[U-Boot] [PATCH 1/3] clk: at91: add USB Host clock driver

Wenyou Yang
2018-02-09T03:34:50Z

Add USB clock driver to configure the input clock and the divider
in the PMC_USB register to generate a 48MHz and a 12MHz signal to
the USB Host OHCI.

Signed-off-by: Wenyou Yang <wenyou.yang@microchip.com>
---

arch/arm/mach-at91/include/mach/at91_pmc.h | 6 ++
drivers/clk/at91/Kconfig | 8 ++
drivers/clk/at91/Makefile | 1 +
drivers/clk/at91/clk-usb.c | 146 +++++++++++++++++++++++++++++
4 files changed, 161 insertions(+)
create mode 100644 drivers/clk/at91/clk-usb.c

diff --git a/arch/arm/mach-at91/include/mach/at91_pmc.h b/arch/arm/mach-at91/include/mach/at91_pmc.h
index 08ad1bf2d0..fbda8d5f63 100644
--- a/arch/arm/mach-at91/include/mach/at91_pmc.h
+++ b/arch/arm/mach-at91/include/mach/at91_pmc.h
@@ -233,9 +233,15 @@ typedef struct at91_pmc {
#define AT91_PMC_PDIV_1 (0 << 12)
#define AT91_PMC_PDIV_2 (1 << 12)

+#define AT91_PMC_USB_USBS_MASK 0x1
+#define AT91_PMC_USB_USBS_OFFSET 0
+#define AT91_PMC_USB_USBS_(x) (x & 0x1)
#define AT91_PMC_USBS_USB_PLLA (0x0) /* USB Clock Input is PLLA */
#define AT91_PMC_USBS_USB_UPLL (0x1) /* USB Clock Input is UPLL */
#define AT91_PMC_USBS_USB_PLLB (0x1) /* USB Clock Input is PLLB, AT91SAM9N12 only */
+#define AT91_PMC_USB_DIV_MASK 0xf
+#define AT91_PMC_USB_DIV_OFFSET 8
+#define AT91_PMC_USB_DIV_(x) ((x & 0xf) << 8)
#define AT91_PMC_USB_DIV_2 (0x1 << 8) /* USB Clock divided by 2 */
#define AT91_PMC_USBDIV_8 (0x7 << 8) /* USB Clock divided by 8 */
#define AT91_PMC_USBDIV_10 (0x9 << 8) /* USB Clock divided by 10 */
diff --git a/drivers/clk/at91/Kconfig b/drivers/clk/at91/Kconfig
index fd56f200b9..8d482a2752 100644
--- a/drivers/clk/at91/Kconfig
+++ b/drivers/clk/at91/Kconfig
@@ -27,6 +27,14 @@ config AT91_UTMI
fast crystal oscillator to meet the frequency accuracy
required by USB.

+config AT91_USB_CLK
+ bool "Support USB OHCI Input Clock"
+ depends on CLK_AT91
+ help
+ This option is used to enable the USB Input Clock, from
+ the device tree, configure the USBS bit (PLLA or UTMI PLL)
+ and USBDIV field of the PMC_USB register.
+
config AT91_H32MX
bool "Support H32MX 32-bit Matrix Clock"
depends on CLK_AT91
diff --git a/drivers/clk/at91/Makefile b/drivers/clk/at91/Makefile
index fbe3cb6581..8cac3f9e18 100644
--- a/drivers/clk/at91/Makefile
+++ b/drivers/clk/at91/Makefile
@@ -7,5 +7,6 @@ obj-y += clk-slow.o clk-main.o clk-plla.o clk-master.o
obj-y += clk-system.o clk-peripheral.o

