ASoC: fsi: add master clock control functions

Current FSI driver required set_rate() platform callback function
to set audio clock if it was master mode,
because it seemed that CPG/FSI-DIV clocks calculation depend on
platform/board/cpu.
But it was calculable regardless of platform.
This patch supports audio clock calculation method,
but the sampling rate under 32kHz is not supported at this point.
Old type set_rate() is still supported now,
but it will be deleted on next version

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 372 insertions, 6 deletions

diff --git a/sound/soc/sh/fsi.c b/sound/soc/sh/fsi.c
index ef257bcb5341..bdaca356aaad 100644
--- a/sound/soc/sh/fsi.c
+++ b/sound/soc/sh/fsi.c
@@ -21,6 +21,7 @@
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <sound/soc.h>
+#include <sound/pcm_params.h>
 #include <sound/sh_fsi.h>
 
 /* PortA/PortB register */
@@ -188,6 +189,14 @@ typedef int (*set_rate_func)(struct device *dev, int rate, int enable);
  */
 
 /*
+ *      FSI clock
+ *
+ * FSIxCLK [CPG] (ick) -------> |
+ *                              |-> FSI_DIV (div)-> FSI2
+ * FSIxCK [external] (xck) ---> |
+ */
+
+/*
  *              struct
  */
 
@@ -227,6 +236,20 @@ struct fsi_stream {
         dma_addr_t              dma;
 };
 
+struct fsi_clk {
+        /* see [FSI clock] */
+        struct clk *own;
+        struct clk *xck;
+        struct clk *ick;
+        struct clk *div;
+        int (*set_rate)(struct device *dev,
+                        struct fsi_priv *fsi,
+                        unsigned long rate);
+
+        unsigned long rate;
+        unsigned int count;
+};
+
 struct fsi_priv {
         void __iomem *base;
         struct fsi_master *master;
@@ -235,6 +258,8 @@ struct fsi_priv {
         struct fsi_stream playback;
         struct fsi_stream capture;
 
+        struct fsi_clk clock;
+
         u32 fmt;
 
