[U-Boot] [PATCH 2/3] clk: at91: add PLLADIV driver

Wenyou Yang
2018-02-09T03:34:51Z

As said in the SAMA5D2 datasheet, the PLLA clock must be divided
by 2 by writing the PLLADIV2 bit in PMC_MCKR, if the ratio between
PCK and MCK is 3 (MDIV = 3). This is the purpose of the driver.

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

drivers/clk/at91/Makefile | 2 +-
drivers/clk/at91/clk-plladiv.c | 88 ++++++++++++++++++++++++++++++++++++++++++
2 files changed, 89 insertions(+), 1 deletion(-)
create mode 100644 drivers/clk/at91/clk-plladiv.c

diff --git a/drivers/clk/at91/Makefile b/drivers/clk/at91/Makefile
index 8cac3f9e18..8c197ff949 100644
--- a/drivers/clk/at91/Makefile
+++ b/drivers/clk/at91/Makefile
@@ -3,7 +3,7 @@
#

obj-y += pmc.o sckc.o
-obj-y += clk-slow.o clk-main.o clk-plla.o clk-master.o
+obj-y += clk-slow.o clk-main.o clk-plla.o clk-plladiv.o clk-master.o
obj-y += clk-system.o clk-peripheral.o

obj-$(CONFIG_AT91_UTMI) += clk-utmi.o
diff --git a/drivers/clk/at91/clk-plladiv.c b/drivers/clk/at91/clk-plladiv.c
new file mode 100644
index 0000000000..0599d2893b
--- /dev/null
+++ b/drivers/clk/at91/clk-plladiv.c
@@ -0,0 +1,88 @@
+/*
+ * 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;
+
+static int at91_plladiv_clk_enable(struct clk *clk)
+{
+ return 0;
+}
+
+static ulong at91_plladiv_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;
+ ulong clk_rate;
+ int ret;
+
+ ret = clk_get_by_index(clk->dev, 0, &source);
+ if (ret)
+ return -EINVAL;
+
+ clk_rate = clk_get_rate(&source);
+ if (readl(&pmc->mckr) & AT91_PMC_MCKR_PLLADIV_2)
+ clk_rate /= 2;
+
+ return clk_rate;
+}
+
+static ulong at91_plladiv_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 clk source;
+ ulong parent_rate;
+ int ret;
+
+ ret = clk_get_by_index(clk->dev, 0, &source);
+ if (ret)
+ return -EINVAL;
+
+ parent_rate = clk_get_rate(&source);
+ if ((parent_rate != rate) && ((parent_rate) / 2 != rate))
+ return -EINVAL;
+
+ if (parent_rate != rate) {
+ writel((readl(&pmc->mckr) | AT91_PMC_MCKR_PLLADIV_2),
+ &pmc->mckr);
+ }
+
+ return 0;
+}
+
+static struct clk_ops at91_plladiv_clk_ops = {
+ .enable = at91_plladiv_clk_enable,
+ .get_rate = at91_plladiv_clk_get_rate,
+ .set_rate = at91_plladiv_clk_set_rate,
+};
+
+static int at91_plladiv_clk_probe(struct udevice *dev)
+{
+ return at91_pmc_core_probe(dev);
+}
+
+static const struct udevice_id at91_plladiv_clk_match[] = {
+ { .compatible = "atmel,at91sam9x5-clk-plldiv" },
+ {}
+};
+
+U_BOOT_DRIVER(at91_plladiv_clk) = {
+ .name = "at91-plladiv-clk",
+ .id = UCLASS_CLK,
+ .of_match = at91_plladiv_clk_match,
+ .probe = at91_plladiv_clk_probe,
+ .platdata_auto_alloc_size = sizeof(struct pmc_platdata),
+ .ops = &at91_plladiv_clk_ops,
+};
--
2.16.0.rc1