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.
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@xxxxxxxxx>
---
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");
+
--
1.8.2.2
--
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