Subject: Re: [PATCH net-next v3 3/4] can: cc770: add platform bus driver for the CC770 and AN82527

From: Marc Kleine-Budde <[email-masked]>
Date: Mon, 28 Nov 2011 13:33:34 +0100

On 11/28/2011 12:30 PM, Wolfgang Grandegger wrote:
> This driver works with both, static platform data and device tree
> bindings. It has been tested on a TQM855L board with two AN82527
> CAN controllers on the local bus.
> 
> CC: [email-masked]
> CC: [email-masked]
> CC: Kumar Gala <[email-masked]>
> Signed-off-by: Wolfgang Grandegger <[email-masked]>

See comment in the _remove function. Otherwise good. Add my:
Acked-by: Marc Kleine-Budde <[email-masked]>

> ---
>  .../devicetree/bindings/net/can/cc770.txt          |   56 ++++
>  drivers/net/can/cc770/Kconfig                      |    7 +
>  drivers/net/can/cc770/Makefile                     |    1 +
>  drivers/net/can/cc770/cc770_platform.c             |  280 ++++++++++++++++++++
>  4 files changed, 344 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/net/can/cc770.txt
>  create mode 100644 drivers/net/can/cc770/cc770_platform.c
> 
> diff --git a/Documentation/devicetree/bindings/net/can/cc770.txt b/Documentation/devicetree/bindings/net/can/cc770.txt
> new file mode 100644
> index 0000000..01e282d
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/net/can/cc770.txt
> @@ -0,0 +1,56 @@
> +Memory mapped Bosch CC770 and Intel AN82527 CAN controller
> +
> +Note: The CC770 is a CAN controller from Bosch, which is 100%
> +compatible with the old AN82527 from Intel, but with "bugs" being fixed.
> +
> +Required properties:
> +
> +- compatible : should be "bosch,cc770" for the CC770 and "intc,82527"
> +	for the AN82527.
> +
> +- reg : should specify the chip select, address offset and size required
> +	to map the registers of the controller. The size is usually 0x80.
> +
> +- interrupts : property with a value describing the interrupt source
> +	(number and sensitivity) required for the controller.
> +
> +Optional properties:
> +
> +- bosch,external-clock-frequency : frequency of the external oscillator
> +	clock in Hz. Note that the internal clock frequency used by the
> +	controller is half of that value. If not specified, a default
> +	value of 16000000 (16 MHz) is used.
> +
> +- bosch,clock-out-frequency : slock frequency in Hz on the CLKOUT pin.
> +	If not specified or if the specified value is 0, the CLKOUT pin
> +	will be disabled.
> +
> +- bosch,slew-rate : slew rate of the CLKOUT signal. If not specified,
> +	a resonable value will be calculated.
> +
> +- bosch,disconnect-rx0-input : see data sheet.
> +
> +- bosch,disconnect-rx1-input : see data sheet.
> +
> +- bosch,disconnect-tx1-output : see data sheet.
> +
> +- bosch,polarity-dominant : see data sheet.
> +
> +- bosch,divide-memory-clock : see data sheet.
> +
> +- bosch,iso-low-speed-mux : see data sheet.
> +
> +For further information, please have a look to the CC770 or AN82527.
> +
> +Examples:
> +
> +can@3,100 {
> +	compatible = "bosch,cc770";
> +	reg = <3 0x100 0x80>;
> +	interrupts = <2 0>;
> +	interrupt-parent = <&mpic>;
> +	bosch,external-clock-frequency = <16000000>;
> +};
> +
> +
> +
> diff --git a/drivers/net/can/cc770/Kconfig b/drivers/net/can/cc770/Kconfig
> index 28e4d48..22c07a8 100644
> --- a/drivers/net/can/cc770/Kconfig
> +++ b/drivers/net/can/cc770/Kconfig
> @@ -11,4 +11,11 @@ config CAN_CC770_ISA
>  	  connected to the ISA bus using I/O port, memory mapped or
>  	  indirect access.
>  
> +config CAN_CC770_PLATFORM
> +	tristate "Generic Platform Bus based CC770 driver"
> +	---help---
> +	  This driver adds support for the CC770 and AN82527 chips
> +	  connected to the "platform bus" (Linux abstraction for directly
> +	  to the processor attached devices).
> +
>  endif
> diff --git a/drivers/net/can/cc770/Makefile b/drivers/net/can/cc770/Makefile
> index 872ecff..9fb8321 100644
> --- a/drivers/net/can/cc770/Makefile
> +++ b/drivers/net/can/cc770/Makefile
> @@ -4,5 +4,6 @@
>  
>  obj-$(CONFIG_CAN_CC770) += cc770.o
>  obj-$(CONFIG_CAN_CC770_ISA) += cc770_isa.o
> +obj-$(CONFIG_CAN_CC770_PLATFORM) += cc770_platform.o
>  
>  ccflags-$(CONFIG_CAN_DEBUG_DEVICES) := -DDEBUG
> diff --git a/drivers/net/can/cc770/cc770_platform.c b/drivers/net/can/cc770/cc770_platform.c
> new file mode 100644
> index 0000000..65e177e
> --- /dev/null
> +++ b/drivers/net/can/cc770/cc770_platform.c
> @@ -0,0 +1,280 @@
> +/*
> + * Driver for CC770 and AN82527 CAN controllers on the platform bus
> + *
> + * Copyright (C) 2009, 2011 Wolfgang Grandegger <[email-masked]>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the version 2 of the GNU General Public License
> + * as published by the Free Software Foundation
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software Foundation,
> + * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

please remove the address.

