++++++---
>  2 files changed, 139 insertions(+), 14 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/spi/spi-davinci.txt
> 
> diff --git a/Documentation/devicetree/bindings/spi/spi-davinci.txt b/Documentation/devicetree/bindings/spi/spi-davinci.txt
> new file mode 100644
> index 0000000..8cb3fee
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/spi/spi-davinci.txt
> @@ -0,0 +1,51 @@
> +Davinci SPI controller device bindings
> +
> +Required properties:
> +- #address-cells: number of cells required to define a chip select
> +	address on the SPI bus. Should be set to 1.
> +- #size-cells: should be zero.
> +- compatible:
> +	- "ti,dm644x-spi" for SPI used similar to that on DM644x SoC family
> +	- "ti,da8xx-spi" for SPI used similar to that on DA8xx SoC family
> +- reg: Offset and length of SPI controller register space
> +- num-cs: Number of chip selects
> +- ti,davinci-spi-intr-line: interrupt line used to connect the SPI
> +	IP to the interrupt controller withn the SoC. Possible values
> +	are 0 and 1. Manual says one of the two possible interrupt
> +	lines can be tied to the interrupt controller. Set this
> +	based on a specifc SoC configuration.
> +- interrupts: interrupt number offset at the irq parent
> +- clocks: spi clk phandle
> +
> +Example of a NOR flash slave device (n25q032) connected to DaVinci
> +SPI controller device over the SPI bus.
> +
> +spi0:spi@...F0000 {
> +	#address-cells			= <1>;
> +	#size-cells			= <0>;
> +	compatible			= "ti,dm644x-spi";
> +	reg				= <0x20BF0000 0x1000>;
> +	num-cs				= <4>;
> +	ti,davinci-spi-intr-line	= <0>;
> +	interrupts			= <338>;
> +	clocks				= <&clkspi>;
> +
> +	flash: n25q032@0 {
> +		#address-cells = <1>;
> +		#size-cells = <1>;
> +		compatible = "st,m25p32";
> +		spi-max-frequency = <25000000>;
> +		reg = <0>;
> +
> +		partition@0 {
> +			label = "u-boot-spl";
> +			reg = <0x0 0x80000>;
> +			read-only;
> +		};
> +
> +		partition@1 {
> +			label = "test";
> +			reg = <0x80000 0x380000>;
> +		};
> +	};
> +};
> diff --git a/drivers/spi/spi-davinci.c b/drivers/spi/spi-davinci.c
> index 147dfa8..e5d8489 100644
> --- a/drivers/spi/spi-davinci.c
> +++ b/drivers/spi/spi-davinci.c
> @@ -28,6 +28,8 @@
>  #include <linux/dmaengine.h>
>  #include <linux/dma-mapping.h>
>  #include <linux/edma.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
>  #include <linux/spi/spi.h>
>  #include <linux/spi/spi_bitbang.h>
>  #include <linux/slab.h>
> @@ -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 __devinit 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 __devinit 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 __devinit 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 __devinit 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 __devexit 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 = __devexit_p(davinci_spi_remove),
> -- 
> 1.7.9.5
> 

-- 
Grant Likely, B.Sc, P.Eng.
Secret Lab Technologies, Ltd.
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