Re: [PATCH 2/2] clk: at91: add Flexcom clock

From: Cyrille Pitchen
Date: Tue Jun 02 2015 - 12:58:48 EST


Le 02/06/2015 18:49, Cyrille Pitchen a écrit :
> Signed-off-by: Cyrille Pitchen <cyrille.pitchen@xxxxxxxxx>
>
> This driver supports the new Atmel Flexcom. The Flexcom is a wrapper which
> integrates one SPI controller, one I2C controller and one USART. Only one
> function can be enabled at a time. This driver selects the function once for
> all, when the Flexcom is probed, according to the value of the new
> "atmel,flexcom-mode" device tree property.
>
> This driver has chosen to present the Flexcom to the system as a clock so the
> implementation is seamless for the existing Atmel SPI, I2C and USART drivers.
>
> Also the Flexcom embeds FIFOs: the latest patches of the SPI, I2C and USART
> drivers take advantage of this new feature.
>
> Conflicts:
> drivers/clk/at91/Makefile
issue with the commit message: sending a new series

Cyrille

> ---
> arch/arm/mach-at91/Kconfig | 3 +
> drivers/clk/at91/Makefile | 1 +
> drivers/clk/at91/clk-flexcom.c | 160 +++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 164 insertions(+)
> create mode 100644 drivers/clk/at91/clk-flexcom.c
>
> diff --git a/arch/arm/mach-at91/Kconfig b/arch/arm/mach-at91/Kconfig
> index fd95f34..8ce9b73 100644
> --- a/arch/arm/mach-at91/Kconfig
> +++ b/arch/arm/mach-at91/Kconfig
> @@ -90,6 +90,9 @@ config HAVE_AT91_SMD
> config HAVE_AT91_H32MX
> bool
>
> +config HAVE_AT91_FLEXCOM
> + bool
> +
> config SOC_SAM_V4_V5
> bool
>
> diff --git a/drivers/clk/at91/Makefile b/drivers/clk/at91/Makefile
> index 89a48a7..74711b8 100644
> --- a/drivers/clk/at91/Makefile
> +++ b/drivers/clk/at91/Makefile
> @@ -10,3 +10,4 @@ obj-$(CONFIG_HAVE_AT91_UTMI) += clk-utmi.o
> obj-$(CONFIG_HAVE_AT91_USB_CLK) += clk-usb.o
> obj-$(CONFIG_HAVE_AT91_SMD) += clk-smd.o
> obj-$(CONFIG_HAVE_AT91_H32MX) += clk-h32mx.o
> +obj-$(CONFIG_HAVE_AT91_FLEXCOM) += clk-flexcom.o
> diff --git a/drivers/clk/at91/clk-flexcom.c b/drivers/clk/at91/clk-flexcom.c
> new file mode 100644
> index 0000000..ce39093
> --- /dev/null
> +++ b/drivers/clk/at91/clk-flexcom.c
> @@ -0,0 +1,160 @@
> +/*
> + * Driver for Atmel AT91 Flexcom
> + *
> + * Copyright (C) 2014 Atmel Corporation
> + *
> + * Author: Cyrille Pitchen <cyrille.pitchen@xxxxxxxxx>
> + *
> + * Based on drivers/clk/clk-axi-clkgen.c
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + */
> +
> +#include <linux/platform_device.h>
> +#include <linux/clk-provider.h>
> +#include <linux/of.h>
> +#include <linux/module.h>
> +
> +
> +#define FX_MR 0x0
> +#define FX_RHR 0x10
> +#define FX_THR 0x20
> +#define FX_VERSION 0xfc
> +
> +#define FX_MR_NO_COM 0
> +#define FX_MR_USART 1
> +#define FX_MR_SPI 2
> +#define FX_MR_TWI 3
> +
> +struct clk_flexcom {
> + struct clk_hw hw;
> + struct device *dev;
> + u8 __iomem *base;
> + u32 mr;
> + bool show_once;
> +};
> +
> +#define to_clk_flexcom(_hw) container_of(_hw, struct clk_flexcom, hw)
> +
> +
> +static int at91_flexcom_enable(struct clk_hw *hw)
> +{
