Re: [PATCH v3 4/5] clk: Hi6220: add stub clock driver
From: Stephen Boyd <hidden>
Date: 2015-08-03 21:37:58
Also in:
linux-arm-kernel, linux-clk, lkml
On 08/03, Leo Yan wrote:
quoted hunk ↗ jump to hunk
diff --git a/drivers/clk/hisilicon/clk-hi6220-stub.c b/drivers/clk/hisilicon/clk-hi6220-stub.c new file mode 100644 index 0000000..0931666 --- /dev/null +++ b/drivers/clk/hisilicon/clk-hi6220-stub.c@@ -0,0 +1,279 @@ +/* + * Hi6220 stub clock driver + * + * Copyright (c) 2015 Hisilicon Limited. + * Copyright (c) 2015 Linaro Limited. + * + * Author: Leo Yan <leo.yan@linaro.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + */ + +#include <linux/clkdev.h>
Is this include used?
+#include <linux/clk-provider.h> +#include <linux/clk.h>
Is this include used?
+#include <linux/err.h> +#include <linux/mfd/syscon.h> +#include <linux/mailbox_client.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/regmap.h> +#include <linux/slab.h> +#include <linux/kernel.h> + +#include <dt-bindings/clock/hi6220-clock.h> + +/* Stub clocks id */ +#define HI6220_STUB_ACPU0 0 +#define HI6220_STUB_ACPU1 1 +#define HI6220_STUB_GPU 2 +#define HI6220_STUB_DDR 5 + +/* Mailbox message */ +#define HI6220_MBOX_MSG_LEN 8 + +#define HI6220_MBOX_FREQ (0xA) +#define HI6220_MBOX_CMD_SET (0x3) +#define HI6220_MBOX_OBJ_AP (0x0) + +/* CPU dynamic frequency scaling */ +#define ACPU_DFS_FREQ_MAX (0x1724) +#define ACPU_DFS_CUR_FREQ (0x17CC) +#define ACPU_DFS_FLAG (0x1B30) +#define ACPU_DFS_FREQ_REQ (0x1B34) +#define ACPU_DFS_FREQ_LMT (0x1B38) +#define ACPU_DFS_LOCK_FLAG (0xAEAEAEAE)
We don't need parenthesis around single values in these macros.
+
+#define to_stub_clk(hw) container_of(hw, struct hi6220_stub_clk, hw)
+
+struct hi6220_stub_clk {
+ u32 id;
+ u32 rate;
+
+ struct device *dev;
+ struct clk_hw hw;
+
+ struct regmap *dfs_map;
+ struct mbox_client cl;
+ struct mbox_chan *mbox;
+};
+
+struct hi6220_mbox_msg {
+ unsigned char type;
+ unsigned char cmd;
+ unsigned char obj;
+ unsigned char src;
+ unsigned char para[4];
+};
+
+union hi6220_mbox_data {
+ unsigned int data[HI6220_MBOX_MSG_LEN];
+ struct hi6220_mbox_msg msg;
+};
+
+static unsigned int hi6220_acpu_get_freq(struct hi6220_stub_clk *stub_clk)
+{
+ unsigned int freq;
+
+ regmap_read(stub_clk->dfs_map, ACPU_DFS_CUR_FREQ, &freq);
+ return freq;
+}
+
+static int hi6220_acpu_set_freq(struct hi6220_stub_clk *stub_clk,
+ unsigned int freq)
+{
+ union hi6220_mbox_data data;
+
+ stub_clk->mbox = mbox_request_channel(&stub_clk->cl, 0);Why not request the channel once in probe?
+ if (IS_ERR(stub_clk->mbox)) {
+ dev_err(stub_clk->dev, "failed get mailbox channel\n");
+ return PTR_ERR(stub_clk->mbox);
+ };
+
+ /* set the frequency in sram */
+ regmap_write(stub_clk->dfs_map, ACPU_DFS_FREQ_REQ, freq);
+
+ /* compound mailbox message */
+ data.msg.type = HI6220_MBOX_FREQ;
+ data.msg.cmd = HI6220_MBOX_CMD_SET;
+ data.msg.obj = HI6220_MBOX_OBJ_AP;
+ data.msg.src = HI6220_MBOX_OBJ_AP;
+
+ mbox_send_message(stub_clk->mbox, &data);
+ mbox_free_channel(stub_clk->mbox);
+ return 0;
+}
+
+static int hi6220_acpu_round_freq(struct hi6220_stub_clk *stub_clk,
+ unsigned int freq)
+{
+ unsigned int limit_flag, limit_freq = UINT_MAX;
+ unsigned int max_freq;
+
+ /* check the constrainted frequency */s/constrainted/constrained/ ?
+ regmap_read(stub_clk->dfs_map, ACPU_DFS_FLAG, &limit_flag);
+ if (limit_flag == ACPU_DFS_LOCK_FLAG)
+ regmap_read(stub_clk->dfs_map, ACPU_DFS_FREQ_LMT, &limit_freq);
+
+ /* check the supported maximum frequency */
+ regmap_read(stub_clk->dfs_map, ACPU_DFS_FREQ_MAX, &max_freq);
+
+ /* calculate the real maximum frequency */
+ max_freq = min(max_freq, limit_freq);
+
+ if (WARN_ON(freq > max_freq))
+ freq = max_freq;
+
+ return freq;
+}
+
+static unsigned long hi6220_stub_clk_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ u32 rate = 0;
+ struct hi6220_stub_clk *stub_clk = to_stub_clk(hw);
+
+ switch (stub_clk->id) {
+ case HI6220_STUB_ACPU0:
+ rate = hi6220_acpu_get_freq(stub_clk);
+
+ /* convert from KHz to Hz */s/KHz/kHz/ ?
