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Message-Id: <1368467199-8702-3-git-send-email-soren.brinkmann@xilinx.com>
Date: Mon, 13 May 2013 10:46:36 -0700
From: Soren Brinkmann <soren.brinkmann@...inx.com>
To: Michal Simek <michal.simek@...inx.com>,
Josh Cartwright <joshc@....teric.us>,
Mike Turquette <mturquette@...aro.org>,
Lars-Peter Clausen <lars@...afoo.de>,
Peter Crosthwaite <peter.crosthwaite@...inx.com>
Cc: linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
Arnd Bergmann <arnd@...db.de>,
Russell King <linux@....linux.org.uk>,
Stephen Warren <swarren@...dotorg.org>,
Soren Brinkmann <soren.brinkmann@...inx.com>
Subject: [PATCH v2 2/5] clk: zynq: Factor out PLL driver
Refactor the PLL driver so it works with the clock controller driver.
Signed-off-by: Soren Brinkmann <soren.brinkmann@...inx.com>
---
drivers/clk/zynq/pll.c | 235 +++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 235 insertions(+)
create mode 100644 drivers/clk/zynq/pll.c
diff --git a/drivers/clk/zynq/pll.c b/drivers/clk/zynq/pll.c
new file mode 100644
index 0000000..47e307c
--- /dev/null
+++ b/drivers/clk/zynq/pll.c
@@ -0,0 +1,235 @@
+/*
+ * Zynq PLL driver
+ *
+ * Copyright (C) 2013 Xilinx
+ *
+ * Sören Brinkmann <soren.brinkmann@...inx.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License v2 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, see <http://www.gnu.org/licenses/>.
+ *
+ */
+#include <linux/clk/zynq.h>
+#include <linux/clk-provider.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+
+/**
+ * struct zynq_pll
+ * @hw: Handle between common and hardware-specific interfaces
+ * @pll_ctrl: PLL control register
+ * @pll_status: PLL status register
+ * @lock: Register lock
+ * @lockbit: Indicates the associated PLL_LOCKED bit in the PLL status
+ * register.
+ */
+struct zynq_pll {
+ struct clk_hw hw;
+ void __iomem *pll_ctrl;
+ void __iomem *pll_status;
+ spinlock_t *lock;
+ u8 lockbit;
+};
+#define to_zynq_pll(_hw) container_of(_hw, struct zynq_pll, hw)
+
+/* Register bitfield defines */
+#define PLLCTRL_FBDIV_MASK 0x7f000
+#define PLLCTRL_FBDIV_SHIFT 12
+#define PLLCTRL_BPQUAL_MASK (1 << 3)
+#define PLLCTRL_PWRDWN_MASK 2
+#define PLLCTRL_PWRDWN_SHIFT 1
+#define PLLCTRL_RESET_MASK 1
+#define PLLCTRL_RESET_SHIFT 0
+
+/**
+ * zynq_pll_round_rate() - Round a clock frequency
+ * @hw: Handle between common and hardware-specific interfaces
+ * @rate: Desired clock frequency
+ * @prate: Clock frequency of parent clock
+ * Returns frequency closest to @rate the hardware can generate.
+ */
+static long zynq_pll_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *prate)
+{
+ u32 fbdiv;
+
+ fbdiv = DIV_ROUND_CLOSEST(rate, *prate);
+ if (fbdiv < 13)
+ fbdiv = 13;
+ else if (fbdiv > 66)
+ fbdiv = 66;
+
+ return *prate * fbdiv;
+}
+
+/**
+ * zynq_pll_recalc_rate() - Recalculate clock frequency
+ * @hw: Handle between common and hardware-specific interfaces
+ * @parent_rate: Clock frequency of parent clock
+ * Returns current clock frequency.
+ */
+static unsigned long zynq_pll_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct zynq_pll *clk = to_zynq_pll(hw);
+ u32 fbdiv;
+
+ /*
+ * makes probably sense to redundantly save fbdiv in the struct
+ * zynq_pll to save the IO access.
+ */
+ fbdiv = (readl(clk->pll_ctrl) & PLLCTRL_FBDIV_MASK) >>
+ PLLCTRL_FBDIV_SHIFT;
+
+ return parent_rate * fbdiv;
+}
+
+/**
+ * zynq_pll_is_enabled - Check if a clock is enabled
+ * @hw: Handle between common and hardware-specific interfaces
+ * Returns 1 if the clock is enabled, 0 otherwise.
