@@ -122,6 +122,7 @@ config MMC_SDHCI_OF_ARASAN
tristate "SDHCI OF support for the Arasan SDHCI controllers"
depends on MMC_SDHCI_PLTFM
depends on OF
+ depends on COMMON_CLK
help
This selects the Arasan Secure Digital Host Controller Interface
(SDHCI). This hardware is found e.g. in Xilinx' Zynq SoC.
@@ -19,6 +19,7 @@
* your option) any later version.
*/
+#include <linux/clk-provider.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of_device.h>
@@ -73,17 +74,24 @@ struct sdhci_arasan_soc_ctl_map {
/**
* struct sdhci_arasan_data
+ * @host: Pointer to the main SDHCI host structure.
* @clk_ahb: Pointer to the AHB clock
* @phy: Pointer to the generic phy
* @phy_on: True if the PHY is turned on.
+ * @sdcardclk_hw: Struct for the clock we might provide to a PHY.
+ * @sdcardclk: Pointer to normal 'struct clock' for sdcardclk_hw.
* @soc_ctl_base: Pointer to regmap for syscon for soc_ctl registers.
* @soc_ctl_map: Map to get offsets into soc_ctl registers.
*/
struct sdhci_arasan_data {
+ struct sdhci_host *host;
struct clk *clk_ahb;
struct phy *phy;
bool phy_on;
+ struct clk_hw sdcardclk_hw;
+ struct clk *sdcardclk;
+
struct regmap *soc_ctl_base;
const struct sdhci_arasan_soc_ctl_map *soc_ctl_map;
};
@@ -307,6 +315,31 @@ static const struct of_device_id sdhci_arasan_of_match[] = {
MODULE_DEVICE_TABLE(of, sdhci_arasan_of_match);
/**
+ * sdhci_arasan_sdcardclk_recalc_rate - Return the card clock rate
+ *
+ * Return the current actual rate of the SD card clock. This can be used
+ * to communicate with out PHY.
+ *
+ * @hw: Pointer to the hardware clock structure.
+ * @parent_rate The parent rate (should be rate of clk_xin).
+ * Returns the card clock rate.
+ */
+static unsigned long sdhci_arasan_sdcardclk_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+
+{
+ struct sdhci_arasan_data *sdhci_arasan =
+ container_of(hw, struct sdhci_arasan_data, sdcardclk_hw);
+ struct sdhci_host *host = sdhci_arasan->host;
+
+ return host->mmc->actual_clock;
+}
+
+static const struct clk_ops arasan_sdcardclk_ops = {
+ .recalc_rate = sdhci_arasan_sdcardclk_recalc_rate,
+};
+
+/**
* sdhci_arasan_update_baseclkfreq - Set corecfg_baseclkfreq
*
* The corecfg_baseclkfreq is supposed to contain the MHz of clk_xin. This
@@ -345,6 +378,83 @@ static void sdhci_arasan_update_baseclkfreq(struct sdhci_host *host)
sdhci_arasan_syscon_write(host, &soc_ctl_map->baseclkfreq, mhz);
}
+/**
+ * sdhci_arasan_register_sdclk - Register the sdclk for a PHY to use
+ *
+ * Some PHY devices need to know what the actual card clock is. In order for
+ * them to find out, we'll provide a clock through the common clock framework
+ * for them to query.
+ *
+ * Note: without seriously re-architecting SDHCI's clock code and testing on
+ * all platforms, there's no way to create a totally beautiful clock here
+ * with all clock ops implemented. Instead, we'll just create a clock that can
+ * be queried and set the CLK_GET_RATE_NOCACHE attribute to tell common clock
+ * framework that we're doing things behind its back. This should be sufficient
+ * to create nice clean device tree bindings and later (if needed) we can try
+ * re-architecting SDHCI if we see some benefit to it.
+ *
+ * @sdhci_arasan: Our private data structure.
+ * @clk_xin: Pointer to the functional clock
+ * @dev: Pointer to our struct device.
