Re: [PATCH v4 08/17] clk: at91: add PMC system clocks
From: Nicolas Ferre
Date: Thu Oct 17 2013 - 12:00:01 EST
On 11/10/2013 11:41, Boris BREZILLON :
This patch adds new at91 system clock implementation using common clk
framework.
Some peripherals need to enable a "system" clock in order to work properly.
Each system clock is given an id based on the bit position in SCER/SCDR
registers.
Signed-off-by: Boris BREZILLON <b.brezillon@xxxxxxxxxxx>
Acked-by: Nicolas Ferre <nicolas.ferre@xxxxxxxxx>
---
drivers/clk/at91/Makefile | 1 +
drivers/clk/at91/clk-system.c | 193 +++++++++++++++++++++++++++++++++++++++++
drivers/clk/at91/pmc.c | 5 ++
drivers/clk/at91/pmc.h | 3 +
4 files changed, 202 insertions(+)
create mode 100644 drivers/clk/at91/clk-system.c
diff --git a/drivers/clk/at91/Makefile b/drivers/clk/at91/Makefile
index e28fb2b..c2b7068 100644
--- a/drivers/clk/at91/Makefile
+++ b/drivers/clk/at91/Makefile
@@ -4,3 +4,4 @@
obj-y += pmc.o
obj-y += clk-main.o clk-pll.o clk-plldiv.o clk-master.o
+obj-y += clk-system.o
diff --git a/drivers/clk/at91/clk-system.c b/drivers/clk/at91/clk-system.c
new file mode 100644
index 0000000..603b4b1
--- /dev/null
+++ b/drivers/clk/at91/clk-system.c
@@ -0,0 +1,193 @@
+/*
+ * drivers/clk/at91/clk-system.c
+ *
+ * Copyright (C) 2013 Boris BREZILLON <b.brezillon@xxxxxxxxxxx>
+ *
+ * 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 SYSTEM_MAX_ID 31
+
+#define to_clk_system(hw) container_of(hw, struct clk_system, hw)
+struct clk_system {
+ struct clk_hw hw;
+ struct at91_pmc *pmc;
+ u8 id;
+};
+
+static int clk_system_enable(struct clk_hw *hw)
+{
+ struct clk_system *sys = to_clk_system(hw);
+ struct at91_pmc *pmc = sys->pmc;
+
+ pmc_write(pmc, AT91_PMC_SCER, 1 << sys->id);
+ return 0;
+}
+
+static void clk_system_disable(struct clk_hw *hw)
+{
+ struct clk_system *sys = to_clk_system(hw);
+ struct at91_pmc *pmc = sys->pmc;
+
+ pmc_write(pmc, AT91_PMC_SCDR, 1 << sys->id);
+}
+
+static int clk_system_is_enabled(struct clk_hw *hw)
+{
+ struct clk_system *sys = to_clk_system(hw);
+ struct at91_pmc *pmc = sys->pmc;
+
+ return !!(pmc_read(pmc, AT91_PMC_SCSR) & (1 << sys->id));
+}
+
+static const struct clk_ops system_ops = {
+ .enable = clk_system_enable,
+ .disable = clk_system_disable,
+ .is_enabled = clk_system_is_enabled,
+};
+
+static struct clk * __init
+at91_clk_register_system(struct at91_pmc *pmc, const char *name,
+ const char *parent_name, u8 id)
+{
+ struct clk_system *sys;
+ struct clk *clk = NULL;
+ struct clk_init_data init;
+
+ if (!parent_name || id > SYSTEM_MAX_ID)
+ return ERR_PTR(-EINVAL);
+
+ sys = kzalloc(sizeof(*sys), GFP_KERNEL);
+ if (!sys)
+ return ERR_PTR(-ENOMEM);
+
+ init.name = name;
+ init.ops = &system_ops;
+ init.parent_names = &parent_name;
+ init.num_parents = 1;
+ /*
+ * CLK_IGNORE_UNUSED is used to avoid ddrck switch off.
+ * TODO : we should implement a driver supporting at91 ddr controller
+ * (see drivers/memory) which would request and enable the ddrck clock.
+ * When this is done we will be able to remove CLK_IGNORE_UNUSED flag.