+ *
+ * Not sure this is a good idea, but since disabled means bypassed for
+ * this clock implementation we say we are always enabled.
+ */
+static int zynq_pll_is_enabled(struct clk_hw *hw)
+{
+ unsigned long flags = 0;
+ u32 reg;
+ struct zynq_pll *clk = to_zynq_pll(hw);
+
+ spin_lock_irqsave(clk->lock, flags);
+
+ reg = readl(clk->pll_ctrl);
+
+ spin_unlock_irqrestore(clk->lock, flags);
+
+ return !(reg & (PLLCTRL_RESET_MASK | PLLCTRL_PWRDWN_MASK));
+}
+
+/**
+ * zynq_pll_enable - Enable clock
+ * @hw: Handle between common and hardware-specific interfaces
+ * Returns 0 on success
+ */
+static int zynq_pll_enable(struct clk_hw *hw)
+{
+ unsigned long flags = 0;
+ u32 reg;
+ struct zynq_pll *clk = to_zynq_pll(hw);
+
+ if (zynq_pll_is_enabled(hw))
+ return 0;
+
+ pr_info("PLL: enable\n");
+
+ /* Power up PLL and wait for lock */
+ spin_lock_irqsave(clk->lock, flags);
+
+ reg = readl(clk->pll_ctrl);
+ reg &= ~(PLLCTRL_RESET_MASK | PLLCTRL_PWRDWN_MASK);
+ writel(reg, clk->pll_ctrl);
+ while (!(readl(clk->pll_status) & (1 << clk->lockbit)))
+ ;
+
+ spin_unlock_irqrestore(clk->lock, flags);
+
+ return 0;
+}
+
+/**
+ * zynq_pll_disable - Disable clock
+ * @hw: Handle between common and hardware-specific interfaces
+ * Returns 0 on success
+ */
+static void zynq_pll_disable(struct clk_hw *hw)
+{
+ unsigned long flags = 0;
+ u32 reg;
+ struct zynq_pll *clk = to_zynq_pll(hw);
+
+ if (!zynq_pll_is_enabled(hw))
+ return;
+
+ pr_info("PLL: shutdown\n");
+
+ /* shut down PLL */
+ spin_lock_irqsave(clk->lock, flags);
+
+ reg = readl(clk->pll_ctrl);
+ reg |= PLLCTRL_RESET_MASK | PLLCTRL_PWRDWN_MASK;
+ writel(reg, clk->pll_ctrl);
+
+ spin_unlock_irqrestore(clk->lock, flags);
+}
+
+static const struct clk_ops zynq_pll_ops = {
+ .enable = zynq_pll_enable,
+ .disable = zynq_pll_disable,
+ .is_enabled = zynq_pll_is_enabled,
+ .round_rate = zynq_pll_round_rate,
+ .recalc_rate = zynq_pll_recalc_rate
+};
+
+/**
+ * clk_register_zynq_pll() - Register PLL with the clock framework
+ * @np Pointer to the DT device node
+ */
+struct clk *clk_register_zynq_pll(const char *name, const char *parent,
+ void __iomem *pll_ctrl, void __iomem *pll_status, u8 lock_index,
+ spinlock_t *lock)
+{
+ struct zynq_pll *pll;
+ struct clk *clk;
+ u32 reg;
+ const char *parent_arr[1] = {parent};
+ unsigned long flags = 0;
+ struct clk_init_data initd = {
+ .name = name,
+ .parent_names = parent_arr,
+ .ops = &zynq_pll_ops,
+ .num_parents = 1,
+ .flags = 0
+ };
+
+ pll = kmalloc(sizeof(*pll), GFP_KERNEL);
+ if (!pll) {
+ pr_err("%s: Could not allocate Zynq PLL clk.\n", __func__);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ /* Populate the struct */
+ pll->hw.init = &initd;
+ pll->pll_ctrl = pll_ctrl;
+ pll->pll_status = pll_status;
+ pll->lockbit = lock_index;
+ pll->lock = lock;
+
+ spin_lock_irqsave(pll->lock, flags);
+
+ reg = readl(pll->pll_ctrl);
+ reg &= ~PLLCTRL_BPQUAL_MASK;
+ writel(reg, pll->pll_ctrl);
+
+ spin_unlock_irqrestore(pll->lock, flags);
+
+ clk = clk_register(NULL, &pll->hw);
+ if (WARN_ON(IS_ERR(clk)))
+ goto free_pll;
+
+ return clk;
+
+free_pll:
+ kfree(pll);
+
+ return clk;
+}
--
1.8.2.3
--
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