clk: at91: add PMC pll clocks

This patch adds new at91 pll clock implementation using common clk framework.

The pll clock layout describe the PLLX register layout.
There are four pll clock layouts:
- at91rm9200
- at91sam9g20
- at91sam9g45
- sama5d3

PLL clocks are given characteristics:
- min/max clock source rate
- ranges of valid clock output rates
- values to set in out and icpll fields for each supported output range

These characteristics are checked during rate change to avoid
over/underclocking.

These characteristics are described in atmel's SoC datasheet in
"Electrical Characteristics" paragraph.

Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com>
Acked-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

1 files changed, 135 insertions, 0 deletions

diff --git a/drivers/clk/at91/clk-plldiv.c b/drivers/clk/at91/clk-plldiv.c
new file mode 100644
index 00000000000..ea226562bb4
--- /dev/null
+++ b/drivers/clk/at91/clk-plldiv.c
@@ -0,0 +1,135 @@
+/*
+ *  Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
+ *
+ * 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/clk-provider.h>
+#include <linux/clkdev.h>
+#include <linux/clk/at91_pmc.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/io.h>
+
+#include "pmc.h"
+
+#define to_clk_plldiv(hw) container_of(hw, struct clk_plldiv, hw)
+
+struct clk_plldiv {
+	struct clk_hw hw;
+	struct at91_pmc *pmc;
+};
+
+static unsigned long clk_plldiv_recalc_rate(struct clk_hw *hw,
+					    unsigned long parent_rate)
+{
+	struct clk_plldiv *plldiv = to_clk_plldiv(hw);
+	struct at91_pmc *pmc = plldiv->pmc;
+
+	if (pmc_read(pmc, AT91_PMC_MCKR) & AT91_PMC_PLLADIV2)
+		return parent_rate / 2;
+
+	return parent_rate;
+}
+
+static long clk_plldiv_round_rate(struct clk_hw *hw, unsigned long rate,
+					unsigned long *parent_rate)
+{
+	unsigned long div;
+
+	if (rate > *parent_rate)
+		return *parent_rate;
+	div = *parent_rate / 2;
+	if (rate < div)
+		return div;
+
+	if (rate - div < *parent_rate - rate)
+		return div;
+
+	return *parent_rate;
+}
+
+static int clk_plldiv_set_rate(struct clk_hw *hw, unsigned long rate,
+			       unsigned long parent_rate)
+{
+	struct clk_plldiv *plldiv = to_clk_plldiv(hw);
+	struct at91_pmc *pmc = plldiv->pmc;
+	u32 tmp;
+
+	if (parent_rate != rate && (parent_rate / 2) != rate)
+		return -EINVAL;
+
+	pmc_lock(pmc);
+	tmp = pmc_read(pmc, AT91_PMC_MCKR) & ~AT91_PMC_PLLADIV2;
+	if ((parent_rate / 2) == rate)
+		tmp |= AT91_PMC_PLLADIV2;
+	pmc_write(pmc, AT91_PMC_MCKR, tmp);
+	pmc_unlock(pmc);
+
+	return 0;
+}
+
+static const struct clk_ops plldiv_ops = {
+	.recalc_rate = clk_plldiv_recalc_rate,
+	.round_rate = clk_plldiv_round_rate,
+	.set_rate = clk_plldiv_set_rate,
+};
+
+static struct clk * __init
+at91_clk_register_plldiv(struct at91_pmc *pmc, const char *name,
+			 const char *parent_name)
+{
+	struct clk_plldiv *plldiv;
+	struct clk *clk = NULL;
+	struct clk_init_data init;
+
+	plldiv = kzalloc(sizeof(*plldiv), GFP_KERNEL);
+	if (!plldiv)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = name;
+	init.ops = &plldiv_ops;
+	init.parent_names = parent_name ? &parent_name : NULL;
+	init.num_parents = parent_name ? 1 : 0;
+	init.flags = CLK_SET_RATE_GATE;
+
+	plldiv->hw.init = &init;
+	plldiv->pmc = pmc;
+
+	clk = clk_register(NULL, &plldiv->hw);
+
+	if (IS_ERR(clk))
+		kfree(plldiv);
+
+	return clk;
+}
+
+static void __init
+of_at91_clk_plldiv_setup(struct device_node *np, struct at91_pmc *pmc)
+{
+	struct clk *clk;
+	const char *parent_name;
+	const char *name = np->name;
+
+	parent_name = of_clk_get_parent_name(np, 0);
+
+	of_property_read_string(np, "clock-output-names", &name);
+
+	clk = at91_clk_register_plldiv(pmc, name, parent_name);
+
+	if (IS_ERR(clk))
+		return;
+
+	of_clk_add_provider(np, of_clk_src_simple_get, clk);
+	return;
+}
+
+void __init of_at91sam9x5_clk_plldiv_setup(struct device_node *np,
+					   struct at91_pmc *pmc)
+{
+	of_at91_clk_plldiv_setup(np, pmc);
+}