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Subject[PATCH 12/14] clk: sparx5: Add Sparx5 SoC DPLL clock driver
Date
This adds a device driver for the Sparx5 SoC DPLL clock

Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Lars Povlsen <lars.povlsen@microchip.com>
---
drivers/clk/Makefile | 1 +
drivers/clk/clk-sparx5.c | 269 +++++++++++++++++++++++++++++++++++++++
2 files changed, 270 insertions(+)
create mode 100644 drivers/clk/clk-sparx5.c

diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index f4169cc2fd318..9332e32667527 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -28,6 +28,7 @@ obj-$(CONFIG_COMMON_CLK_CDCE925) += clk-cdce925.o
obj-$(CONFIG_ARCH_CLPS711X) += clk-clps711x.o
obj-$(CONFIG_COMMON_CLK_CS2000_CP) += clk-cs2000-cp.o
obj-$(CONFIG_ARCH_EFM32) += clk-efm32gg.o
+obj-$(CONFIG_ARCH_SPARX5) += clk-sparx5.o
obj-$(CONFIG_COMMON_CLK_FIXED_MMIO) += clk-fixed-mmio.o
obj-$(CONFIG_COMMON_CLK_FSL_SAI) += clk-fsl-sai.o
obj-$(CONFIG_COMMON_CLK_GEMINI) += clk-gemini.o
diff --git a/drivers/clk/clk-sparx5.c b/drivers/clk/clk-sparx5.c
new file mode 100644
index 0000000000000..685b3028a7071
--- /dev/null
+++ b/drivers/clk/clk-sparx5.c
@@ -0,0 +1,269 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Microchip Sparx5 SoC Clock driver.
+ *
+ * Copyright (c) 2019 Microchip Inc.
+ *
+ * Author: Lars Povlsen <lars.povlsen@microchip.com>
+ */
+
+#include <linux/io.h>
+#include <linux/clk-provider.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <dt-bindings/clock/microchip,sparx5.h>
+
+#define PLL_DIV_MASK GENMASK(7, 0)
+#define PLL_PRE_DIV_MASK GENMASK(10, 8)
+#define PLL_PRE_DIV_SHIFT 8
+#define PLL_ROT_DIR BIT(11)
+#define PLL_ROT_SEL_MASK GENMASK(13, 12)
+#define PLL_ROT_SEL_SHIFT 12
+#define PLL_ROT_ENA BIT(14)
+#define PLL_CLK_ENA BIT(15)
+
+#define MAX_SEL 4
+#define MAX_PRE BIT(3)
+
+#define KHZ 1000
+#define MHZ (KHZ*KHZ)
+
+#define BASE_CLOCK (2500UL*MHZ)
+
+static u8 sel_rates[MAX_SEL] = { 0, 2*8, 2*4, 2*2 };
+
+static const char *clk_names[N_CLOCKS] = {
+ "core", "ddr", "cpu2", "arm2",
+ "aux1", "aux2", "aux3", "aux4",
+ "synce",
+};
+
+struct s5_hw_clk {
+ struct clk_hw hw;
+ void __iomem *reg;
+ int index;
+};
+
+struct s5_clk_data {
+ void __iomem *base;
+ struct s5_hw_clk s5_hw[N_CLOCKS];
+};
+
+struct pll_conf {
+ int freq;
+ u8 div;
+ bool rot_ena;
+ u8 rot_sel;
+ u8 rot_dir;
+ u8 pre_div;
+};
+
+#define to_clk_pll(hw) container_of(hw, struct s5_hw_clk, hw)
+
+unsigned long calc_freq(const struct pll_conf *pdata)
+{
+ unsigned long rate = BASE_CLOCK / pdata->div;
+
+ if (pdata->rot_ena) {
+ unsigned long base = BASE_CLOCK / pdata->div;
+ int sign = pdata->rot_dir ? -1 : 1;
+ int divt = sel_rates[pdata->rot_sel] * (1 + pdata->pre_div);
+ int divb = divt + sign;
+
+ rate = mult_frac(base, divt, divb);
+ rate = roundup(rate, 1000);
+ }
+
+ return rate;
+}
+
+static unsigned long clk_calc_params(unsigned long rate,
+ struct pll_conf *conf)
+{
+ memset(conf, 0, sizeof(*conf));
+
+ conf->div = DIV_ROUND_CLOSEST_ULL(BASE_CLOCK, rate);
+
+ if (BASE_CLOCK % rate) {
+ struct pll_conf best;
+ ulong cur_offset, best_offset = rate;
+ int i, j;
+
+ /* Enable fractional rotation */
+ conf->rot_ena = true;
+
+ if ((BASE_CLOCK / rate) != conf->div) {
+ /* Overshoot, adjust other direction */
+ conf->rot_dir = 1;
+ }
+
+ /* Brute force search over MAX_PRE * (MAX_SEL - 1) = 24 */
+ for (i = 0; i < MAX_PRE; i++) {
+ conf->pre_div = i;
+ for (j = 1; j < MAX_SEL; j++) {
+ conf->rot_sel = j;
+ conf->freq = calc_freq(conf);
+ cur_offset = abs(rate - conf->freq);
+ if (cur_offset == 0)