         int chan_num:16;
@@ -716,14 +741,335 @@ static void fsi_spdif_clk_ctrl(struct fsi_priv *fsi, int enable)
 /*
  *              clock function
  */
+static int fsi_clk_init(struct device *dev,
+                        struct fsi_priv *fsi,
+                        int xck,
+                        int ick,
+                        int div,
+                        int (*set_rate)(struct device *dev,
+                                        struct fsi_priv *fsi,
+                                        unsigned long rate))
+{
+        struct fsi_clk *clock = &fsi->clock;
+        int is_porta = fsi_is_port_a(fsi);
+
+        clock->xck      = NULL;
+        clock->ick      = NULL;
+        clock->div      = NULL;
+        clock->rate     = 0;
+        clock->count    = 0;
+        clock->set_rate = set_rate;
+
+        clock->own = devm_clk_get(dev, NULL);
+        if (IS_ERR(clock->own))
+                return -EINVAL;
+
+        /* external clock */
+        if (xck) {
+                clock->xck = devm_clk_get(dev, is_porta ? "xcka" : "xckb");
+                if (IS_ERR(clock->xck)) {
+                        dev_err(dev, "can't get xck clock\n");
+                        return -EINVAL;
+                }
+                if (clock->xck == clock->own) {
+                        dev_err(dev, "cpu doesn't support xck clock\n");
+                        return -EINVAL;
+                }
+        }
+
+        /* FSIACLK/FSIBCLK */
+        if (ick) {
+                clock->ick = devm_clk_get(dev,  is_porta ? "icka" : "ickb");
+                if (IS_ERR(clock->ick)) {
+                        dev_err(dev, "can't get ick clock\n");
+                        return -EINVAL;
+                }
+                if (clock->ick == clock->own) {
+                        dev_err(dev, "cpu doesn't support ick clock\n");
+                        return -EINVAL;
+                }
+        }
+
+        /* FSI-DIV */
+        if (div) {
+                clock->div = devm_clk_get(dev,  is_porta ? "diva" : "divb");
+                if (IS_ERR(clock->div)) {
+                        dev_err(dev, "can't get div clock\n");
+                        return -EINVAL;
+                }
+                if (clock->div == clock->own) {
+                        dev_err(dev, "cpu doens't support div clock\n");
+                        return -EINVAL;
+                }
+        }
+
+        return 0;
+}
+
+#define fsi_clk_invalid(fsi) fsi_clk_valid(fsi, 0)
+static void fsi_clk_valid(struct fsi_priv *fsi, unsigned long rate)
+{
+        fsi->clock.rate = rate;
+}
+
+static int fsi_clk_is_valid(struct fsi_priv *fsi)
+{
+        return  fsi->clock.set_rate &&
+                fsi->clock.rate;
+}
+
+static int fsi_clk_enable(struct device *dev,
+                          struct fsi_priv *fsi,
+                          unsigned long rate)
+{
+        struct fsi_clk *clock = &fsi->clock;
+        int ret = -EINVAL;
+
+        if (!fsi_clk_is_valid(fsi))
+                return ret;
+
+        if (0 == clock->count) {
+                ret = clock->set_rate(dev, fsi, rate);
+                if (ret < 0) {
+                        fsi_clk_invalid(fsi);
+                        return ret;
+                }
+
+                if (clock->xck)
+                        clk_enable(clock->xck);
+                if (clock->ick)
+                        clk_enable(clock->ick);
+                if (clock->div)
+                        clk_enable(clock->div);
+
+                clock->count++;
+        }
+
+        return ret;
+}
+
+static int fsi_clk_disable(struct device *dev,
+                            struct fsi_priv *fsi)
+{
+        struct fsi_clk *clock = &fsi->clock;
+
+        if (!fsi_clk_is_valid(fsi))
+                return -EINVAL;
+
+        if (1 == clock->count--) {
+                if (clock->xck)
+                        clk_disable(clock->xck);
+                if (clock->ick)
+                        clk_disable(clock->ick);
+                if (clock->div)
+                        clk_disable(clock->div);
+        }
+
+        return 0;
+}
+
+static int fsi_clk_set_ackbpf(struct device *dev,
+                              struct fsi_priv *fsi,
+                              int ackmd, int bpfmd)
+{
+        u32 data = 0;
+
+        /* check ackmd/bpfmd relationship */
+        if (bpfmd > ackmd) {
+                dev_err(dev, "unsupported rate (%d/%d)\n", ackmd, bpfmd);
+                return -EINVAL;
+        }
+
+        /*  ACKMD */
+        switch (ackmd) {
+        case 512:
+                data |= (0x0 << 12);
+                break;
+        case 256:
+                data |= (0x1 << 12);
+                break;
+        case 128:
+                data |= (0x2 << 12);
+                break;
+        case 64:
+                data |= (0x3 << 12);
+                break;
+        case 32:
+                data |= (0x4 << 12);
+                break;
+        default:
+                dev_err(dev, "unsupported ackmd (%d)\n", ackmd);
+                return -EINVAL;
+        }
+
+        /* BPFMD */
+        switch (bpfmd) {
+        case 32:
+                data |= (0x0 << 8);
+                break;
+        case 64:
+                data |= (0x1 << 8);
+                break;
+        case 128:
+                data |= (0x2 << 8);
+                break;
+        case 256:
+                data |= (0x3 << 8);
+                break;
+        case 512:
+                data |= (0x4 << 8);
+                break;
+        case 16:
+                data |= (0x7 << 8);
+                break;
+        default:
+                dev_err(dev, "unsupported bpfmd (%d)\n", bpfmd);
+                return -EINVAL;
+        }
+
+        dev_dbg(dev, "ACKMD/BPFMD = %d/%d\n", ackmd, bpfmd);
+
+        fsi_reg_mask_set(fsi, CKG1, (ACKMD_MASK | BPFMD_MASK) , data);
+        udelay(10);
+
+        return 0;
+}
+
+static int fsi_clk_set_rate_external(struct device *dev,
+                                     struct fsi_priv *fsi,
+                                     unsigned long rate)
+{
+        struct clk *xck = fsi->clock.xck;
+        struct clk *ick = fsi->clock.ick;
+        unsigned long xrate;
+        int ackmd, bpfmd;
+        int ret = 0;
+
+        /* check clock rate */
+        xrate = clk_get_rate(xck);
+        if (xrate % rate) {
+                dev_err(dev, "unsupported clock rate\n");
+                return -EINVAL;
+        }
+
+        clk_set_parent(ick, xck);
+        clk_set_rate(ick, xrate);
+
+        bpfmd = fsi->chan_num * 32;
+        ackmd = xrate / rate;
+
+        dev_dbg(dev, "external/rate = %ld/%ld\n", xrate, rate);
+
+        ret = fsi_clk_set_ackbpf(dev, fsi, ackmd, bpfmd);
+        if (ret < 0)
+                dev_err(dev, "%s failed", __func__);
+
+        return ret;
+}
+
+static int fsi_clk_set_rate_cpg(struct device *dev,
+                                struct fsi_priv *fsi,
+                                unsigned long rate)
+{
+        struct clk *ick = fsi->clock.ick;
+        struct clk *div = fsi->clock.div;
+        unsigned long target = 0; /* 12288000 or 11289600 */
+        unsigned long actual, cout;
+        unsigned long diff, min;
+        unsigned long best_cout, best_act;
+        int adj;
+        int ackmd, bpfmd;
+        int ret = -EINVAL;
+
+        if (!(12288000 % rate))
+                target = 12288000;
+        if (!(11289600 % rate))
+                target = 11289600;
+        if (!target) {
+                dev_err(dev, "unsupported rate\n");
+                return ret;
+        }
+
+        bpfmd = fsi->chan_num * 32;
+        ackmd = target / rate;
+        ret = fsi_clk_set_ackbpf(dev, fsi, ackmd, bpfmd);
+        if (ret < 0) {
+                dev_err(dev, "%s failed", __func__);
+                return ret;
+        }
+
+        /*
+         * The clock flow is
+         *
+         * [CPG] = cout => [FSI_DIV] = audio => [FSI] => [codec]
+         *
+         * But, it needs to find best match of CPG and FSI_DIV
+         * combination, since it is difficult to generate correct
+         * frequency of audio clock from ick clock only.
+         * Because ick is created from its parent clock.
+         *
+         * target       = rate x [512/256/128/64]fs
+         * cout         = round(target x adjustment)
+         * actual       = cout / adjustment (by FSI-DIV) ~= target
+         * audio        = actual
+         */
+        min = ~0;
+        best_cout = 0;
+        best_act = 0;
+        for (adj = 1; adj < 0xffff; adj++) {
+
+                cout = target * adj;
+                if (cout > 100000000) /* max clock = 100MHz */
+                        break;
+
+                /* cout/actual audio clock */
+                cout    = clk_round_rate(ick, cout);
+                actual  = cout / adj;
+
+                /* find best frequency */
+                diff = abs(actual - target);
+                if (diff < min) {
+                        min             = diff;
+                        best_cout       = cout;
+                        best_act        = actual;
+                }
+        }
+
+        ret = clk_set_rate(ick, best_cout);
+        if (ret < 0) {
+                dev_err(dev, "ick clock failed\n");
+                return -EIO;
+        }
+
+        ret = clk_set_rate(div, clk_round_rate(div, best_act));
+        if (ret < 0) {
+                dev_err(dev, "div clock failed\n");
+                return -EIO;
+        }
+
+        dev_dbg(dev, "ick/div = %ld/%ld\n",
+                clk_get_rate(ick), clk_get_rate(div));
+
+        return ret;
+}
+
 static int fsi_set_master_clk(struct device *dev, struct fsi_priv *fsi,
                               long rate, int enable)
 {
         set_rate_func set_rate = fsi_get_info_set_rate(fsi);
         int ret;
 