> + struct clk_flexcom *dev = to_clk_flexcom(hw);
> + u32 version;
> +
> + if (!dev->show_once) {
> + dev->show_once = true;
> + version = __raw_readl(dev->base + FX_VERSION);
> + dev_info(dev->dev, "version: %#x\n", version);
> + }
> +
> + __raw_writel(dev->mr, dev->base + FX_MR);
> + return 0;
> +}
> +
> +static void at91_flexcom_disable(struct clk_hw *hw)
> +{
> + struct clk_flexcom *dev = to_clk_flexcom(hw);
> +
> + __raw_writel(FX_MR_NO_COM, dev->base + FX_MR);
> +}
> +
> +static const struct clk_ops at91_flexcom_ops = {
> + .enable = at91_flexcom_enable,
> + .disable = at91_flexcom_disable,
> +};
> +
> +static int at91_flexcom_probe(struct platform_device *pdev)
> +{
> + struct device_node *np = pdev->dev.of_node;
> + struct clk_flexcom *dev;
> + struct resource *mem;
> + const char *parent_name, *clk_name, *mode;
> + struct clk *clk;
> + struct clk_init_data init;
> + u32 mr = FX_MR_NO_COM;
> + int err;
> +
> + if (!np)
> + return -ENODEV;
> +
> + err = of_property_read_string(np, "atmel,flexcom-mode", &mode);
> + if (err)
> + return err;
> +
> + if (!strcmp(mode, "usart"))
> + mr = FX_MR_USART;
> + else if (!strcmp(mode, "spi"))
> + mr = FX_MR_SPI;
> + else if (!strcmp(mode, "twi") || !strcmp(mode, "i2c"))
> + mr = FX_MR_TWI;
> + else
> + return -EINVAL;
> +
> + dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
> + if (!dev)
> + return -ENOMEM;
> +
> + mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + dev->base = devm_ioremap_resource(&pdev->dev, mem);
> + if (IS_ERR(dev->base))
> + return PTR_ERR(dev->base);
> +
> + parent_name = of_clk_get_parent_name(np, 0);
> + if (!parent_name)
> + return -EINVAL;
> +
> + clk_name = np->name;
> + of_property_read_string(np, "clock-output-names", &clk_name);
> +
> + init.name = clk_name;
> + init.ops = &at91_flexcom_ops;
> + init.flags = 0;
> + init.parent_names = &parent_name;
> + init.num_parents = 1;
> +
> + dev->hw.init = &init;
> + dev->dev = &pdev->dev;
> + dev->mr = mr;
> + platform_set_drvdata(pdev, dev);
> +
> + clk = devm_clk_register(&pdev->dev, &dev->hw);
> + if (IS_ERR(clk))
> + return PTR_ERR(clk);
> +
> + return of_clk_add_provider(np, of_clk_src_simple_get, clk);
> +}
> +
> +static int at91_flexcom_remove(struct platform_device *pdev)
> +{
> + of_clk_del_provider(pdev->dev.of_node);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id at91_flexcom_dt_ids[] = {
> + { .compatible = "atmel,sama5d2-flexcom" },
> + { /* sentinel */ }
> +};
> +
> +MODULE_DEVICE_TABLE(of, at91_flexcom_dt_ids);
> +
> +static struct platform_driver at91_flexcom_driver = {
> + .driver = {
> + .name = "at91_flexcom",
> + .of_match_table = of_match_ptr(at91_flexcom_dt_ids),
> + },
> + .probe = at91_flexcom_probe,
> + .remove = at91_flexcom_remove,
> +};
> +module_platform_driver(at91_flexcom_driver);
> +
> +MODULE_ALIAS("platform:at91_flexcom");
> +MODULE_DESCRIPTION("Atmel AT91 Flexcom driver");
> +MODULE_AUTHOR("Cyrille Pitchen <cyrille.pitchen@xxxxxxxxx>");
> +MODULE_LICENSE("GPL v2");
> +
>

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