clk: at91: add PMC smd clock

This patch adds at91 smd (Soft Modem) clock implementation using common clk
framework.

Not used by any driver right now.

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>

5 files changed, 189 insertions, 0 deletions

diff --git a/arch/arm/mach-at91/Kconfig b/arch/arm/mach-at91/Kconfig
index b76dc4c62af9..97033f792eea 100644
--- a/arch/arm/mach-at91/Kconfig
+++ b/arch/arm/mach-at91/Kconfig
@@ -39,6 +39,9 @@ config AT91_SAM9G45_RESET
 config AT91_SAM9_TIME
         bool
 
+config HAVE_AT91_SMD
+        bool
+
 config SOC_AT91SAM9
         bool
         select AT91_SAM9_TIME
@@ -85,6 +88,7 @@ config SOC_SAMA5D3
         select HAVE_AT91_DBGU1
         select AT91_USE_OLD_CLK
         select HAVE_AT91_UTMI
+        select HAVE_AT91_SMD
         select HAVE_AT91_USB_CLK
         help
           Select this if you are using one of Atmel's SAMA5D3 family SoC.
@@ -157,6 +161,7 @@ config SOC_AT91SAM9X5
         select SOC_AT91SAM9
         select AT91_USE_OLD_CLK
         select HAVE_AT91_UTMI
+        select HAVE_AT91_SMD
         select HAVE_AT91_USB_CLK
         help
           Select this if you are using one of Atmel's AT91SAM9x5 family SoC.
diff --git a/drivers/clk/at91/Makefile b/drivers/clk/at91/Makefile
index 61db058be0c0..0e92b716f934 100644
--- a/drivers/clk/at91/Makefile
+++ b/drivers/clk/at91/Makefile
@@ -9,3 +9,4 @@ obj-y += clk-system.o clk-peripheral.o
 obj-$(CONFIG_AT91_PROGRAMMABLE_CLOCKS)  += clk-programmable.o
 obj-$(CONFIG_HAVE_AT91_UTMI)            += clk-utmi.o
 obj-$(CONFIG_HAVE_AT91_USB_CLK)         += clk-usb.o
+obj-$(CONFIG_HAVE_AT91_SMD)             += clk-smd.o
diff --git a/drivers/clk/at91/clk-smd.c b/drivers/clk/at91/clk-smd.c
new file mode 100644
index 000000000000..144d47ecfe63
--- /dev/null
+++ b/drivers/clk/at91/clk-smd.c
@@ -0,0 +1,171 @@
+/*
+ *  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 SMD_SOURCE_MAX          2
+
+#define SMD_DIV_SHIFT           8
+#define SMD_MAX_DIV             0xf
+
+struct at91sam9x5_clk_smd {
+        struct clk_hw hw;
+        struct at91_pmc *pmc;
+};
+
+#define to_at91sam9x5_clk_smd(hw) \
+        container_of(hw, struct at91sam9x5_clk_smd, hw)
+
+static unsigned long at91sam9x5_clk_smd_recalc_rate(struct clk_hw *hw,
+                                                    unsigned long parent_rate)
+{
+        u32 tmp;
+        u8 smddiv;
+        struct at91sam9x5_clk_smd *smd = to_at91sam9x5_clk_smd(hw);
+        struct at91_pmc *pmc = smd->pmc;
+
+        tmp = pmc_read(pmc, AT91_PMC_SMD);
+        smddiv = (tmp & AT91_PMC_SMD_DIV) >> SMD_DIV_SHIFT;
+        return parent_rate / (smddiv + 1);
+}
+
+static long at91sam9x5_clk_smd_round_rate(struct clk_hw *hw, unsigned long rate,
+                                          unsigned long *parent_rate)
+{
+        unsigned long div;
+        unsigned long bestrate;
+        unsigned long tmp;
+
+        if (rate >= *parent_rate)
+                return *parent_rate;
+
+        div = *parent_rate / rate;
+        if (div > SMD_MAX_DIV)
+                return *parent_rate / (SMD_MAX_DIV + 1);
+
+        bestrate = *parent_rate / div;
+        tmp = *parent_rate / (div + 1);
+        if (bestrate - rate > rate - tmp)
+                bestrate = tmp;
+
+        return bestrate;
+}
+
+static int at91sam9x5_clk_smd_set_parent(struct clk_hw *hw, u8 index)
+{
+        u32 tmp;
+        struct at91sam9x5_clk_smd *smd = to_at91sam9x5_clk_smd(hw);
+        struct at91_pmc *pmc = smd->pmc;
+
+        if (index > 1)
+                return -EINVAL;
+        tmp = pmc_read(pmc, AT91_PMC_SMD) & ~AT91_PMC_SMDS;
+        if (index)
+                tmp |= AT91_PMC_SMDS;
+        pmc_write(pmc, AT91_PMC_SMD, tmp);
+        return 0;
+}
+
+static u8 at91sam9x5_clk_smd_get_parent(struct clk_hw *hw)
+{
+        struct at91sam9x5_clk_smd *smd = to_at91sam9x5_clk_smd(hw);