+ /* Perfect fit */
+ goto done;
+ if (cur_offset < best_offset) {
+ /* Better fit found */
+ best_offset = cur_offset;
+ best = *conf;
+ }
+ }
+ }
+ /* Best match */
+ *conf = best;
+ }
+
+done:
+ return conf->freq;
+}
+
+static int clk_pll_enable(struct clk_hw *hw)
+{
+ struct s5_hw_clk *pll = to_clk_pll(hw);
+ u32 val = readl(pll->reg);
+
+ val |= PLL_CLK_ENA;
+ writel(val, pll->reg);
+ pr_debug("%s: Enable val %04x\n", clk_names[pll->index], val);
+ return 0;
+}
+
+static void clk_pll_disable(struct clk_hw *hw)
+{
+ struct s5_hw_clk *pll = to_clk_pll(hw);
+ u32 val = readl(pll->reg);
+
+ val &= ~PLL_CLK_ENA;
+ writel(val, pll->reg);
+ pr_debug("%s: Disable val %04x\n", clk_names[pll->index], val);
+}
+
+static int clk_pll_set_rate(struct clk_hw *hw,
+ unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct s5_hw_clk *pll = to_clk_pll(hw);
+ struct pll_conf conf;
+ unsigned long eff_rate;
+ int ret = 0;
+
+ eff_rate = clk_calc_params(rate, &conf);
+ if (eff_rate == rate) {
+ u32 val;
+
+ val = readl(pll->reg) & PLL_CLK_ENA;
+ val |= PLL_DIV_MASK & conf.div;
+ if (conf.rot_ena) {
+ val |= (PLL_ROT_ENA |
+ (PLL_ROT_SEL_MASK &
+ (conf.rot_sel << PLL_ROT_SEL_SHIFT)) |
+ (PLL_PRE_DIV_MASK &
+ (conf.pre_div << PLL_PRE_DIV_SHIFT)));
+ if (conf.rot_dir)
+ val |= PLL_ROT_DIR;
+ }
+ pr_debug("%s: Rate %ld >= 0x%04x\n",
+ clk_names[pll->index], rate, val);
+ writel(val, pll->reg);
+ } else {
+ pr_err("%s: freq unsupported: %ld paren %ld\n",
+ clk_names[pll->index], rate, parent_rate);
+ ret = -ENOTSUPP;
+ }
+
+ return ret;
+}
+
+static unsigned long clk_pll_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ /* Don't care */
+ return 0;
+}
+
+static long clk_pll_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ struct pll_conf conf;
+ unsigned long eff_rate;
+
+ eff_rate = clk_calc_params(rate, &conf);
+ pr_debug("%s: Rate %ld rounded to %ld\n", __func__, rate, eff_rate);
+
+ return eff_rate;
+}
+
+static const struct clk_ops s5_pll_ops = {
+ .enable = clk_pll_enable,
+ .disable = clk_pll_disable,
+ .set_rate = clk_pll_set_rate,
+ .round_rate = clk_pll_round_rate,
+ .recalc_rate = clk_pll_recalc_rate,
+};
+
+static struct s5_clk_data *s5_clk_alloc(struct device_node *np)
+{
+ struct s5_clk_data *clk_data;
+
+ clk_data = kzalloc(sizeof(*clk_data), GFP_KERNEL);
+ if (WARN_ON(!clk_data))
+ return NULL;
+
+ clk_data->base = of_iomap(np, 0);
+ if (WARN_ON(!clk_data->base))
+ return NULL;
+
+ return clk_data;
+}
+
+static struct clk_hw *s5_clk_hw_get(struct of_phandle_args *clkspec, void *data)
+{
+ struct s5_clk_data *pll_clk = data;
+ unsigned int idx = clkspec->args[0];
+
+ if (idx >= N_CLOCKS) {
+ pr_err("%s: invalid index %u\n", __func__, idx);
+ return ERR_PTR(-EINVAL);
+ }
+
+ return &pll_clk->s5_hw[idx].hw;
+}
+
+static void __init s5_pll_init(struct device_node *np)
+{
+ int i, ret;
+ struct s5_clk_data *pll_clk;
+ struct clk_init_data init = { 0 };
+
+ pll_clk = s5_clk_alloc(np);
+ if (!pll_clk)
+ return;
+
+ init.ops = &s5_pll_ops;
+ init.parent_names = NULL;
+ init.num_parents = 0;
+
+ for (i = 0; i < N_CLOCKS; i++) {
+ struct s5_hw_clk *s5_hw = &pll_clk->s5_hw[i];
+
+ init.name = clk_names[i];
+ s5_hw->index = i;
+ s5_hw->reg = pll_clk->base + (i * sizeof(u32));
+ s5_hw->hw.init = &init;
+ ret = of_clk_hw_register(np, &s5_hw->hw);
+ if (ret) {
+ pr_err("failed to register %s clock\n", init.name);
+ return;
+ }
+ }
+
+ of_clk_add_hw_provider(np, s5_clk_hw_get, pll_clk);
+}
+CLK_OF_DECLARE_DRIVER(microchip_s5, "microchip,sparx5-dpll", s5_pll_init);
--
2.26.2
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