> + */
> +
> +/*
> + * If platform data are used you should have similar definitions
> + * in your board-specific code:
> + *
> + *   static struct cc770_platform_data myboard_cc770_pdata = {
> + *           .osc_freq = 16000000,
> + *           .cir = 0x41,
> + *           .cor = 0x20,
> + *           .bcr = 0x40,
> + *   };
> + *
> + * Please see include/linux/can/platform/cc770.h for description of
> + * above fields.
> + *
> + * If the device tree is used, you need a CAN node definition in your
> + * DTS file similar to:
> + *
> + *   can@3,100 {
> + *           compatible = "bosch,cc770";
> + *           reg = <3 0x100 0x80>;
> + *           interrupts = <2 0>;
> + *           interrupt-parent = <&mpic>;
> + *           bosch,external-clock-frequency = <16000000>;
> + *   };
> + *
> + * See "Documentation/devicetree/bindings/net/can/cc770.txt" for further
> + * information.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/interrupt.h>
> +#include <linux/netdevice.h>
> +#include <linux/delay.h>
> +#include <linux/can.h>
> +#include <linux/can/dev.h>
> +#include <linux/can/platform/cc770.h>
> +
> +#include <linux/of_platform.h>
> +
> +#include "cc770.h"
> +
> +#define DRV_NAME "cc770_platform"
> +
> +MODULE_AUTHOR("Wolfgang Grandegger <[email-masked]>");
> +MODULE_DESCRIPTION("Socket-CAN driver for CC770 on the platform bus");
> +MODULE_LICENSE("GPL v2");
> +
> +#define CC770_PLATFORM_CAN_CLOCK  16000000
> +
> +static u8 cc770_platform_read_reg(const struct cc770_priv *priv, int reg)
> +{
> +	return in_8(priv->reg_base + reg);
> +}
> +
> +static void cc770_platform_write_reg(const struct cc770_priv *priv, int reg,
> +				     u8 val)
> +{
> +	out_8(priv->reg_base + reg, val);
> +}
> +
> +static int __devinit cc770_get_of_node_data(struct platform_device *pdev,
> +					    struct cc770_priv *priv)
> +{
> +	struct device_node *np = pdev->dev.of_node;
> +	const u32 *prop;
> +	int prop_size;
> +	u32 clkext;
> +
> +	prop = of_get_property(np, "bosch,external-clock-frequency",
> +			       &prop_size);
> +	if (prop && (prop_size ==  sizeof(u32)))
> +		clkext = *prop;
> +	else
> +		clkext = CC770_PLATFORM_CAN_CLOCK; /* default */
> +	priv->can.clock.freq = clkext;
> +
> +	/* The system clock may not exceed 10 MHz */
> +	if (priv->can.clock.freq > 10000000) {
> +		priv->cpu_interface |= CPUIF_DSC;
> +		priv->can.clock.freq /= 2;
> +	}
> +
> +	/* The memory clock may not exceed 8 MHz */
> +	if (priv->can.clock.freq > 8000000)
> +		priv->cpu_interface |= CPUIF_DMC;
> +
> +	if (of_get_property(np, "bosch,divide-memory-clock", NULL))
> +		priv->cpu_interface |= CPUIF_DMC;
> +	if (of_get_property(np, "bosch,iso-low-speed-mux", NULL))
> +		priv->cpu_interface |= CPUIF_MUX;
> +
> +	if (!of_get_property(np, "bosch,no-comperator-bypass", NULL))
> +		priv->bus_config |= BUSCFG_CBY;
> +	if (of_get_property(np, "bosch,disconnect-rx0-input", NULL))
> +		priv->bus_config |= BUSCFG_DR0;
> +	if (of_get_property(np, "bosch,disconnect-rx1-input", NULL))
> +		priv->bus_config |= BUSCFG_DR1;
> +	if (of_get_property(np, "bosch,disconnect-tx1-output", NULL))
> +		priv->bus_config |= BUSCFG_DT1;
> +	if (of_get_property(np, "bosch,polarity-dominant", NULL))
> +		priv->bus_config |= BUSCFG_POL;
> +
> +	prop = of_get_property(np, "bosch,clock-out-frequency", &prop_size);
> +	if (prop && (prop_size == sizeof(u32)) && *prop > 0) {
> +		u32 cdv = clkext / *prop;
> +		int slew;
> +
> +		if (cdv > 0 && cdv < 16) {
> +			priv->cpu_interface |= CPUIF_CEN;
> +			priv->clkout |= (cdv - 1) & CLKOUT_CD_MASK;
> +
> +			prop = of_get_property(np, "bosch,slew-rate",
> +					       &prop_size);
> +			if (prop && (prop_size == sizeof(u32))) {
> +				slew = *prop;
> +			} else {
> +				/* Determine default slew rate */
> +				slew = (CLKOUT_SL_MASK >>