+        struct at91_pmc *pmc = smd->pmc;
+
+        return pmc_read(pmc, AT91_PMC_SMD) & AT91_PMC_SMDS;
+}
+
+static int at91sam9x5_clk_smd_set_rate(struct clk_hw *hw, unsigned long rate,
+                                       unsigned long parent_rate)
+{
+        u32 tmp;
+        struct at91sam9x5_clk_smd *smd = to_at91sam9x5_clk_smd(hw);
+        struct at91_pmc *pmc = smd->pmc;
+        unsigned long div = parent_rate / rate;
+
+        if (parent_rate % rate || div < 1 || div > (SMD_MAX_DIV + 1))
+                return -EINVAL;
+        tmp = pmc_read(pmc, AT91_PMC_SMD) & ~AT91_PMC_SMD_DIV;
+        tmp |= (div - 1) << SMD_DIV_SHIFT;
+        pmc_write(pmc, AT91_PMC_SMD, tmp);
+
+        return 0;
+}
+
+static const struct clk_ops at91sam9x5_smd_ops = {
+        .recalc_rate = at91sam9x5_clk_smd_recalc_rate,
+        .round_rate = at91sam9x5_clk_smd_round_rate,
+        .get_parent = at91sam9x5_clk_smd_get_parent,
+        .set_parent = at91sam9x5_clk_smd_set_parent,
+        .set_rate = at91sam9x5_clk_smd_set_rate,
+};
+
+static struct clk * __init
+at91sam9x5_clk_register_smd(struct at91_pmc *pmc, const char *name,
+                            const char **parent_names, u8 num_parents)
+{
+        struct at91sam9x5_clk_smd *smd;
+        struct clk *clk = NULL;
+        struct clk_init_data init;
+
+        smd = kzalloc(sizeof(*smd), GFP_KERNEL);
+        if (!smd)
+                return ERR_PTR(-ENOMEM);
+
+        init.name = name;
+        init.ops = &at91sam9x5_smd_ops;
+        init.parent_names = parent_names;
+        init.num_parents = num_parents;
+        init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;
+
+        smd->hw.init = &init;
+        smd->pmc = pmc;
+
+        clk = clk_register(NULL, &smd->hw);
+        if (IS_ERR(clk))
+                kfree(smd);
+
+        return clk;
+}
+
+void __init of_at91sam9x5_clk_smd_setup(struct device_node *np,
+                                        struct at91_pmc *pmc)
+{
+        struct clk *clk;
+        int i;
+        int num_parents;
+        const char *parent_names[SMD_SOURCE_MAX];
+        const char *name = np->name;
+
+        num_parents = of_count_phandle_with_args(np, "clocks", "#clock-cells");
+        if (num_parents <= 0 || num_parents > SMD_SOURCE_MAX)
+                return;
+
+        for (i = 0; i < num_parents; i++) {
+                parent_names[i] = of_clk_get_parent_name(np, i);
+                if (!parent_names[i])
+                        return;
+        }
+
+        of_property_read_string(np, "clock-output-names", &name);
+
+        clk = at91sam9x5_clk_register_smd(pmc, name, parent_names,
+                                          num_parents);
+        if (IS_ERR(clk))
+                return;
+
+        of_clk_add_provider(np, of_clk_src_simple_get, clk);
+}
diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
index 4fba500dec38..7b9db603b936 100644
--- a/drivers/clk/at91/pmc.c
+++ b/drivers/clk/at91/pmc.c
@@ -315,6 +315,13 @@ static const struct of_device_id pmc_clk_ids[] __initdata = {
                 .data = of_at91sam9n12_clk_usb_setup,
         },
 #endif
+        /* SMD clock */
+#if defined(CONFIG_HAVE_AT91_SMD)
+        {
+                .compatible = "atmel,at91sam9x5-clk-smd",
+                .data = of_at91sam9x5_clk_smd_setup,
+        },
+#endif
         { /*sentinel*/ }
 };
 
diff --git a/drivers/clk/at91/pmc.h b/drivers/clk/at91/pmc.h
index 2483ddc0868b..ba8d14233f80 100644
--- a/drivers/clk/at91/pmc.h
+++ b/drivers/clk/at91/pmc.h
@@ -108,4 +108,9 @@ extern void __init of_at91sam9n12_clk_usb_setup(struct device_node *np,
                                                 struct at91_pmc *pmc);
 #endif
 
+#if defined(CONFIG_HAVE_AT91_SMD)
+extern void __init of_at91sam9x5_clk_smd_setup(struct device_node *np,
+                                               struct at91_pmc *pmc);
+#endif
+
 #endif /* __PMC_H_ */