+ * Returns 0 on success and error value on error
+ */
+static int sdhci_arasan_register_sdclk(struct sdhci_arasan_data *sdhci_arasan,
+ struct clk *clk_xin,
+ struct device *dev)
+{
+ struct device_node *np = dev->of_node;
+ struct clk_init_data sdcardclk_init;
+ const char *parent_clk_name;
+ int ret;
+
+ /* Providing a clock to the PHY is optional; no error if missing */
+ if (!of_find_property(np, "#clock-cells", NULL))
+ return 0;
+
+ ret = of_property_read_string_index(np, "clock-output-names", 0,
+ &sdcardclk_init.name);
+ if (ret) {
+ dev_err(dev, "DT has #clock-cells but no clock-output-names\n");
+ return ret;
+ }
+
+ parent_clk_name = __clk_get_name(clk_xin);
+ sdcardclk_init.parent_names = &parent_clk_name;
+ sdcardclk_init.num_parents = 1;
+ sdcardclk_init.flags = CLK_GET_RATE_NOCACHE;
+ sdcardclk_init.ops = &arasan_sdcardclk_ops;
+
+ sdhci_arasan->sdcardclk_hw.init = &sdcardclk_init;
+ sdhci_arasan->sdcardclk =
+ devm_clk_register(dev, &sdhci_arasan->sdcardclk_hw);
+ sdhci_arasan->sdcardclk_hw.init = NULL;
+
+ ret = of_clk_add_provider(np, of_clk_src_simple_get,
+ sdhci_arasan->sdcardclk);
+ if (ret)
+ dev_err(dev, "Failed to add clock provider\n");
+
+ return ret;
+}
+
+/**
+ * sdhci_arasan_unregister_sdclk - Undoes sdhci_arasan_register_sdclk()
+ *
+ * Should be called any time we're exiting and sdhci_arasan_register_sdclk()
+ * returned success.
+ *
+ * @dev: Pointer to our struct device.
+ */
+static void sdhci_arasan_unregister_sdclk(struct device *dev)
+{
+ struct device_node *np = dev->of_node;
+
+ if (!of_find_property(np, "#clock-cells", NULL))
+ return;
+
+ of_clk_del_provider(dev->of_node);
+}
+
static int sdhci_arasan_probe(struct platform_device *pdev)
{
int ret;
@@ -362,6 +472,7 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
pltfm_host = sdhci_priv(host);
sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
+ sdhci_arasan->host = host;
match = of_match_node(sdhci_arasan_of_match, pdev->dev.of_node);
sdhci_arasan->soc_ctl_map = match->data;
@@ -411,10 +522,14 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
sdhci_arasan_update_baseclkfreq(host);
+ ret = sdhci_arasan_register_sdclk(sdhci_arasan, clk_xin, &pdev->dev);
+ if (ret)
+ goto clk_disable_all;
+
ret = mmc_of_parse(host->mmc);
if (ret) {
dev_err(&pdev->dev, "parsing dt failed (%u)\n", ret);
- goto clk_disable_all;
+ goto unreg_clk;
}
sdhci_arasan->phy = ERR_PTR(-ENODEV);
@@ -425,13 +540,13 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
if (IS_ERR(sdhci_arasan->phy)) {
ret = PTR_ERR(sdhci_arasan->phy);
dev_err(&pdev->dev, "No phy for arasan,sdhci-5.1.\n");
- goto clk_disable_all;
+ goto unreg_clk;
}
ret = phy_init(sdhci_arasan->phy);
if (ret < 0) {
dev_err(&pdev->dev, "phy_init err.\n");
- goto clk_disable_all;
+ goto unreg_clk;
}
host->mmc_host_ops.hs400_enhanced_strobe =
@@ -447,6 +562,8 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
err_add_host:
if (!IS_ERR(sdhci_arasan->phy))
phy_exit(sdhci_arasan->phy);
+unreg_clk:
+ sdhci_arasan_unregister_sdclk(&pdev->dev);
clk_disable_all:
clk_disable_unprepare(clk_xin);
clk_dis_ahb:
@@ -469,6 +586,8 @@ static int sdhci_arasan_remove(struct platform_device *pdev)
phy_exit(sdhci_arasan->phy);
}
+ sdhci_arasan_unregister_sdclk(&pdev->dev);
+
ret = sdhci_pltfm_unregister(pdev);
clk_disable_unprepare(clk_ahb);