> +					CLKOUT_SL_SHIFT) -
> +					((cdv * clkext - 1) / 8000000);
> +				if (slew < 0)
> +					slew = 0;
> +			}
> +			priv->clkout |= (slew << CLKOUT_SL_SHIFT) &
> +				CLKOUT_SL_MASK;
> +		} else {
> +			dev_dbg(&pdev->dev, "invalid clock-out-frequency\n");
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int __devinit cc770_get_platform_data(struct platform_device *pdev,
> +					     struct cc770_priv *priv)
> +{
> +
> +	struct cc770_platform_data *pdata = pdev->dev.platform_data;
> +
> +	priv->can.clock.freq = pdata->osc_freq;
> +	if (priv->cpu_interface | CPUIF_DSC)
> +		priv->can.clock.freq /= 2;
> +	priv->clkout = pdata->cor;
> +	priv->bus_config = pdata->bcr;
> +	priv->cpu_interface = pdata->cir;
> +
> +	return 0;
> +}
> +
> +static int __devinit cc770_platform_probe(struct platform_device *pdev)
> +{
> +	struct net_device *dev;
> +	struct cc770_priv *priv;
> +	struct resource *mem;
> +	resource_size_t mem_size;
> +	void __iomem *base;
> +	int err, irq;
> +
> +	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	irq = platform_get_irq(pdev, 0);
> +	if (!mem || irq <= 0)
> +		return -ENODEV;
> +
> +	mem_size = resource_size(mem);
> +	if (!request_mem_region(mem->start, mem_size, pdev->name))
> +		return -EBUSY;
> +
> +	base = ioremap(mem->start, mem_size);
> +	if (!base) {
> +		err = -ENOMEM;
> +		goto exit_release_mem;
> +	}
> +
> +	dev = alloc_cc770dev(0);
> +	if (!dev) {
> +		err = -ENOMEM;
> +		goto exit_unmap_mem;
> +	}
> +
> +	dev->irq = irq;
> +	priv = netdev_priv(dev);
> +	priv->read_reg = cc770_platform_read_reg;
> +	priv->write_reg = cc770_platform_write_reg;
> +	priv->irq_flags = IRQF_SHARED;
> +	priv->reg_base = base;
> +
> +	if (pdev->dev.of_node)
> +		err = cc770_get_of_node_data(pdev, priv);
> +	else if (pdev->dev.platform_data)
> +		err = cc770_get_platform_data(pdev, priv);
> +	else
> +		err = -ENODEV;
> +	if (err)
> +		goto exit_free_cc770;
> +
> +	dev_dbg(&pdev->dev,
> +		 "reg_base=0x%p irq=%d clock=%d cpu_interface=0x%02x "
> +		 "bus_config=0x%02x clkout=0x%02x\n",
> +		 priv->reg_base, dev->irq, priv->can.clock.freq,
> +		 priv->cpu_interface, priv->bus_config, priv->clkout);
> +
> +	dev_set_drvdata(&pdev->dev, dev);
> +	SET_NETDEV_DEV(dev, &pdev->dev);
> +
> +	err = register_cc770dev(dev);
> +	if (err) {
> +		dev_err(&pdev->dev,
> +			"couldn't register CC700 device (err=%d)\n", err);
> +		goto exit_free_cc770;
> +	}
> +
> +	return 0;
> +
> +exit_free_cc770:
> +	free_cc770dev(dev);
> +exit_unmap_mem:
> +	iounmap(base);
> +exit_release_mem:
> +	release_mem_region(mem->start, mem_size);
> +
> +	return err;
> +}
> +
> +static int __devexit cc770_platform_remove(struct platform_device *pdev)
> +{
> +	struct net_device *dev = dev_get_drvdata(&pdev->dev);
> +	struct cc770_priv *priv = netdev_priv(dev);
> +	struct resource *mem;
> +
> +	unregister_cc770dev(dev);
> +	iounmap(priv->reg_base);
> +	free_cc770dev(dev);
> +
> +	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);

Can this fail?

> +	if (mem)
> +		release_mem_region(mem->start, resource_size(mem));
> +	else
> +		dev_err(&pdev->dev, "couldn't release mem region");
> +
> +	return 0;
> +}
> +
> +static struct of_device_id __devinitdata cc770_platform_table[] = {
> +	{.compatible = "bosch,cc770"}, /* CC770 from Bosch */
> +	{.compatible = "intc,82527"},  /* AN82527 from Intel CP */
> +	{},
> +};
> +
> +static struct platform_driver cc770_platform_driver = {
> +	.driver = {
> +		.name = DRV_NAME,
> +		.owner = THIS_MODULE,
> +		.of_match_table = cc770_platform_table,
> +	},
> +	.probe = cc770_platform_probe,
> +	.remove = __devexit_p(cc770_platform_remove),
> +};
> +
> +module_platform_driver(cc770_platform_driver);

nice, I like the new module_platform_driver.

-- 
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