+ */
+ init.flags = CLK_IGNORE_UNUSED;
+
+ sys->id = id;
+ sys->hw.init = &init;
+ sys->pmc = pmc;
+
+ clk = clk_register(NULL, &sys->hw);
+ if (IS_ERR(clk))
+ kfree(sys);
+
+ return clk;
+}
+
+struct clk_system_data {
+ struct clk **clks;
+ u8 *ids;
+ unsigned int clk_num;
+};
+
+static struct clk * __init
+of_clk_src_system_get(struct of_phandle_args *clkspec, void *data)
+{
+ struct clk_system_data *clk_data = data;
+ unsigned int id = clkspec->args[0];
+ int i;
+
+ if (id > SYSTEM_MAX_ID)
+ goto err;
+
+ for (i = 0; i < clk_data->clk_num; i++) {
+ if (clk_data->ids[i] == id)
+ return clk_data->clks[i];
+ }
+
+err:
+ pr_err("%s: invalid clock id %d\n", __func__, id);
+ return ERR_PTR(-EINVAL);
+}
+
+static void __init
+of_at91_clk_sys_setup(struct device_node *np, struct at91_pmc *pmc)
+{
+ int i;
+ int num;
+ u32 id;
+ struct clk *clk;
+ u8 *ids;
+ struct clk **clks;
+ struct clk_system_data *clktab;
+ const char *name;
+ struct device_node *sysclknp;
+ const char *parent_name;
+
+ num = of_get_child_count(np);
+ if (num > (SYSTEM_MAX_ID + 1))
+ return;
+
+ clktab = kzalloc(sizeof(*clktab), GFP_KERNEL);
+ if (!clktab)
+ return;
+
+ ids = kzalloc(num * sizeof(*ids), GFP_KERNEL);
+ if (!ids)
+ goto out_free_clktab;
+
+ clks = kzalloc(num * sizeof(*clks), GFP_KERNEL);
+ if (!clks)
+ goto out_free_ids;
+
+ i = 0;
+ for_each_child_of_node(np, sysclknp) {
+ name = sysclknp->name;
+
+ if (of_property_read_u32(sysclknp, "atmel,clk-id", &id))
+ goto out_free_clks;
+
+ parent_name = of_clk_get_parent_name(sysclknp, 0);
+
+ clk = at91_clk_register_system(pmc, name, parent_name, id);
+ if (IS_ERR(clk))
+ goto out_free_clks;
+
+ clks[i] = clk;
+ ids[i] = id;
+
+ i++;
+ }
+
+ clktab->clk_num = num;
+ clktab->clks = clks;
+ clktab->ids = ids;
+ of_clk_add_provider(np, of_clk_src_system_get, clktab);
+ return;
+
+out_free_clks:
+ kfree(clks);
+out_free_ids:
+ kfree(ids);
+out_free_clktab:
+ kfree(clktab);
+}
+
+void __init of_at91rm9200_clk_sys_setup(struct device_node *np,
+ struct at91_pmc *pmc)
+{
+ of_at91_clk_sys_setup(np, pmc);
+}
diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
index 6f08879..ce76ba6 100644
--- a/drivers/clk/at91/pmc.c
+++ b/drivers/clk/at91/pmc.c
@@ -243,6 +243,11 @@ static const struct of_device_id pmc_clk_ids[] __initdata = {
.compatible = "atmel,at91sam9x5-clk-master",
.data = of_at91sam9x5_clk_master_setup,
},
+ /* System clocks */
+ {
+ .compatible = "atmel,at91rm9200-clk-system",
+ .data = of_at91rm9200_clk_sys_setup,
+ },
{ /*sentinel*/ }
};
diff --git a/drivers/clk/at91/pmc.h b/drivers/clk/at91/pmc.h
index 2e1dcb8..f88ef41 100644
--- a/drivers/clk/at91/pmc.h
+++ b/drivers/clk/at91/pmc.h
@@ -74,4 +74,7 @@ extern void __init of_at91rm9200_clk_master_setup(struct device_node *np,
extern void __init of_at91sam9x5_clk_master_setup(struct device_node *np,
struct at91_pmc *pmc);
+extern void __init of_at91rm9200_clk_sys_setup(struct device_node *np,
+ struct at91_pmc *pmc);
+
#endif /* __PMC_H_ */
--
Nicolas Ferre
--
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