-        if (!set_rate)
-                return 0;
+        /*
+         * CAUTION
+         *
+         * set_rate will be deleted
+         */
+        if (!set_rate) {
+                if (enable)
+                        return fsi_clk_enable(dev, fsi, rate);
+                else
+                        return fsi_clk_disable(dev, fsi);
+        }
 
         ret = set_rate(dev, rate, enable);
         if (ret < 0) /* error */
@@ -1355,6 +1701,7 @@ static int fsi_dai_startup(struct snd_pcm_substream *substream,
 {
         struct fsi_priv *fsi = fsi_get_priv(substream);
 
+        fsi_clk_invalid(fsi);
         fsi->rate = 0;
 
         return 0;
@@ -1365,6 +1712,7 @@ static void fsi_dai_shutdown(struct snd_pcm_substream *substream,
 {
         struct fsi_priv *fsi = fsi_get_priv(substream);
 
+        fsi_clk_invalid(fsi);
         fsi->rate = 0;
 }
 
@@ -1446,9 +1794,25 @@ static int fsi_dai_set_fmt(struct snd_soc_dai *dai, unsigned int fmt)
                 return -EINVAL;
         }
 
-        if (fsi_is_clk_master(fsi) && !set_rate) {
-                dev_err(dai->dev, "platform doesn't have set_rate\n");
-                return -EINVAL;
+        if (fsi_is_clk_master(fsi)) {
+                /*
+                 * CAUTION
+                 *
+                 * set_rate will be deleted
+                 */
+                if (set_rate)
+                        dev_warn(dai->dev, "set_rate will be removed soon\n");
+
+                switch (flags & SH_FSI_CLK_MASK) {
+                case SH_FSI_CLK_EXTERNAL:
+                        fsi_clk_init(dai->dev, fsi, 1, 1, 0,
+                                     fsi_clk_set_rate_external);
+                        break;
+                case SH_FSI_CLK_CPG:
+                        fsi_clk_init(dai->dev, fsi, 0, 1, 1,
+                                     fsi_clk_set_rate_cpg);
+                        break;
+                }
         }
 
         /* set format */
@@ -1472,8 +1836,10 @@ static int fsi_dai_hw_params(struct snd_pcm_substream *substream,
 {
         struct fsi_priv *fsi = fsi_get_priv(substream);
 
-        if (fsi_is_clk_master(fsi))
+        if (fsi_is_clk_master(fsi)) {
                 fsi->rate = params_rate(params);
+                fsi_clk_valid(fsi, fsi->rate);
+        }
 
         return 0;
 }