+ rate *= 1000;
+ break;
+
+ default:
+ dev_err(stub_clk->dev, "%s: un-supported clock id %d\n",
+ __func__, stub_clk->id);
+ break;
+ }
+
+ return rate;
+}
+
+static int hi6220_stub_clk_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct hi6220_stub_clk *stub_clk = to_stub_clk(hw);
+ unsigned long new_rate = rate / 1000; /* Khz */s/KHz/kHz/ ?
+ int ret = 0;
+
+ switch (stub_clk->id) {
+ case HI6220_STUB_ACPU0:
+ ret = hi6220_acpu_set_freq(stub_clk, new_rate);
+ if (ret < 0)
+ return ret;
+
+ break;
+
+ default:
+ dev_err(stub_clk->dev, "%s: un-supported clock id %d\n",
+ __func__, stub_clk->id);
+ break;
+ }
+
+ stub_clk->rate = new_rate;Why do we store away the rate? Is this used anywhere?
+
+ pr_debug("%s: set rate=%ldKhz\n", __func__, new_rate);
+ return ret;
+}
+
+static long hi6220_stub_clk_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ struct hi6220_stub_clk *stub_clk = to_stub_clk(hw);
+ unsigned long new_rate = rate / 1000; /* Khz */s/KHz/kHz/ ?
+
+ switch (stub_clk->id) {
+ case HI6220_STUB_ACPU0:
+ new_rate = hi6220_acpu_round_freq(stub_clk, new_rate);
+
+ /* convert from KHz to Hz */s/KHz/kHz/ ?
+ new_rate *= 1000;
+ break;
+
+ default:
+ dev_err(stub_clk->dev, "%s: un-supported clock id %d\n",
+ __func__, stub_clk->id);
+ break;
+ }
+
+ return new_rate;
+}
+
+static struct clk_ops hi6220_stub_clk_ops = {const?
+ .recalc_rate = hi6220_stub_clk_recalc_rate,
+ .round_rate = hi6220_stub_clk_round_rate,
+ .set_rate = hi6220_stub_clk_set_rate,
+};
+
+static int hi6220_stub_clk_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct clk_init_data init;
+ struct hi6220_stub_clk *stub_clk;
+ struct clk *clk;
+ struct device_node *np = pdev->dev.of_node;
+
+ stub_clk = devm_kzalloc(&pdev->dev, sizeof(*stub_clk), GFP_KERNEL);just use dev?
+ if (!stub_clk)
+ return -ENOMEM;
+
+ stub_clk->dfs_map = syscon_regmap_lookup_by_phandle(np,
+ "hisilicon,hi6220-clk-sram");
+ if (IS_ERR(stub_clk->dfs_map)) {
+ dev_err(dev, "failed to get sram regmap\n");
+ return PTR_ERR(stub_clk->dfs_map);
+ }
+
+ stub_clk->hw.init = &init;
+ stub_clk->dev = dev;
+ stub_clk->id = HI6220_STUB_ACPU0;
+
+ /* Use mailbox client with blocking mode */
+ stub_clk->cl.dev = &pdev->dev;just use dev?
+ stub_clk->cl.tx_done = NULL; + stub_clk->cl.tx_block = true; + stub_clk->cl.tx_tout = 500; + stub_clk->cl.knows_txdone = false; + + init.name = "acpu0"; + init.ops = &hi6220_stub_clk_ops; + init.num_parents = 0; + init.flags = CLK_IS_ROOT; + + clk = clk_register(NULL, &stub_clk->hw);
why not devm_clk_register?
+ if (IS_ERR(clk)) + return PTR_ERR(clk); + + of_clk_add_provider(pdev->dev.of_node, of_clk_src_simple_get, clk);
And check this for an error return value? Also, just use dev?
+ + /* initialize buffer to zero */ + regmap_write(stub_clk->dfs_map, ACPU_DFS_FLAG, 0x0); + regmap_write(stub_clk->dfs_map, ACPU_DFS_FREQ_REQ, 0x0); + regmap_write(stub_clk->dfs_map, ACPU_DFS_FREQ_LMT, 0x0); + + dev_dbg(&pdev->dev, "Registered clock '%s'\n", init.name);
just use dev?
+ return 0;
+}
+
+static const struct of_device_id hi6220_stub_clk_of_match[] = {
+ { .compatible = "hisilicon,hi6220-stub-clk", },
+ {}
+};
+
+static struct platform_driver hi6220_stub_clk_driver = {
+ .driver = {
+ .name = "hi6220-stub-clk",
+ .of_match_table = of_match_ptr(hi6220_stub_clk_of_match),We can leave off of_match_ptr() here.
+ }, + .probe = hi6220_stub_clk_probe, +};
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