mmc: sdhci-of-at91: introduce driver for the Atmel SDMMC
Introduce driver for he Atmel SDMMC available on sama5d2. It is a sdhci
compliant controller.
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
diff --git a/drivers/mmc/host/sdhci-of-at91.c b/drivers/mmc/host/sdhci-of-at91.c
new file mode 100644
index 0000000..7a9f4b1
--- /dev/null
+++ b/drivers/mmc/host/sdhci-of-at91.c
@@ -0,0 +1,192 @@
+/*
+ * Atmel SDMMC controller driver.
+ *
+ * Copyright (C) 2015 Atmel,
+ * 2015 Ludovic Desroches <ludovic.desroches@atmel.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/mmc/host.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+
+#include "sdhci-pltfm.h"
+
+#define SDMMC_CACR 0x230
+#define SDMMC_CACR_CAPWREN BIT(0)
+#define SDMMC_CACR_KEY (0x46 << 8)
+
+struct sdhci_at91_priv {
+ struct clk *hclock;
+ struct clk *gck;
+ struct clk *mainck;
+};
+
+static const struct sdhci_ops sdhci_at91_sama5d2_ops = {
+ .set_clock = sdhci_set_clock,
+ .set_bus_width = sdhci_set_bus_width,
+ .reset = sdhci_reset,
+ .set_uhs_signaling = sdhci_set_uhs_signaling,
+};
+
+static const struct sdhci_pltfm_data soc_data_sama5d2 = {
+ .ops = &sdhci_at91_sama5d2_ops,
+};
+
+static const struct of_device_id sdhci_at91_dt_match[] = {
+ { .compatible = "atmel,sama5d2-sdhci", .data = &soc_data_sama5d2 },
+ {}
+};
+
+static int sdhci_at91_probe(struct platform_device *pdev)
+{
+ const struct of_device_id *match;
+ const struct sdhci_pltfm_data *soc_data;
+ struct sdhci_host *host;
+ struct sdhci_pltfm_host *pltfm_host;
+ struct sdhci_at91_priv *priv;
+ unsigned int caps0, caps1;
+ unsigned int clk_base, clk_mul;
+ unsigned int gck_rate, real_gck_rate;
+ int ret;
+
+ match = of_match_device(sdhci_at91_dt_match, &pdev->dev);
+ if (!match)
+ return -EINVAL;
+ soc_data = match->data;
+
+ priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv) {
+ dev_err(&pdev->dev, "unable to allocate private data\n");
+ return -ENOMEM;
+ }
+
+ priv->mainck = devm_clk_get(&pdev->dev, "baseclk");
+ if (IS_ERR(priv->mainck)) {
+ dev_err(&pdev->dev, "failed to get baseclk\n");
+ return PTR_ERR(priv->mainck);
+ }
+
+ priv->hclock = devm_clk_get(&pdev->dev, "hclock");
+ if (IS_ERR(priv->hclock)) {
+ dev_err(&pdev->dev, "failed to get hclock\n");
+ return PTR_ERR(priv->hclock);
+ }
+
+ priv->gck = devm_clk_get(&pdev->dev, "multclk");
+ if (IS_ERR(priv->gck)) {
+ dev_err(&pdev->dev, "failed to get multclk\n");
+ return PTR_ERR(priv->gck);
+ }
+
+ host = sdhci_pltfm_init(pdev, soc_data, 0);
+ if (IS_ERR(host))
+ return PTR_ERR(host);
+
+ /*
+ * The mult clock is provided by as a generated clock by the PMC
+ * controller. In order to set the rate of gck, we have to get the
+ * base clock rate and the clock mult from capabilities.
+ */
+ clk_prepare_enable(priv->hclock);
+ caps0 = readl(host->ioaddr + SDHCI_CAPABILITIES);
+ caps1 = readl(host->ioaddr + SDHCI_CAPABILITIES_1);
+ clk_base = (caps0 & SDHCI_CLOCK_V3_BASE_MASK) >> SDHCI_CLOCK_BASE_SHIFT;
+ clk_mul = (caps1 & SDHCI_CLOCK_MUL_MASK) >> SDHCI_CLOCK_MUL_SHIFT;
+ gck_rate = clk_base * 1000000 * (clk_mul + 1);
+ ret = clk_set_rate(priv->gck, gck_rate);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to set gck");
+ goto hclock_disable_unprepare;
+ return -EINVAL;
+ }
+ /*
+ * We need to check if we have the requested rate for gck because in
+ * some cases this rate could be not supported. If it happens, the rate
+ * is the closest one gck can provide. We have to update the value
+ * of clk mul.
+ */
+ real_gck_rate = clk_get_rate(priv->gck);
+ if (real_gck_rate != gck_rate) {
+ clk_mul = real_gck_rate / (clk_base * 1000000) - 1;
+ caps1 &= (~SDHCI_CLOCK_MUL_MASK);
+ caps1 |= ((clk_mul << SDHCI_CLOCK_MUL_SHIFT) & SDHCI_CLOCK_MUL_MASK);
+ /* Set capabilities in r/w mode. */
+ writel(SDMMC_CACR_KEY | SDMMC_CACR_CAPWREN, host->ioaddr + SDMMC_CACR);
+ writel(caps1, host->ioaddr + SDHCI_CAPABILITIES_1);
+ /* Set capabilities in ro mode. */
+ writel(0, host->ioaddr + SDMMC_CACR);
+ dev_info(&pdev->dev, "update clk mul to %u as gck rate is %u Hz\n",
+ clk_mul, real_gck_rate);
+ }
+
+ clk_prepare_enable(priv->mainck);
+ clk_prepare_enable(priv->gck);
+
+ pltfm_host = sdhci_priv(host);
+ pltfm_host->priv = priv;
+
+ ret = mmc_of_parse(host->mmc);
+ if (ret)
+ goto clocks_disable_unprepare;
+
+ sdhci_get_of_property(pdev);
+
+ ret = sdhci_add_host(host);
+ if (ret)
+ goto clocks_disable_unprepare;
+
+ return 0;
+
+clocks_disable_unprepare:
+ clk_disable_unprepare(priv->gck);
+ clk_disable_unprepare(priv->mainck);
+hclock_disable_unprepare:
+ clk_disable_unprepare(priv->hclock);
+ sdhci_pltfm_free(pdev);
+ return ret;
+}
+
+static int sdhci_at91_remove(struct platform_device *pdev)
+{
+ struct sdhci_host *host = platform_get_drvdata(pdev);
+ struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+ struct sdhci_at91_priv *priv = pltfm_host->priv;
+
+ sdhci_pltfm_unregister(pdev);
+
+ clk_disable_unprepare(priv->gck);
+ clk_disable_unprepare(priv->hclock);
+ clk_disable_unprepare(priv->mainck);
+
+ return 0;
+}
+
+static struct platform_driver sdhci_at91_driver = {
+ .driver = {
+ .name = "sdhci-at91",
+ .owner = THIS_MODULE,
+ .of_match_table = sdhci_at91_dt_match,
+ .pm = SDHCI_PLTFM_PMOPS,
+ },
+ .probe = sdhci_at91_probe,
+ .remove = sdhci_at91_remove,
+};
+
+module_platform_driver(sdhci_at91_driver);
+
+MODULE_DESCRIPTION("SDHCI driver for at91");
+MODULE_AUTHOR("Ludovic Desroches <ludovic.desroches@atmel.com>");
+MODULE_LICENSE("GPL v2");