[RFC PATCH 5/7] mmc: sh_mobile_sdhi: Add UHS-I mode support

Ben Hutchings
2015-04-30T12:32:23Z

Implement voltage switch, supporting modes up to SDR-50.

Based on work by Shinobu Uehara, Rob Taylor, William Towle and Ian Molton.

This uses two voltage regulators, one external and one on the pfc.

Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
---
drivers/mmc/host/sh_mobile_sdhi.c | 48 +++++++++++++++++++++++++++++++++++++
1 file changed, 48 insertions(+)

diff --git a/drivers/mmc/host/sh_mobile_sdhi.c b/drivers/mmc/host/sh_mobile_sdhi.c
index 92a58c6007fe..c8538a256e22 100644
--- a/drivers/mmc/host/sh_mobile_sdhi.c
+++ b/drivers/mmc/host/sh_mobile_sdhi.c
@@ -30,6 +30,7 @@
#include <linux/mfd/tmio.h>
#include <linux/sh_dma.h>
#include <linux/delay.h>
+#include <linux/regulator/consumer.h>

#include "tmio_mmc.h"

@@ -84,6 +85,7 @@ MODULE_DEVICE_TABLE(of, sh_mobile_sdhi_of_match);

struct sh_mobile_sdhi {
struct clk *clk;
+ struct regulator *vqmmc_ref;
struct tmio_mmc_data mmc_data;
struct tmio_mmc_dma dma_priv;
};
@@ -148,6 +150,41 @@ static void sh_mobile_sdhi_set_clk_div(struct platform_device *pdev, int clk)
}
}

+static int sh_mobile_sdhi_start_signal_voltage_switch(
+ struct tmio_mmc_host *host, unsigned char signal_voltage)
+{
+ struct sh_mobile_sdhi *priv = host_to_priv(host);
+ int min_uV, max_uV;
+ int ret;
+
+ if (signal_voltage == MMC_SIGNAL_VOLTAGE_330) {
+ min_uV = 2700000;
+ max_uV = 3600000;
+ } else if (signal_voltage == MMC_SIGNAL_VOLTAGE_180) {
+ min_uV = 1700000;
+ max_uV = 1950000;
+ } else {
+ return -EINVAL;
+ }
+
+ if (!IS_ERR(host->mmc->supply.vqmmc)) {
+ ret = regulator_set_voltage(host->mmc->supply.vqmmc,
+ min_uV, max_uV);
+ if (ret)
+ return ret;
+ }
+
+ if (!IS_ERR(priv->vqmmc_ref)) {
+ ret = regulator_set_voltage(priv->vqmmc_ref,
+ min_uV, max_uV);
+ if (ret)
+ return ret;
+ }
+
+ usleep_range(5000, 5500);
+ return 0;
+}
+
static int sh_mobile_sdhi_wait_idle(struct tmio_mmc_host *host)
{
int timeout = 1000;
@@ -240,6 +277,13 @@ static int sh_mobile_sdhi_probe(struct platform_device *pdev)
goto eprobe;
}

+ priv->vqmmc_ref = devm_regulator_get_optional(&pdev->dev, "vqmmc-ref");
+ if (IS_ERR(priv->vqmmc_ref)) {
+ if (PTR_ERR(priv->vqmmc_ref) == -EPROBE_DEFER)
+ return -EPROBE_DEFER;
+ dev_info(&pdev->dev, "No vqmmc reference regulator found\n");
+ }
+
host = tmio_mmc_host_alloc(pdev);
if (!host) {
ret = -ENOMEM;
@@ -253,6 +297,10 @@ static int sh_mobile_sdhi_probe(struct platform_device *pdev)
host->clk_enable = sh_mobile_sdhi_clk_enable;
host->clk_disable = sh_mobile_sdhi_clk_disable;
host->multi_io_quirk = sh_mobile_sdhi_multi_io_quirk;
+
+ host->start_signal_voltage_switch
+ = sh_mobile_sdhi_start_signal_voltage_switch;
+
/* SD control register space size is 0x100, 0x200 for bus_shift=1 */
if (resource_size(res) > 0x100)
host->bus_shift = 1;
--
1.7.10.4