obj-$(CONFIG_AT91_UTMI) += clk-utmi.o
+obj-$(CONFIG_AT91_USB_CLK) += clk-usb.o
obj-$(CONFIG_AT91_H32MX) += clk-h32mx.o
obj-$(CONFIG_AT91_GENERIC_CLK) += clk-generated.o
diff --git a/drivers/clk/at91/clk-usb.c b/drivers/clk/at91/clk-usb.c
new file mode 100644
index 0000000000..36622c09dc
--- /dev/null
+++ b/drivers/clk/at91/clk-usb.c
@@ -0,0 +1,146 @@
+/*
+ * Copyright (C) 2018 Microhip / Atmel Corporation
+ * Wenyou.Yang <wenyou.yang@microchip.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <clk-uclass.h>
+#include <dm/device.h>
+#include <linux/io.h>
+#include <mach/at91_pmc.h>
+#include "pmc.h"
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#define AT91_USB_CLK_SOURCE_MAX 2
+#define AT91_USB_CLK_MAX_DIV 15
+
+struct at91_usb_clk_priv {
+ u32 num_clksource;
+};
+
+static ulong at91_usb_clk_get_rate(struct clk *clk)
+{
+ struct pmc_platdata *plat = dev_get_platdata(clk->dev);
+ struct at91_pmc *pmc = plat->reg_base;
+ struct clk source;
+ u32 tmp, usbdiv;
+ u8 source_index;
+ int ret;
+
+ tmp = readl(&pmc->pcr);
+ source_index = (tmp >> AT91_PMC_USB_USBS_OFFSET) &
+ AT91_PMC_USB_USBS_MASK;
+ usbdiv = (tmp >> AT91_PMC_USB_DIV_OFFSET) & AT91_PMC_USB_DIV_MASK;
+
+ ret = clk_get_by_index(clk->dev, source_index, &source);
+ if (ret)
+ return 0;
+
+ return clk_get_rate(&source) / (usbdiv + 1);
+}
+
+static ulong at91_usb_clk_set_rate(struct clk *clk, ulong rate)
+{
+ struct pmc_platdata *plat = dev_get_platdata(clk->dev);
+ struct at91_pmc *pmc = plat->reg_base;
+ struct at91_usb_clk_priv *priv = dev_get_priv(clk->dev);
+ struct clk source, best_source;
+ ulong tmp_rate, best_rate = rate, source_rate;
+ int tmp_diff, best_diff = -1;
+ u32 div, best_div = 0;
+ u8 best_source_index = 0;
+ u8 i;
+ u32 tmp;
+ int ret;
+
+ for (i = 0; i < priv->num_clksource; i++) {
+ ret = clk_get_by_index(clk->dev, i, &source);
+ if (ret)
+ return ret;
+
+ source_rate = clk_get_rate(&source);
+ if (IS_ERR_VALUE(source_rate))
+ return source_rate;
+
+ for (div = 1; div < AT91_USB_CLK_MAX_DIV + 2; div++) {
+ tmp_rate = DIV_ROUND_CLOSEST(source_rate, div);
+ tmp_diff = abs(rate - tmp_rate);
+
+ if (best_diff < 0 || best_diff > tmp_diff) {
+ best_rate = tmp_rate;
+ best_diff = tmp_diff;
+
+ best_div = div - 1;
+ best_source = source;
+ best_source_index = i;
+ }
+
+ if (!best_diff || tmp_rate < rate)
+ break;
+ }
+
+ if (!best_diff)
+ break;
+ }
+
+ debug("AT91 USB: best sourc: %s, best_rate = %ld, best_div = %d\n",
+ best_source.dev->name, best_rate, best_div);
+
+ ret = clk_enable(&best_source);
+ if (ret)
+ return ret;
+
+ tmp = AT91_PMC_USB_USBS_(best_source_index) |
+ AT91_PMC_USB_DIV_(best_div);
+ writel(tmp, &pmc->usb);
+
+ return 0;
+}
+
+static struct clk_ops at91_usb_clk_ops = {
+ .get_rate = at91_usb_clk_get_rate,
+ .set_rate = at91_usb_clk_set_rate,
+};
+
+static int at91_usb_clk_ofdata_to_platdata(struct udevice *dev)
+{
+ struct at91_usb_clk_priv *priv = dev_get_priv(dev);
+ u32 cells[AT91_USB_CLK_SOURCE_MAX];
+ u32 num_clksource;
+
+ num_clksource = fdtdec_get_int_array_count(gd->fdt_blob,
+ dev_of_offset(dev),
+ "clocks", cells,
+ AT91_USB_CLK_SOURCE_MAX);
+
+ if (!num_clksource)
+ return -1;
+
+ priv->num_clksource = num_clksource;
+
+ return 0;
+}
+
+static int at91_usb_clk_probe(struct udevice *dev)
+{
+ return at91_pmc_core_probe(dev);
+}
+
+static const struct udevice_id at91_usb_clk_match[] = {
+ { .compatible = "atmel,at91sam9x5-clk-usb" },
+ {}
+};
+
+U_BOOT_DRIVER(at91_usb_clk) = {
+ .name = "at91-usb-clk",
+ .id = UCLASS_CLK,
+ .of_match = at91_usb_clk_match,
+ .probe = at91_usb_clk_probe,
+ .ofdata_to_platdata = at91_usb_clk_ofdata_to_platdata,
+ .priv_auto_alloc_size = sizeof(struct at91_usb_clk_priv),
+ .platdata_auto_alloc_size = sizeof(struct pmc_platdata),
+ .ops = &at91_usb_clk_ops,
+};
--
2.16.0.rc1